U.S. patent application number 17/071250 was filed with the patent office on 2021-03-18 for coating including inorganic fullerene-like particles and inorganic tubular-like particles.
The applicant listed for this patent is Nanotech Industrial Solutions, Inc.. Invention is credited to George Diloyan, Ronen Kreizman, Eugene Kverel, Alon Shapira.
Application Number | 20210079194 17/071250 |
Document ID | / |
Family ID | 1000005251500 |
Filed Date | 2021-03-18 |
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United States Patent
Application |
20210079194 |
Kind Code |
A1 |
Kverel; Eugene ; et
al. |
March 18, 2021 |
COATING INCLUDING INORGANIC FULLERENE-LIKE PARTICLES AND INORGANIC
TUBULAR-LIKE PARTICLES
Abstract
In one embodiment, a coating is provided that includes a
deposition surface, and a coating on the deposition surface. The
coating may include particles of a metal chalcogenide comprising a
fullerene-like geometry, a tubular-like geometry or a combination
of fullerene-like geometries and tubular-like geometries. The metal
chalcogenide composition has a molecular formula of MX.sub.2.
Inventors: |
Kverel; Eugene; (New York,
NY) ; Kreizman; Ronen; (Rehovot, IL) ;
Diloyan; George; (Cranford, NJ) ; Shapira; Alon;
(Givatayim, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Nanotech Industrial Solutions, Inc. |
Avenel |
NJ |
US |
|
|
Family ID: |
1000005251500 |
Appl. No.: |
17/071250 |
Filed: |
October 15, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14180955 |
Feb 14, 2014 |
10815357 |
|
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17071250 |
|
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61766898 |
Feb 20, 2013 |
|
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61766399 |
Feb 19, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10M 125/22 20130101;
C23C 30/00 20130101; C08K 3/30 20130101; C08K 3/041 20170501; C08K
7/00 20130101; C08K 2003/3009 20130101; C25D 15/00 20130101; C08K
3/04 20130101; C10M 149/14 20130101; E21B 17/00 20130101 |
International
Class: |
C08K 3/30 20060101
C08K003/30; C08K 7/00 20060101 C08K007/00; E21B 17/00 20060101
E21B017/00; C25D 15/00 20060101 C25D015/00; C23C 30/00 20060101
C23C030/00; C10M 125/22 20060101 C10M125/22; C10M 149/14 20060101
C10M149/14 |
Claims
1. A composite coating composition: a matrix phase of a polymeric
material; a dispersed phase of particles of a metal chalcogenide
comprising a fullerene-like geometry, a tubular-like geometry or a
combination thereof, the dispersed phase having an outer layer
comprising at least one sectioned portion, the at least one
sectioned portion extends along a direction away from the curvature
of the multilayered structure, the at least one sectioned portion
engaged to remaining section of the outer layer, the dispersed
phase of particles being present substantially throughout a matrix
phase of a polymeric base material, wherein the metal chalcogenide
composition has a molecular formula of MX.sub.2, where M is a
metallic element selected from the group consisting of titanium
(Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe),
cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), zirconium (Zr),
niobium (Nb), molybdenum (Mo), technetium (Tc), ruthenium (Ru),
rhodium (Rh), palladium (Pd), silver (Ag), cadmium (Cd), hafnium
(Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os),
iridium (Jr), platinum (Pt), gold (Au), mercury (Hg) and
combinations thereof, and X is a chalcogen element selected from
the group consisting of sulfur (S), selenium (Se), tellurium (Te),
oxygen (O) and combinations thereof.
2. The composite coating composition of claim 1, wherein the
polymeric material is selected from the group consisting of
elastomers, epoxies, thermoplastic polymers, polyamides,
polyphthalamide, polyphthalamide blend, poly-amide-imide,
polyethylene, cross-linked polyethylene, polyester, polyurethanes,
polyproplenes, and combinations thereof.
3. The composite coating composition of claim 1, wherein the
particles of the metal chalcogenide having said at least one of the
fullerene-like geometry and the tubular-like geometry are present
in the base material layer in an amount of greater than 0.1 wt
%.
4. The composite coating composition of claim 1, wherein the
particles of the metal chalcogenide having the molecular formula
MX.sub.2 are tungsten disulfide (WS.sub.2), molybdenum disulfide
(MoS.sub.2) or a combination thereof.
5. The composite coating composition of claim 1, wherein the
particles of the metal chalcogenide having the molecular formula
MX.sub.2 have a fullerene-like geometry and a diameter ranging from
5 nm to 5 .mu.m.
6. The composite coating composition of claim 1, wherein the
particles of the metal chalcogenide having the molecular formula
MX.sub.2 have a tube-like geometry and a diameter ranging 1 nm to
150 nm.
7. The composite coating of claim 6, wherein the tube-like geometry
includes a length ranging from 10 nm to 15 cm.
8. The composite coating composition of claim 1, wherein the
particles of the metal chalcogenide are functionalized with at
least one of non-anionic surfactants, anionic surfactants, cationic
surfactants, zwitterionic surfactants, surfactants, silanes,
thiols, polymers and dopants.
9. The composite coating composition of claim 1, wherein the
polymeric material is an epoxy.
10. The composite coating composition claim 9, wherein the
polymeric material is selected from the group consisting of
bisphenol A epoxy resin, bisphenol F epoxy resin, novolac epoxy
resin, aliphatic epoxy resin, glycidylamine epoxy resin and
combinations thereof
11. A coating method comprising: providing a deposition surface;
and depositing by solvent transport medium a coating on the
deposition surface includes particles of a metal chalcogenide
comprising a fullerene-like geometry, a tubular-like geometry or a
combination of fullerene-like geometries and tubular-like
geometries particles, wherein the metal chalcogenide composition
has a molecular formula of MX.sub.2 and M is a metallic element
selected from the group consisting of titanium (Ti), vanadium (V),
chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni),
copper (Cu), zinc (Zn), zirconium (Zr), niobium (Nb), molybdenum
(Mo), technetium (Tc), ruthenium (Ru), rhodium (Rh), palladium
(Pd), silver (Ag), cadmium (Cd), hafnium (Hf), tantalum (Ta),
tungsten (W), rhenium (Re), osmium (Os), iridium (Jr), platinum
(Pt), gold (Au), mercury (Hg) and combinations thereof, and X is a
chalcogen element selected from the group consisting of sulfur (S),
selenium (Se), tellurium (Te), oxygen (O) and combinations
thereof.
12. The coating method of claim 11, wherein the particles of a
metal chalcogenide provide a dispersed phase of a metal
chalcogenide having an outer layer comprising at least one
sectioned portion for the fullerene-like geometries and
tubular-like geometries, the at least one sectioned portion extends
along a direction away from the curvature of the outer layer for
the fullerene-like geometries and tubular-like geometries
particles, the at least one sectioned portion engaged to remaining
section of the outer layer.
13. The coating method of claim 11, wherein the coating further
comprises a base material layer selected from the group consisting
base material layer comprises a polymer selected from the group
consisting of elastomers, epoxies, thermoplastic polymers,
polyamides, polyphthalamide, polyphthalamide blend,
poly-amide-imide, polyethylene, cross-linked polyethylene,
polyester, polyurethanes, polyproplenes, and combinations
thereof.
14. The coating method of claim 11, wherein the solvent transport
medium includes a solvent selected from the group consisting of
acetic acid, acetone, acetonitrile, benzene, n-butanol, butyl
acetate, carbon tetrachloride, chloroform, cyclohexane,
1,2-dichloroethane, dichloromethane, dimethylformamide,
N,N-dimethylacetamide (DMAC), propylene carbonate (PC), dimethyl
sulfoxide, dioxane, ethanol, ethyl acetate, di-ethyl ether,
heptane, hexane, methanol, methyl-t-butyl ether, methyl ethyl
ketone, pentane, n-propanol, iso-propanol, di-iso-propyl ether,
tetrahydrofuran, toluene, NMP, ethyl benzene trichloroethylene,
water, xylene and combinations thereof.
15. The coating method of claim 11, wherein depositing comprises
brushing.
16. The coating method of claim 11, wherein depositing comprises
spraying.
17. The coating method of claim 11, wherein the particles of the
metal chalcogenide having the molecular formula MX.sub.2 are
tungsten disulfide (WS.sub.2), molybdenum disulfide (MoS.sub.2) or
a combination thereof.
18. The coating method of claim 11, wherein the particles of the
metal chalcogenide having the molecular formula MX.sub.2 have a
fullerene-like geometry and a diameter ranging from 5 nm to 5
.mu.m.
19. The coating method of claim 11, wherein the particles of the
metal chalcogenide having the molecular formula MX.sub.2 have a
tube-like geometry and a diameter ranging 1 nm to 150 nm and a
length ranging from 10 nm to 15 cm.
20. The coating method of claim 11, wherein the particles of the
metal chalcogenide are functionalized with at least one of
non-anionic surfactants, anionic surfactants, cationic surfactants,
zwitterionic surfactants, surfactants, silanes, thiols, polymers
and dopants.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 61/766,898 filed Feb. 20, 2013, titled "Coating
including inorganic fullerene-like particles and inorganic
tubular-like particles" and U.S. Provisional Application No.
61/766,399 filed Feb. 19, 2013, titled "Composite materials
including fullerene-like hollow particles and inorganic
tubular-like particles in a polymer matrix", and U.S. patent
application Ser. No. 14/180,955 filed Feb. 14, 2014, titled
"Composite materials including fullerene-like hollow particles and
inorganic tubular-like particles in a polymer matrix", which are
incorporated herein in their entirety by reference.
FIELD OF THE INVENTION
[0002] The present disclosure relates to lubricating coatings.
BACKGROUND
[0003] Every year damage caused by insufficient lubrication and
wear is extremely costly. When components are moved under force
with respect to each other, properties like coefficient of
friction, frictional force and resistance against abrasion have a
decisive influence on the operability and service life of processes
and systems. Moreover, the requirements which need to be met by
tribological systems are continually increasing. Customers are
demanding smaller size and lower weight, while at the same time
increasing performance and often also customers are demanding
lubricant-free operation.
SUMMARY OF THE INVENTION
[0004] In one embodiment of the present disclosure, a coating is
provided that includes an inorganic material of a metal
chalcogenide. The inorganic material of the metal chalcogenide has
a fullerene-like geometry and/or has a tubular-like geometry. The
metal chalcogenide composition has a molecular formula of MX.sub.2,
where M is a metallic element selected from the group consisting of
titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron
(Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), zirconium
(Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), ruthenium
(Ru), rhodium (Rh), palladium (Pd), silver (Ag), cadmium (Cd),
hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium
(Os), iridium (Ir), platinum (Pt), gold (Au), mercury (Hg) and
combinations thereof, and X is a chalcogen element selected from
the group consisting of sulfur (S), selenium (Se), tellurium (Te),
oxygen (O) and combinations thereof. The inorganic material of the
metal chalcogenide having the molecular formula MX.sub.2 is present
in the coating in an amount of greater than 0.1 wt %.
[0005] In another embodiment, a polymeric coating is provided that
includes an inorganic material of a metal chalcogenide. The metal
chalcogenide has a fullerene-like geometry and/or has a
tubular-like geometry. The metal chalcogenide composition has a
molecular formula of MX.sub.2, where M is a metallic element
selected from the group consisting of titanium (Ti), vanadium (V),
chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni),
copper (Cu), zinc (Zn), zirconium (Zr), niobium (Nb), molybdenum
(Mo), technetium (Tc), ruthenium (Ru), rhodium (Rh), palladium
(Pd), silver (Ag), cadmium (Cd), hafnium (Hf), tantalum (Ta),
tungsten (W), rhenium (Re), osmium (Os), iridium (Ir), platinum
(Pt), gold (Au), mercury (Hg) and combinations thereof, and X is a
chalcogen element selected from the group consisting of sulfur (S),
selenium (Se), tellurium (Te), oxygen (O) and combinations thereof.
The inorganic material of the metal chalcogenide having the
molecular formula MX.sub.2 is present in polymeric base material in
an amount of greater than 0.1 wt %.
[0006] In another aspect of the disclosure, a coating method is
provided that includes providing a deposition surface, and
depositing by a physical vapor deposition (PVD) method a coating on
the deposition surface. The coating includes particles of a metal
chalcogenide having at least one of a fullerene-like geometry and a
tubular-like geometry. The metal chalcogenide composition has a
molecular formula of MX.sub.2, in which M is a metallic element
selected from the group consisting of titanium (Ti), vanadium (V),
chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni),
copper (Cu), zinc (Zn), zirconium (Zr), niobium (Nb), molybdenum
(Mo), technetium (Tc), ruthenium (Ru), rhodium (Rh), palladium
(Pd), silver (Ag), cadmium (Cd), hafnium (Hf), tantalum (Ta),
tungsten (W), rhenium (Re), osmium (Os), iridium (Ir), platinum
(Pt), gold (Au), mercury (Hg) and combinations thereof, and X is a
chalcogen element selected from the group consisting of sulfur (S),
selenium (Se), tellurium (Te), oxygen (O) and combinations
thereof.
[0007] In another aspect of the present disclosure, a coating
method is provided that includes depositing by an electroplating
method a coating on a deposition surface. The coating includes
particles of a metal chalcogenide having at least one of a
fullerene-like geometry and a tubular-like geometry. The metal
chalcogenide composition has a molecular formula of MX.sub.2,
wherein M is a metallic element selected from the group consisting
of titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron
(Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), zirconium
(Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), ruthenium
(Ru), rhodium (Rh), palladium (Pd), silver (Ag), cadmium (Cd),
hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium
(Os), iridium (Jr), platinum (Pt), gold (Au), mercury (Hg) and
combinations thereof, and X is a chalcogen element selected from
the group consisting of sulfur (S), selenium (Se), tellurium (Te),
oxygen (O) and combinations thereof.
[0008] In yet another aspect, a coating method is provided that
includes providing a deposition surface; and depositing by solvent
transport medium a coating on the deposition surface that includes
particles of a metal chalcogenide comprising a fullerene-like
geometry, a tubular-like geometry or a combination of
fullerene-like geometries and tubular-like geometries particles.
The metal chalcogenide composition has a molecular formula of
MX.sub.2, wherein M is a metallic element selected from the group
consisting of titanium (Ti), vanadium (V), chromium (Cr), manganese
(Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn),
zirconium (Zr), niobium (Nb), molybdenum (Mo), technetium (Tc),
ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), cadmium
(Cd), hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re),
osmium (Os), iridium (Jr), platinum (Pt), gold (Au), mercury (Hg)
and combinations thereof, and X is a chalcogen element selected
from the group consisting of sulfur (S), selenium (Se), tellurium
(Te), oxygen (O) and combinations thereof.
[0009] In yet a further embodiment, a coating method is provided
that includes providing a deposition surface; and depositing a
composite polymeric coating on the deposition surface that includes
polymeric base material and a dispersed phase of a metal
chalcogenide comprising a fullerene-like geometry, a tubular-like
geometry or a combination of fullerene-like geometries and
tubular-like geometries particles. The metal chalcogenide
composition has a molecular formula of MX.sub.2, wherein M is a
metallic element selected from the group consisting of titanium
(Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe),
cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), zirconium (Zr),
niobium (Nb), molybdenum (Mo), technetium (Tc), ruthenium (Ru),
rhodium (Rh), palladium (Pd), silver (Ag), cadmium (Cd), hafnium
(Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os),
iridium (Jr), platinum (Pt), gold (Au), mercury (Hg) and
combinations thereof, and X is a chalcogen element selected from
the group consisting of sulfur (S), selenium (Se), tellurium (Te),
oxygen (O) and combinations thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The following detailed description, given by way of example
and not intended to limit the disclosure solely thereto, will best
be appreciated in conjunction with the accompanying drawings,
wherein like reference numerals denote like elements and parts, in
which:
[0011] FIG. 1 is a transmission electron microscope (TEM) image of
a metal chalcogenide having a molecular formula MX.sub.2 and a
fullerene-like geometry, in accordance with one embodiment of the
present disclosure.
[0012] FIG. 2 is a transmission electron microscope (TEM) image of
a metal chalcogenide having a molecular formula MX.sub.2 and a
tubular-like geometry, in accordance with one embodiment of the
present disclosure.
[0013] FIGS. 3A and 3B are scanning electron microscope (SEM)
images of metal chalcogenide having a molecular formula MX.sub.2
with a fullerene-like geometry that is dispersed within a polymer
matrix, in accordance with one embodiment of the present
disclosure.
[0014] FIG. 4A is an illustration depicting a non-coated
surface.
[0015] FIG. 4B is an illustration depicting a non-coated surface
under friction.
[0016] FIG. 5 is transmission electron microscope (TEM) image of a
multi-layered nanosphere of metal chalcogenide having a molecular
formula MX.sub.2 with a fullerene-like geometry under a stress that
exfoliates tribofilm lamellas that fill and re-smoothen damaged
surfaces, in accordance with one embodiment of the present
disclosure.
[0017] FIG. 6 is a transmission electron microscope (TEM) image of
a surface coated with the tribofilm.
[0018] FIG. 7A is an illustration depicting a surface that has been
coated with a coating including a polymeric base material and a
dispersed phase of metal chalcogenide having a molecular formula
MX.sub.2 and a fullerene-like geometry, in accordance with one
embodiment of the present disclosure.
[0019] FIGS. 7B and 7C are illustrations depicting the application
of a friction force to the surface that has been coated with a
coating including a polymeric base material and a dispersed phase
of metal chalcogenide having a molecular formula MX.sub.2 and a
fullerene-like geometry, in accordance with one embodiment of the
present disclosure.
DETAILED DESCRIPTION
[0020] Detailed embodiments of the present disclosure are described
herein; however, it is to be understood that the disclosed
embodiments are merely illustrative of the compositions, structures
and methods of the disclosure that may be embodied in various
forms. In addition, each of the examples given in connection with
the various embodiments are intended to be illustrative, and not
restrictive. Further, the figures are not necessarily to scale,
some features may be exaggerated to show details of particular
components. Therefore, specific structural and functional details
disclosed herein are not to be interpreted as limiting, but merely
as a representative basis for teaching one skilled in the art to
variously employ the compositions, structures and methods disclosed
herein. References in the specification to "one embodiment", "an
embodiment", "an example embodiment", etc., indicate that the
embodiment described may include a particular feature, structure,
or characteristic, but every embodiment may not necessarily include
the particular feature, structure, or characteristic. Moreover,
such phrases are not necessarily referring to the same
embodiment.
[0021] In one embodiment, a coating is provided that includes an
inorganic material of a metal chalcogenide composition having a
fullerene-like geometry and/or tubular-like geometry. The metal
chalcogenide composition has a molecular formula of MX.sub.2, where
M is a metallic element selected from the group consisting of
titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron
(Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), zirconium
(Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), ruthenium
(Ru), rhodium (Rh), palladium (Pd), silver (Ag), cadmium (Cd),
hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium
(Os), iridium (Ir), platinum (Pt), gold (Au), mercury (Hg) and
combinations thereof, and X is a chalcogen element selected from
the group consisting of sulfur (S), selenium (Se), tellurium (Te),
oxygen (O) and combinations thereof. In one example, the metal
chalcogenide composition is tungsten disulfide (WS.sub.2). The
particles of the metal chalcogenide can be functionalized with at
least one of non-anionic surfactants, anionic surfactants, cationic
surfactants, zwitterionic surfactants, surfactants, silanes,
thiols, polymers and dopants.
[0022] The deposition surface that the coating is formed on may be
composed of metals, such as steel, aluminum, copper alloys, and
zinc alloys. In other examples, the deposition surface that the
coating is formed on may be a dielectric, polymeric or ceramic
material. In some other examples, the deposition surface may be a
semiconductor material. The coating composition may further include
a base material layer selected from the group consisting of chrome
(Cr), chromium oxide (Cr.sub.2O.sub.3), diamond like carbon (DLC),
silicon carbide (SiC), silicon nitride (Si.sub.3N.sub.4), titanium
carbide (TiC), nickel titanium (NiTi), aluminum oxide (AhO.sub.3),
boron carbide (B.sub.4C), boron, tungsten cobalt (WCo) and
combinations thereof. In some embodiments, the base material layer
provides the majority of the coating.
[0023] In some embodiments, the base material for the coating
composition is a polymeric material. In one example, base material
is provided by an elastomer. An elastomer is a cross-linked,
amorphous polymer when above its glass transition temperature. Each
of the monomers, which link to form the polymer in an elastomer is
usually made of carbon, hydrogen, oxygen and/or silicon. At ambient
temperatures, elastomers are relatively soft, e.g., E.about.3 MPa,
and deformable. Elastomers are usually thermosets (requiring
vulcanization), but may also be thermoplastic. The long polymer
chains cross-link during curing, i.e., vulcanizing. The elasticity
is derived from the ability of the long chains to reconfigure
themselves to distribute an applied stress. The covalent
cross-linkages ensure that the elastomer will return to its
original configuration when the stress is removed. As a result of
this extreme flexibility, elastomers can reversibly extend from
5-700%, depending on the specific material, without the
cross-linkages or with short, uneasily reconfigured chains, the
applied stress would result in a permanent deformation.
[0024] Examples of elastomers that are suitable for use with the
present disclosure include unsaturated rubbers that can be cured by
sulfur vulcanization, which include, but are not limited to:
natural polyisoprene: cis-1,4-polyisoprene natural rubber (NR) and
trans-1,4-polyisoprene gutta-percha; synthetic polyisoprene (IR for
Isoprene Rubber); polybutadiene (BR for Butadiene Rubber);
chloroprene rubber (CR), polychloroprene, neoprene, baypren etc;
butyl rubber (copolymer of isobutylene and isoprene, IIR);
halogenated butyl rubbers (chioro butyl rubber: CIIR; bromo butyl
rubber: BIIR); styrene-butadiene rubber (copolymer of styrene and
butadiene, SBR); nitrile rubber (copolymer of butadiene and
acrylonitrile, NBR)(also called Buna N rubbers); hydrogenated
nitrile rubbers (HNBR); therban; and zetpol.
[0025] In another embodiment, examples of elastomers that are
suitable for use with the present disclosure include saturated
rubbers that cannot be cured by sulfur vulcanization, which
include, but are not limited to: EPM (ethylene propylene rubber, a
copolymer of ethylene and propylene) and EPDM rubber (ethylene
propylene diene rubber, a terpolymer of ethylene, propylene and a
diene-component); Epichlorohydrin rubber (ECO); Polyacrylic rubber
(ACM, ABR); Silicone rubber (SI, Q, VMQ); Fluorosilicone Rubber
(FVMQ); Fluoroelastomers (FKM, and FEPM) Viton, Tecnoflon, Fluorel,
Aflas and Dai-El; Perfluoroelastomers (FFKM) Tecnoflon PFR, Kalrez,
Chernraz, Perlast; Polyether block amides (PEBA); Chiorosulfonated
polyethylene (CSM); Ethylene-vinyl acetate (EVA) and combinations
thereof.
[0026] Other types of elastomers that are suitable for use with the
present disclosure include thermoplastic elastomers (TPE); the
proteins resilin and elastin; and polysulfide rubber. In some
embodiments, when an elastomer serves as the base material of the
coating having a dispersed phase of an inorganic material of a
metal chalcogenide composition with a fullerene-like or
tubular-like geometry, the mechanical properties of the coating
including the fullerene-like or tubular-like geometry inorganic
material of metal chalcogenide composition are greater than the
elastomer by itself. For example, the stress strain behavior of the
coating is increased in comparison to the performance of the
elastomer without the dispersed phase of the fullerene-like or
tubular-like geometry inorganic material of metal chalcogenide
composition. The coating also has greater lubricating qualities
that the elastomer by itself.
[0027] In another embodiment, the polymer that is selected for the
base material of the coating may be an epoxy. Epoxies are typically
thermosetting. Epoxy resins, also known as polyepoxides are a class
of reactive prepolymers and polymers which contain epoxide groups.
Epoxy resins may be reacted (cross-linked) either with themselves
through catalytic homopolymerization, or with a wide range of
co-reactants including polyfunctional amines, acids (and acid
anhydrides), phenols, alcohols and thiols. These co-reactants are
often referred to as hardeners or curatives, and the cross-linking
reaction is commonly referred to as curing. Epoxy compositions that
are suitable for use with the present disclosure may include
bisphenol A epoxy resin, bisphenol F epoxy resin, novolac epoxy
resin, aliphatic epoxy resin, glycidylamine epoxy resin and
combinations thereof. One example of the repeating unit for an
epoxy that is suitable for use with the present disclosure is a
diglycidyl: ether of bisphenol A, DGEPA, as follows:
##STR00001##
[0028] In some embodiments, when an epoxy serves as base layer for
the coating having a dispersed phase of an inorganic material of a
metal chalcogenide composition, such as tungsten disulfide
(WS.sub.2), with a fullerene like or tubular-like geometry, the
mechanical properties of the coating are greater than the
mechanical properties of the epoxy by itself. For example, the peel
strength and shear strength performance of the coating including
the epoxy base material and the inorganic materials of the metal
chalcogenide composition with the fullerene-like or tubular-like
geometry is greater than the peel strength and shear strength
performance of the epoxy by itself, i.e., the epoxy without the
dispersed phase of an inorganic material of a metal chalcogenide
composition with a fullerene like or tubular-like geometry.
[0029] In some embodiments, the inclusion of the dispersed phase of
an inorganic material of the metal chalcogenide composition with
the fullerene-like or tubular-like geometry can double the peel
strength and shear strength performance of the composite when
compared to the epoxy. Impact strength is also increased. Energy
absorbance, as indicated from the area under the stress-strain
curve (e.g. of a tensile test according to ASTM D638) is also
increased when compared to epoxy.
[0030] In another embodiment, the polymer for the base material of
the coating may be a thermoplastic material, such as polyether
ether ketone (PEEK) and polypropylene (PP). PEEK polymers are
obtained by step-growth polymerization by the dialkylation of
bisphenolate salts. When PEEK is employed as the matrix, e.g., base
material, of a coating including a dispersed phase of inorganic
materials of the metal chalcogenide composition with the
fullerene-like or tubular-like geometry, the mechanical properties
of the coating are greater than the mechanical properties of PEEK
without the dispersed phase of inorganic materials. For example,
the Young's modulus may be doubled by the inclusion of the
dispersed phase of inorganic materials of the metal chalcogenide
composition with the fullerene-like or tubular-like geometry into a
matrix of PEEK. Impact strength is also increased. Applications for
PEEK in accordance with the present disclosure include medical
implants, aerospace structures, automotive structures, bearings,
piston parts, pumps, compressor plate valves, and cable
insulation.
[0031] Polypropylene (PP) is an addition polymer made from the
monomer propylene. Low-density polyethylene (LDPE) and high-density
polyethylene (HDPE) are both suitable for use with the present
disclosure, as well as other density characterizations for
polypropylene (PP). Polypropylene (PP) may be suitable for use as
the base material of a coating in accordance with the present
disclosure, and is suitable for use in automotive and aerospace
applications. Polypropylene (PP) may also be suitable for coatings
used in shielding piping and wire cable sheathing applications. The
mechanical properties and impact strength of polypropylene (PP) is
increased by incorporation of a dispersed phase of inorganic
material having a metal chalcogenide composition with a
fullerene-like or tubular like geometry.
[0032] In another embodiment, the polymer for the base material of
the coating may be a polyamide. A polyamide is a polymer containing
monomers of amides joined by peptide bonds. An amide group has the
formula --CONH.sub.2. An amide link has this structure:
##STR00002##
[0033] The polyamide polymer may have a high crystallinity, a low
crystallinity or may be amorphous. Polyamide polymers that are
suitable for use with the present disclosure may be homopolymers or
copolymers. The polyamide polymers may aliphatic, semi aromatic,
aromatic or a combination thereof.
[0034] In one embodiment, the polyamide used for the base material
of the coating may be nylon. Nylon may be an aliphatic polymer. In
nylon, the repeating units contain chains of carbon atoms. There
are various different types of nylon depending on the nature of
those chains. Examples of nylons that may be suitable for use as
the base material layer of the coating may include nylon-6,6;
nylon-6; nylon-6,9; nylon-6,10; nylon-6,12; nylon-11; nylon-12 and
nylon-4,6. The repeating unit for nylon-6 is as follows:
##STR00003##
[0035] The repeating unit for nylon 6-6 is as follows:
##STR00004##
[0036] In some embodiments, nylons are condensation copolymers
formed by reacting equal parts of a diamine and a dicarboxylic
acid, so that amides are formed at both ends of each monomer in a
process analogous to polypeptide biopolymers. Chemical elements
included are carbon, hydrogen, nitrogen, and oxygen.
[0037] In another embodiment, the polyamide for the base layer of
the coating is kevlar. Kevlar is similar in structure to nylon-6,6
except that instead of the amide links joining chains of carbon
atoms together, they join benzene rings.
[0038] In another embodiment, the polyamide used for the base
material of the coating may be polyphthalamide (aka. PPA, High
Performance Polyamide). PPA is a thermoplastic synthetic resin of
the polyamide (nylon) family. PPA's are polyamides containing
aromatic rings in their backbones, which gives them high mechanical
strength and thermal resistance. The term PPA is used when 60% or
more moles of the carboxylic acid portion of the repeating unit in
the polymer chain is composed of a combination of terephthalic
(TPA) and isophthalic (IPA) acids. PPA's may be a semi-crystalline
material composed from a diacid and a diamine. PPA is typically
formed by the reaction of aromatic acids with aliphatic diamines.
In some embodiments, the diacid portion contains at least 55%
terephthalic acid (TPA) or isophthalic acid (IPA). Molar masses for
PPA's made with direct polycondensation techniques range between
12,000 and 16,000 g/mol.
[0039] In another embodiment, the polyamide used for the base
material of the coating may be a polyphthalamide blend. For
example, the base material of the coating may be composed of at
least one of polyphthalamide/polyamide blends and
polyphthalamide/polyamide/polyolefin blends.
[0040] Other polyamides that are suitable for use as the base
material of the coating include polyvinyl chloride (PVC), polyester
(PES), polyethermide (PEI) and polyphenylene sulfide (PPS).
[0041] In some embodiments, the base material of the coating may be
composed of polyamide-imides. The polyamide-imides may be
thermosetting or thermoplastic amorphous polymers. Polamide-imide
polymers include a polymer chain that comprises amide linkages
alternating with imide linkages. The mer unit for one example of a
polyamide-imide used in accordance with the present disclosure is
as follows:
##STR00005##
[0042] Polyamide-imides may be made from isocyanates and TMA
(trimellic acid-anhydride) in N-methylpyrrolidone (NMP). For
example, one route to the formation of polyamide-imides is the
condensation of an aromatic diamine, such as methylene dianiline
(MDA) and trimellitic acid chloride (TMAC). Reaction of the
anhydride with the diamine produces an intermediate amic acid. The
acid chloride functionality reacts with the aromatic amine to give
the amide bond and hydrochloric acid (HCl) as a byproduct. In the
commercial preparation of polyamideimides, the polymerization is
carried out in a dipolar, aprotic solvent such as
N-methylpyrrolidone (NMP), dimethylacetamide (DMAC),
dimethylformamide (DMF), or dimethylsulfoxide (DMSO) at
temperatures between 20-60.degree. C. The byproduct hydrochloric
acid (HCl) is typically neutralized in situ or removed by washing
it from the precipitated polymer. In another example,
polyamide-imides may be formed by reacting diisocyanate, often
4,4'-methylenediphenyldiisocyanate (MDI), with trimellitic
anhydride (TMA). Polyamide-imides that are suitable for the methods
and structures disclosed herein may be available from Solvay
Advanced Polymers under the trademark Torlon, such as Torlon 4301,
Torlon ai-10, Torlon ai-10 LM or Torlon 4000. Polyamide-imides
(PAI) may be used in conjunction with fluoropolymers.
[0043] In some embodiments, the base layer of the coating may be
provided by polyethylene (PE). The term polyethylene describes a
family of resins obtained by polymerizing ethylene gas,
H.sub.2C.dbd.CH.sub.2. In some examples, low density polyethylene
typically has a density value ranging from 0.91 to 0.925
g/cm.sup.3, linear low density polyethylene is in the range of
0.918 to 0.94 g/cm.sup.3, while high density polyethylene ranges
from 0.935 to 0.96 g/cm.sup.3 and above.
[0044] In another embodiment, the base layer of the coating may be
cross linked polyethylene (PEX). Typically, PEX is made from high
density polyethylene (HDPE). cross linked polyethylene (PEX)
contains cross-linked bonds in the polymer structure, changing the
thermoplastic to a thermoset. In one embodiment, in order to be
classified as being cross linked polyethylene (PEX), the required
degree of cross-linking, according to ASTM Standard F 876-93, is
between 65% and 89%.
[0045] In yet another embodiment, the polymer for the base layer of
the coating may be a polyester. Polyester is a category of polymers
which contain the ester functional group in their main chain. In
some examples, polyester that is suitable for the base layer of the
coating may include polybutylene terephthalate (PBT) and
polyethylene terephthalate (PET). The repeating unit of
polybutylene terephthalate (PBT) is as follows:
##STR00006##
[0046] The repeating unit of polyethylene terephthalate (PET) is as
follows:
##STR00007##
[0047] Polyesters are synthesized by reacting an organic acid, in
this case terephthalic acid, with an alcohol. In the case of
polybutylene terephthalate (PBT), the alcohol is generically
referred to as butylene glycol, while in polyethylene terephthalate
(PET) it is ethylene glycol. The resulting polymers are known,
therefore, as polybutylene terephthalate (PBT) and polyethylene
terephthalate (PET).
[0048] In one embodiment, the inorganic material of the metal
chalcogenide having the molecular formula MX.sub.2 with the
fullerene-like geometry and/or tubular-like geometry is present in
the coating in an amount of greater than 0.1 wt %. For example, the
inorganic material of the metal chalcogenide having the molecular
formula MX.sub.2 may be present in the coating in an amount ranging
from 0.1 wt % to 99.5 wt %. In yet another example, the inorganic
material of the metal chalcogenide having the molecular formula
MX.sub.2 may be present in the coating in an amount ranging from
0.5 wt % to 70 wt %. In some examples, the inorganic material of
the metal chalcogenide having the molecular formula MX.sub.2 may be
present in the coating in an amount greater than 0.01% by
volume.
[0049] In some embodiments, such as when the coating includes a
polymeric base material layer, the coating may be a composite
structure. A composite, such as a composite coating, is a material
composed of two or more distinct phases, e.g., matrix phase and
dispersed phase, and having bulk properties different from those of
any of the constituents by themselves. As used herein, the term
"matrix phase" denotes the phase of the composite, and contains the
dispersed phase, and shares a load with it. In some embodiments,
the matrix phase may be the majority component of the composite
coating. In some embodiments, when the coating includes a polymeric
base material layer, the matrix phase may be provided by the
polymer base material layer. As used herein, the term "dispersed
phase" denotes a second phase (or phases) that is embedded in the
matrix phase of the composite. A composite coating in accordance
with the present disclosure includes a dispersed phase of an
inorganic material of a metal chalcogenide composition with a
fullerene-like or tubular-like geometry that is present in a second
material that provides a matrix phase.
[0050] In other embodiments, substantially the entire coating is
comprised of the inorganic material of a metal chalcogenide
composition having a fullerene-like geometry and/or tubular-like
geometry.
[0051] The component of the coating that is provided by the
inorganic material of the metal chalcogenide composition may have a
fullerene-like geometry. As used herein, the term "fullerene-like"
denotes a sphere like geometry. The core of the fullerene-like
geometry may be hollow, solid, amorphous, or a combination of
hollow, solid and amorphous portions. A fullerene like geometry may
also be referred to as having a cage geometry. In one example, an
inorganic material having the metal chalcogenide composition with a
fullerene like geometry may be a cage geometry that is hollow at
its core and layered at is periphery. In another example, an
inorganic material having the metal chalcogenide composition with a
fullerene like geometry may be a cage geometry that is solid at its
core and layered at is periphery. For example, the inorganic
material having the metal chalcogenide composition and the
fullerene like geometry may be a single layer or double layered
structure. The inorganic material having the metal chalcogenide
composition and the fullerene like geometry is not limited on only
single layer or double layered structures, as the inorganic
material may have any number of layers. For example, the metal
chalcogenide composition may be layered to include 5 layers to 100
layers of metal chalcogenide material that can exfoliate from the
particle. In another embodiment, the metal chalcogenide composition
may be layered to include 10 layers to 50 layers of metal
chalcogenide material that can exfoliate from the particle. In yet
another embodiment, the metal chalcogenide composition may be
layered to include 15 layers to 20 layers of metal chalcogenide
material that can exfoliate from the particle. These structures are
also referred to in the art as being "nested layer structures".
[0052] One example of an inorganic material having the metal
chalcogenide composition and the fullerene like geometry
fullerene-like geometry is depicted in FIG. 1. FIG. 1 depicts a
transmission electron microscope (TEM) image of an inorganic
material having a tungsten disulfide (WS.sub.2) composition with a
fullerene-like geometry. In another example, the inorganic material
having the metal chalcogenide composition and the inorganic
fullerene like geometry is composed of molybdenum disulfide
(MoS.sub.2). It is noted that the inorganic material with the
fullerene-like geometry that is depicted in FIG. 1 is not limited
to only tungsten disulfide (WS.sub.2) and molybdenum disulfide
(MoS.sub.2). Inorganic materials with a metal chalcogenide
composition and having a fullerene-like geometry may have any
inorganic composition that meets the formula MX.sub.2, where M is a
metallic element selected from the group consisting of titanium
(Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe),
cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), zirconium (Zr),
niobium (Nb), molybdenum (Mo), technetium (Tc), ruthenium (Ru),
rhodium (Rh), palladium (Pd), silver (Ag), cadmium (Cd), hafnium
(Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os),
iridium (Ir), platinum (Pt), gold (Au), mercury (Rg) and
combinations thereof, and X is a chalcogen element selected from
the group consisting of sulfur (S), selenium (Se), tellurium (Te),
oxygen (O) and combinations thereof.
[0053] The inorganic material having the metal chalcogenide
composition and fullerene-like geometry may have a diameter ranging
from 1 nm to 15 microns. In another embodiment, the inorganic
material having the metal chalcogenide composition and the
fullerene-like geometry may have a diameter ranging from 2 nm to 10
microns. In yet another embodiment, the inorganic material having
the metal chalcogenide composition and the fullerene-like geometry
may have a diameter ranging from 5 nm to 5 microns. The inorganic
material having the metal chalcogenide composition and the
fullerene-like geometry may have a diameter that is any value
within the above ranges. It is noted that the above dimensions are
provided for illustrative purposes only, and are not intended to
limit the present disclosure. In some embodiments, most of the
nanoparticles will have diameters ranging between 20 nm to 500 nm,
and even more typically will have diameters between 30 nm to 200
nm.
[0054] The component of the coating that is provided by the
inorganic material of the metal chalcogenide composition may also
have tubular-like geometry. As used herein, the term "tubular-like
geometry" denotes a columnar or cylindrical geometry, in which one
axis of the intercalation compound. In some embodiments, an
inorganic material having the metal chalcogenide composition and
the tubular-like geometry may be a cage geometry that is hollow at
its core and layered at its periphery. In other embodiments, an
inorganic material having the metal chalcogenide composition and
the tubular-like geometry may be a cage geometry that is solid at
its core, and/or amorphous at its core, and layered at its
periphery. For example, the inorganic material having the metal
chalcogenide composition and the tubular-like geometry may be a
single layer or double layered structure. These structures are also
referred to in the art as being "nested layer structures". The
number of layers in the inorganic material having the metal
chalcogenide composition and the tubular-like geometry may be
similar to the number of layers in the inorganic material having
the metal chalcogenide composition and the fullerene-like geometry.
In some examples, the minimum number of layers for the inorganic
material having the tubular-like geometry is approximately 4
layers.
[0055] One example of an inorganic material having the metal
chalcogenide composition and the tubular-like geometry is depicted
in FIG. 2. FIG. 2 depicts a transmission electron microscope (TEM)
image of an intercalation compound having a tungsten disulfide
(WS.sub.2) composition with an inorganic tubular-like geometry. In
another example, the inorganic material having the metal
chalcogenide composition and the tubular-like geometry is composed
of molybdenum disulfide (MoS.sub.2). It is noted that the inorganic
material having the metal chalcogenide composition and the
tubular-like geometry that is depicted in FIG. 2 is not limited to
only tungsten disulfide (WS.sub.2) and molybdenum disulfide
(MoS.sub.2). Inorganic materials having a tubular-like geometry may
have any inorganic composition that meets the formula MX.sub.2,
where M is a metallic element selected from the group consisting of
titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron
(Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), zirconium
(Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), ruthenium
(Ru), rhodium (Rh), palladium (Pd), silver (Ag), cadmium (Cd),
hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium
(Os), iridium (Ir), platinum (Pt), gold (Au), mercury (Hg), and
combinations thereof, and X is a chalcogen element selected from
the group consisting of sulfur (S), selenium (Se), tellurium (Te)
and oxygen (O).
[0056] The inorganic materials having the metal chalcogenide
composition and the tubular-like geometry may have a diameter,
i.e., distance perpendicular to the greatest axis of the
tubular-like geometry, ranging from 1 nm to 300 nm. In another
embodiment, the inorganic materials having the metal chalcogenide
composition and the tubular-like geometry may have a diameter
ranging from 5 nm to 125 nm. In yet another embodiment, the
inorganic materials have the metal chalcogenide composition and the
tubular-like geometry with a diameter ranging from 10 nm to 100 nm.
The inorganic materials having the metal chalcogenide composition
and the tubular-like geometry may have a length, i.e., greatest
axis of the tubular-like geometry, that ranges from 1 nm to 20 cm.
In another embodiment, the inorganic materials having the metal
chalcogenide composition and the tubular-like geometry may have a
length, i.e., greatest axis of the tubular-like geometry, that
ranges from 5 nm to 15 cm. In yet another embodiment, the inorganic
materials having the metal chalcogenide composition and the
tubular-like geometry may have a length, i.e., greatest axis of the
tubular-like geometry, that ranges from 100 nm to 10 cm. The
inorganic materials having the metal chalcogenide composition and
the tubular-like geometry may have a length or diameter that is any
value within the above ranges. It is noted that the above
dimensions are provided for illustrative purposes only, and are not
intended to limit the present disclosure.
[0057] The inorganic materials having the metal chalcogenide
composition, e.g., WS.sub.2, and the fullerene-like geometry and/or
tubular-like geometry may be produced via sulfidization of tungsten
oxide nanoparticles in reduction atmosphere in fluidized bed
reactor. The inorganic materials having the metal chalcogenide
composition and the fullerene-like geometry and/or tubular-like
geometry may be formed in accordance with at least one of the
methods disclosed in U.S. Pat. Nos. 6,217,843, 6,710,020,
6,841,142, 7,018,606 and 7,641,886, which are each incorporated
herein in their entirety. It is noted that the methods disclosed in
the aforementioned patents are only some examples of methods that
are suitable for forming the inorganic materials having the metal
chalcogenide composition and the fullerene-like and/or tubular-like
geometry. Any method may be employed for forming the
above-described inorganic materials having the metal chalcogenide
composition, so long as the compound formed has a fullerene-like
and/or tubular-like geometry.
[0058] In some embodiments, the coating may include a second
dispersed phase of a carbon containing material, such as carbon
nanotubes, e.g., single wall carbon nanotubes (CNT) or multi-wall
carbon nanotubes (SWNT), or graphitic materials, such as carbon
black (CB), graphitic fibers, diamond like carbon (DLC) and
graphite platelets. The second dispersed phase of carbon containing
materials could be used in polymer matrices for reinforcement or in
order to obtain desired physical, chemical or mechanical
properties.
[0059] In one embodiment, the carbon containing material that is
provided by carbon nanotubes may have a high purity on the order of
about 95% to about 99% carbon. In an even further embodiment, the
carbon nanotubes have a high purity on the order of about 99% or
greater. The diameter of a single wall carbon nanotube may range
from about 1 nanometer to about 400 nanometers. In another
embodiment, the diameter of a single wall carbon nanotube may range
from about 1.2 nanometers to about 1.6 nanometers. In one
embodiment, the nanotubes used in accordance with the present
invention have an aspect ratio of length to diameter on the order
of approximately 200:1. In the final coating, a carbon containing
material may be present in the final coating in an amount ranging
from 01 wt. % to 10 wt. %.
[0060] In some embodiments, in which the coating includes, a
polymer base material, the carbon containing material may be
present in the polymer matrix with the metal chalcogenide inorganic
material with the fullerene-like or tubular-like geometry, wherein
the carbon containing material is present in an amount ranging from
0.1 wt % to 60 wt. %. In another embodiment, the carbon containing
material may be present in the polymer matrix in an amount ranging
from 0.1 wt % to 40 wt. %. In yet another embodiment, the carbon
containing material in the polymer matrix in an amount ranging from
0.1 wt % to 30 wt. %.
[0061] In one embodiment, the thickness of the coating including
the base material and at least the inorganic materials having the
metal chalcogenide composition and the fullerene-like geometry
and/or tubular-like geometry may range from 5 microns to 50
mircons. In another embodiment, the thickness of the coating
including the base material and the inorganic materials having the
metal chalcogenide composition and the fullerene-like geometry
and/or tubular-like geometry may range from 5 microns to 20
microns. In yet another embodiment, the thickness of the coating
including the base material and the inorganic materials having the
metal chalcogenide composition and the fullerene-like geometry
and/or tubular-like geometry may range from 2 microns to 10
microns. FIGS. 3A and 3B depict one embodiment of a coating
including a polymeric base material and a dispersed phase of
nanospheres with a fullerene-like geometry and metal chalcogenide
composition with a molecular formula MX.sub.2, such as
WS.sub.2.
[0062] In one embodiment, the inorganic material having the metal
chalcogenide composition and the fullerene-like geometry and/or
tubular-like geometry is present in the polymeric base material at
volume percent ranging from 0.001% to 80%. In another embodiment,
the inorganic material having the metal chalcogenide composition
and the fullerene-like geometry and/or tubular-like geometry is
present in the polymeric base material at volume percent ranging
from 0.01% to 30%.
[0063] In another aspect of the present disclosure, a deposition
method is provided to form a coating including inorganic materials
having the metal chalcogenide composition and the fullerene-like
geometry and/or tubular-like geometry. In some embodiments, such as
the methods of forming a coating including a polymeric base
material, the deposition surface of the component being coated may
be treated with a surface pre-treatment prior to being coated.
[0064] In some embodiments, the pre-treatment process modifies the
surface of the substrate, i.e., modifies by a mechanism of surface
exchange (not the addition of a new layer), in order to allow
better wetting, coating, interlocking on the substrate surface,
chemical computability and consequently to all of these, improved
adhesion and coating performance. One example of a surface exchange
methods that are suitable for use with the present disclosure
include phosphating.
[0065] Phosphating is a chemical process for treating the
deposition surface, such as an iron containing deposition surface,
e.g., steel, whereby the metal-phosphate modified surfaces that are
hardly soluble are formed on the base material. Phosphating of
depositions surfaces including iron, such as carbon steel, may
include manganese phosphate, zinc phosphate, iron phosphate and a
combination thereof. In addition to iron and steel, other materials
that may be treated using a phosphating pretreatment include zinc,
cadmium, aluminum, tin and galvanized steel, and combinations
thereof.
[0066] The metal-phosphate modified surfaced created by phosphating
are porous, absorbent and are suitable without further treatment
for coating. In some embodiments, the application of phosphate
pre-treatment processes makes use of phosphoric acid and takes
advantage of the low solubility of phosphates in medium or high pH
solutions. Iron, zinc or manganese phosphate salts may be dissolved
in a solution of phosphoric acid. In some embodiments, when a
deposition surface of steel or iron parts is placed in the
phosphoric acid, an acid and metal reaction takes place which
locally depletes the hydronium (H.sub.3O.sup.+) ions, raising the
pH, and causing the dissolved salt to fall out of solution and be
precipitated on the surface. The acid and metal reaction also
creates iron phosphate locally which may also be deposited, such as
zinc phosphate or manganese phosphate. In some embodiments, the
acid and metal reaction also generates hydrogen gas in the form of
tiny bubbles that adhere to the surface, e.g., deposition surface,
of the metal being treated. The presence of the hydrogen bubbles
adhering to the deposition surface can prevent the acid from
reaching the metal being treated and slows down the reaction. To
overcome the formation of hydrogen bubbles at the deposition
surface during the phosphating pre-treatment process, sodium
nitrite may be added to act as an oxidizing agent that reacts with
the hydrogen to form water. In this example, hydrogen is prevented
from forming a passivation layer on the surface by the oxidant
additive. In one embodiment, the process sequence for a phosphating
pre-treatment process includes cleaning the deposition surface,
rinsing, surface activation, phosphating, rinsing and drying.
Surface activation may include activating the metal with, for
example, a titanium based alkali chemical, to obtain fine
crystalline structure for phosphate coating, which will increase
corrosion resistance and adhesion properties. Prior to phosphating,
the substrate is degreased (using organic solvents and/or an
alkaline cleaner), roughened (via sand blasting), with rinsing
between each of these steps (with distilled or deionized
water).
[0067] In addition to phosphating, other pre-treatment processes
that are suitable for use with the present disclosure include oxide
coatings. Oxide coatings are in fact corrosion products having a
thickness of less than 0.25 microns, which provide for good
adhesion of the later formed coating. Oxide coatings may be formed
using heat, chemical reaction or electrochemical reactions. Some
examples of oxide coating processes suitable for the pretreatment
of the deposition surface include gun-bluing oxidation, oxides
formed from chemical baths, and anodizing.
[0068] In other embodiments, the pre-treatment process for treating
the deposition surface prior to coating may be chromate coatings.
Chromate coating are a chemical conversion process. Chromate
coatings may be formed by reaction of water solutions of chromic
acid or chromium salts. Chromate coatings as a pre-treatment
process may be applied to metal deposition surfaces, such as
aluminum surfaces, zinc surfaces, cadmium surfaces and magnesium
surfaces.
[0069] It is noted that the above description of pre-treatment
processes are provided for illustrative purposes only and are not
intended to limit the present disclosure. It is further noted that
the above described pre-treatment processes may be optional in some
of the following described deposition methods for forming the
coating.
[0070] In one embodiment, the deposition method employs physical
vapor deposition (PVD) to form a coating including the inorganic
materials having the metal chalcogenide composition and the
fullerene-like geometry and/or tubular-like geometry. Physical
vapor deposition (PVD) is a process to produce a metal deposition
species that can be deposited on electrically conductive materials
as a thin adhered pure metal or alloy coating. The process may be
carried out in a vacuum chamber at high vacuum (10.sup.-6 torr).
Examples of PVD processes include plating, single target
sputtering, dual target sputtering, cathodic arc deposition,
electron beam physical vapor deposition, evaporation deposition,
pulsed laser deposition, and combinations thereof.
[0071] Cathodic arc deposition is a PVD method, in which a high
power electric arc discharged at the target (source) material
blasts away some into highly ionized material to be deposited onto
the workpiece. Electron beam physical vapor deposition is a PVD
method in which the material to be deposited is heated by electron
bombardment in a vacuum and is transported by diffusion to be
deposited by condensation on the (cooler) workpiece, i.e.,
deposition surface. Evaporative deposition is a PVD method, in
which the material to be deposited is heated to a high vapor
pressure by electrically resistive heating in a "low" vacuum.
Pulsed laser deposition is a PVD method in which a high power laser
ablates material from the target into a vapor. As used herein,
"sputtering" means a method of depositing a film of material on a
deposition surface, in which a target of the desired material,
i.e., source, is bombarded with particles, e.g., ions, which knock
atoms from the target, and the dislodged target material deposits
on the deposition surface. Examples of sputtering apparatuses
include DC diode type systems, radio frequency (RF) sputtering,
magnetron sputtering, and ionized metal plasma (IMP)
sputtering.
[0072] In each of the above described PVD methods, a target is
provided as a source material for deposition. To provide the
coatings of the present disclosure the target may include a powder
of the base material layer in combination with the inorganic
materials having the metal chalcogenide composition and the
fullerene-like geometry and/or tubular-like geometry. When the
target includes both the material for the base material layer and
the inorganic materials having the metal chalcogenide composition
and the fullerene-like geometry and/or tubular-like geometry, the
system may be referred to as a single target. The material for the
base material layer and the inorganic materials having the metal
chalcogenide composition and fullerene-like geometry and/or
tubular-like geometry may be milled together to provide a
sufficient particle size using at least one of high-shear mixers,
two or three roll mixers, homogenizers, bead mills, ultrasonic
pulverizer, attritor, agitator, ball mill, bead mill, basket mill,
colloid mill, high speed disperser, edge runner, jar mill, low
speed paddle mixer, variable speed mixer, paste mixer, ribbon
blender, pug mixer, nauta mixer, sand/perl mill, triple roll mill,
two roll mill, planetary mixer, slow speed mixer, high speed mixer,
twin shaft mixer, multi shaft mixer, sigma kneader, rotor-Stator
mixer, homogenizer/emulsifier, high shear mixer, conical blender,
V-blender, double cone blender, suspended mixer and combinations
thereof. In some embodiments, a fluid medium, such as water or an
alcohol, is employed during milling. In other embodiments, two
targets may be employed in the physical vapor deposition (PVD)
process. For example, one target may provide the source for the
base material layer, and a second target may provide the source for
the inorganic materials having the metal chalcogenide composition
and the fullerene-like geometry and/or tubular-like geometry.
[0073] In some embodiments, when forming the target for the
physical vapor deposition (PVD) method the particles of the metal
chalcogenide may be functionalizing with an agent that is selected
from the group consisting of non-anionic surfactants, anionic
surfactants, cationic surfactants, zwitterionic surfactants,
surfactants, silanes, thiols, polymers and dopants.
[0074] Following formation of the target, the deposition surface
may be cleaned of any oxide or surface residue, and the coating may
be applied by the physical vapor deposition (PVD) process.
[0075] In another aspect of the present disclosure, the coating may
be deposited using an electroplating process. Electroplating is a
process that uses electrical current to control the flow of charged
particles, such as metal cations and anions, so that they form a
coherent metal coating on an electrode, which may provide the
deposition surface. The process used in electroplating is called
electrodeposition. It is analogous to a galvanic cell acting in
reverse. The part to be plated is the cathode of the circuit. In
one technique, the anode is made of the metal to be plated on the
part. Both components are immersed in a solution called an
electrolyte containing one or more dissolved metal salts as well as
other ions that permit the flow of electricity. A power supply
supplies a direct current to the anode, oxidizing the metal atoms
that comprise it and allowing them to dissolve in the solution. At
the cathode, the dissolved metal ions in the electrolyte solution
are reduced at the interface between the solution and the cathode,
such that they "plate out" onto the cathode.
[0076] In one embodiment, both the component that provides the base
material layer in combination with the inorganic materials having
the metal chalcogenide composition and the fullerene-like geometry
or tubular-like geometry are positioned within the plating
solution.
[0077] In one example, the electroplating process is a chrome
plating process applied to a steel bearing, in which the chrome
plating includes an inorganic material of a tungsten disulfide
(WS.sub.2) or molybdenum disulfide (MoS.sub.2) composition having a
fullerene-like geometry and/or tubular-like geometry. In one
example, a chrome plating process includes degreasing of the
deposition surface to remove soiling and placement of the
deposition surface into a chrome plating vat. Once the deposition
surface is present in the chrome plating vat it is allowed to warm
to solution temperature, and a plating current is applied to the
system, under which the deposition surface is left for the required
time to attain thickness. In some embodiments, the electroplating
method may include non-anionic, anionic, cationic, zwitterionic,
surfactants, silanes, thiols, polymers to functionalize a surface
of a deposition precursor for the coating method. The
electroplating method may further include doping and alloying.
[0078] Hexavalent chromium plating, also known as hex-chrome,
Cr.sup.+6, and chrome (VI) plating, uses chromic anhydride, also
known as chromium trioxide, as the main ingredient of the plating
bath that is contained within the plating vat. In another
embodiment, the chromium bath is a mixture of chromium trioxide
(CrO.sub.3) and sulfuric acid (sulfate, SO.sub.4). Trivalent
chromium plating, also known as tri-chrome, Cr.sup.+3, and chrome
(III) plating, uses chromium sulfate or chromium chloride as the
main ingredient of the plating bath. The inorganic material of
tungsten disulfide (WS.sub.2) or molybdenum disulfide (MoS.sub.2)
composition having a fullerene-like geometry and/or tubular-like
geometry may be included in the plating bath for incorporation into
the coating during plating of the deposition surface. The inorganic
material of a tungsten disulfide (WS.sub.2) or molybdenum disulfide
(MoS.sub.2) composition having a fullerene-like geometry and/or
tubular-like geometry may be functionalized to provide the
appropriate charge for plating to the deposition surface.
[0079] In another embodiment, the coating may be formed by chemical
vapor deposition (CVD). Chemical vapor deposition (CVD) is a
deposition process in which a deposited species is formed as a
result of a chemical reaction between gaseous reactants at greater
than room temperature, wherein solid product of the reaction is
deposited on the surface on which a film, coating, or layer of the
solid product is to be formed. Variations of CVD processes suitable
for providing at least one element of the coating include, but are
not limited to: Atmospheric Pressure CVD (APCVD), Low Pressure CVD
(LPCVD), Plasma Enhanced CVD (PECVD), Metal-Organic CVD (MOCVD),
atomic layer deposition, and combinations thereof.
[0080] In yet another embodiment, the coating may be formed by
solvent transport medium a coating on the deposition surface
includes particles of a metal chalcogenide comprising a
fullerene-like geometry, a tubular-like geometry or a combination
of fullerene-like geometries and tubular-like geometries particles,
wherein the metal chalcogenide composition has a molecular formula
of MX.sub.2. In some embodiments, the coating formed by the solvent
transport medium may be one method that can be employed for forming
a coating including a polymeric base material, e.g., a polymer
provides the matrix phase of the coating containing a dispersed
phase of nanospheres with a fullerene-like geometry and/or tubular
like geometry, and metal chalcogenide composition with a molecular
formula MX.sub.2. In some embodiments, when the coating includes a
polymeric base material, a pre-treatment process, such as
phosphating with manganese phosphate, zinc phosphate, and/or iron
phosphate, is applied to the deposition surface prior to applying
the coating.
[0081] The solvent transport medium may include an aqueous medium
or alkyds, acrylics, vinyl-acrylics, vinyl acetate/ethylene (V AE),
polyurethanes, polyesters, melamine resins, epoxy, or oil based
medium. The solvent transport medium applied to the deposition
surface using at least one of brushing, dipping, spraying, curtain
coating and combinations thereof. The solvent transport medium may
include non-anionic surfactants, anionic surfactants, cationic
surfactants, zwitterionic surfactants, surfactants, silanes,
thiols, polymers, doping and alloying additives to functionalize a
surface of the particles of the metal chalcogenide.
[0082] In some embodiments, such as the embodiments in which the
coating includes a polymeric base material, the solvent for
applying the coating may include alcohols, such as ethanol and
isopropanol, pyrrolidones, such as N-Methyl-2-pyrrolidone (NMP) and
N-ethyl-2-pyrrolidone (NEP), xylenes, ethylbenzene, and
n-butyl-acetate. Some examples of solvents that are suitable for
forming coatings by solvent transport medium include acetic acid,
acetone, acetonitrile, benzene, n-butanol, butyl acetate, carbon
tetrachloride, chloroform, cyclohexane, 1,2-dichloroethane,
dichloromethane, dimethylformamide, N,N-dimethylacetamide (DMAC),
propylene carbonate (PC), dimethyl sulfoxide, dioxane, ethanol,
ethyl acetate, di-ethyl ether, heptane, hexane, methanol,
methyl-t-butyl ether, methyl ethyl ketone, pentane, n-propanol,
iso-propanol, di-iso-propyl ether, tetrahydrofuran, toluene,
trichloroethylene, water, xylene and combinations thereof. Xylene
(also referred to as Dimethylbenzenes) is an aromatic hydrocarbon
consisting of a benzene ring with two methyl substituents. Xylene
as a solvent transport medium may xylenes having a molecular
formula of C.sub.8H.sub.10, C.sub.6H.sub.4(CH.sub.3).sub.2 or
combinations thereof. In some examples, xylene may include
ortho-xylene (1, 2-Dimethylbenzene), meta-xylene
(1,3-Dimethylbenzene), para-xylene (1,4-Dimethylbenzene) and
combinations thereof.
[0083] In some embodiments, in which the coating includes a base
layer of a polymer containing a dispersed phase of the inorganic
material of a metal chalcogenide composition with a fullerene like
or tubular-like geometry, such as tungsten disulfide (WS.sub.2),
the coating method may begin with forming a dispersion. When the
inorganic material of a metal chalcogenide composition with a
fullerene like or tubular-like geometry has a geometry with a
greatest dimension greater than 10.sup.-6 nm, the dispersion may be
a suspension, in which the inorganic material of a metal
chalcogenide composition with a fullerene like or tubular-like
geometry can settle from suspension, but may be reintroduced into
the suspension by agitation by a mechanical means, e.g., by shaking
or stirring. In some examples, additives may be employed to improve
the stability of the dispersion. For example, in some embodiments,
when the inorganic material of a metal chalcogenide composition
with a fullerene like or tubular-like geometry has a geometry with
a greatest dimension of 10.sup.-9 nm, the dispersion is a
suspension, in which the metal chalcogenide with a fullerene like
or tubular-like geometry stays in suspension. In other embodiments,
when the inorganic material of a metal chalcogenide composition
with a fullerene like or tubular-like geometry has a geometry with
a greatest dimension ranging from 10.sup.-6 nm to 10.sup.-8 nm, the
dispersion is a colloidal dispersion, in which the metal
chalcogenide with a fullerene like or tubular-like geometry stays
in suspension.
[0084] In some embodiments, the dispersion for forming the coating
may include at least one solvent, at least one precursor for
polymer formation and a metal chalcogenide having a molecular
formula MX.sub.2 and a fullerene and/or tubular-like geometry. For
example, the amount of metal chalcogenide having a molecular
formula MX.sub.2 and a fullerene and/or tubular-like geometry in
the dispersion may range from 0.1 wt. % to 50 wt. %. In another
example, the amount of metal chalcogenide having a molecular
formula MX.sub.2, and a fullerene and/or tubular-like geometry in
the dispersion may range from 0.1 wt. % to 20 wt. %. In different
embodiments, the amount of metal chalcogenide in the dispersion may
be at least 16 wt. %, 17 wt. %, 18 wt. %, 19 wt. %, 20 wt. %, 21
wt. %, 22 wt. %, 23 wt. %, 24 wt. %, 25 wt. %, 26 wt. %, 27 wt. %,
28 wt. % nm, 29 wt. %, 31 wt. %, 32 wt. %, 33 wt. %, 34 wt. % or 35
wt. % or any range therebetween (e.g., 15 wt. % to 20 wt. %, 20 wt.
% to 25 wt. %, 25 wt. % to 30 wt. %, or 30 wt. % to 35 wt. %), or
between any of the foregoing values and up to or less than 50 wt.
%. The metal chalcogenide may be any of the above described
compositions having the molecular formula MX.sub.2, such as
tungsten disulfide (WS.sub.2). In some embodiments, the metal
chalcogenide may include more than one composition. For example,
the metal chalcogenide composition with a fullerene like or
tubular-like geometry may include a portion of tungsten disulfide
WS.sub.2 in combination with molybdenum disulfide MoS.sub.2. Other
particles may also be introduced to this dispersion, e.g., graphite
and MoS.sub.2 platelets.
[0085] The amount of polymer precursor in the dispersion may from 5
wt. % to 40 wt. %. In another example, the amount of polymer
precursor in the dispersion may range from 7 wt. % to 15 wt. %. In
different embodiments, the amount of polymer precursor in the
dispersion may be at least 5 wt. %, 6 wt. %, 7 wt. %, 8 wt. %, 9
wt. %, 10 wt. %, 11 wt. %, 12 wt. %, 13 wt. %, 14 wt. %, 15 wt. %,
16 wt. %, 17 wt. %, 18 wt. %, 19 wt. % or 20 wt. % or any range
there between (e.g., 5 wt. % to 10 wt. %, 10 wt. % to 15 wt. %, or
15 wt. % to 20 wt. %, or between any of the foregoing values and up
to or less than 30 wt. %. The polymer precursor may be any material
that can provide one of the aforementioned polymers for the base
layer of the coating. For example, the polymer precursor may
provide a polyamide and/or polyamide imide.
[0086] The amount of solvent in the dispersion may range from 20
wt. % to 90 wt. %. In another example, the amount of solvent in the
dispersion may range from 50 wt. % to 90 wt. %. In different
embodiments, the amount of solvent in the dispersion may be at
least 40 wt. %, 42 wt. %, 44 wt. %, 46 wt. %, 48 wt. %, 50 wt. %,
52 wt. %, 54 wt. %, 56 wt. %, 58 wt. %, 60 wt. %, 62 wt. %, 64 wt.
% or 65 wt. % or any range therebetween (e.g., 40 wt. % to 45 wt.
%, 45 wt. % to 55 wt. %, 55 wt. % to 60 wt. % or 60 wt. % to 65 wt.
%), or between any of the foregoing values and up to or less than
70 wt. %. The solvent may include any the aforementioned solvents.
For example, the solvent may include a combination of NMP
(M-methyl-2-pyrrolidone), xylene, and ethylbenzene. The solvent
content can be set to provide a concentrated dispersion product
that is to be diluted by the customer prior to use, or at a solvent
content for use without dilution.
[0087] In some embodiments, the dispersion may further include a
carbon containing material, such as graphite, carbon black or
carbon nanotubes.
[0088] In some embodiments, the dispersion may be formed by mixing
the solvent, polymer precursor, the metal chalcogenide having a
molecular formula MX.sub.2 and a fullerene and/or tubular-like
geometry, and the optional carbon containing material through the
use of a mixer, such as two or three roll mixers, homogenizers,
bead mills, ultrasonic pulverizer, ribbon blender, v blender,
colloid mills, stirrers, agitators, blending systems, continuous
processor, cone screw blender, double planetary, counter-rotating,
vacuum mixer, dispersion mixer, magnetic stirrers, high shear
mixtures and variations thereof.
[0089] In one example, in which the dispersion is formed in a
high-shear mixer, such as a high speed mixer sold under the
tradename DISPERMAT.RTM. by VMA-GETZMANN GMBH. The high-shear mixer
may include a double jacket for containing the cooling liquid. The
high shear mixture may employ metallic media beads, e.g., 2 mm
diameter media, or ceramic media beads, e.g., 0.4 m to 0.6 mm
diameter ceramic media. A nylon impeller is used to stir the media
and the material being formed into the dispersion. The vessel of
the high-shear mixture is connected to a cooling system, and sealed
during the mixing process to eliminate evaporation of solvents.
[0090] In another example, in which the dispersion is formed in a
stirred bead mill, such as a stirred bead mill produced by WAB, the
media to form the dispersion may be stirred in a vessel, and pumped
into a closed chamber with ZrO.sub.2 beads that stir at a high
velocity. The grinded media may be circulated and stirred from
between the chamber and the vessel of the stirred bead mill.
[0091] Table 1 is the composition of one example of a dispersion,
in accordance with the present disclosure.
TABLE-US-00001 TABLE 1 EXAMPLE: DISPERSION COMPOSITION MATERIAL
PERCENTAGE (BY WT. %) NMP (M-methy-2-pyrrolidone) 42.6 PAI
(poly-amide-imide) 6.4 Tungsten disulfide (WS.sub.2) 21 Xlyene 22.7
Ethylbenzene 7.3
[0092] For the composition of the dispersion that is described in
Table 1, the media beads, e.g., 0.8 mm ceramic beads, of the high
shear mixer or the stirred bead mill may be present at
approximately 267 gram beads per 100 grams of material being mixed
in forming the dispersion.
[0093] In one embodiment, the procedure for mixing the dispersion
for forming the coating having the polymeric base material in a
high shear mixer includes dissolving the polymer precursor, e.g.,
poly-amide-imine (PAI), in solvent, such as NMP
(M-methyl-2-pyrrolidone). For example, mixing the polymer precursor
with solvent, may include pouring a measured amount of solvent into
the vessel of the stirring apparatus followed by adding metal
and/or ceramic media beads. The polymer precursor material, e.g.,
poly-amide-imide (PAI), may then be added to the solvent and media
that is contained within the vessel, wherein the mixture is stirred
for 5 minutes to 30 minutes, e.g., 15 minutes, under cooling and
sealing.
[0094] In a following step, the metal chalcogenide having the
molecular formula MX.sub.2 and a fullerene and/or tubular-like
geometry, e.g., fullerene geometry tungsten disulfide WS.sub.2, may
then be added to the mixture of the polymer precursor and solvent
in the vessel of the high shear mixer. In some embodiments, when
the optional carbon-containing material is being introduced, the
carbon containing material can be mixed into the mixture of the
polymer precursor and the solvent with the metal chalcogenide
having the molecular formula MX.sub.2 and a fullerene and/or
tubular-like geometry. In some embodiments, a homogeneous mix of
inorganic fullerene-like and/or tubular particles with
carbon-containing materials is provided by premixing the inorganic
material having the metal chalcogenide composition and the
fullerene-like and/or tubular-like geometry with the carbon
containing material.
[0095] In one embodiment, the premixing step for mixing the
inorganic material having the metal chalcogenide composition and
the fullerene-like and/or tubular-like geometry with the carbon
containing material may be done by dry mixing. In another
embodiment, the premixing step may employ a solvent as a mixing
media, such as alcohol. Examples of mixing media that are suitable
for mixing the inorganic material having the metal chalcogenide
composition and the fullerene-like and/or tubular-like geometry
with the carbon containing materials include an alcohol, such as
methyl alcohol, ethyl alcohol, isopropyl alcohol, propanol,
butanol, hexanol, heptanol, octanol, ethylene glycol, glycerol and
combinations thereof. In another embodiment, the mixing media may
be an inert solvent. The carbon containing material and is optional
and may be omitted from the dispersion.
[0096] The combination of the metal chalcogenide having the
molecular formula MX.sub.2 and a fullerene and/or tubular-like
geometry, the polymer precursor, the solvent and the optional
carbon containing material may then be stirred for three hours to
nine hours. In one example, stirring of the metal chalcogenide,
polymer precursor, and the solvent may be mixed for six hours. In
one embodiment, the dispersion may be finalized by adding
additional solvent, such as xylene, ethylbenzene and combinations
thereof. The function of xylene and ethylbenzene is to form a
liquid that is paintable (via spray, brush etc.), they are used as
thinners for the highly viscous mixture based on PAI in NMP. The
mixture may then be stirred for an additional 5 minutes to 20
minutes, e.g., 15 minutes. The media from the high shear mixer may
then be sieved from the dispersion, and the dispersion may then be
stored for use. It is important to store it in a sealed vessel,
e.g. a metallic can, in order to prevent water absorption and
degradation.
[0097] In another aspect of the present disclosure, the dispersion
of solvent, polymer precursor, the metal chalcogenide having a
molecular formula MX.sub.2 and a fullerene and/or tubular-like
geometry, and the optional carbon containing material may be
applied to a metal surface to form a coating of a polymeric base
layer (also referred to as polymer matrix) with a dispersed phase
of the inorganic material of a metal chalcogenide composition with
a fullerene like or tubular-like geometry, and an optional
dispersed phase of carbon containing material. In some embodiments,
the dispersion provides nanoparticulate suspension in a carrier
solvent, which is to be applied to a deposition surface via
brushing, dipping or spraying to form a coating that reduces the
coefficient of friction (COF) and wear of the deposition surface.
In some embodiments, the dispersion allows for shipping of the
product to an intended user, which allows for storage of the
dispersion until it is used in a coating application.
[0098] In some embodiments, the application of the dispersion of
solvent, polymer precursor, the metal chalcogenide having a
molecular formula MX.sub.2 and a fullerene and/or tubular-like
geometry, and the optional carbon containing material may be
applied to a metal surface to form a coating of a polymeric base
layer (also referred to as polymer matrix) using a process sequence
that includes surface conditioning for the deposition surface,
phosphating the deposition surface, and spraying the dispersion
onto the depositions surface to form a coating. In this example,
the deposition surface may be an iron containing surface, such as
carbon steel.
[0099] In one embodiment, the conditioning step for applying the
coating from the dispersion, such as the dispersion having the
composition in Table 1, to the deposition surface may begin with
sonicating the deposition surface in a hot chemical soap, i.e, 80
parts water: 20 parts soap. The time period for sonicating may
range from 10 minutes to 20 minutes. In one example, the time
period for sonicating may be on the order of 15 minutes. Another
form of treatment with chemical soap may be via an alkaline formula
designated for metal cleaning, e.g. Enprep Q576.
[0100] In one embodiment, the phosphating step may include mixing
all of the phosphating ingredients in a container suitable, such as
a glass container, for the deposition surface to be phosphated and
heated to a temperature ranging from 95.degree. C. to 98.degree. C.
The phosphating ingredients for treating an iron containing
deposition surface, such as carbon steel, may include the
composition of Table 2, as follows:
TABLE-US-00002 TABLE 2 EXAMPLE: PHOSPHATING COMPOSITION MATERIAL
AMOUNT Ento-Phos MN-850 26-30 ml DDW (doule distilled water) 170 ml
Iron sulfate 300 mg-480 mg
[0101] In another embodiment, a surface treatment is provided by a
designated chemical bath (made of, e.g. polystyrene) with built in
heater, agitation setup (e.g. condensed air outlet pipe), and a
thermometer. Additionally, there are other phosphating processes
that are suitable for use with the present disclosure including
different materials and conditions. For example, a process of
zinc-phosphate surface exchange treatment may be employed at a
temperature ranging from 60.degree. C.-88.degree. C. with the
following composition including Amphos in an amount ranging from
300-240 ml, Amphos in an amount ranging from 504-480 ml, DDW (doule
distilled water) to complete to 12 L, and sodium carbonate (soda
ash) at approximately 5 grams.
[0102] The deposition surface may be dipped in the solution
described in Table 2 for a time period ranging from 5 minutes to 30
minutes. For example, the time period for submersion of the
deposition surface within the phosphating solution may range from 6
minutes to 15 minutes. The time period of the phosphating treatment
may vary depending on the size and geometry of the deposition
surface. In some examples, the time period for phosphating may
continue until the formation of bubbles within the phosphating
solution becomes seldom. The formation of bubbles indicate the
phosphate exchange process at the surface, when an equilibrium is
formed, the bubbles stop. Following the submersion time in the
phosphating solution, the component including the deposition
surface is removed from the phosphating solution and washed with
water, such as double distilled water. It is noted that any of the
above mentioned pretreatment processes for surface treating the
deposition surface prior to forming the coating may be substituted
for the phosphating step.
[0103] The deposition surface may then be coated. For example, a
dispersion, as described above, e.g., the dispersion described in
Table 1, may be applied using a spray deposition process. In one
example, the spray deposition process includes a device to spray a
coating (paint, ink, varnish, etc.) through the air onto the
deposition surface. For example, the spray deposition process may
include the use of an air-pressurized spray gun with an air source
provided by an air compressor. In one example, in a manual
operation method the air-gun sprayer is positioned about 6 inches
to 10 inches (15-25 cm) from the deposition surface, and moved back
and forth over the deposition surface, each stroke overlapping the
previous to ensure a continuous coat.
[0104] In an automatic process the gun head is attached to a
mounting block and delivers the stream of dispersion material for
forming the coating having the polymeric material from that
position. The deposition surface being coated is usually placed on
rollers or a turntable to ensure overall equal coverage of all
sides.
[0105] In some embodiments, the air spay system may be a HVLP (High
Volume Low Pressure) system, in which the spray gun use 8-20 cfm
(13.6-34 m.sup.3/hr); or a LVLP (Low Volume Low Pressure), which
operates at a lower pressure and lower volume of air than HVLP
systems. In another embodiment, the coating may be applied by
electrostatic spray painting. In electrostatic spray painting or
powder coating, the atomized particles of the dispersion are
electrically charged, thereby repelling each other and spreading
themselves evenly as they exit the spray nozzle of the gun. The
deposition surface being coated is charged oppositely or grounded.
The dispersion for the coating is then attracted to deposition
surface giving a more even coat than wet spray painting, and also
greatly increasing the percentage of paint that sticks to the
object. In other embodiments, the dispersion for the coating may be
applied to the deposition surface using hot spray, air assisted
airless spray guns, airless spray guns, automated linear spray
systems, vacuum coating systems, automated flat line spray systems
and combinations thereof.
[0106] It is noted that spraying is only one example of a
deposition method for applying the dispersion for forming the
coating onto the deposition surface. It is noted that other methods
for applying the dispersion to the deposition surface include
brushing, dipping or curtain coating.
[0107] Following application of the coating onto the deposition
surface, e.g., spraying of the dispersion onto the deposition
surface, the coating may be dried. For example, drying of the
coating may begin with ambient drying, i.e., drying at room
temperature, e.g., 20.degree. C. to 25.degree. C., for a time
period of 15 minutes to 1 hour, e.g., 30 minutes. In some cases,
this step is skipped, in order to avoid water absorption to the
coating, and the coated substrate is directly heated to
60-80.degree. C. Following ambient drying, the coating may be dried
at temperature of 60.degree. C. to 100.degree. C., e.g., 90.degree.
C., for 15 minutes to 1 hour, e.g., 30 minutes. In a following
process step, the coating may be cured at a temperature ranging
from 200.degree. C. to 240.degree. C., e.g., 220.degree. C., for 15
minutes to 1 hour, e.g., 30 minutes. The temperature of the coating
may be increased using furnaces, ovens, induction heaters,
resistance heaters, and combinations thereof. Following curing, the
coating may be allowed to cool to room temperature.
[0108] FIG. 5 depicts one embodiment of how continuous friction
applied to a metal chalcogenide of tungsten disulfide (WS.sub.2)
having a fullerene like geometry 15 will exfoliate the outer layers
of material onto a frictional surface that is applying pressure to
the tungsten disulfide material, wherein the exfoliating outer
layers create a tribofilm layer 20. A "tribofilm" is defined as a
thin solid film generated as a consequence of sliding contact,
which is adhered on a contacting, i.e., frictional, surface, but
has different chemical composition, structure and tribological
behavior than the contacting surface.
[0109] One example, of a tribofilm layer 20 formed on a surface 25
is depicted in FIG. 6. The exfoliated nano-particle layers
accumulate in wear crevices in the surface 25 that the tribofilm
layer 20 is formed on, and attaches to the metal surface, creating
a continuous super-lubricating tribofilm layer 20. The exfoliated
tribofilm layers from the metal chalcogenide of the coating may be
referred to as lamellas. The lamellas orient parallel to the
deposition surface in the direction of the frictional motion. Even
between highly loaded stationary surfaces the lamellar structure is
able to prevent contact.
[0110] In some embodiments, the tribofilm layer 20 provides a
damping effect to absorb shock between the surface 25 that the
tribofilm layer 20 is formed on an a second surface that the
tribofilm layer 20 is formed on. The particles, being closed-cage,
absorb pressure. Additionally, in the direction of motion the
lamellas of the tribofilm layer 20 easily shear over each other
resulting in a low friction. The lubricating tribofilm layer 20
repairs wear damage, prevents further wear, reduces the coefficient
of friction and reduces the local temperature.
[0111] Dynamic mechanical systems, such as certain parts within
combustions engines used in transportation applications, which
withstand friction conditions with a metallic counterpart can be
modified with a polymer film (in thickness of a few .mu.m and up,
depending on the required tolerance) including dispersed phase of
the inorganic material of a metal chalcogenide composition with a
fullerene like or tubular-like geometry. The significance of such a
film is both in reducing the coefficient of friction (COF), and in
impeding the wear of the surface. For example, main crankshaft
(slide-journal) bearings of vehicles work normally under
hydrodynamic lubrication regime. However, under certain conditions,
e.g., the beginning of engine run and high-cornering of vehicles,
local `oil-starvation` occurs at bearing surfaces, resulting in
mixed or even boundary lubrication conditions. In vehicles
employing fuel-efficient technologies, such as `start-stop` and
hybrid engines, this difficulty is amplified.
[0112] Referring to FIGS. 7A-7C, a polymer coating 100 containing
metal chalcogenide, e.g., tungsten disulfide WS.sub.2, with a
fullerene like or tubular-like geometry 15 decreases the
coefficient, protects the bearing surface 35 and prevents its wear,
thanks to its inherent active protection layer. FIG. 7A depicts the
polymer coating 100 on a bearing surface 35 prior to the
application of frictional force, such as contact between the
frictional contact surface 40 and the polymer coating 100.
Frictional contact between the polymer coating 100 that is present
on the bearing surface 35 and the friction contact surface 40 is
depicted in FIG. 7B, in which motion between the frictional
contacting surfaces is illustrated by the depicted arrows. As
depicted in FIG. 7C, wear of a coating 100 including the
chalcogenide of tungsten disulfide (WS.sub.2) having a fullerene
like geometry 15 creates a tribofilm 20a of exfoliated material of
metal chalcogenide, e.g., tungsten disulfide WS.sub.2, with a
fullerene like or tubular-like geometry 15 from the polymer coating
100 on the surface 40 contacting the polymer coating 100. Further,
exfoliated material of metal chalcogenide, e.g., tungsten disulfide
WS.sub.2, with a fullerene like or tubular-like geometry 15 from
the polymer coating 100 can create a fresh tribofilm 20b on the
coating 100 itself. Consequently, the coefficient of friction for
the coated structure is constantly low. The phenomena described
with reference to FIGS. 7A-7C prolong the life of the automotive
components coated in accordance with the present disclosure, reduce
fuel consumption, and increase vehicle reliability. Although, FIGS.
7A-7C describe the advantages of the exfoliated tribofilm from a
coating having a polymeric base material, the description is
equally applicable to all the coatings described in the present
disclosure, so long as the coating contains inorganic metal
chalcogenide having the composition MX.sub.2, with a fullerene like
or tubular-like geometry, such as tungsten disulfide WS.sub.2.
[0113] The common coatings for metallic bearing surfaces are
currently lead-based alloys (e.g. Babbitt), which are undesirable.
Some alternatives to lead containing films are composed of polymers
with an addition of PTFE, graphite and/or molybdenum disulfide. The
first advantage of a polymer coating containing metal chalcogenide,
e.g., tungsten disulfide WS.sub.2, with a fullerene like or
tubular-like geometry over these solid lubricants is their
resistance to extreme conditions, namely, high pressures and
temperatures.
[0114] For example, the shock-wave resistance of WS.sub.2 nanotubes
has been studied and compared to that of carbon nanotubes, in which
it has been determined that WS.sub.2 nanotubes are capable of
withstanding shear stress caused by shock waves of up to 21 GPa.
Under similar shock conditions, WS.sub.2 tubes are more stable than
carbon nanotubes, the latter being transformed into a diamond
phase. In some embodiments, the supershock-absorbing ability of the
IF-WS.sub.2 enables them to survive pressures up to 25 GPa
accompanied with concurrent temperatures of up to 1000.degree. C.
without any significant structural degradation or phase change.
IF-WS.sub.2 are stable in air at temperatures higher than
400.degree. C.
[0115] Another advantage of the disclosed metal chalcogenide, e.g.,
tungsten disulfide (WS.sub.2), with a fullerene like or
tubular-like geometry is the high strength of the individual
nanoparticles, i.e., tungsten disulfide (WS.sub.2), making the
material that is coated more resistant to wear, which is another
desirable property of a tribological coating in accordance with the
present disclosure.
[0116] One application for the coating including particles of a
metal chalcogenide comprising a fullerene-like geometry, a
tubular-like geometry or a combination of fullerene-like geometries
and tubular-like geometries is the automotive market, including
both vehicle manufacturers and vehicle maintenance providers. For
example, coatings in accordance with the present disclosure may be
applied to internal combustion engine components, such as, pistons,
piston rings, piston pins, crankshafts, crankshaft bearings, main
bearings, camshafts, camshaft bearings, timing chain, timing gears,
intake and exhaust valves, valve springs, valve guides, push rods,
rocker arms, rocker arm shafts, hydraulic lifters, solid lifters,
hydraulic roller lifters, solid roller lifters, camshaft followers,
camshaft button, camshaft plug, compression rings, connecting rod
bearings, connecting rod bolts, connecting rod caps, connecting
rods, engine mounts, exhaust manifolds, exhaust valves, oil rings,
pins, valve keepers, valve retainers, valve seats, and combinations
thereof. In some embodiments, the coatings in accordance with the
present disclosure may be applied to automotive transmission
components, such as torque converter components, vacuum modulator
components, accumulator rings, accumulator seals, bands, bearings,
boost valves, bushings, chains, check balls, clips, clutch drums,
clutch pistons, clutch plates, clutch seals, clutch packs, control
rings, counter shafts, servo components, detent camshafts, gears,
governor components, idler shafts, input shafts, intermediate
shafts, output shaft, main shafts, manual valves, modulator valves,
planetary gear carriers, planetary gears, pump gears, pump guide
rings, pump vanes, ring gears, roller clutches, servo rings, servo
seals, servo sleeve, shift forks, shift shafts, shift valves,
shifter shaft, snap rings, shift solenoids, speedometer drive,
sprags, sprockets, strators, strator shafts, sun gear shell, sun
gears, synchronizer key(s), synchronizer ring, synchronizer
sleeves, synchronizer(s), throttle valve, turbine, transfer shaft,
valve body and associated components, valve pack and combinations
thereof. The coating may also be applied to supercharger and turbo
charger components, such as vanes, turbines, impellers, shafts,
bearings and housings. In other embodiments, the coating may be
applied to components of automotive front differential, rear
differential and transfer cases. For example, the coating may be
applied to pinion bearings, pinion gears, pinion flange, propeller
shafts, "U" joints and "U" joint caps, pinion flange, propeller
shafts, axle shafts, axle bearings and races, axle flange, axle
shafts, CV joints, carrier bearings, center bearings, drive axle,
drive axle bearings, drive shaft, flex disc, half shafts, pinion
gear, pins, ring gear, shaft couplings, side gears, spyder gears,
yoke, lock ring, pinion and related mechanisms. It is noted that
the above description of automotive applications is provided for
illustrative purposes only, and is not intended to limit the
present disclosure. The coatings disclosed herein may be applied to
any automotive component that experiences friction, and would
benefit from a lower coefficient of friction coating, such as
manual and automatic locking hub and bearing assembly, C/V axles,
plain bearings, spindles, gears, chain elements, valves and
combinations thereof.
[0117] Some other applications for the coatings may be include
household and general maintenance, e.g. locking systems, springs,
bolts, slides, and hinges etc. This could apply for any type of
industrial mechanical system. In some other embodiments, the
coatings disclosed herein may be applied to metal working
applications, e.g., forging and wire drawing etc. In yet other
embodiments, the coatings disclosed herein may be applicable to
weapons (small-arms) lubrication. One of the advantages of the
disclosed coatings for lubrication in weapons is the reduction or
even total elimination of the use of liquid lubrication, which can
increase the firearm maintenance intervals, and improve their
performance in the battle field (solid lubrication is not prone to
the absorption of moist and dry debris, such as its liquid
equivalent).
[0118] In some embodiments, in comparison to a coating that does
not include particles having the fullerene-like geometry and/or
tubular-like geometry, the coating including the inorganic material
of the metal chalcogenide composition having the fullerene-like
geometry and/or tubular-like geometry provides a smoother surface,
greater scratch resistance, reduced coefficient of friction and
reduced wear. In some examples, a coating including the inorganic
material of the metal chalcogenide composition having the
fullerene-like geometry and/or tubular-like geometry will have up
to 3.times. less wear, and up to 1.75 less friction, than a coating
having a comparable base material layer without the inorganic
material of the metal chalcogenide composition having the
fullerene-like geometry and/or tubular-like geometry.
[0119] The following examples are provided to further illustrate
the present invention and demonstrate some advantages that arise
therefrom. It is not intended that the invention be limited to the
specific examples disclosed.
Examples
[0120] Layered materials, such as molybdenum disulfide and graphite
are in use worldwide in lubrication coating systems. In the present
example, a coating having a polymer base material, and a dispersed
phase of tungsten disulfide (WS.sub.2) with the fullerene like
geometry was prepared in accordance with the present disclosure is
compared with existing lubricants that include molybdenum disulfide
(MoS.sub.2).
[0121] First, coating formulations having a polymer base material
and a dispersed phase of tungsten disulfide (WS.sub.2) with the
fullerene like or tubular-like geometry were produced, in which one
of the coating formulations intended for application via spray
coating and a second coating formation is intended for application
via brushing. The formulations are represented in the following
Table 3:
TABLE-US-00003 TABLE 3 Material Spraying Brushing PAI
(polyamide-imide) 6.4 9.5 NMP (N-methyl-pyrrolidone) 42.6 38.0 3AG
(IF powder) 21.0 33.5 Butyl acetate 19.0 Ethyl benzene 7.3 Xylene
22.7
[0122] The mixtures described in Table 3 were grinded for 8 hours
in a high-shear mixer (Dispermat) with 0.6 mm ceramic beads.
[0123] The comparative molybdenum disulfide (MoS.sub.2) products
are included in Table 4, as follows:
TABLE-US-00004 TABLE 4 Product Manufacturer polymer Molykote D7620
Dow Corning PAI Evercoat 643 Everlube Epoxy Xylane 1052 Whitford
classified
The tribological characterization techniques used in this project
were--Brugger test (DIN 51347) to measure its wear resistance, and
roller on block (ASTM G77), to measure the COF. The results of the
tribological testing are included in Table 5, as follows:
TABLE-US-00005 TABLE 5 Product Brugger [MPa] COF Molykote D7620
112.5 0.013 Ecoalube 643 170.9 0.054 Xylane 1052 97.4 0.074
WS.sub.2 brushing product 194.3 0.034 Neat PAI 24.1 0.049 WS.sub.2
spraying product 180.0 0.040
[0124] While the claimed methods and structures has been
particularly shown and described with respect to preferred
embodiments thereof, it will be understood by those skilled in the
art that the foregoing and other changes in form and details may be
made therein without departing from the spirit and scope of the
presently claimed methods and structures.
* * * * *