U.S. patent application number 12/025506 was filed with the patent office on 2008-12-11 for compositions and processes for deposition of metal ions onto surfaces of conductive substrates.
Invention is credited to Frank G. Defalco.
Application Number | 20080302267 12/025506 |
Document ID | / |
Family ID | 40094169 |
Filed Date | 2008-12-11 |
United States Patent
Application |
20080302267 |
Kind Code |
A1 |
Defalco; Frank G. |
December 11, 2008 |
COMPOSITIONS AND PROCESSES FOR DEPOSITION OF METAL IONS ONTO
SURFACES OF CONDUCTIVE SUBSTRATES
Abstract
The present invention provides compositions and processes for
preparing metallic ions for deposition on and/or into conductive
substrates, such as metals, to substantially eliminate friction
from metal to metal contact. It is used in the aqueous embodiment
to form new metal surfaces on all metal substrates. The processes
form stable aqueous solutions of metal and metalloid ions that can
be adsorbed or absorbed on and/or into conductive substrates. The
aqueous solutions consist of ammonium alkali metal phosphate salts,
and/or ammonium alkali metal sulfate salts mixed with a water
soluble metal or metalloid salt from Group I through Group VIII of
the periodic table of elements. The aqueous solutions allow for a
nano deposition of the metal ions on and/or into the surfaces of
conductive substrates. The surfaces created by the deposited metal
ions will provide metal passivation and substantially eliminate
friction in metal-to-metal contact without the use of hydrocarbon
based lubricants.
Inventors: |
Defalco; Frank G.; (Houston,
TX) |
Correspondence
Address: |
BUSH INTELLECTUAL PROPERTY LAW GROUP, LLC
P.O. BOX 381146
BIRMINGHAM
AL
35238
US
|
Family ID: |
40094169 |
Appl. No.: |
12/025506 |
Filed: |
February 4, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60933242 |
Jun 5, 2007 |
|
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Current U.S.
Class: |
106/1.23 ;
106/1.22; 106/1.24 |
Current CPC
Class: |
C23C 18/00 20130101;
C23C 22/03 20130101; C23C 22/08 20130101; C23C 22/42 20130101; C23C
22/05 20130101 |
Class at
Publication: |
106/1.23 ;
106/1.24; 106/1.22 |
International
Class: |
C23C 20/04 20060101
C23C020/04 |
Claims
1. A process for producing aqueous solutions of non-alkaline metals
for deposition onto surfaces, comprising the steps: 1) forming a
solution of water with orthophosphoric acid; 2) adding ammonium
hydroxide to the solution of step 1; 3) adding an alkali metal
hydroxide in water to the solution produced by steps 1 and 2; and
4) adding a non-alkaline metal salt to the solution produced by
steps 1, 2 and 3.
2. The process of claim 1, wherein step 1 further comprises forming
a solution of 0.5 to 1.5 parts of water with 0.5 to 1.5 parts of
orthophosphoric acid, wherein said orthophosphoric acid is 75% to
85%; step 2 further comprises adding 0.5 to 1.5 parts of ammonium
hydroxide to the solution of step 1, wherein said ammonium
hydroxide is 20 to 30%; step 3 further comprises adding 0.5 to 1.5
parts of an alkali metal hydroxide in water to the solution
produced by steps 1 and 2, wherein said alkali metal hydroxide in
water is 40% to 60%; and step 4 further comprises adding 0.1 to 10
grams of an non-alkaline metal salt to each 80 to 100 ml of the
solution produced by steps 1, 2 and 3.
3. The process of claim 1, wherein said non-alkaline metal salt is
a salt of copper, silver, gold beryllium, magnesium, zinc, cadmium,
aluminum, gallium, indium, silicon, tin, lead, titanium, zirconium,
hafnium, antimony, bismuth; vanadium, niobium, tantalum, selenium,
tellurium, chromium, molybdenum, tungsten, manganese, iron, cobalt,
nickel, palladium, or rhodium, or a combination thereof.
4. The process of claim 1 wherein said alkali metal hydroxide is
sodium hydroxide, potassium hydroxide, or lithium hydroxide, or a
combination thereof.
5. A process for producing aqueous solutions of non-alkaline metals
for deposition onto surfaces, comprising the steps: 1) forming a
solution of 0.5 to 1.5 parts of water with 0.5 to 1.5 parts of
orthophosphoric acid, wherein said orthophosphoric acid is 75% to
85%; 2) adding 0.5 to 1.5 parts of ammonium hydroxide to the
solution of step 1, wherein said ammonium hydroxide is 20 to 30%;
3) adding 0.5 to 1.5 parts of an alkali metal hydroxide in water to
the solution produced by steps 1 and 2, wherein said alkali metal
hydroxide in water is 40% to 60%; and 4) adding 0.1 to 10 grams of
an non-alkaline metal salt to each 80 to 100 ml of the solution
produced by steps 1, 2 and 3.
6. The process of claim 5, wherein said non-alkaline metal salt is
a salt of copper, silver, gold beryllium, magnesium, zinc, cadmium,
aluminum, gallium, indium, silicon, tin, lead, titanium, zirconium,
hafnium, antimony, bismuth; vanadium, niobium, tantalum, selenium,
tellurium, chromium, molybdenum, tungsten, manganese, iron, cobalt,
nickel, palladium, or rhodium, or a combination thereof.
7. The process of claim 6 wherein said alkali metal hydroxide is
sodium hydroxide, potassium hydroxide, or lithium hydroxide, or a
combination thereof.
8. A process for producing aqueous solutions of non-alkaline metals
for deposition onto surfaces, comprising the steps: 1) forming a
solution of water with sulfuric acid; 2) adding ammonium hydroxide
to the solution of step 1; 3) adding an alkali metal hydroxide in
water to the solution produced by steps 1 and 2; and 4) adding a
non-alkaline metal salt to the solution produced by steps 1, 2 and
3.
9. The process of claim 8, wherein step 1 further comprises forming
a solution of 0.5 to 1.5 parts of water with 0.5 to 1.5 parts of
concentrated sulfuric acid; step 2 further comprises adding 0.5 to
1.5 parts of ammonium hydroxide to the solution of step 1, wherein
said ammonium hydroxide is 20 to 30%; step 3 further comprises
adding 0.5 to 1.5 parts of an alkali metal hydroxide in water to
the solution produced by steps 1 and 2, wherein said alkali metal
hydroxide in water is 40% to 60%; and step 4 further comprises
adding 0.1 to 10 grams of an non-alkaline metal salt to each 80 to
100 ml of the solution produced by steps 1, 2 and 3.
10. The process of claim 8, wherein said non-alkaline metal salt is
a salt of copper, silver, gold beryllium, magnesium, zinc, cadmium,
aluminum, gallium, indium, silicon, tin, lead, titanium, zirconium,
hafnium, antimony, bismuth; vanadium, niobium, tantalum, selenium,
tellurium, chromium, molybdenum, tungsten, manganese, iron, cobalt,
nickel, palladium, or rhodium, or a combination thereof.
11. The process of claim 8 wherein said alkali metal hydroxide is
sodium hydroxide, potassium hydroxide, or lithium hydroxide, or a
combination thereof.
12. A process for producing aqueous solutions of non-alkaline
metals for deposition onto surfaces, comprising the steps: 1)
forming a solution of 0.5 to 1.5 parts of water with 0.5 to 1.5
parts of concentrated sulfuric acid; 2) adding 0.5 to 1.5 parts of
ammonium hydroxide to the solution of step 1, wherein said ammonium
hydroxide is 20 to 30%; 3) adding 0.5 to 1.5 parts of an alkali
metal hydroxide in water to the solution produced by steps 1 and 2,
wherein said alkali metal hydroxide in water is 40% to 60%; and 4)
adding 0.1 to 10 grams of an non-alkaline metal salt to each 80 to
100 ml of the solution produced by steps 1, 2 and 3.
13. The process of claim 12, wherein said non-alkaline metal salt
is copper, silver, gold beryllium, magnesium zinc, cadmium,
aluminum, gallium, indium, silicon, tin, lead, titanium, zirconium,
hafnium, antimony, bismuth; Group V-B: vanadium, niobium, tantalum,
selenium, tellurium, chromium, molybdenum, tungsten, manganese,
iron, cobalt, nickel, palladium, or rhodium, or a combination
thereof.
14. The process of claim 13 wherein said alkali metal hydroxide is
sodium hydroxide, potassium hydroxide, or lithium hydroxide, or a
combination thereof.
15. An aqueous composition of a non-alkaline metal salt, comprising
water, a mineral acid, ammonium hydroxide, an alkali metal
hydroxide, and a non-alkaline metal salt.
16. The aqueous composition of claim 15 wherein said mineral acid
is orthophosphoric acid or sulfuric acid.
17. The aqueous composition of claim 16 wherein said non-alkaline
metal salt is a salt of copper, silver, gold, beryllium, magnesium,
zinc, cadmium, aluminum, gallium, indium, silicon, tin, lead,
titanium, zirconium, hafnium, antimony, bismuth; vanadium, niobium,
tantalum, selenium, tellurium, chromium, molybdenum, tungsten,
manganese, iron, cobalt, nickel, palladium, or rhodium, or a
combination thereof.
18. The aqueous composition of claim 17 wherein said alkali metal
hydroxide is sodium hydroxide, potassium hydroxide, or lithium
hydroxide, or a combination thereof.
19. The aqueous composition of claim 18 wherein said non-alkaline
metal salt will form a permanent coating 0.05 to 10 microns
thickness on the surface of a metal when said aqueous composition
is applied to said surface, wherein said coating will reduce the
wear of the surface of the metal.
20. The aqueous composition of claim 15 wherein said non-alkaline
metal salt will form a permanent coating 0.05 to 10 microns
thickness on the surface of a metal when said aqueous composition
is applied to said surface, wherein said aqueous composition is
produced by the process of claim 1.
21. The aqueous composition of claim 15 wherein said non-alkaline
metal salt will form a permanent coating 0.05 to 10 microns
thickness on the surface of a metal when said aqueous composition
is applied to said surface, wherein said aqueous composition is
produced by the process of claim 8.
Description
REFERENCE TO RELATED PATENT APPLICATION
[0001] The present application claims priority to U.S. Provisional
Patent Application No. 60/933,242, filed Jun. 5, 2007, the
disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to compositions and processes
for coating metals and, more particularly, to aqueous compositions
of metals for coating metal surfaces, and processes for making
these aqueous compositions.
[0004] 2. Technical Background
[0005] Many methods have been developed to form new conversion
surfaces on commodity metals such as ferrous metals, steel,
stainless steel, aluminum, zinc and titanium. These methods include
electroplating, phosphating (conversion surfaces), chemical vapor
deposition, ion sputtering, and other techniques. An early
electroplating method for silver was developed in England in 1870.
Later, methods of plating noble metals, i.e. copper and gold were
developed. These metals had to be complexed with cyanide to make an
adherent deposit on the substrate material. The use of cyanide is
still the preferred method of forming an adherent first deposit of
noble metals on substrates. Cyanide, an extremely toxic material,
is an environmental hazard and a danger to public health. Numerous
safety procedures have to be in place to use cyanide, and even then
users may be subjected to fumes that are dangerously toxic. As
electroplating technology has unfolded over the years, techniques
to electroplate other elements such as zinc, cadmium, nickel, and
chromium were developed and became widely used in the commercial
world for engineering and decorative purposes.
[0006] Electroplated deposits on a substrate surface do not go into
the metal interstices of the surface. As a result the deposits are
not tenacious enough to maintain their integrity when the substrate
is "cold worked" to yield point. Zinc electrodeposits are destroyed
by cold working at 61,000 PSI, cadmium at 69,000 PSI, while the
steel substrate will have a yield point of 80,000 PSI or stronger.
This has always been a significant problem in the electroplating
industry. The electroplater has to deal with many different
parameters to create efficient deposition procedures to accomplish
desired end results. Electroplating requires procedures for
pretreatment, pre-cleaning, and rinsing controlled plating baths,
and special anodes. Electroplating generally follows the rules of
the Electromotive Series that a more noble metal can be plated on a
less noble metal, but not the reverse direction. This limits the
ability to plate all the metals in the periodic table onto other
metal substrates in the periodic table.
[0007] Another method of surface modification is phosphating,
wherein a phosphate conversion surface is formed on steels and
aluminum. Phosphate conversion surfaces are widely used for
corrosion inhibition and as a base for paints. Phosphating is one
of the most widely used techniques in the commercial world with
major uses in the auto industry as an undercoat to inhibit
corrosion and as an anchor to retain paint.
[0008] Conversion coating phosphating methods require large plating
baths and are energy intensive and time consuming. Phosphating
requires at least ten minutes or longer to get a commercially
acceptable, adherent conversion surface. The industry has developed
many accelerants over the years to speed up the conversion
process.
[0009] In the latter part of the 20.sup.th century, new and exotic
techniques were developed to obtain better surfaces on metals.
These methods modified the metals with a coating on a substrate by
vapor deposition techniques such as vacuum evaporation, sputtering,
magnetron sputtering, or ion plating. These techniques can be used
to harden metal surfaces such as metal working tools including
tungsten carbide inserts, drills, hobbs, etc. Chemical vapor
deposition is applied in a vacuum chamber and the metal is ionized
in a nitrogen atmosphere and deposited on and diffuses into the
substrates. Some examples of the results of these techniques are
titanium nitride and boron nitrides. The deposition is generally by
line of sight and the process is limited to the shape, size and
configuration of the substrate metals. This process is expensive,
requiring special equipment and high energy usage. The deposits are
formed under exacting conditions of temperature, gas composition,
etc. These techniques result in deposits that have dense, smooth,
defect free surfaces useful for many commercial products.
[0010] Many metals form a passive oxide surface that are beneficial
in protecting the metal from corrosion. Such metals are aluminum
and stainless steels and titaniums. The oxide film that forms on
stainless steel is a mono-molecular layer that renders the surface
passive. The oxide layer that forms on carbon steel is deleterious
to the metal and is called rust.
[0011] U.S. Pat. No. 6,755,917, issued to Hardin, et al. describes
a solution for providing conversion coating on the surface of a
metallic material. The solution includes a peroxidic species and is
limited to at least one metal from Group 1B, IIB, IVA, VA, VIA AND
VIII of the periodic table. Specifically, Hardin also provides a
liquid acidic aqueous concentrate for the replenishing of a
conversion coating solution according to the invention, wherein the
concentrate contains rare earth ions (as herein defined) and
monovalent anions in a molar ratio of total rare earth ions:
monovalent anions of from 1:200 to 1:6 and/or rare earth ions and
divalent anions in a molar ratio of total rare earth ions:divalent
anions of from 1:100 to 1:3 and/or the concentrate contains at
least one metal selected from Groups IB, IIB, IVA, VA, VIA and VII,
preferably from the group of Cu, Ag, Au, Cd, Hg, Ni, Pd, Pt, Co,
Rh, Ir, Ru, Os, Sn, Pb, Sb, Bi, Se and Te and anions such that the
molar ratio of the sum of the elements in this group: anions is in
the range from 1:50 to 1:10,000. Further, the Hardin methods are
limited to an acidic aqueous solution.
[0012] It is known that thin mono-molecular oxide films present on
stainless steel can provide an excellent passivation surface to
metals. It has been theorized that corrosion may one day be
conquered by a thin molecular layer on metal surfaces. It has been
further theorized that significant reductions in friction could be
obtained with thin, tenacious metallic films.
[0013] In the October 1996 issue of Scientific American, Jacqueline
Krim, PhD, published a paper titled "Friction at the Atomic Scale".
Her findings led to the conclusion that "at the atomic level with
metal to metal contact there is no friction." This surprising
finding called into question many of the beliefs that friction was
a condition that could only be alleviated by the use of a lubricant
to reduce the heat generated by metals sliding over one another.
Another surprising conclusion was that, at the atomic level,
"friction arises from atomic lattice vibrations when atoms close to
the surface are set into motion by the sliding action of atoms in
the opposing surface. These vibrations are really sound waves. In
this way, some of the mechanical energy needed to slide one surface
over the other, is converted to sound energy, which is eventually
transformed into heat." Heat causes friction. To maintain the
sliding, more mechanical energy must be added. Krim further posits
"Solids vibrate only at certain distinct frequencies, so the amount
of mechanical energy depends on the frequencies actually excited.
If the atoms in the opposing surface resonates with the frequency
of the other surface, then friction arises. But if the opposing
surface is not resonant with any of the other surface's own
frequencies, then sound waves are not generated. This feature opens
the exciting possibility that sufficiently small solids, which have
relatively few resonant frequencies, might exhibit nearly
frictionless sliding."
[0014] Another surprising result of her work was that dry films
were slipperier than liquid films. This was counterintuitive to all
current thought on friction. Further tests by other scientists
validated that metal to metal contact at the atomic level
eliminated friction, and that liquid lubricants caused friction
with the "stick/slip" action. The liquid would stick in the gaps in
the metal and then slip out. This caused vibrations in the lattices
and generated sound waves which converted to heat, causing
friction.
[0015] Estimates are that friction reduction could save up to 1.6%
of Gross National Product or over two hundred billion dollars
annually. Hence, a process that virtually eliminates friction on
commodity metals would be new and useful but has never been
available. It is clear that such a process would have great value
and aid in the nation's quest for energy independence and greatly
reduce infrastructure replacement costs for corroding metal
structures, underground pipelines, storage tanks, bridges and
overpasses.
[0016] Phosphate conversion surfaces are used in commercial plants
to reduce decibel levels. High decibel levels are an ongoing
workplace hazard and are detrimental to human health causing early
hearing loss. Governmental regulatory agencies such OSHA and the
EPA are constantly urging industry to develop lower decibel levels
in manufacturing operations. Therefore any conversion surface that
reduces decibel levels would be advantageous for human health and
improving the work place environment.
[0017] U.S. Pat. No. 7,087,104 issued to Choi et al., describes a
system and method for storing a solution containing a subset of a
group consisting of a metal ion, a complexing agent, an ammonium
salt, and a strong base. Near the time of use, the solution is used
to form an electroless deposition solution containing the entire
group. In one embodiment of the invention, the metal ion includes a
cobalt ion, the complexing agent includes citric acid, the ammonium
salt includes ammonium chloride, and the strong base includes
tetramethylammonium hydroxide. The base solution is prepared and
then set a side for 2 days to allow for stabilization prior to use.
Another solution has to be prepared and then mixed with the first
solution just prior to use in a plating bath. This requires complex
logistics and skilled operators to make the final preparation at
the plant bath site.
[0018] In U.S. Pat. No. 5,310,419 issued to McCoy et al. methods
are disclosed for preparing electrolyte solutions for
electroplating of metals and other uses. It was discovered that
with the use of an external electromotive source that all metals in
the Periodic table could be electrodeposited on conductive
substrates.
[0019] U.S. Pat. No. 5,340,788 issued to Defalco, et al., discloses
a method for preparing an oil additive that is applied to parts of
internal combustion engines using the lubricating oil as the
carrier fluid. The solution is mixed with a polyethylene glycol for
introduction into the lubricating oil.
SUMMARY OF THE INVENTION
[0020] The present invention provides compositions and processes
for preparing metallic ions for deposition on and/or into
conductive substrates, such as metals, to substantially eliminate
friction from metal to metal contact. It is used in the aqueous
embodiment to form new metal surfaces on all metal substrates. The
processes form stable aqueous solutions of metal and metalloid ions
that can be adsorbed or absorbed on and/or into conductive
substrates. The aqueous solutions consist of ammonium alkali metal
phosphate salts, and/or ammonium alkali metal sulfate salts mixed
with a water soluble metal or metalloid salt from Group I through
Group VIII of the periodic table of elements. The aqueous solutions
allow for a nano deposition of the metal ions on and/or into the
surfaces of conductive substrates. The surfaces created by the
deposited metal ions will provide metal passivation and
substantially eliminate friction in metal-to-metal contact without
the use of hydrocarbon based lubricants.
[0021] The process of the present invention for the production of
ion complexes is performed in an aqueous reaction medium, and the
ion complexes are used as an aqueous solution in the forming of
conversion surfaces on metallic objects. To prepare the inorganic
ion complexes the following reactants are required: (a) at least
one water soluble non-alkaline metal salt selected from Groups
I-VIII of the Periodic Table; (b) an alkali metal hydroxide; c) a
sulfur-containing compound and/or a phosphorous containing
compound, such as mineral acids; d) ammonium hydroxide; and e)
water. A parent solution A can be produced when the reactants
orthophosphoric acid, water, ammonium hydroxide and an alkali metal
hydroxide are mixed together. An exothermic reaction occurs and the
temperature of the aqueous solution is approximately 100.degree. C.
A measured amount of a metallic salt such as silver nitrate, zinc
oxide, aluminum salts such as aluminum sulfate, ammonium molybdate,
ammonium tungstate or any water soluble metal salt can then be
introduced into the reaction vessel, stirred and heated until the
metallic salt is totally dissolved in the aqueous medium. A parent
solution B can be produced when the reactants sulfuric acid, water,
ammonium hydroxide and the alkali metal hydroxide are mixed
together. An exothermic reaction occurs and the temperature of the
aqueous solution is approximately 100.degree. C. A measured amount
of a metallic salt, such as boric acid, or copper sulfate, or
ammonium molydate can then be introduced into the reaction vessel
and dissolved. The metallic ions then become soluble in the aqueous
solution and do not precipitate and remain stable. The alkali metal
hydroxide can be any hydroxide of a metal in Group IA of the
Periodic Table, principally sodium hydroxide, potassium hydroxide,
lithium hydroxide, with potassium hydroxide being the preferred
reactant.
[0022] The aqueous solutions of metals also deposit nitrogen on the
surface of metals. Wear tests show that metal coatings created by
application of the aqueous solutions reduce wear of metal as
effectively as oil-based lubricants.
[0023] An advantage of the present invention is that the solution
can be applied to any structure, regardless of configuration with
none of the disadvantages and limitations of the current
electroless, chemical vapor or electroplating technology in
commercial use today.
[0024] Another advantage is a ground stable solution that can be
shipped to any location.
[0025] Another advantage is a simplified process using an aqueous
solution for forming a conversion coating on a metallic
material.
[0026] Another advantage is the creation of an oxide free
conversion surface to all metallic substrates.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 shows deposits of silver-phosphorous-potassium on
stainless steel.
[0028] FIG. 2 shows deposit of silicon-phosphorous-potassium on
aluminum.
[0029] FIG. 3 shows deposit of silicon-phosphorous-potassium on
stainless steel.
[0030] FIG. 4 shows deposit of zinc-phosphorous-potassium on
aluminum.
[0031] FIG. 5 shows deposit of aluminum-phosphorous-potassium on
1010 carbon steel.
[0032] FIG. 6 shows deposit of copper-phosphorous-potassium on 1010
carbon steel.
[0033] FIG. 7 shows deposit of molybdenum-phosphorous-potassium on
1010 carbon steel.
[0034] FIG. 8 shows deposit of molybdenum-phosphorous-potassium on
stainless steel.
[0035] FIG. 9 shows deposit of silicon-phosphorous-potassium on
1010 carbon steel panel deposited from oil phase.
[0036] FIG. 10 shows the thickness of a boron coating on aluminum
from scanning electron microscope images.
[0037] FIG. 11 shows the thickness of a molybdenum coating on
aluminum from scanning electron microscope images.
[0038] FIG. 12 shows the presence of nitrogen-silicon-potassium on
1010 carbon steel in EDAX chart I.
[0039] FIG. 13 shows the presence of nitrogen-silicon-potassium on
aluminum in EDAX chart II.
[0040] FIG. 14 shows the presence of nitrogen-silicon-potassium on
stainless steel in EDAX chart III.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0041] While the following description details the preferred
embodiments of the present invention, it is to be understood that
the invention is not limited in its application to the details of
construction and arrangement of the parts illustrated in the
accompanying drawings, since the invention is capable of other
embodiments and of being practiced in various ways.
[0042] There is a need for an inexpensive, efficacious, easy to
apply technique to reduce metal to metal friction at the atomic
level. Surprisingly, when metal ions are produced according to the
present invention, the ions so produced diffuase into metal
interstices. Surprisingly, the ions produced do not follow the
rules of the Electromotive Series, i.e. aluminum can be deposited
on ferrous metals, which is not anticipated in any previous
literature. Surprisingly, silver ions generated by the present
invention remain photo stable in aqueous solution in the presence
of sunlight. Ionic photo stable silver can be achieved only through
expensive techniques by ion sputtering, as described in U.S. Pat.
No. 5,985,308 or by methods described in U.S. Pat. No. 6,897,349
involved with complexing with different solvents such as alcohols
and a chloride anion donating compound. Ionic Silver has been the
subject of much research. Although there are many known methods of
stabilizing ionic silver, none of these use an aqueous solution.
Deposition of an adherent silver surface on metallic pieces by mere
immersion, brushing, or spraying would be of great value. Ionic
silver that is stable in aqueous solution would have wide
applications in electronics and in medicine, for example, for its
antimicrobial properties in bandages for wound healing and for
forming an anti-microbial surface on medical instruments.
[0043] The present invention does not require the use of applied
external electromotive force, but forms a thin tenacious metallic
film on substrates by mere immersion, brushing or spraying. The
surprising finding of this invention is that the new conversion
surface can be made to deposit in a monomolecular layer onto and
into the substrate. Most plating specifications require thickness
of the deposits of one mil (23-24 microns). The present invention
provides permanent thin films on conductive substrates, from 0.05
to 10 microns thickness.
[0044] The process of the present invention for the production of
ion complexes is performed in an aqueous reaction medium, and the
ion complexes are used as an aqueous solution in the forming of
conversion surfaces on metallic objects. To prepare the inorganic
ion complexes the following reactants are required: a) at least one
water soluble non-alkaline metal salt selected from Groups I-VIII
of the Periodic Table; b) an alkali metal hydroxide; c) a
sulfur-containing compound and/or a phosphorous containing
compound, such as mineral acids; d) ammonium hydroxide; and e)
water.
[0045] The non-alkaline metal salt reactant may be from any
non-alkaline metal of Groups I-VIII of the Periodic Table.
Representative, non-limiting examples of applicable non-alkaline
water soluble metals salts include those derived from: Group I-B:
copper, silver, gold; Group II-A: beryllium, magnesium; Group II-B:
zinc, cadmium; Group III-A: aluminum, gallium, indium; Group IV-A:
silicon, tin, lead; Group IV-B: titanium, zirconium, hafnium; Group
V-A: antimony, bismuth; Group V-B: vanadium, niobium, tantalum;
Group VI-A: selenium, tellurium; Group VI-B: chromium, molybdenum,
tungsten; Group VII-B: manganese; and Group VIII: iron, cobalt,
nickel, palladium rhodium.
[0046] While silicon, as a member of Group IV-A, is considered to
be a metalloid and is not generally defined as a metallic element,
silicon acts in the method of the present invention as a
non-alkaline metal. Accordingly, the expression "non-alkaline metal
of Groups I-VIII of the Periodic Table" is meant to embrace any and
all of the above and equivalent metals, including silicon. As will
be further recognized, the term "non-alkaline metal of Groups
I-VIII of the Periodic Table" does not embrace the alkali metals of
Group I-A. The alkaline earth metals, calcium, strontium, and
barium of Group II-A, are similarly not within the scope of the
term. On the other hand, beryllium and magnesium of Group II-A can
be applicably employed in the practice of this invention and these
metals also fall within the scope of the expression "non-alkaline
metal of Groups I-VIII of the Periodic Table" as used herein.
Combinations of the non-alkaline metal salts may also be used.
[0047] A parent solution A can be produced when the reactants
orthophosphoric acid, water, ammonium hydroxide and an alkali metal
hydroxide are mixed together. An exothermic reaction occurs and the
temperature of the aqueous solution is approximately 100.degree. C.
A measured amount of a metallic salt such as silver nitrate, zinc
oxide, aluminum salts such as aluminum sulfate, ammonium molybdate,
ammonium tungstate or any water soluble metal salt can then be
introduced into the reaction vessel, stirred and heated until the
metallic salt is totally dissolved in the aqueous medium. The
alkali metal hydroxide can be any hydroxide of a metal in Group IA
of the Periodic Table, principally sodium hydroxide, potassium
hydroxide, lithium hydroxide, with potassium hydroxide being the
preferred reactant. Combinations of these alkali metal hydroxides
may also be used.
Preparation of Parent Solution A
[0048] Into a reaction vessel add about 0.5 to 1.5 liters,
preferably about 1.0 liter, of water and about 0.5 to 1.5 liters,
preferably about 1.0 liter, of orthophosphoric acid, about 75% to
85%, preferably about 80%, by volume. Then add about 0.5 to 1.5
liters, preferably about 1.0 liter, of ammonium hydroxide, about
15-35%, preferably about 26%, by volume. Then add about 0.5 to 1.5
liters, preferably about 1.0 liter, of potassium hydroxide, about
20-60%, preferably about 49%, by volume.
[0049] A parent solution B can be produced when the reactants
sulfuric acid, water, ammonium hydroxide and the alkali metal
hydroxide are mixed together. An exothermic reaction occurs and the
temperature of the aqueous solution is approximately 100.degree. C.
A measured amount of a non-alkaline metal salt, such as boric acid,
or copper sulfate, or ammonium molydate can then be introduced into
the reaction vessel and dissolved. The metallic ions then become
soluble in the aqueous solution and do not precipitate and remain
stable. The alkali metal hydroxide can be any hydroxide of a metal
in Group IA of the Periodic Table, principally sodium hydroxide,
potassium hydroxide, lithium hydroxide, with potassium hydroxide
being the preferred reactant. Combinations of these alkali metal
hydroxides may also be used.
Preparation of Parent Solution B
[0050] Into a reaction vessel add about 1 to 3 liters, preferably
about 2 liters, of water and about 0.5 to 1.5 liters, preferably
about 1 liter, of concentrated sulfuric acid. Then add about 0.5 to
1.5 liters, preferably about 1 liter, of ammonium hydroxide, about
15-35%, preferably about 26%, by volume. Then add about 0.5 to 1.5
liters, preferably about 1.0 liter, of potassium hydroxide, about
20-60%, preferably about 49%, by volume. Care must be taken as the
reaction is highly exothermic.
Example of a Silver Nitrate Parent Solution A
[0051] Using about 80 to 120 ml, preferably about 100 ml, of Parent
A solution, adjust the solution pH to approximately 7 using
phosphoric acid. Add about 0.1-10 grams, preferably about 1 gram,
of silver nitrate to the solution. Stir and heat until the silver
salt is completely dissolved in the solution. Immerse a coupon of
1010 steel in the silver nitrate solution for one minute. A thin,
tenacious, bright film of silver is formed on the steel coupon. The
surface is examined using Scanning Electron Microscopy (SEM). It is
not known for silver to form an adherent deposit on steel except by
use of a cyanide solution and applied external electromotive force.
The present process of silver deposition can be performed without
the presence of cyanide and applied external electromotive force to
produce a tenacious non-immersion deposit. The silver nitrate
solution can be placed in a glass container and exposed to sunlight
for several weeks. The silver does not become photosensitive,
indicating that silver can be stabilized by the inexpensive process
of the present invention which would be widely useful in areas such
as antimicrobial activity and protection of the surfaces of medical
instruments. A 2''.times.2' sheet of Alcoa aluminum foil wrap can
be contacted with the silver nitrate solution and then rubbed into
the surface. The surface of the aluminum foil will be coated with a
film of silver. A 410 stainless steel coupon can be immersed in the
silver nitrate solution for one minute. A thin tenacious film of
silver will be formed on the stainless steel.
[0052] A cotton gauze bandage can be immersed in the silver
solution and then exposed to sunlight for several days. The bandage
will not turn black as expected when ionic silver is exposed to
sunlight, indicating the usefulness of the treated bandage use as
an anti-microbial bandage for health and wound healing. The gauze
treated bandage can be subjected to a flame from a propane torch.
The cotton will be charred when in direct contact with the flame
tip, but the gauze does not ignite, indicating a use of the silver
solution as a flame retardant for fabrics.
Example of an Ammonium Molybdate Parent Solution A
[0053] Using about 80 to 120 ml, preferably about 100 ml, of Parent
solution A add about 0.1-10 grams, preferably about 1 gram, of
ammonium molybdate to the solution. Stir and heat until the
ammonium molybdate is completely dissolved. Immerse a 1010 steel
coupon in the solution for one minute. A thin, tenacious film of
molybdenum is formed on the steel coupon. A strip of aluminum foil
2''.times.2'' was immersed in the solution for 30 seconds. A thin
deposit of molybdenum formed on the aluminum coupon. In
"Electroplating`Frederick A Lowenheim, McGraw Hill Book company,
page 141 states "from the standpoint of their electrode potentials,
it should be possible to electroplate such metals as tungsten and
molybdenum from aqueous solutions with a pH of about 5.
Nevertheless (in spite of claims in the literature), these metals
cannot be deposited in pure form from aequous solutions." Thus the
present invention provides an unexpected method for forming a
molybdenum surface on steel and other conductive substrates.
Example of an Ammonium Tungstate Parent Solution A
[0054] Using about 80 to 120 ml, preferably about 100 ml of Parent
solution A add about 0.1-10 grams, preferably about 1 gram, of
ammonium tungstate to the solution. Stir and heat until the
metallic salt is completely dissolved. Immerse a 1010 steel strip
in the solution for one minute. A thin, bright, tenacious film of
tungsten has formed on steel strip. As was the case with
molybdenum, the present invention provides an unexpected method of
forming a tungsten surface on steel.
Example of a Parent Copper Sulfate Parent Solution B
[0055] Using about 80 to 120 ml, preferably about 100 ml of Parent
Solution B add about 0.1-10 grams, preferably about 1 gram, of
copper sulfate to the solution. Stir and heat until the metallic
salt is completely dissolved in the solution. Immerse a 1010 steel
panel in the solution for up to two minutes. An adherent, visible
copper deposit forms on the steel coupon. The only practical way to
deposit adherent copper plates on active metals such as zinc and
steel is to use a cyanide bath. In spite of many efforts to
dispense with cyanide-containing plating baths because of
environmental restriction, no practical substitute for the cyanide
copper bath has been developed. It is known that copper without
cyanide and applied external electomotive force will form an
immersion deposit which is valueless. A standard ASTM test for an
adherent deposit is to place plastic adhesive tape on the plated
surface and pull the tape. If the deposit is an immersion deposit,
the copper will peel off with the tape. If the deposit is adherent,
then the copper will not peel off with the plastic adhesive tape.
When plastic adhesive tape was applied to the copper surface in
this example, the copper film remained adherent.
Example of an Aluminum Sulfate Parent Solution B
[0056] Using about 80 to 120 ml, preferably about 100 ml, of Parent
solution B add about 0.1-10 grams, preferably about 2 grams, of
aluminum sulfate to the solution. Stir and heat the solution until
completely dissolved. Immerse a coupon of 1010 steel in the
solution for 1 minute. A thin, tenacious, shiny adherent film of
aluminum is formed on the steel coupon.
Example of a Boric Acid Parent Solution B
[0057] Using about 80 to 120 ml, preferably about 100 ml, of Parent
solution B add about 0.1-10 grams, preferably about 2 grams, of
boric acid to the solution. Stir and heat until completely
dissolved. Immerse a 1010 steel coupon in the solution for one
minute. A thin, tenacious bright film of boron is formed on the
steel coupon. A coupon of aluminum foil 2''.times.2'' was immersed
in the solution. A thin film of boron formed on the aluminum. A
stainless steel coupon was immersed in the solution and a thin
metallic film of boron formed on the stainless steel.
Example of an Ammonium Tungstate Parent Solution B
[0058] Using about 80 to 120 ml, preferably about 100 ml, of Parent
solution B add 2 ml of ammonium tungstate, 12% by volume to the
solution. Stir and heat until thoroughly dissolved. Immerse a 1010
steel coupon in the solution for one minute. A thin, tenacious
bright metallic film of tungsten is formed on the steel
surface.
Example of a Combination of Parent Solution a and Parent Solution
B
[0059] Combine about 160 ml of Parent solution A and about 40 ml of
parent solution B. Raise the pH of the solution, combined to above
12 with potassium hydroxide by adding about 10 ml of potassium
hydroxide, about 49% by weight. Heat and stir until the potassium
hydroxide is completely dissolved. This solution can be misted into
a hydrocarbon stream such as natural gas or vaporized gasoline in
an internal combustion engine to enhance fuel combustion. The
solution may be misted into the air intakes of internal combustion
engines to increase the volume of air available for combustion to
enhance fuel economy.
Example of an Oil Derivate of the Combination of Parent Solution a
and Ammonium Tungstate Parent Solution B
[0060] About 160 ml of Parent Solution A and about 40 ml of
ammonium tungstate Parent Solution B are blended together. Using
about 200 ml of highly refined mineral oil, blend into the mineral
oil about 20 ml (10% by volume) of the mixed solution of Parent
Solution A and ammonium tungstate Parent Solution B. Dehydrate this
oil solution to drive off the water and precipitate the salts by
raising the temperature above 100.degree. C. When the oil solution
becomes bright and clear, allow the oil to cool down and then
decant the oil. The decantate can then be used as an oil additive
or as a fuel additive. It is well known that tungsten has catalytic
properties. Any metal such as platinum, iron, etc, that has
catalytic properties can be used by this technique for
manufacturing a fuel and lubricant additive.
Examples of Conversion Surfaces
[0061] Three substrate materials were chosen: aluminum foil made by
ALCOA, 1010 carbon steel, and 400 series stainless steel. These
substrate metals were chosen as representative of the most widely
used metals in the world. The metal ion solutions were chosen to
show that any metal ion produced by this invention can be deposited
on and into various metal substrates, resulting in new metallic
surfaces heretofore unknown. The metal ion solutions were prepared
according to parent solution A. Samples were not pretreated to
remove oxides, soils, rust or oils, but were immersed for 30
seconds each at ambient conditions and dried using ambient air and
a paper towel. Samples were then examined by EDS (Electron
dispersive spectroscopy) by Vista Engineering of Birmingham, Ala.
These results are as shown on the analytical charts in FIGS. 1-9.
FIG. 1 shows deposits of silver-phosphorous-potassium on stainless
steel. FIG. 2 shows deposit of silicon-phosphorous-potassium on
aluminum. FIG. 3 shows deposit of silicon-phosphorous-potassium on
stainless steel. FIG. 4 shows deposit of zinc-phosphorous-potassium
on aluminum. FIG. 5 shows deposit of aluminum-phosphorous-potassium
on 1010 carbon steel. FIG. 6 shows deposit of
copper-phosphorous-potassium on 1010 carbon steel. FIG. 7 shows
deposit of molybdenum-phosphorous-potassium on 1010 carbon steel.
FIG. 8 shows deposit of molybdenum-phosphorous-potassium on
stainless steel. FIG. 9 shows deposit of
silicon-phosphorous-potassium on 1010 carbon steel panel deposited
from oil phase.
Examples of Thickness Measurements of Metal Coatings Applied to an
Aluminum Surface
[0062] An ammonium molybdate Parent Solution A and a boric acid
Parent Solution B were prepared as described above. Coatings of
each solution were applied to an aluminum surface and the coatings
were allowed to dry. The thickness of the aluminum coatings were
measured using known scanning electron microscope techniques at the
NASA Marshall Flight Center. The thickness of the coatings were
calculated from the scanning electron microscope images. The images
are shown in FIG. 10 for the boron coating and in FIG. 11 for
molybdenum coating. The coating 10 is shown on the surface of the
aluminum metal 11, against background 12. Several measurements were
made along the length of the coating 10. The mean thickness
.+-.standard error for the coatings were 1.32+0.11 microns (n=7)
for molybdenum and 1.22+0.25 microns for Boron (n=4).
Examples of Nitrogen Deposits
[0063] Under current technology, nitrogen can only be deposited
onto a metallic substrate by CVD (chemical vapor deposition), an
expensive and very limited method of forming nitride surfaces. The
method of the present invention also deposits nitrogen onto the
metal substrate along with the metal being deposited. The
analytical capabilities of SEM are limited to identifying elements
of oxygen and above in the periodic table of the elements. Oxygen
has an atomic weight of 8 and nitrogen has an atomic weight of 7.
EDAX (electron dispersive analytical x-ray) can identify elements
down to 6 in the period table. Aqueous solutions of silicon were
prepared according to parent sample A described above. Coatings
were applied to various metals and samples were run on EDAX at
Corrmet Laboratories in Houston, Tex. with results as follows: FIG.
12 shows the presence of nitrogen-silicon-potassium on 1010 carbon
steel in EDAX chart I. FIG. 13 shows the presence of
nitrogen-silicon-potassium on aluminum in EDAX chart II. FIG. 14
shows the presence of nitrogen-silicon-potassium on stainless steel
in EDAX chart III. These analytical results show that an entirely
new technology for nitrogen/metallic surfaces on substrates can be
available using the compositions and methods of the present
invention.
Wear Tests
[0064] Wear testing was run on a dry film coating of the present
invention, in comparison with a standard oil-based lubricant at
Engineered Lubricants, Maryland Heights, Mo. On an Epsilon Linear
Precision Test Machine, Tribology Testing Equipment. The machine is
used to evaluate wear and extreme pressure properties of fluids and
greases. The machine has the ability to evaluate the rate of wear
throughout the test duration and compare wear in real time to all
other indicated variables such as torque, friction, coefficient of
friction, load specimen, RPM, specimen temperature, fluid
temperature, specimen cycles, and test duration. Stainless steel
pins and V Bars were used with the pins rotating against the V Bars
under conditions up to 4,000 psi. The heat generated in the oil
during the test is drawn off continuously. A stainless steel pin
and V block were run in standard lubricating oil for 50 minutes.
Wear was continuously recorded. A 1A stainless steel pin V block
were immersed in the aqueous silicon/phosphate solution of the
present invention for one minute, extracted and mailed to the
testing laboratory. The wear test was run with the pre-coated pin
and block for 50 minutes. The test results showed that wear using
the oil-based lubricant and the dry film of the present invention
were identical with 0.06 of an inch wear pattern. Thus, the dry
film of silicon/phosphorous of the present invention has the same
wear pattern as that observed using a standard lubricant.
[0065] The foregoing description has been limited to specific
embodiments of this invention. It will be apparent, however, that
variations and modifications may be made by those skilled in the
art to the disclosed embodiments of the invention, with the
attainment of some of all of its advantages and without departing
from the spirit and scope of the present invention. For example,
the present invention is not limited to the metals listed above,
but is inclusive of all metals, including refractory metals. The
solutions do not require the use of a peroxidic compound, a rare
earth or an accelerator additive. The pH can be acidic, or neutral
or alkaline depending upon which pH is the best solution for
deposition of the ions for conversion surfaces. Further, the
solution can be applied at ambient temperature without the
pre-treatment and pre-cleaning steps required in the Hardin
process. The solution can be applied to standing objects such as
bridges, overpasses and other metallic structures in situ. These
methods of application for forming conversion surfaces greatly
decrease costs and allow for passivation of metal structures
already built. Other metal surface techniques include pinging,
glass beading, galvanizing.
[0066] It will be understood that various changes in the details,
materials, and arrangements of the parts which have been described
and illustrated above in order to explain the nature of this
invention may be made by those skilled in the art without departing
from the principle and scope of the invention as recited in the
following claims.
* * * * *