U.S. patent application number 13/178859 was filed with the patent office on 2012-01-19 for wheels having oxide coating and method of making the same.
This patent application is currently assigned to FORD GLOBAL TECHNOLOGIES, LLC. Invention is credited to Larry P. Haack, Steven J. Simko, Ann Marie Straccia.
Application Number | 20120015209 13/178859 |
Document ID | / |
Family ID | 45467235 |
Filed Date | 2012-01-19 |
United States Patent
Application |
20120015209 |
Kind Code |
A1 |
Straccia; Ann Marie ; et
al. |
January 19, 2012 |
Wheels Having Oxide Coating And Method of Making The Same
Abstract
In one embodiment, an article includes a surface; a metallic
layer including a first metal and contacting the surface; and an
oxide layer including an oxide of a second metal different from the
first metal and contacting the metallic layer. The article may
further include a polymer layer contacting the surface of the oxide
layer directed away from the article surface. In certain instances,
the article is a vehicle wheel.
Inventors: |
Straccia; Ann Marie;
(Southgate, MI) ; Haack; Larry P.; (Ann Arbor,
MI) ; Simko; Steven J.; (Shelby Township,
MI) |
Assignee: |
FORD GLOBAL TECHNOLOGIES,
LLC
Dearborn
MI
|
Family ID: |
45467235 |
Appl. No.: |
13/178859 |
Filed: |
July 8, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61365477 |
Jul 19, 2010 |
|
|
|
Current U.S.
Class: |
428/632 ;
427/294; 427/404; 427/535; 428/334; 428/336; 428/469 |
Current CPC
Class: |
B60B 2310/616 20130101;
Y10T 428/31551 20150401; B60B 19/00 20130101; Y10T 428/12611
20150115; B60B 2310/654 20130101; B60Y 2200/11 20130101; C23C 16/50
20130101; C23C 28/00 20130101; Y10T 428/265 20150115; B60B 2310/614
20130101; Y10T 428/31663 20150401; Y10T 428/263 20150115; C23C
16/06 20130101 |
Class at
Publication: |
428/632 ;
427/535; 427/294; 427/404; 428/334; 428/336; 428/469 |
International
Class: |
B32B 15/04 20060101
B32B015/04; B05D 3/00 20060101 B05D003/00; B05D 1/36 20060101
B05D001/36; H05H 1/24 20060101 H05H001/24 |
Claims
1. An article comprising: a substrate including a surface; a
metallic layer including a first metal and contacting the surface;
and an oxide layer including an oxide of a second metal different
from the first metal and contacting the metallic layer surface
directed away from the article surface.
2. The article of claim 1, wherein the metallic layer includes a
first metallic surface contacting the oxide layer, a second
metallic surface, and a metallic bulk between the first and second
metallic surfaces, the first metallic surface including a higher
concentration of polar groups than the second metallic surface.
3. The article of claim 1, wherein the metallic layer includes less
than 5 percent by weight of oxygen.
4. The article of claim 1, wherein the oxide layer includes no less
than 5 percent by weight of oxygen.
5. The article of claim 1, wherein the oxide layer has a thickness
of 1 to 5 nanometers.
6. The article of claim 1, further comprising a polymer layer such
that the oxide layer is positioned between the metallic layer and
the polymer layer.
7. The article of claim 6, wherein the polymer layer includes a
first polymer surface contacting the oxide layer, a second polymer
surface, and a polymer bulk spacing apart the first and second
polymer surfaces, the first polymer surface includes an increased
concentration of polar groups relative to the second polymer
surface.
8. The article of claim 6, wherein the polymer layer has a
thickness of 50 to 100 micrometers.
9. The article of claim 1, further comprising a first primer layer
positioned between the article surface and the metallic layer.
10. The article of claim 9, further comprising a second primer
layer chemically different from the first primer layer, the second
primer layer positioned between the first primer layer and the
metallic layer.
11. The article of claim 1, wherein the metallic layer includes a
metal alloy of the first metal.
12. The article of claim 1, wherein the substrate includes a metal,
a polymer, or both.
13. An article comprising: a substrate including a surface; a first
primer layer contacting the surface; a metallic layer including a
first metal and contacting the first primer layer; an oxide layer
including an oxide of a second metal different from the first metal
and contacting the metallic layer surface directed away from the
article substrate; and a polymer layer contacting the oxide layer
surface directed away from the article surface.
14. A method of coating a surface, comprising: forming an oxide
layer on a surface with a metallic layer, the metallic layer
including a first metal and the oxide layer including an oxide of a
second metal different from the first metal.
15. The method of claim 14, wherein the step of forming is carried
out in a vacuum.
16. The method of claim 14, further comprising forming the metallic
layer in a vacuum.
17. The method of claim 14, further comprising forming a first
primer layer positioned between the article surface and the
metallic layer.
18. The method of claim 17, further comprising forming a second
primer layer positioned between the first primer layer and the
metallic layer.
19. The method of claim 14, further comprising subjecting the
surface to a plasma treatment prior to forming the metallic
layer.
20. The method of claim 14, further comprising forming a polymer
layer subsequent to the step of forming the oxide layer.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. provisional
application Ser. No. 61/365,477 filed Jul. 19, 2010 which is
incorporated herein by reference in its entirety.
TECHNICAL FIELD
[0002] One or more embodiments of the present invention relate to
an article such as a vehicle wheel having a decorative coating,
including in particular an oxide coating, and method of making the
same.
BACKGROUND
[0003] Articles such as coated wheels in the art may experience
coating layer failure when exposed to contact with physical objects
such as gravel or stones, as well as extreme temperatures and/or
rapid temperature changes. It is desirable to provide wheels that
are relatively resistant to one or more such layer failures.
SUMMARY
[0004] In one aspect, an article is provided. In one embodiment,
the article includes a surface; a metallic layer including a first
metal and contacting the surface; and an oxide layer including an
oxide of a second metal different from the first metal and
contacting the metallic layer surface directed away from the
article surface. In certain instances, the metallic layer includes
less than 5 percent by weight of oxygen. In certain other
instances, the oxide layer includes no less than 5 percent by
weight of oxygen. In yet certain other instances, the oxide layer
has a thickness of 1 to 5 nanometers. In yet certain other
instances, the metallic layer includes a metal alloy of the first
metal. In yet certain other instances, the article includes a
metal, a polymer, or both.
[0005] In another embodiment, the article further includes a
polymer layer contacting the surface of the oxide layer directed
away from the article surface. In certain instances, the polymer
layer has a thickness of 50 to 100 micrometers.
[0006] In yet another embodiment, the article further includes a
first primer layer positioned between the surface and the metallic
layer. In yet another embodiment, the article further includes a
second primer layer chemically different from the first primer
layer, the second primer layer positioned between the first primer
layer and the metallic layer.
[0007] In another aspect, a method of coating a surface is
provided. In one embodiment, the method includes forming an oxide
layer on a surface with a metallic layer, the metallic layer
including a first metal and the oxide layer including an oxide of a
second metal different from the first metal. In certain instances,
the forming step is carried out in a vacuum. In certain other
instances, the method further includes forming the metallic layer
in a vacuum.
[0008] In another embodiment, the method includes forming a first
primer layer positioned between the surface and the metallic layer.
In yet another embodiment, the method further includes forming a
second primer layer positioned between the first primer layer and
the metallic layer.
[0009] In yet another embodiment, the method further includes
subjecting the surface to a plasma treatment prior to forming the
metallic layer.
[0010] In yet another embodiment, the method further includes
forming a top polymer layer subsequent to the step of forming the
oxide layer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIGS. 1A and 1B respectively depict a front view and a side
view of a vehicle wheel according to one embodiment;
[0012] FIG. 2 depicts a cross-sectional view of surface layers of
an article such as a vehicle wheel according to another embodiment;
and
[0013] FIG. 3 depicts a process flow of making an article such as a
coated wheel according to yet another embodiment.
DETAILED DESCRIPTION
[0014] As required, detailed embodiments of the present invention
are disclosed herein. However, it is to be understood that the
disclosed embodiments are merely exemplary of the invention that
may be embodied in various and alternative forms. Therefore,
specific structural and functional details disclosed herein are not
to be interpreted as limiting, but merely as a representative basis
for the claims and/or a representative basis for teaching one
skilled in the art to variously employ the present invention.
[0015] Moreover, except where otherwise expressly indicated, all
numerical quantities in the description and in the claims are to be
understood as modified by the word "about" in describing the
broader scope of this invention. Unless expressly stated to the
contrary, the description of a group or class of material is
suitable or preferred for a given purpose in connection with the
invention implies that mixtures of any two or more members of the
group or class may be equally suitable or preferred.
[0016] In durability testing of aluminum wheels having a
chrome/aluminum alloy, inter-layer adhesion failure has been
reported to occur between the alloy layer and an adjacent polymer
or resin layer. This may resemble what may occur during a car wash
on a cold day, or alternatively, when a vehicle wheel is contacted
with gravel or stones during driving. The present invention, in one
or more embodiments, is believed to solve the adhesion failure
problems mentioned above.
[0017] In one embodiment, and as depicted in FIGS. 1A and 1B, an
article such as a vehicle wheel generally shown at 10 includes a
front portion 12 and rim portion 14. To the outer surfaces of the
front portion 12 and/or rim portion 14 is applied a coating system
which is detailed herein, with relatively improved inter-layer
adhesion and hence greater resistance to damage from contact or
temperature challenges. In the case of the article being a vehicle
wheel, the vehicle wheel may be formed of any suitable material
such as steel, aluminum alloy, cast aluminum, magnesium, and/or
magnesium alloy.
[0018] In another embodiment, and as depicted in FIG. 2, an article
such as a vehicle wheel generally shown at 200 includes a substrate
202 having a surface 212, to which is applied a metallic layer 206
including a first metal (not shown), and an oxide layer 208
contacting the metallic layer 206 and including an oxide of a
second metal (not shown) different from the first metal. In certain
instances, the article 200 may further include one or more primer
polymer layers generally shown at 204, which are positioned between
the metallic layer 206 and the substrate 202, the surface 212 of
the substrate 202 in particular. In the event that two or more
primer polymer layers 204 are employed, the primer polymer layers
204 may be chemically different from each other. In certain other
instances, the article 200 may further include one or more outer
polymer layers generally shown at 210. In the event that two or
more top polymer layers 210 are employed, the outer polymer layers
210 may be chemically different from each other.
[0019] Without wanting to be limited to any particular theory, it
is believed that the oxide layer 208 helps provide additional polar
groups on the metallic layer 206 and/or the outer polymer layer 210
for improved adhesion there between.
[0020] In one or more embodiments, "layer," as referenced in the
metallic layer 206, the oxide layer 208, the outer polymer layer
210 and the primer polymer layer 204, may include sub-layers of
identical chemical composition, each of which may be individually
applied.
[0021] The primer polymer layer 204, the metallic layer 206, the
oxide layer 208 and/or the outer polymer layer 210 may be applied
by any suitable coating processes. A non-limiting example of the
coating process is cold gas spraying, as disclosed in U.S. Pat. No.
5,302,414, which is incorporated by reference herein in its
entirety. In the process of cold gas spraying, a layer is applied
by spraying a high velocity flow of powder, which is in solid
state, at a temperature which is lower than the melting point of
the powder material. Another non-limiting example of the coating
process is, as disclosed in U.S. Pat. No. 5,795,626, which is
incorporated by reference herein in its entirety, triboelectric
discharge kinetic spraying and thermal spray technologies including
high velocity combustion, low velocity combustion, plasma spray and
twin wire arc spray. Another non-limiting example of the coating
process is electrolytic coating involving one or more cationic
polymers. The polymer coating bath may be an aqueous electrolytic
bath, containing cationic polymers which may be deposited onto the
surface from an electrolytic bath.
[0022] In certain instances, the metallic layer 206 and/or the
oxide layer may be applied via physical vapor deposition (PVD). A
non-limiting example of the PVD method is disclosed in "Coatings
Durability and Mechanical Reliability of PVD--Bright Chrome Coated
Aluminum Wheels" authorized by Charles J. Russo, SAE 2007-01-1530,
which is incorporated by reference herein in its entirety. Without
wanting to be limited by any particular theory, it is believed that
the PVD method is relatively more environmental friendly than other
locating methods, such as electrolytic cladding methods which often
use toxic electrolytic solutions.
[0023] The primer polymer layer 204 and/or the outer polymer layer
210 may each independently include any suitable polymer
compositions, such as those disclosed in the following
publications: U.S. Pat. Nos. 4,170,579 and 4,610,769 to Bosso et
al., U.S. Pat. No. 5,096,556 to Corrigan et al., U.S. Pat. No.
4,432,850 to Moriarity et al., and U.S. Pat. No. 4,689,131 to Roue,
all of which are incorporated by reference herein in their
entirety. In certain instances, the top polymer layer 210 includes
an acrylate, with or without a pigment.
[0024] The article 200 may be coated according to a method
generally shown at 300 as depicted in FIG. 3. In one embodiment,
the method 300 includes a step 312 of forming an oxide layer on a
surface having a metal oxide layer. The method 300 may further
include one or more of steps 302, 303, 304, 306, 308, 310 and
314.
[0025] At step 302, the surface is etched for cleaning and to
remove surface oxides, using, in particular, an acid etching
process.
[0026] At step 303, the surface is modified with a conversion
coating for anti-corrosion treatment.
[0027] At step 304, the conversion coated surface is coated with a
first primer layer mainly to level the surface. This first primer
layer may be applied using any suitable spraying or powder layer
process and is subsequently cured. If the substrate is heat stable,
such as metal-based substrate, the curing may be done in an oven.
If the substrate is heat labile, such as plastics-based substrate,
the curing may be carried out using ultraviolet light curing.
[0028] After cure, the article such as a vehicle wheel is
transferred to a vacuum chamber such as a PVD vacuum chamber. In
this chamber, the existing cured coating layer is treated with a
gas plasma, followed by deposition of a thin metallic layer.
Non-limiting examples of the gas applied in the gas plasma may
include argon, oxygen, nitrogen, air, or combinations thereof. In
certain instances, argon plasma is used in this step to provide a
relatively more subtle plasma treatment. The gas plasma treatment
of the primer layer is performed to enhance adhesion to the applied
metallic layer. In certain instances, the metallic layer is again
subjected to a gas plasma within the PVD vacuum chamber.
[0029] At step 306, the surface may be further coated with a second
primer layer. The second primer layer may be chemically different
from the first primer layer. In this scenario, while the first
primer layer is mainly to level the surface, the second primer
layer is to prime the surface for subsequent layers, particular for
subsequent application of the metallic layer.
[0030] At step 308, the surface may be subject to a plasma
treatment, such as a plasma using argon gas, to activate the
surface for subsequent metallic layer application.
[0031] At step 310, the surface is coated with the metallic layer.
One or both of the steps 310 and 312 may be carried out under
vacuum, and in certain instances, via the application of plasma
vapor deposition. With the use of PVD, the oxide composition may be
injected into the metallic layer at a relatively high energy such
that the thickness of the oxide layer may be controlled to be
extremely thin, such as 1 to 5 nanometers. At this thickness, the
oxide layer is believed to be transparent enough so as not to
reduce the metallic appearance of the underlying metallic layer to
any significant degree, while providing benefits in improving
adhesion.
[0032] At step 314, the surface may be coated with an outer polymer
layer (in some instances, a top polymer layer), which functions as
a protective layer over the metallic layer from the
environment.
[0033] The metallic layer 206 may include any suitable metal
elements. Suitable metal elements include transition metals, and
those from groups 13 and 14 of the periodic table. In certain
instances, the metallic layer 206 includes chrome, aluminum, or
alloys thereof.
[0034] The oxide layer 208 may include one or more oxides selected
from the group consisting of oxides of electropositive elements,
oxides of electronegative elements, oxides of amphoteric elements,
and combinations thereof, as long as at least one of the oxides
being an oxide of a metal different from the metal included in the
metallic layer 206. In certain instances, the oxide layer 208
includes one or more of a titanium oxide (TiO.sub.2), a silicon
oxide (SiO.sub.2), nickel oxide (Ni.sub.2O.sub.3), tin oxide
(SnO.sub.2), and/or aluminum oxide (Al.sub.2O.sub.3).
[0035] Non-limiting examples of the oxide of the oxide layer 208
include an oxide of one or more elements of the first row of
transition metals such as nickel, iron, cobalt, copper, and zinc,
or those from the second row of transition metals such as zirconium
or yttrium. Without wanting to be limited to any particular theory,
it is believed that these metals are capable of forming oxides in
the form of hydroxides M(OH).sub.x. Metal hydroxides M(OH).sub.x
possess exchangeable hydrogen atoms that are able to form strong
and durable covalent bonds with coupling agents in the outer
polymer layer 210. For instance, cyano groups in the outer polymer
layer 210 may react to form urethane linkages, and siloxane
coupling agents will form M-O--Si bonds. Thus the metal oxide
binder can be matched with specific coupling agents in the outer
polymer layer 210 to meet necessary bonding requirements.
[0036] In certain instances, the metallic layer 206 includes a
first metallic surface contacting the oxide layer, a second
metallic surface, and a metallic bulk spacing apart the first and
second metallic surfaces, the first metallic surface includes an
increased concentration of polar groups relative to the second
metallic surface. The polar groups include hydroxyl groups
OH.sup.-. In certain particular instances, the concentration of the
polar groups, and hydroxyl groups in particular, of the first
metallic surface is at least 5 percent, 10 percent, 15 percent or
20 percent greater in atomic weight relative to that of the second
metallic surface.
[0037] In certain other instances, the polymer layer 210 includes a
first polymer surface contacting the oxide layer, a second polymer
surface, and a polymer bulk spacing apart the first and second
polymer surfaces, the first polymer surface includes an increased
concentration of polar groups relative to the second polymer
surface. The polar groups include hydroxyl groups OH.sup.-. In
certain particular instances, the concentration of the polar
groups, and hydroxyl groups in particular, of the first polymer
surface is at least 5 percent, 10 percent, 15 percent or 20 percent
greater in atomic weight relative to that of the second polymer
surface.
[0038] In certain instances, the thickness of the oxide layer 208
is relatively small to not impart a color change to the underlying
metallic layer in any significant degree. In certain instances, the
thickness of the oxide layer 208 is less than 10 nm, and
particularly 1 to 5 nanometers.
[0039] In one or more embodiment, the parameter of the color change
can be expressed, according to the International Commission on
Illumination (CIE), as .DELTA.E*.sub.ab in terms of the CIELAB
color space by the equation,
.DELTA.E*.sub.ab= {square root over
((.DELTA.L*).sup.2+(.DELTA.a*).sup.2+(.DELTA.b*).sup.2)}{square
root over
((.DELTA.L*).sup.2+(.DELTA.a*).sup.2+(.DELTA.b*).sup.2)}{square
root over
((.DELTA.L*).sup.2+(.DELTA.a*).sup.2+(.DELTA.b*).sup.2)}
[0040] where is L is the color brightness, and a and b are the
complimentary color-opponent dimensions. A non-limiting example of
the color change determination may be found according to Hans G.
Volz, "Industrial Color Testing--Fundamentals and Techniques",
second, completely revised edition, translated by Ben Teague,
Wiley-VCH, New York (2001), which is incorporated by reference
herein in its entirety.
[0041] In certain instances, the oxide layer 208 as deposited onto
the metallic layer 206 is relatively thin such that .DELTA.E*, the
color difference of the metallic layer 206 before and after
deposition of the oxide layer 208, is less than 2.3, a number
associated with a "just noticeable difference" of color differences
to the human eye. In certain particular instances, .DELTA.E* is
less than 1.0, which is identified as a color difference
indistinguishable to the human eye.
[0042] The thickness of the oxide layer 208 may be determined using
any suitable methods. A non-limiting example involves the use of
ion sputter depth profiling, coupled with a surface sensitive
analysis technique such as Auger electron spectroscopy (AES), X-ray
photoelectron spectroscopy (XPS), and secondary ion mass
spectrometry (SIMS). In this method, a beam of ions, typically rare
gas ions such as argon, is directed at the surface of a solid.
These ions interact with the surface in a process called a
collision cascade. Material is removed from the surface by ion
sputtering. Over time this process removes material from the
surface, exposing subsurface layers. These are measured by one of
the above mentioned surface analysis techniques. By measuring the
surface composition as a function of sputter time, the composition
and thickness of thin films can be determined. A reference for the
method may be found in Hofmann, S., "Quantitative Depth Profiling
is Surface Analysis: A Review", Surface and Interface Analysis, 2
(4) 148 (1980), which is incorporated by reference herein in its
entirety.
[0043] Another non-limiting example of the method involves
ellipsometry. The sample is illuminated with a beam of polarized
light and the resulting change in polarization of the reflected
beam is measured. The degree of polarization change that occurs is
determined by the optical constants of the thin film, including the
film thickness. A reference for this method may be found at
Tomkins, H. G., "A users Guide to Ellipsometry, New York, 1993,
Academic Press, Inc., which is incorporated by reference herein in
its entirety.
[0044] Although being directed to a wheel, the above described
layer structure and/or method of forming are equally applicable to
any suitable substrates and surfaces thereof, including plastics,
metals, polymers, and combinations thereof.
EXAMPLES
[0045] A 200 nm layer of chrome is deposited by plasma vapor
deposition (PVD) in an argon atmosphere at a partial pressure of 11
mTorr onto a substrate using a Perkin-Elmer ULTEK model 2400 RF
sputtering system. A paint layer of a carbamate coat composition at
50 .mu.m thickness is applied over the chrome layer and baked to
cure.
[0046] A second chrome layer is deposited in an identical manner
onto a companion sample, onto which is subsequently deposited by
PVD a silicon oxide (silica) layer at a thickness of 5 nm. The
silica layer is thin enough to be essentially transparent and not
obscure the coloration of the chrome. A clear carbamate paint layer
of 50 .mu.m thickness is then applied over the silica layer and
baked to cure.
[0047] A third chrome layer is deposited in an identical manner
onto a companion sample, onto which is subsequently deposited by
PVD a titanium oxide (titania) layer at a thickness of 5 nm. The
titania layer is thin enough to be essentially transparent and not
to obscure the coloration of the chrome. A clear carbamate paint
layer of 50 .mu.m thickness is then applied over the titania layer
and baked to cure.
[0048] A cross-hatch adhesion test is performed on each sample to
test the relative adhesion strength of the carbamate paint layer to
the underlying chrome layer, or chrome layer coated with an oxide
binder layer. The cross-hatch adhesion test may be carried out
according to Standard Test Methods for Measuring Adhesion by Tape
Test, ASTM D3359.
[0049] These tests reveal a 98% delamination of the carbamate paint
layer from the chrome layer, a 49% delamination of the carbamate
paint layer from the chrome layer coated with the silica binder
layer, and a 6% delamination of the carbamate paint layer from the
chrome layer coated with the titania binder layer. The experiments
reveal that adhesion to chrome can be greatly improved, or
delamination failure can be greatly reduced, by the addition of an
oxide binder layer.
[0050] For this experiment a carbamate paint system is utilized as
it is able to readily differentiate adhesion strength between the
layers tested. In practice, other paint systems such as acrylic
paints or epoxy paints might likely yield stronger adhesion to the
chrome layer, but would still be susceptible to adhesion failure in
durability when subjected to testing at elevated humidity or when
subjected to rapid changes in temperature without the exceptional
durability imparted by an oxide layer.
[0051] While the best mode for carrying out the invention has been
described in detail, those familiar with the art to which this
invention relates will recognize various alternative designs and
embodiments for practicing the invention as defined by the
following claims.
* * * * *