U.S. patent application number 10/994537 was filed with the patent office on 2005-08-18 for method for depositing nickel- and chromium (vi) -free metal matte layers.
Invention is credited to Brecht, Joachim, Mobius, Andreas, Pies, Peter, Schaaf, Hans-Paul.
Application Number | 20050178668 10/994537 |
Document ID | / |
Family ID | 34428874 |
Filed Date | 2005-08-18 |
United States Patent
Application |
20050178668 |
Kind Code |
A1 |
Mobius, Andreas ; et
al. |
August 18, 2005 |
Method for depositing nickel- and chromium (VI) -free metal matte
layers
Abstract
A method for depositing metal matte layers free of nickel and
chromium(VI).
Inventors: |
Mobius, Andreas; (Kaarst,
DE) ; Brecht, Joachim; (Keltern-Dietlingen, DE)
; Pies, Peter; (Koln, DE) ; Schaaf, Hans-Paul;
(Remscheid, DE) |
Correspondence
Address: |
SENNIGER POWERS LEAVITT AND ROEDEL
ONE METROPOLITAN SQUARE
16TH FLOOR
ST LOUIS
MO
63102
US
|
Family ID: |
34428874 |
Appl. No.: |
10/994537 |
Filed: |
November 22, 2004 |
Current U.S.
Class: |
205/170 ;
205/182 |
Current CPC
Class: |
C23C 28/322 20130101;
C25D 5/10 20130101; C23C 18/165 20130101; C23C 28/34 20130101; C25D
3/56 20130101; C23C 28/341 20130101; C23C 28/023 20130101; C23C
28/345 20130101; C23C 28/021 20130101; C23C 28/343 20130101; C25D
5/12 20130101; C23C 28/321 20130101; C25D 3/02 20130101; C23C 18/31
20130101 |
Class at
Publication: |
205/170 ;
205/182 |
International
Class: |
C25D 005/10 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 21, 2003 |
DE |
103 54 760.6 |
Claims
What is claimed is:
1. A method for depositing a matte layer free of nickel and
chromium(VI) onto a substrate, the method comprising: (a) coating
the substrate with a first matte metal layer that is free of
nickel; (b) metallizing the first matte metal layer with a second
metal layer that is free of nickel and chromium(VI), which assumes
the matte effect of the first matte metal layer; wherein the first
matte metal layer comprises at least one metal selected from the
group consisting of copper, silver, tin, zinc, or an alloy that
does not contain nickel; and wherein the second metal layer
comprises at least one metal selected from the group consisting of
copper, tin, zinc, chromium(III), silver, gold, ruthenium,
platinum, palladium, or an alloy of these metals.
2. The method of claim 1, wherein the first matte metal layer is
deposited chemically.
3. The method of claim 1, wherein the first matte metal layer is
electrolytically deposited.
4. The method of claim 1, wherein the second metal layer is
chemically deposited.
5. The method of claim 1, wherein the second metal layer is
deposited electrolytically.
6. The method of claim 1 further comprising coating the second
metal layer with a third layer.
7. The method of claim 6, wherein the third layer comprises
chromium.
8. The method of claim 6, wherein the third layer comprises
chromium alloyed with at least one element selected from the group
consisting of vanadium, molybdenum, carbon, phosphorous, tungsten,
and mixtures thereof.
9. The method of claim 1, the method further comprising coating the
second metal layer with a third layer and at least one hard layer
applied by CVD or PVD.
10. The method of claim 9, wherein the hard layer comprises a
material selected from the group consisting of chromium carbide,
titanium nitride, titanium carbide, zirconium nitride, zirconium
carbide, silicon dioxide, diamond-like carbon, and combinations
thereof.
11. The method of claim 9 wherein the third layer comprises
chromium.
12. The method of claim 9, wherein the third layer comprises
chromium alloyed with at least one element selected from the group
consisting of vanadium, molybdenum, carbon, phosphorous, tungsten,
and mixtures thereof.
13. A method for imparting a decorative matte finish to a surface
of an article comprising: coating the surface with a first matte
layer of metal which a) contains at least one metallic material
selected from the group consisting of copper, tin, silver, zinc,
and metal alloys, and b) is substantially nickel-free; and
depositing a second matte layer over the first matte layer, which
second matte layer is a layer of metal which a) contains at least
one metallic material selected from the group consisting of copper,
tin, zinc, chromium, silver, gold, ruthenium, platinum, palladium,
and metal alloys of the foregoing, b) is substantially free of
nickel, c) is deposited from a composition which is substantially
free of chromium (VI), and d) has a matte appearance.
14. The method of claim 13 further comprising depositing a third
layer over the second metal layer, wherein the third layer
comprises chromium, wherein the depositing the third layer is by a
process employing a chromium-containing composition which is
substantially free of chromium (VI).
15. The method of claim 14, wherein the third layer comprises
chromium alloyed with at least one element selected from the group
consisting of vanadium, molybdenum, carbon, phosphorous, tungsten,
and mixtures thereof.
16. The method of claim 13 further comprising depositing a third
layer over the second metal layer and a hard layer over the second
metal layer by CVD or PVD.
17. The method of claim 16, wherein the hard layer comprises a
material selected from the group consisting of chromium carbide,
titanium nitride, titanium carbide, zirconium nitride, zirconium
carbide, silicon dioxide, diamond-like carbon, and combinations
thereof.
18. The method of claim 16 wherein the third layer comprises
chromium.
19. The method of claim 18, wherein the third layer comprises
chromium alloyed with at least one element selected from the group
consisting of vanadium, molybdenum, carbon, phosphorous, tungsten,
and mixtures thereof.
20. The method of claim 13 wherein the coating the surface with the
first matte layer of metal comprises immersing the surface in an
electrolyte comprising Cu ions and applying an external source of
electrical current to the electrolyte to electrolytically deposit a
Cu-based layer as the first matte layer.
21. The method of claim 20 wherein the electrolyte comprises, by
approximate composition: 18-25 g/L Cu.sup.2+180-210 g/L
H.sub.2SO.sub.4 30-80 mg/L Cl.sup.-.
22. The method of claim 21 wherein the electrical current has a
current density between about 1 A/dm.sup.2 and 5 A/dm.sup.2 and the
electrolyte has a temperature in a range between about 18.degree.
C. and 35.degree. C.
23. The method of claim 13 wherein the second matte layer comprises
tin and the depositing the second matte layer comprises immersing
the surface in an electrolyte comprising Sn ions and applying an
external source of electrical current to the electrolyte to
electrolytically deposit a Sn-based layer as the second matte
layer.
24. The method of claim 23 wherein the second matte layer is
deposited using an electrolyte comprising, by approximate
composition: g/L Sn.sup.2+10 g/L Cu.sup.2+240 g/L methanesulfonic
acid 32.2 g/L aromatic, nonionic wetting agent 2 g/L antioxidation
agent 25 g/L stabilizer/complexing agent.
25. The method of claim 23 wherein the second matte layer is
deposited using an electrolyte comprising, by approximate
composition: 18 g/L Sn.sup.2+2 g/L Cu.sup.2+258 g/L methanesulfonic
acid 9 g/L aromatic, nonionic wetting agent.
26. The method of claim 23 wherein the second matte layer is
deposited using an electrolyte comprising, by approximate
composition: 17.0-25.0 g/L Sn.sup.2+10.0-15.0 g/L Cu.sup.2+1.3-1.9
g/L Zn.sup.2+45.0-60.0 g/L KCN 0.5-2 mL/L wetting agent 0.1-1 mL/L
gloss additive.
27. The method of claim 26 wherein the electrolyte has a pH value
of between about 12.4 and about 12.9.
28. The method of claim 26 wherein the second matte layer is
deposited at a temperature range of between about 50.degree. C. and
60.degree. C. and with a current density of between about 2
A/dm.sup.2 and about 4 A/dm.sup.2.
29. The method of claim 13, wherein the second matte layer is
deposited using an electrolyte comprising, by approximate
composition: 8.0-12.0 g/L Sn.sup.2+5.0-10.0 g/L Cu.sup.2+1.0-3.0
g/L Zn.sup.2 23.0-30.0 g/L KCN
30. The method of claim 29, wherein the electrolyte has a pH value
of between about 13.2 and about 13.6.
31. The method of claim 29, wherein the second matte layer is
deposited at a temperature range of between about 39.degree. C. and
45.degree. C. and with a current density of between about 0.3
A/dm.sup.2 and 0.7 A/dm.sup.2.
32. The method of claim 13, wherein the first matte metal layer
comprises copper.
33. The method of claim 13, wherein the second matte layer
comprises tin and copper.
34. The method of claim 13, wherein the second matte layer
comprises tin, copper, and zinc.
35. The method of claim 32, wherein the first matte metal layer is
between about 5 .mu.m and about 30 .mu.m thick.
36. The method of claim 35, wherein the second matte layer is
between about 5 .mu.m and about 30 .mu.m thick.
37. A method for imparting a decorative matte finish to a surface
of an article comprising: immersing the surface in a first
electrolyte comprising Cu ions and applying an external source of
electrical current to the first electrolyte to electrolytically
deposit a Cu-based layer as a first matte layer, wherein the first
electrolyte is substantially nickel-free; and depositing a second
matte layer over the first matte layer by immersing the surface in
a second electrolyte comprising Sn ions and applying an external
source of electrical current to the second electrolyte to
electrolytically deposit a Sn-based layer as the second matte
layer, wherein the second electrolyte is substantially free of
nickel and is substantially free of chromium (VI).
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to a method for
depositing nickel- and chromium(VI)-free metal matte layers on
substrates.
BACKGROUND OF THE INVENTION
[0002] Metal matte layers are used for functional or decorative
surface refinement in various areas. Thus, for example, in the area
of jewelry production, surfaces are coated with appropriate matte
layers for aesthetic reasons. In the area of household appliances
or food preparation apparatuses or facilities, surfaces are often
equipped with matte layers for decorative reasons.
[0003] The matte layers previously known in the state of the art
are deposited from nickel-containing electrolytes, mostly
chromium(VI)-containing electrolytes, and form a cover layer
containing nickel. Although chromium(VI) is not detectable in the
end layer with a careful operation, in particular, when rinsing
after chrome-plating, there is some concern about layers which have
been deposited from such electrolytes.
[0004] Nickel can lead to allergenic reactions with intensive skin
contact or with the intake of nickel traces via foods. In the case
of jewelry, it is precisely close skin contact and the nickel
desorption promoted by sweat and moisture which lead to strong skin
irritations. In the case of household appliances and food
preparation facilities or apparatuses, contacting food with matte
surfaces may, under certain circumstances, lead to the dissolving
out of nickel, since the chromium layer does not always
sufficiently cover the underlying microstructural surface.
[0005] For the aforementioned reasons, great efforts are being
made, especially in the jewelry industry and in the area of the
production of household appliances and food preparation apparatuses
or facilities, to avoid such surface coatings.
[0006] However, since matted surfaces have a great aesthetic
effect, corresponding surfaces in the aforementioned areas are
currently used widely in spite of their disadvantages.
[0007] Taking into consideration what has been said in the
preceding, the problem addressed by this invention is the provision
of a method for the deposition of matte nickel- and
chromium(VI)-free metal layers.
SUMMARY OF THE INVENTION
[0008] Among the objects of the invention, therefore, is the
provision of a method to deposit matte surface layer free of nickel
and chromium(VI) on substrates.
[0009] Briefly, therefore, the invention is directed to a method
for depositing a matte layer free of nickel and chromium(VI) onto a
substrate. The method comprises coating the substrate with a first
matte metal layer that is free of nickel; and metallizing the first
matte metal layer with a second metal layer that is free of nickel
and chromium(VI), which assumes the matte effect of the first matte
metal layer. The first matte metal layer comprises at least one
metal selected from the group consisting of copper, silver, tin,
zinc, or an alloy that does not contain nickel. The second metal
layer comprises at least one metal selected from the group
consisting of copper, tin, zinc, chromium(III), silver, gold,
ruthenium, platinum, palladium, or an alloy of these metals.
[0010] The invention is also directed to a method for imparting a
decorative matte finish to a surface of an article comprising
coating the surface with a first matte layer of metal which a)
contains at least one metallic material selected from the group
consisting of copper, tin, silver, zinc, and metal alloys, and b)
is substantially nickel-free; and depositing a second matte layer
over the first matte layer, which second matte layer is a layer of
metal which a) contains at least one metallic material selected
from the group consisting of copper, tin, zinc, chromium, silver,
gold, ruthenium, platinum, palladium, and metal alloys of the
foregoing, b) is substantially free of nickel, c) is deposited from
a composition which is substantially free of chromium (VI), and d)
has a matte appearance.
[0011] Other objects and features of this invention will be in part
apparent and in part pointed out hereinafter.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0012] This application claims priority from German application
number 103 54 760.6, the entire disclosure of which is explicitly
incorporated by reference.
[0013] In accordance with this invention, a method for the
deposition of nickel- and chromium(VI)-free metal matte layers is
provided, the method comprising the following steps:
[0014] a) coating a substrate with a first matte layer;
[0015] b) metallizing the first matte metal layer with a second
metal layer that assumes the matte effect of the first metal layer
to obtain a coated substrate with a matted surface. According to
the invention, the first matte metal layer is nickel-free and the
second metal layer is free from nickel and chromium(VI). The metal
used to produce the first matte metal layer comprises at least one
metal of the group consisting of copper, silver, tin, zinc, or an
alloy that does not contain nickel. The metal used to produce the
second metal layer comprises at least one metal of the group
consisting of copper, tin, zinc, chromium(III), silver, gold,
ruthenium, platinum, palladium, or an alloy of these metals.
[0016] In the context of this invention, the term "matte" refers to
a dull, non-glare, or pearl surface finish.
[0017] In one aspect, the use of matte copper layers as a first
matte metal layer turns out to be particularly suitable with the
method of the invention. Such copper layers are obtained with the
method of galvanic or chemical metallization, known in the state of
the art.
[0018] In another aspect according to the invention, a second metal
layer assuming the matte effect of the first metal layer using
copper-tin alloys, such as white bronzes, proves to be particularly
favorable. Such second metal layers impart the aesthetic impression
of chromed matte nickel layers, but exhibit no allergenic potential
and have sufficient mechanical stability and corrosion
resistance.
[0019] In another aspect of the invention, if the mechanical
stability is to be increased for technical application reasons, the
proposal is made to metallize a third metal layer onto the second
metal layer, which assumes the matte effect of the first metal
layer, the third layer having corresponding mechanical
characteristics. Here, the deposition of a chromium or chromium
alloy layer, such as chromium alloys comprising vanadium,
molybdenum, carbon, phosphorous, or tungsten from
chromium(III)-containing electrolytes have proved to be suitable.
Likewise, hard layers applied by a CVD or PVD, such as chromium
carbide, titanium nitride/carbide, zirconium nitride/carbide,
silicon dioxide, or DLC (diamond-like carbon) or combinations of
these layers, have also proved to be suitable.
[0020] In one embodiment, the thickness of each layer is at least
about 3 .mu.m, for example, each layer is between about 5 .mu.m and
about 30 .mu.m thick. In one such embodiment, the layers are about
10 .mu.m thick.
[0021] With regard to the first matte metal layer, in one exemplary
embodiment, an electrolyte suitable for carrying out the method of
the invention is prepared with an acidic matte copper electrolyte,
which produces matte layers by employing additives. For example,
one electrolyte comprises the additive Cuprostar LP1, which is an
additive commercially available from Enthone Inc. Such an
electrolyte is applied to a substrate by applying a current. Other
examples for electrolytes which can be used in the method of the
invention for the deposition of matte copper layers are currentless
copper electrolytes, such as ENPLATE CU 872, commercially available
from Enthone Inc.
[0022] With regard to the second metal layer, in one embodiment
according to this invention, a first matte copper layer obtained by
means of a copper electrolyte according to this invention can be
metallized with a copper-tin alloy in the next method step. An
advantageous electrolyte for the galvanic deposition of copper-tin
alloys, such as white bronzes, comprises tin and copper ions in the
form of cyanides, as well as suitable additives such as alkali
liquor and free cyanide. Alkylsulfonic acid electrolytes comprising
an aromatic, nonionic wetting agent can also be used. The
electrolyte may optionally comprise additional stabilizers and/or
anionic and/or nonionic complexing agents, aliphatic wetting
agents, antioxidation agents, and other metal salts.
[0023] The metals tin and copper, which are introduced into the
electrolytes mainly for the deposition of bronzes, can be present
predominantly as cyanides. In the case of the acidic electrolytes,
they can be present as salts of alkylsulfonic acids, preferably as
methane sulfonates, or as salts of mineral acids, preferably as
sulfates. In one preferred embodiment, the tin salt tin methane
sulfonate is used in the electrolyte. It is advantageously added to
the electrolyte in a quantity of about 5-195 g/L of electrolyte.
This corresponds to a use of about 2-75 g/L divalent tin ions. In
another preferred embodiment, possibly coupled with the preceding
preferred embodiment, the copper salt copper methane sulfonate is
used in the electrolyte. It is advantageously added to the
electrolyte in a quantity of about 8-280 g/L. This corresponds to a
use of about 2-70 g/L divalent copper ions.
[0024] Since the deposition rate in the acidic medium is clearly
higher, an acid, preferably a mineral and/or an alkylsulfonic acid,
is added to the electrolyte in quantities of about 140-382 g/L of
electrolyte. The use of methanesulfonic acid is particularly
advantageous, since it both causes an advantageous solubility of
the metal salts and simultaneously, as a result of its acid
strength, specifies or facilitates the setting of the pH value
needed for the method. In addition, the methanesulfonic acid has
the advantageous characteristic of substantially contributing to
the stability of the bath.
[0025] In the following examples, which are given by way of
illustration and are not limiting on the invention, electrolytes
are described which are suitable for carrying out the method of the
invention.
EXAMPLE 1
[0026] This is an acidic matte copper electrolyte, which can be
used to produce the first matte metal layer by additives. An
electrolyte was prepared comprising, by approximate
composition:
[0027] 18-25 g/L Cu.sup.2+
[0028] 180-210 g/L H.sub.2SO.sub.4
[0029] 30-80 mg/L Cl.sup.-
[0030] 1-10 mL/L Cuprostar LP1
[0031] Cuprostar LP1 is an additive commercially available from
Enthone Inc. The electrolyte was used to coat a substrate at a
temperature range of between about 18.degree. C. and 35.degree. C.
The electrolyte was used to coat a substrate by applying a current
density between about 1 A/dm.sup.2 and 5 A/dm.sup.2.
EXAMPLES 2-5
[0032] For purposes of illustration, the following examples
describe electrolytes suitable for use depositing the second metal
layer.
EXAMPLE 2
[0033] An electrolyte was prepared comprising, by approximate
composition:
[0034] 5 g/L Sn.sup.2+
[0035] 10 g/L Cu.sup.2+
[0036] 240 g/L Methane sulfonic acid
[0037] 32.2 g/L Aromatic, nonionic wetting agent
[0038] 2 g/L Antioxidation agent
[0039] 25 g/L Stabilizer/complexing agent
EXAMPLE 3
[0040] An electrolyte was prepared comprising, by approximate
composition:
[0041] 18 g/L Sn.sup.2+
[0042] 2 g/L Cu.sup.2+
[0043] 258 g/L Methane sulfonic acid
[0044] 9 g/L Aromatic, nonionic wetting agent
EXAMPLE 4
[0045] An electrolyte was prepared comprising, by approximate
composition:
[0046] 17.0-25.0 g/L Sn.sup.2+
[0047] 10.0-15.0 g/L Cu.sup.2+
[0048] 1.3-1.9 g/L Zn.sup.2+
[0049] 45.0-60.0 g/L KCN
[0050] 0.5-2 mL/L Wetting agent
[0051] 0.1-1 mL/L Gloss additive
[0052] The electrolyte of this example has a pH value of between
about 12.4-12.9. It was applied to a substrate by applying a
current density between about 2 and 4 A/dm.sup.2 while holding the
electrolyte in a temperature range between about 50.degree. C. and
about 60.degree. C.
EXAMPLE 5
[0053] An electrolyte was prepared comprising, by approximate
composition:
[0054] 8.0-12.0 g/L Sn.sup.2+
[0055] 5.0-10.0 g/L Cu.sup.2+
[0056] 1.0-3.0 g/L Zn.sup.2
[0057] 23.0-30.0 g/L KCN
[0058] 0.1-2 mL/L ATC solution No. 4 from Enthone Inc.
[0059] 0.1-2 mL/L BRONZEX WMF Brightener NG from Enthone Inc.
[0060] The electrolyte of this example has a pH value of between
about 13.2-13.6. It was applied to a substrate by applying a
current density between about 0.3 A/dm.sup.2 and 0.7 A/dm.sup.2
while holding the electrolyte in a temperature range between about
39.0.degree. C. and 45.0.degree. C.
[0061] When introducing elements of the present invention or the
preferred embodiment(s) thereof, the articles "a," "an," "the," and
"said" are intended to mean that there are one or more of the
elements. The terms "comprising," "including," and "having" are
intended to be inclusive and mean that there may be additional
elements other than the listed elements.
[0062] In view of the above, it will be seen that the several
objects of the invention are achieved and other advantageous
results attained.
[0063] As various changes could be made in the above methods and
products without departing from the scope of the invention, it is
intended that all matter contained in the above description and
shown in any accompanying drawings shall be interpreted as
illustrative and not in a limiting sense.
* * * * *