Process for applying protective and decorative coating on an article

A method for depositing a multi-layered protective and decorative coating on the article comprising first depositing at least one coating layer on the article by electroplating, removing the electroplated article from the electroplating bath and subjecting it to pulse blow drying to produce a spot-free surface on the electroplated article, and then depositing, by physical vapor deposition, at least one vapor deposited coating layer on the electroplated article. The electroplated layers are selected from copper, nickel and chrome. The physical vapor deposited layers are selected from non-precious refractory metals, non-precious refractory metal alloys, non-precious refractory metal compounds, and non-precious refractory metal alloy compounds.

FIELD OF THE INVENTION 
The present invention is directed to a method of applying protective and 
decorative coatings to articles 
BACKGROUND OF THE INVENTION 
Providing an article such as, for example, a brass faucet or lock with a 
multilayered coating by depositing a first coating layer or series of 
coating layers by electroplating and then depositing a second coating 
layer or series of coating layers on the electroplated coating layer by 
physical vapor deposition is known in the art. Such a multilayered coating 
provides abrasion and corrosion protection to the article, is decorative, 
and levels off any imperfections such as nicks and scratches on the 
article. Thus, for example, a brass article having a duplex nickel layer 
comprised of bright nickel and semi-bright nickel electroplated thereon 
and a zirconium nitride layer deposited on the duplex nickel layer by 
physical vapor deposition is smooth, has improved abrasion and corrosion 
resistance, and has the color of polished brass. 
It is generally the vapor deposited layer which provides the abrasion 
protection and decorative appearance. However, the vapor deposited coating 
layer is generally quite thin, typically in the range of from about one to 
20 millionths of an inch. Due to the thinness of the vapor deposited 
coating any water spots or any other surface defects such as nickel or 
chrome stains from or caused by the electroplating process show through 
and indeed are accentuated by the thin vapor deposited coating. Even 
spots, stains or discolorations which are not visible to the naked eye on 
the electroplated article will become visible after the vapor deposited 
coating is applied. 
It is thus currently necessary to thoroughly inspect, clean and dry each 
article as it comes out of the electroplating bath. One conventional way 
of cleaning the electroplated articles is to run the articles through a 
water based cleaning system and use nitrogen drying to dry the articles. 
This is quite expensive and not always successful. Another method involves 
hand drying and cleaning each individual article. This hand drying, while 
more effective than a nitrogen based drying system, is very labor 
intensive and, therefore, also quite expensive. Hand drying also involves 
handling the electroplated articles which may result in dropping or 
bumping the articles against other objects with consequent damage to the 
articles. 
It would be very advantageous if an efficient and effective drying method 
for the electroplated articles were available which eliminated the 
problems associated with conventional, currently used cleaning and drying 
methods. It is an object of the instant invention to provide such a 
system. 
SUMMARY OF THE INVENTION 
The instant invention comprises a method of applying a multi layer 
protective and decorative coating to an article. The method involves first 
applying at least one coating layer by electroplating. The electroplated 
article is then removed from the electroplating bath and subjected to 
pulse blow drying for spot-free drying. The dried electroplated article is 
then placed in a vapor deposition chamber and at least one coating layer 
is vapor deposited on the electroplated article. 
The electroplating comprises applying at least one layer selected from 
copper, nickel and chrome. The copper plating includes both alkaline 
copper plating and acid copper plating. The nickel plating includes the 
electroplating of bright nickel, semi-bright nickel, and a duplex nickel 
layer comprised of bright nickel and semi-bright nickel. 
Before the electroplated article is subjected to a vapor deposition process 
in order to apply at least one thin vapor deposited coating layer onto the 
electroplated coating the article is pulse blow dried in order to remove 
any wet spots or nickel or chrome stains. 
After pulse blow drying at least one coating layer is deposited by physical 
vapor deposition onto the top electroplated layer. The vapor deposited 
layer or layers are selected from non-precious refractory metals, 
non-precious refractory metal alloys, non-precious refractory metal 
compounds, and non-precious refractory metal alloy compounds. The 
non-precious refractory metal compounds and non-precious refractory metal 
alloy compounds include the nitrides, oxides, carbides, carbonitrides, and 
reaction products of a refractory metal or refractory metal alloy, oxygen 
and nitrogen.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The method of this invention is especially characterized by providing a 
decorative and protective vapor deposited thin coating layer on an 
electroplated undercoating which is free of blemishes or imperfections 
such as water spots, nickel spots and chrome spots. These blemishes or 
imperfections are generally due to spots remaining on the electroplated 
surface of the article as a result of the electroplating process. When the 
thin vapor deposited coating layer is applied over these spots they are 
greatly accentuated by this thin physical vapor deposited coating layer. 
The method of the instant invention comprises first depositing on at least 
a portion of the surface of an article at least one electroplated coating 
layer, removing the electroplated article from the electroplating bath and 
subjecting it to pulse blow drying to remove any spots from the surface 
thereof, and applying, by physical vapor deposition, at least one thin 
coating layer onto the clean and dry electroplated surface. 
Pulse blow drying and a pulse blow dryer are described in European Patent 0 
486 711, the disclosure of which is incorporated herein by reference. The 
pulse blow dryer is illustrated in FIG. 1. Briefly it comprises a housing 
similar to a conventional and well known circulating air drier. 
Ventilator, heating device, and air circulation shutters correspond to 
known and conventional designs. A movable nozzle device is additionally 
installed at each side of the station. The nozzle device is equipped with 
little nozzle pipes, about 150 mm long, and provided with 15 borings which 
correspond to the width of the travel direction. Each little nozzle pipe 
is supplied with air by means of solenoid valves. The solenoid valves are 
controlled by a microprocessor allowing the valves to be opened one after 
the other. The opening intervals can be adjusted between 20 and 100 ms via 
the control device. In case of wide driers, the valves are opened in 
groups, i.e. from 6-8 little nozzle pipes, one pipe is always open. The 
nozzle devices are moved up and down in opposite direction with an 
adjustable speed. The speed is normally approximately one to two strokes 
per minute. The stroke corresponds to the height of the rack plus 50 mm on 
top and bottom. 
By the pulse-like connection of the individual little nozzle pipes to the 
compressed air supply with a nominal pressure of six bars, 15 air 
jets/pipe will result. These air jets atomize the water droplets on the 
surface of the parts. Due to the repeated blowing off of the surface of 
the articles with the pulsating air jets and stepping on from nozzle pipe 
to nozzle pipe in the horizontal position, one air jet is generated for 
approximately 1 cm.sup.2 of surface. 
The alternating passing and blowing-in of the sharp air jets into borings, 
blindholes, undercuts, and edges lead to a suction effect which removes 
the liquid even from the hollow spaces. This effect is so intense that 
even long borings in hollow parts, large interior spaces and threaded 
holes are dried well. When removing the parts from the racks, no water 
flows out from the hollow spaces and thus the quality of the surface is 
not spoiled by water stains. 
A programmable control device allows a selection of the pulse frequency, 
the speed of the nozzle device, the number of valves simultaneously 
opened, the number of strokes, and the temperature. These parameters can 
be assigned to the articles to be treated. In a drying program, the speed 
and pulse frequency can be separately adjusted for every stroke. Large 
articles with a great drag-out can be blown off very quickly at the first 
stroke with short air pulses. The main quantity of adhesive water droplets 
is blown off here. 
During the following strokes, the speed will be automatically reduced and 
the pulse frequency will be extended. The stronger air pulses and the 
valves opened for a longer period have a considerably better suction 
effect resulting in an improved drying of the hollow spaces. 
As the main quantity of water is blown off, i.e. atomized, only a very thin 
adsorption layer remains to be dried up. Therefore, only short drying 
periods of two to five minutes are needed at a circulating air temperature 
of 50.degree.-70.degree. C. 
The pulse blow drying provides stainless drying. Thus electroplated 
articles can have a physical vapor deposited thin coating applied thereon 
without any further cleaning or drying of the electroplated articles. 
The article can be comprised of any platable substrate such as metal or 
plastic. The metals that the article can be comprised of include brass, 
zinc, steel and aluminum. The electroplated coating which is deposited by 
electroplating on at least a portion of the surface of the article can be 
comprised of one layer or more than one layer. Preferred electroplated 
coatings include copper, including alkaline copper and acid copper, 
nickel, including bright nickel and semi-bright nickel, and chrome. 
If the article is comprised of brass typically at least one nickel layer 
and chrome layer are electroplated on said article, with the nickel layer 
being deposited directly on the surface of the article and the chrome 
layer being deposited on the nickel layer. Brass articles can also have a 
copper layer applied directly on the surface thereof. At least one nickel 
layer is then electroplated on the copper layer. A chrome layer is then 
electroplated on the nickel layer. 
The nickel layer is deposited on at least a portion of the surface of the 
substrate article by conventional and well known electroplating processes. 
These processes include using a conventional electroplating bath such as, 
for example, a Watts bath as the plating solution. Typically such baths 
contain nickel sulfate, nickel chloride, and boric acid dissolved in 
water. All chloride, sulfamate and fluoroborate plating solutions can also 
be used. These baths can optionally include a number of well known and 
conventionally used compounds such as leveling agents, brighteners, and 
the like. To produce specularly bright nickel layer at least one 
brightener from class I and at least one brightener from class II is added 
to the plating solution. Class I brighteners are organic compounds which 
contain sulfur. Class II brighteners are organic compounds which do not 
contain sulfur. Class II brighteners can also cause leveling and, when 
added to the plating bath without the sulfur-containing class I 
brighteners, result in semi-bright nickel deposits. These class I 
brighteners include alkyl naphthalene and benzene sulfonic acids, the 
benzene and naphthalene di- and trisulfonic acids, benzene and naphthalene 
sulfonamides, and sulfonamides such as saccharin, vinyl and allyl 
sulfonamides and sulfonic acids. The class II brighteners generally are 
unsaturated organic materials such as, for example, acetylenic or 
ethylenic alcohols, ethoxylated and propoxylated acetylenic alcohols, 
coumarins, and aldehydes. These class I and class II brighteners are well 
known to those skilled in the art and are readily commercially available. 
They are described, inter alia, in U.S. Pat. No. 4,421,611 incorporated 
herein by reference. 
The nickel layer can be a monolithic layer comprised of, for example, 
semi-bright nickel or bright nickel; or it can be a duplex layer 
containing a layer comprised of semi-bright nickel and a layer comprised 
of bright nickel. The thickness of the nickel layer is generally in the 
range of from about 100 millionths (0.000100) of an inch, preferably about 
150 millionths (0.000150) of an inch to about 3,500 millionths (0.0035) of 
an inch. 
As is well known in the art before the nickel layer is deposited on the 
substrate the substrate is subjected to said activation by being placed in 
a conventional and well known acid bath. 
In one embodiment as illustrated in FIG. 2, the nickel layer 13 is actually 
comprised of two different nickel layers 14 and 16. Layer 14 is comprised 
of semi-bright nickel while layer 16 is comprised of bright nickel. This 
duplex nickel deposit provides improved corrosion protection to the 
underlying substrate. The semi-bright, sulfur-free plate 14 is deposited, 
by conventional electroplating processes, directly on the surface of the 
article substrate 12. The substrate 12 containing the semi-bright nickel 
layer 14 is then placed in a bright nickel plating bath and the bright 
nickel layer 16 is deposited on the semi-bright nickel layer 14. 
The thickness of the semi-bright nickel layer and the bright nickel layer 
is a thickness effective to provide improved corrosion protection. 
Generally, the thickness of the semi-bright nickel layer is at least about 
50 millionths (0.00005) of an inch, preferably at least about 100 
millionths (0.0001) of an inch, and more preferably at least about 150 
millionths (0.00015) of an inch. The upper thickness limit is generally 
not critical and is governed by secondary considerations such as cost. 
Generally, however, a thickness of about 1,500 millionths (0.0015) of an 
inch, preferably about 1,000 millionths (0.001) of an inch, and more 
preferably about 750 millionths (0.00075) of an inch should not be 
exceeded. The bright nickel layer 16 generally has a thickness of at least 
about 50 millionths (0.00005) of an inch, preferably at least about 125 
millionths (0.000125) of an inch, and more preferably at least about 250 
millionths (0.00025) of an inch. The upper thickness range of the bright 
nickel layer is not critical and is generally controlled by considerations 
such as cost. Generally, however, a thickness of about 2,500 millionths 
(0.0025) of an inch, preferably about 2,000 millionths (0.002) of an inch, 
and more preferably about 1,500 millionths (0.0015) of an inch should not 
be exceeded. The bright nickel layer 16 also functions as a leveling layer 
which tends to cover or fill in imperfections in the substrate. 
In another embodiment of the invention as illustrated in FIG. 2 a chrome 
layer 20 is electroplated onto the nickel layer 13. The chrome layer 20 
may be deposited on the nickel layer 13 by conventional and well known 
chromium electroplating techniques. These techniques, along with various 
chrome plating baths, are disclosed in Brassard, "Decorative 
Electroplating--A Process in Transition", Metal Finishing, pp. 105-108, 
June 1988; Zaki, "Chromium Plating", PF Directory, pp. 146-160; and in 
U.S. Pat. Nos. 4,460,438, 4,234,396, and 4,093,522, all of which are 
incorporated herein by reference. 
Chrome plating baths are well known and commercially available. A typical 
chrome plating bath contains chromic acid or salts thereof, and catalyst 
ion such as sulfate or fluoride. The catalyst ions can be provided by 
sulfuric acid or its salts and fluosilicic acid. The baths may be operated 
at a temperature of about 112.degree.-116.degree. F. Typically in chrome 
plating a current density of about 150 amps per square foot, at about 5 to 
9 volts is utilized. 
The chrome layer generally has a thickness of at least about 2 millionths 
(0.000002) of an inch, preferably at least about 5 millionths (0.000005) 
of an inch, and more preferably at least about 8 millionths (0.000008) of 
an inch. Generally, the upper range of thickness is not critical and is 
determined by secondary considerations such as cost. However, the 
thickness of the chrome layer should generally not exceed about 60 
millionths (0.00006) of an inch, preferably about 50 millionths (0.00005) 
of an inch, and more preferably about 40 millionths (0.00004) of an inch. 
In another embodiment of the invention, as illustrated in FIG. 3, 
especially when the substrate article is comprised of zinc or brass, a 
copper layer 17 or layers are electroplated on at least a portion of the 
article surface 12. Nickel layer 16 is then electroplated on the copper 
followed by electroplating of chrome 20 on the nickel layer. The nickel 
layer may be a monolithic layer as illustrated in FIG. 3 and comprised of, 
for example, bright nickel or it may be a duplex nickel layer comprised 
of, for example, a bright nickel layer and a semi-bright nickel layer. The 
copper coating 17 may be comprised of a monolithic copper layer or two 
different copper layers, for example, an alkaline copper layer on the 
surface of the article and an acid copper layer on the alkaline copper 
layer. In the embodiment illustrated in FIG. 3 the copper coating 17 is a 
monolithic copper layer comprised of acid copper. 
Copper electroplating processes and copper electroplating baths are 
conventional and well known in the art. They include the electroplating of 
acid copper and alkaline copper. They are described, inter alia, in U.S. 
Pat. Nos. 3,725,220; 3,769,179; 3,923,613; 4,242,181 and 4,877,450, the 
disclosures of which are incorporated herein by reference. 
The preferred copper layer is selected from alkaline copper and acid 
copper. The copper layer may be monolithic and consist of one type of 
copper such as alkaline copper or acid copper, or it may comprise two 
different copper layers such as a layer comprised of alkaline copper 11a 
(not shown) and a layer comprised of acid copper 11b (not shown). 
The thickness of the copper layer is generally in the range of from at 
least about 100 millionths (0.0001) of an inch, preferably at least about 
150 millionths (0.00015) of an inch to about 3,500 millionths (0.0035), 
preferably about 2,000 millionths (0.002) of an inch. 
When a duplex copper layer is present comprised of, for example, an 
alkaline copper layer and an acid copper layer, the thickness of the 
alkaline copper layer is generally at least about 50 millionths (0.00005) 
of an inch, preferably at least about 75 millionths (0.000075) of an inch. 
The upper thickness limit is generally not critical. Generally, a 
thickness of about 1,500 millionths (0.0015) of an inch, preferably about 
1,000 millionths (0.001) of an inch should not be exceeded. The thickness 
of the acid copper layer is generally at least about 50 millionths 
(0.0005) of an inch, preferably at least about 75 millionths (0.00075) of 
an inch. The upper thickness limit is generally not critical. Generally, a 
thickness of about 1,500 millionths (0.0015) of an inch, preferably about 
1,000 millionths (0.001) of an inch should not be exceeded. 
Some illustrative, non-limiting examples of electroplated layers include 
substrate/nickel such as bright nickel/chrome, substrate/semi-bright 
nickel/bright nickel/chrome, substrate/nickel such as bright nickel, 
substrate/semi-bright nickel/bright nickel, substrate/copper such as acid 
copper/nickel such as bright nickel/chrome, substrate/alkaline copper/acid 
copper/nickel such as bright nickel/chrome, substrate/copper such as 
alkaline copper/semi-bright nickel/bright nickel/chrome, 
substrate/alkaline copper/acid copper/semi-bright nickel/bright 
nickel/chrome, substrate/copper such as acid copper/nickel such as bright 
nickel, substrate/copper such as alkaline copper/semi-bright nickel/bright 
nickel, and substrate/alkaline copper/acid copper/semi-bright 
nickel/bright nickel. 
After the article has had the various electroplated coating layers, as 
exemplified supra and in FIGS. 2 and 3, deposited thereon by 
electroplating it is then subjected to pulse blow drying to blow off any 
spots, stains, moisture or droplets and produce an electroplated article 
having a stainless top surface. After completion of the pulse blow drying 
the electroplated article is placed in a physical vapor deposition chamber 
and one or more thin coating layers are deposited by physical vapor 
deposition on the surface of the electroplated article. 
The layers which are deposited by physical vapor deposition are metallic 
layers and are selected from non-precious refractory metals, non-precious 
refractory metal alloys, non-precious refractory metal compounds, and 
non-precious refractory metal alloy compounds. The non-precious refractory 
metals include hafnium, tantalum, titanium and zirconium. The preferred 
refractory metals are titanium and zirconium, with zirconium being more 
preferred. 
The non-precious refractory metal alloys include the alloys of the above 
mentioned refractory metals with the binary alloys being preferred. The 
preferred binary alloys are the binary alloys of zirconium, with the 
binary alloys of zirconium and titanium being more preferred. 
The non-precious refractory metal and metal alloy compounds include the 
nitrides, oxides, carbides and carbonitrides of the non-precious 
refractory metals and metal alloys. Also included among the non-precious 
refractory metal and metal alloy compounds useful in the instant invention 
are the reaction products of a non-precious refractory metal or metal 
alloy, oxygen and nitrogen. Examples of these non-precious refractory 
metal compounds include zirconium nitride, zirconium oxide, zirconium 
carbide, zirconium carbonitride, reaction products of zirconium, oxygen 
and nitrogen, titanium nitride, titanium oxide, titanium carbonitride, 
reaction products of titanium, oxygen and nitrogen, hafnium nitride, 
hafnium oxide, hafnium carbonitride, tantalum oxide, tantalum nitride, 
tantalum carbide, and the like. 
The reaction products of a non-precious refractory metal, such as for 
example zirconium, oxygen and nitrogen comprise zirconium oxide, zirconium 
nitride and zirconium oxy-nitride. 
Some illustrative non-limiting examples of the non-precious refractory 
metal alloy compounds include zirconium-titanium nitride, 
zirconium-titanium oxide, zirconium-titanium carbide, zirconium-titanium 
carbonitride, hafnium-zirconium nitride, hafnium-tantalum oxide, 
tantalum-titanium carbide, and reaction products of zirconium-titanium 
alloy, oxygen and nitrogen. 
The layers comprised of refractory metals and refractory metal alloys are 
deposited on at least a portion of the surface of the electroplated 
article by conventional and well known physical vapor deposition processes 
such as, for example, ion sputtering, cathodic arc electron evaporation 
beam deposition, and the like. Ion sputtering techniques and equipment are 
disclosed, inter alia, in T. Van Vorous, "Planar Magnetron Sputtering; A 
New Industrial Coating Technique", Solid State Technology, Dec. 1976, pp. 
62-66; U. Kapacz and S. Schulz, "Industrial Application of Decorative 
Coatings--Principle and Advantages of the Sputter Ion Plating Process", 
Soc. Vac. Coat., Proc. 34th Arn. Tech. Conf., Philadelphia, U.S.A., 1991, 
48-61; J. Vossen and W. Kern "Thin Film Processes II", Academic Press, 
1991; R. Boxman et al, "Handbook of Vacuum Arc Science and Technology", 
Noyes Pub., 1995; and U.S. Pat. Nos. 4,162,954 and 4,591,418, all of which 
are incorporated herein by reference. 
Briefly, in the sputtering deposition process the refractory metal such as 
titanium or zirconium target, which is the cathode, and the substrate are 
placed in a vacuum chamber. The air in the chamber is evacuated to produce 
vacuum conditions in the chamber. An inert gas, such as Argon, is 
introduced into the chamber. The gas particles are ionized and are 
accelerated to the target to dislodge titanium or zirconium atoms. The 
dislodged target material is then typically deposited as a coating film on 
the substrate. 
In cathodic arc evaporation an electric arc of typically several hundred 
amperes is struck on the surface of a metal cathode such as zirconium or 
titanium. The arc vaporizes the cathode material, which then condenses on 
the substrate forming a coating. 
Reactive ion sputtering is generally similar to ion sputter deposition 
except that a reactive gas such as, for example, oxygen or nitrogen which 
reacts with the dislodged target material is introduced into the chamber. 
Thus, in the case where zirconium nitride is a layer the target is 
comprised of zirconium and nitrogen gas is the reactive gas introduced 
into the chamber. By controlling the amount of nitrogen available to react 
with the zirconium, the color of the zirconium nitride can be made to be 
similar to that of brass of various hues. 
Generally, more than one layer comprised of refractory metal, refractory 
metal alloy, refractory metal compound and refractory metal alloy compound 
is deposited on the electroplated article. Thus, for example, a layer 
comprised of refractory metal or refractory metal alloy such as zirconium 
is vapor deposited on the electroplated article; a sandwich layer 
comprised of alternating layers of refractory metal or refractory metal 
alloy such as zirconium and refractory metal compound or refractory metal 
alloy compound such as zirconium nitride is then deposited on the 
zirconium layer; and a layer comprised of the reaction products of a 
refractory metal or refractory metal alloy such as zirconium, oxygen and 
nitrogen is deposited on the sandwich layer. 
In another embodiment a layer comprised of a first refractory metal 
compound or refractory metal alloy compound, preferably a nitride, is 
vapor deposited on the refractory metal or refractory metal alloy layer. A 
layer comprised of a different second refractory metal compound or 
refractory metal alloy compound, preferably an oxide or the reaction 
products of a refractory metal or refractory metal alloy, oxygen and 
nitrogen, is then vapor deposited on said first refractory metal compound 
or refractory metal alloy compound layer. 
Generally the refractory metal or refractory metal alloy layer has a 
thickness of at least about 0.25 millionths (0.00000025) of an inch, 
preferably at least about 0.5 millionths (0.0000005) of an inch, and more 
preferably at least about one millionth (0.000001) of an inch. The upper 
thickness range is not critical and is generally dependent upon 
considerations such as cost. Generally, however, the layer comprised of 
refractory metal or refractory metal alloy should not be thicker than 
about 50 millionths (0.00005) of an inch, preferably about 15 millionths 
(0.000015) of an inch, and more preferably about 10 millionths (0.000010) 
of an inch. 
Generally the refractory metal or refractory metal alloy layer functions, 
inter alia, to improve the adhesion of a layer comprised of refractory 
metal compound, refractory metal alloy compound, reaction products of 
refractory metal or refractory metal alloy, oxygen and nitrogen to the 
electroplated article. Thus, the refractory metal or refractory metal 
alloy layer generally has a thickness which is at least effective to 
improve the adhesion of a layer comprised of refractory metal compound, 
refractory metal alloy compound, and reaction products of a refractory 
metal or refractory metal alloy, oxygen and nitrogen to the electroplated 
article. 
In a preferred embodiment of the present invention the refractory metal 
layer is comprised of zirconium, titanium, or zirconium-titanium alloy, 
preferably zirconium or zirconium-titanium alloy, and is deposited by 
physical vapor deposition processes such as, for example, ion sputtering 
or electron beam evaporation. 
The layer comprised of refractory metal compound, refractory metal alloy 
compound, or reaction products of refractory metal or refractory metal 
alloy compound, oxygen and nitrogen generally has a thickness which is at 
least about 2 millionths (0.000002) of an inch, preferably at least about 
4 millionths (0.000004) of an inch, and more preferably at least about 6 
millionths (0.000006) of an inch. The upper thickness range is generally 
not critical and is dependent upon considerations such as cost. Generally 
a thickness of about 30 millionths (0.00003) of an inch, preferably about 
25 millionths (0.000025) of an inch, and more preferably about 20 
millionths (0.000020) of an inch should not be exceeded. 
This layer generally provides wear resistance, abrasion resistance and the 
desired color or appearance. This layer is preferably comprised of 
zirconium nitride or zirconium-titanium alloy nitride which has the color 
of brass. The thickness of this layer is at least effective to provide 
wear resistance, abrasion resistance, and the desired color or appearance. 
In another embodiment of the invention a sandwich layer comprised of 
alternating layers of a non-precious refractory metal compound or 
non-precious refractory metal alloy compound and a non-precious refractory 
metal or non-precious refractory metal alloy is deposited over the 
refractory metal or refractory metal alloy layer such as zirconium or 
zirconium-titanium alloy. An exemplary structure of this embodiment is 
illustrated in FIG. 4 wherein 22 represents the refractory metal or 
refractory metal alloy layer, preferably zirconium or zirconium-titanium 
alloy, 26 represents the sandwich layer, 28 represents a non-precious 
refractory metal compound layer or non-precious refractory metal alloy 
compound layer, and 30 represents a non-precious refractory metal layer or 
non-precious refractory metal alloy layer. 
The non-precious refractory metals and non-precious refractory metal alloys 
comprising layers 30 include hafnium, tantalum, titanium, zirconium, 
zirconium-titanium alloy, zirconium-hafnium alloy, and the like; 
preferably zirconium, titanium, or zirconium-titanium alloy; and more 
preferably zirconium or zirconium-titanium alloy. 
The non-precious refractory metal compounds and non-precious refractory 
metal alloy compounds comprising layers 28 include hafnium compounds, 
tantalum compounds, titanium compounds, zirconium compounds, and 
zirconium-titanium alloy compounds; preferably titanium compounds, 
zirconium compounds, or zirconium-titanium alloy compounds; and more 
preferably zirconium compounds or zirconium-titanium alloy compounds. 
These compounds are selected from nitride, carbides and carbonitrides, 
with the nitride being preferred. Thus, the titanium compound is selected 
from titanium nitrides, titanium carbide and titanium carbonitride, with 
titanium nitride being preferred. The zirconium compound is selected from 
zirconium nitride, zirconium carbide and zirconium carbonitride, with 
zirconium nitride being preferred. 
The sandwich layer 26 generally has an average thickness of from about 50 
millionths (0.00005) of an inch to about one millionth (0.000001) of an 
inch, preferably from about 40 millionths (0.00004) of an inch to about 
two millionths (0.000002) of an inch, and more preferably from about 30 
millionths (0.00003) of an inch to about three millionths (0.000003) of an 
inch. 
Each of layers 28 and 30 generally has a thickness of at least about 0.002 
millionths (0.00000002) of an inch, preferably at least about 0.1 
millionths (0.0000001) of an inch, and more preferably at least about 0.5 
millionths (0.0000005) of an inch. Generally, layers 28 and 30 should not 
be thicker than about 25 millionths (0.000025) of an inch, preferably 
about 10 millionths (0.00001) of an inch, and more preferably about 5 
millionths (0.000005) of an inch. 
A method of forming the sandwich layer 26 is by utilizing ion sputter 
plating to deposit a layer 30 of non-precious refractory metal such as 
zirconium or titanium followed by reactive ion sputter plating to deposit 
a layer 28 of non-precious refractory metal nitride such as zirconium 
nitride or titanium nitride. 
Preferably the flow rate of nitrogen gas is varied (pulsed) during the 
reactive ion sputter plating between zero (no nitrogen gas is introduced) 
to the introduction of nitrogen at a desired value to form multiple 
alternating layers of metal 30 and metal nitride 28 in the sandwich layer 
26. 
The number of alternating layers of refractory metal 30 and refractory 
metal compound layers 28 in sandwich layer 26 is generally at least about 
2, preferably at least about 4, and more preferably at least about 6. 
Generally, the number of alternating layers of refractory metal 30 and 
refractory metal compound 30 in sandwich layer 26 should not exceed about 
50, preferably about 40, and more preferably about 30. 
In one embodiment of the invention, as illustrated in FIG. 4, vapor 
deposited over the sandwich layer 26 is a layer 32 comprised of a 
non-precious refractory metal compound or non-precious refractory metal 
alloy compound, preferably a nitride, carbide or carbonitride, and more 
preferably a nitride. 
Layer 32 is comprised of a hafnium compound, a tantalum compound, a 
titanium compound, a zirconium-titanium alloy compound, or a zirconium 
compound, preferably a titanium compound, a zirconium-titanium alloy 
compound, or a zirconium compound, and more preferably a zirconium 
compound or a zirconium-titanium alloy compound. The titanium compound is 
selected from titanium nitride, titanium carbide, and titanium 
carbonitride, with titanium nitride being preferred. The zirconium 
compound is selected from zirconium nitride, zirconium carbonitride, and 
zirconium carbide, with zirconium nitride being preferred. 
Layer 32 provides wear and abrasion resistance and the desired color or 
appearance, such as for example, polished brass. Layer 32 is deposited on 
layer 26 by any of the well known and conventional physical vapor 
deposition techniques such as reactive ion sputtering. 
Layer 32 has a thickness at least effective to provide abrasion resistance 
and/or the color of brass. Generally, this thickness is at least 2 
millionths (0.000002) of an inch, preferably at least 4 millionths 
(0.000004) of an inch, and more preferably at least 6 millionths 
(0.000006) of an inch. The upper thickness range is generally not critical 
and is dependent upon considerations such as cost. Generally a thickness 
of about 30 millionths (0.00003) of an inch, preferably about 25 
millionths (0.000025) of an inch, and more preferably about 20 millionths 
(0.000020) of an inch should not be exceeded. 
Zirconium nitride is the preferred coating material as it most closely 
provides the appearance of polished brass. 
In one embodiment of the invention, as illustrated in FIG. 4, a layer 34 
comprised of the reaction products of a non-precious refractory metal or 
metal alloy, an oxygen containing gas such as oxygen, and nitrogen is 
deposited onto layer 32. The metals that may be employed in the practice 
of this invention are those which are capable of forming both a metal 
oxide and a metal nitride under suitable conditions, for example, using a 
reactive gas comprised of oxygen and nitrogen. The metals may be, for 
example, tantalum, hafnium, zirconium, zirconium-titanium alloy, and 
titanium, preferably titanium, zirconium-titanium alloy and zirconium, and 
more preferably zirconium and zirconium-titanium alloy. 
The reaction products of the metal or metal alloy, oxygen and nitrogen are 
generally comprised of the metal or metal alloy oxide, metal or metal 
alloy nitride and metal or metal alloy oxy-nitride. Thus, for example, the 
reaction products of zirconium, oxygen and nitrogen comprise zirconium 
oxide, zirconium nitride and zirconium oxy-nitride. 
The layer 34 can be deposited by a well known and conventional physical 
vapor deposition techniques, including reactive ion sputtering of a pure 
metal target and a gas or a composite target of oxides, nitride and/or 
metals. 
These metal oxides and metal nitride including zirconium oxide and 
zirconium nitride alloys and their preparation and deposition are 
conventional and well known and are disclosed, inter alia, in U.S. Pat. 
No. 5,367,285, the disclosure of which is incorporated herein by 
reference. 
The metal, oxygen and nitrogen reaction products containing layer 34 
generally has a thickness of at least about 0.1 millionths (0.0000001) of 
an inch, preferably at least about 0.15 millionths (0.00000015) of an 
inch, and more preferably at least about 0.2 millionths (0.0000002) of an 
inch. Generally, the metal oxy-nitride layer should not be thicker than 
about one millionth (0.000001) of an inch, preferably about 0.5 millionths 
(0.0000005) of an inch, and more preferably about 0.4 millionths 
(0.0000004) of an inch. 
In another embodiment, as illustrated in FIG. 5, instead of the layer 34 
comprised of the reaction products of a refractory metal or refractory 
metal alloy, oxygen and nitrogen being deposited on layer 32 a layer 36 
comprised of non-precious refractory metal oxide or refractory metal alloy 
oxide is applied by physical vapor deposition onto layer 32. The 
refractory metal oxides and refractory metal alloy oxides of which layer 
36 is comprised include, but are not limited to, hafnium oxide, tantalum 
oxide, zirconium oxide, titanium oxide, and zirconium-titanium alloy 
oxide, preferably titanium oxide, zirconium oxide, and zirconium-titanium 
alloy oxide, and more preferably zirconium oxide and zirconium-titanium 
alloy oxide. 
Layer 36 has a thickness of at least about 0.1 millionths (0.0000001) of an 
inch, preferably at least about 0.15 millionths (0.00000015) of an inch, 
and more preferably at least about 0.2 millionths (0.0000002) of an inch. 
Generally the metal or metal alloy oxide layer 36 should not be thicker 
than about 2 millionths (0.000002) of an inch, preferably about 1.5 
millionths (0.0000015) of an inch, and more preferably about one millionth 
(0.000001) of an inch. 
FIG. 6 illustrates an article substrate 12 having a bright nickel layer 16 
electroplated on its surface and a chrome layer 20 electroplated on the 
bright nickel layer 16. On the electroplated chrome layer are deposited by 
physical vapor deposition, after the substrate article 12 having 
electroplated layers 16 and 20 thereon has been subjected to pulse blow 
drying, layer 22 comprised of zirconium, sandwich layer 26 comprised of 
alternating layers 28 and 30 comprised of, respectively, zirconium nitride 
and zirconium, layer 32 comprised of zirconium nitride, and layer 34 
comprised of the reaction products of zirconium, oxygen and nitrogen. 
In order that the invention may be more readily understood the following 
example is provided. The example is illustrative and does not limit the 
invention thereof. 
EXAMPLE I 
Brass faucets are placed in a conventional soak cleaner bath containing the 
standard and well known soaps, detergents, defloculants and the like which 
is maintained at a pH of 8.9-9.2 and a temperature of 
180.degree.-200.degree. F. for about 10 minutes. The brass faucets are 
then placed in a conventional ultrasonic alkaline cleaner bath. The 
ultrasonic cleaner bath has a pH of 8.9-9.2, is maintained at a 
temperature of about 160.degree.-180.degree. F., and contains the 
conventional and well known soaps, detergents, defloculants and the like. 
After the ultrasonic cleaning the faucets are rinsed and placed in a 
conventional alkaline electro cleaner bath. The electro cleaner bath is 
maintained at a temperature of about 140.degree.-180.degree. F., a pH of 
about 10.5-11.5, and contains standard and conventional detergents. The 
faucets are then rinsed twice and placed in a conventional acid activator 
bath. The acid activator bath has a pH of about 2.0-3.0, is at an ambient 
temperature, and contains a sodium fluoride based acid salt. The faucets 
are then rinsed twice and placed in a bright nickel plating bath for about 
12 minutes. The bright nickel bath is generally a conventional bath which 
is maintained at a temperature of about 130.degree.-150.degree. F., a pH 
of about 4.0, contains NiSO.sub.4, NiCl.sub.2 boric acid, and brighteners. 
A bright nickel layer of an average thickness of about 400 millionths 
(0.0004) of an inch is deposited on the faucet surface. The bright nickel 
plated faucets are rinsed three times and then placed in a conventional, 
commercially available hexavalent chromium plating bath using conventional 
chromium plating equipment for about seven minutes. The hexavalent 
chromium bath is a conventional and well known bath which contains about 
32 ounces/gallon of chromic acid. The bath also contains the conventional 
and well known chromium plating additives. The bath is maintained at a 
temperature of about 112.degree.-116.degree. F., and utilizes a mixed 
sulfate/fluoride catalyst. The chromic acid to sulfate ratio is about 
200:1. A chromium layer of about 10 millionths (0.00001) of an inch is 
deposited on the surface of the bright nickel layer. The faucets are 
thoroughly rinsed in deionized water. 
The electroplated faucets are placed on a rack and the rack moves through a 
pulse blow dryer manufactured by LPW-Anlagen GmbH of Germany and described 
in European patent application EP 0486 711 A1. The blow dryer is equipped 
with a row of small nozzles which emit pulsating air jets at 80 psi. The 
dryer is maintained at a temperature of 130.degree. F. The electroplated 
faucets remain in the pulse blow dryer a total of 210 seconds, with the 
rack moving through the dryer two feet in five seconds. The rack remains 
motionless for 37 seconds and then advances again. The pulses last for 
about 20 miliseconds. The faucets are removed from the pulse blow dryer 
and are placed in a cathodic arc evaporation plating vessel. The vessel is 
generally a cylindrical enclosure containing a vacuum chamber which is 
adapted to be evacuated by means of pumps. A source of argon gas is 
connected to the chamber by an adjustable valve for varying the rate of 
flow of argon into the chamber. In addition, a source of nitrogen gas is 
connected to the chamber by an adjustable valve for varying the rate of 
flow of nitrogen into the chamber. 
A cylindrical cathode is mounted in the center of the chamber and connected 
to negative outputs of a variable D.C. power supply. The positive side of 
the power supply is connected to the chamber wall. The cathode material 
comprises zirconium. 
The plated faucets are mounted on spindles, 16 of which are mounted on a 
ring around the outside of the cathode. The entire ring rotates around the 
cathode while each spindle also rotates around its own axis, resulting in 
a so-called planetary motion which provides uniform exposure to the 
cathode for the multiple faucets mounted around each spindle. The ring 
typically rotates at several rpm, while each spindle makes several 
revolutions per ring revolution. The spindles are electrically isolated 
from the chamber and provided with rotatable contacts so that a bias 
voltage may be applied to the substrates during coating. 
The vacuum chamber is evacuated to a pressure of about 5.times.10.sup.-3 
millibar and heated to about 150.degree. C. 
The electroplated faucets are then subjected to a high-bias arc plasma 
cleaning in which a (negative) bias voltage of about 500 volts is applied 
to the electroplated faucets while an arc of approximately 500 amperes is 
struck and sustained on the cathode. The duration of the cleaning is 
approximately five minutes. 
Argon gas is introduced at a rate sufficient to maintain a pressure of 
about 3.times.10.sup.-2 millibars. A layer of zirconium having an average 
thickness of about four millionths (0.000004) of an inch is deposited on 
the chrome plated faucets during a three minute period. The cathodic arc 
deposition process comprises applying D.C. power to the cathode to achieve 
a current flow of about 500 amps, introducing argon gas into the vessel to 
maintain the pressure in the vessel at about 1.times.10.sup.-2 millibar, 
and rotating the faucets in a planetary fashion described above. 
After the zirconium layer is deposited the sandwich layer is applied onto 
the zirconium layer. A flow of nitrogen is introduced into the vacuum 
chamber periodically while the arc discharge continues at approximately 
500 amperes. The nitrogen flow rate is pulsed, i.e. changed periodically 
from a maximum flow rate, sufficient to fully react the zirconium atoms 
arriving at the substrate to form zirconium nitride, and a minimum flow 
rate equal to zero or some lower value not sufficient to fully react with 
all the zirconium. The period of the nitrogen flow pulsing is one to two 
minutes (30 seconds to one minute on, then off). The total time for pulsed 
deposition is about 15 minutes, resulting in a sandwich stack with 10 to 
15 layers of thickness of about one to 1.5 millionths of an inch each. The 
deposited material in the sandwich layer alternates between fully reacted 
zirconium nitride and zirconium metal (or substoichiometric ZrN with much 
smaller nitrogen content). 
After the sandwich layer is deposited, the nitrogen flow rate is left at 
its maximum value (sufficient to form fully reacted zirconium nitride) for 
a time of five to ten minutes to form a thicker "color layer" on top of 
the sandwich layer. After this zirconium nitride layer is deposited, an 
additional flow of oxygen of approximately 0.1 standard liters per minute 
is introduced for a time of thirty seconds to one minute, while 
maintaining nitrogen and argon flow rates at their previous values. A thin 
layer of mixed reaction products is formed (zirconium oxy-nitride), with 
thickness approximately 0.2 to 0.5 millionths of an inch. The arc is 
extinguished at the end of this last deposition period, the vacuum chamber 
is vented and the coated substrates removed.