MXPA06008397A - Coated article - Google Patents

Abstract

An article is coated with a multi-layer coating having a bronze color. In a preferred embodiment, the coating comprises a nickel or polymer basecoat layer, and a color and protective stack layer comprised of layers of carbon-rich refractory metal or refractory metal alloy carbonitride alternating with layers of nitrogen-rich refractory metal or refractory metal alloy carbonitride. In another embodiment, the alternating layers of the color stack layer may comprise layers of carbon-rich refractory metal carbides or carbon-rich refractory metal alloy carbides alternating with layers of nitrogen-rich refractory metal. nitrides or nitrogen-rich refractory metal alloy nitrides.

Description

ARTICLE COATED FIELD OF THE INVENTION This invention relates to articles, particularly brass articles, having a multi-layer decorative and protective coating having the bronze appearance or color, particularly antique bronze, thereon. BACKGROUND OF THE INVENTION It is currently the practice with various brass articles such as faucets, faucet plates, door knobs, door handles, door plates and the like to polish and polish the surface of the article first to a high gloss and then apply a organic protective coating, such as one comprising acrylics, urethanes, epoxies and the like, on this polished surface. This system has the disadvantage that the polishing and polishing operation, particularly if the article is of a complex shape, requires a lot of work. Also, known organic coatings are not always as durable as desired, and are susceptible to acid attack. It could, therefore, be very advantageous if brass articles, or indeed other articles, such as plastic, ceramic or metallic, could be provided with coating which provides the article with an appearance No. Ref .: 174223 decorative as well as provide wear resistance, abrasion resistance and corrosion resistance. This multi-layer coating includes a decorative and protective color layer of a refractory metal nitride such as zirconium nitride or titanium nitride. This layer with color, when it is. Zirconium nitride, provides a brass color, and when it is titanium nitride it provides a gold color. U.S. Patent Nos. 5,922,478; 6,033,790 and 5,654,108 ,. among other things, they describe a coating which provides an article with a decorative color, such as polished brass, provides wear resistance, abrasion resistance and corrosion resistance. It could be very disadvantageous if a coating could be provided which provides substantially the same properties as coatings containing zirconium nitride or titanium nitride but instead of being brass or gold-colored outside bronze, particularly of antique bronze color. The present invention provides such a coating. SUMMARY OF THE INVENTION The present invention is directed to an article coated with a multi-layer coating having a bronze color. The coating comprises a colored and protective stack layer comprised of layers of refractory metal rich in carbon or refractory metal alloy carbonitride alternated with layers of refractory metal rich in nitrogen or refractory metal or alloy carbonitride. refractory metal. In another embodiment, the alternating layers of the stack layer. with color may comprise layers of carbon-rich refractory metal carbides or carbon-rich refractory metal alloy carbides alternated with layers of nitrogen-rich refractory metal nitrides or nitrogen-rich refractory metal alloy nitrides. The present invention is also directed to an article such as a plastic, ceramic, cement or metallic article having a decorative and protective multilayer coating deposited on at least a portion of its surface. More particularly, it is directed to an article or substrate, particularly a metallic article such as stainless steel, aluminum, brass or zinc, which has deposited on its surface multiple superposed layers of certain specific types of materials. The coating is decorative and also provides corrosion resistance, wear resistance and abrasion resistance. The coating provides the appearance or color to bronze, particularly antique bronze, that is, it has a two-tone color: dark gray and dark yellow. Thus, a surface of the article that has the coating on it simulates a bronze, particularly an antique bronze surface. In the preferred embodiment, the article first has one or more base coat layers deposited on its surface. On top of the basecoat layers, one or more layers deposited in the vapor phase is deposited by vapor deposition such as physical deposition in the vapor phase. A first base coat layer deposited directly on the surface of the substrate is comprised of nickel or a polymeric material. When the layer is nickel, this is a layer applied by electroplating. The nickel may be monolithic or it may consist of two nickel-different layers such as, for example, a layer of semi-bright nickel deposited directly on the surface of the substrate and a layer of bright nickel superimposed on the semi-glossy nickel layer . Arranged on the layers of nickel or polymer layer is a shock layer comprised of a refractory metal or metal alloy such as zirconium, titanium, hafnium, tantalum or zirconium-titanium alloy, preferably zirconium, titanium or zirconium-titanium alloy. In a mode arranged intermediate the base coat layer and the shock layer is a reinforcement layer comprised of chromium. Above the shock layer is a layer with protective and decorative color comprised of a stack layer comprised of layers of refractory carbon-carbon refractory metal or carbon alternating with layers of refractory metal carbonitride rich in nitrogen or nitride, such as carbonitride. zirconium, titanium carbonitride, tantalum carbonitride and hafnium carbonitride, and the carbonitrides of refractory metal alloys, such as a titanium-zirconium alloy. In another embodiment, these alternating layers can be a carbide without nitrogen content and a nitride without carbon content. These alternating layers of the pile layer may contain a small percentage of oxygen to increase the dark appearance of the coating. The small amount of oxygen has a range from about 2 to about 15 atomic percent. For zirconium, in the carbon-rich zirconium carbonitride layer, the carbon content is generally between about 25 to about 50 atomic percent, nitrogen content between about 5 to about 35 atomic percent, and this layer has a gray color Dark. In the nitrogen-rich zirconium carbonitride layer, the nitrogen content is between about 25 to about 50 atomic percent, carbon content between about 5 to about 35 atomic percent; and this layer has a dark yellow color with a slight reddish tint. Neither of these two layers is thick enough by itself to make the coating have its own color. However, when two or more of these layers are present, the overall color of the pile layer mimics an antique bronze appearance of two shades of dark gray and dark yellow. On top of this layer with color, a very thin layer of refractory metal oxide or refractory metal alloy oxide is deposited to improve the corrosion and chemical resistance of the coating. BRIEF DESCRIPTION OF THE FIGURES FIG. 1 is a cross-sectional view, not to scale, of a portion of the substrate having a multilayer coating comprising a duplex nickel base coating, a refractory metal layer, a stack layer comprised of alternating layers of refractory carbonitride carbon-rich or carbide layers and layers of refractory carbonitride rich in nitrogen or nitride, and a thin refractory metal oxide layer; FIG. 2 is a view similar to Fig. 2 except that a reinforcing chromium layer is present intermediate to the upper base coat layer and the refractory metal shock layer. DETAILED DESCRIPTION OF THE PREFERRED MODALITIES The article or substrate 12 may be comprised of any material on which an electroplated layer may be applied, such as plastic, for example, ABS, polyolefin, polyvinyl chloride, and phenol formaldehyde, ceramics, cement, metal or metal alloy. In one embodiment, it is comprised of a metal or metal alloy such as copper, steel, brass, zinc, aluminum, nickel alloys and the like. In the present invention, as illustrated in Figs. 1 and 2, a first layer or series of layers are applied to the surface of the article by metallization such as electroplating in the case of a nickel coating. In the case of a polymeric base coat, the polymer is applied by conventional means. A second series of layers are applied to the surface of the base coat layer or layers by vapor deposition. The electroplated polymer or layers serves, inter alia, as a base coat which levels the surface of the article and as a corrosion barrier to improve the corrosion resistance. In one embodiment of the present invention a nickel layer 13 can be deposited on the surface of the article. The nickel layer can be any of conventional nickels that are deposited by metallization, for example, bright nickel, semi-gloss nickel, satin nickel, etc. The nickel layer 13 can be deposited on at least a portion of the surface of the substrate 12 by conventional and well known electroplating processes. These processes include using a conventional electroplating bath such as, for example, a Watts bath as the metallization solution. Typically such baths contain nickel sulfate, nickel chloride, and boric acid dissolved in water. All metallization solutions of chloride, sulfamate and fluoroborate can also be used. These baths may optionally include a number of conventionally used and well known compounds such as leveling agents, brighteners, and the like. To produce the bright nickel layer specularly at least one class I brightener and at least one class II brightener are added to the metallization solution. Class I brighteners are organic compounds which contain sulfur. Class II brighteners can also cause leveling and, when added to the metalization bath without Class I sulfur-containing brighteners, results in semi-glossy nickel deposits. These class I brighteners include alkyl naphthalene and benzenesulfonic acids, benzene and naphthalene di- and trisulphonic acids, benzene and naphthalene sulfonamides, and sulfonamides such as saccharin, vinyl and allylsulfonamides and sulfonic acids. Class II brighteners are generally 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. These are described, inter alia, in U.S. Patent No. 4,421,611 incorporated herein by reference. The nickel layer may be comprised of a monolithic layer such as semi-gloss nickel, satin nickel, or bright nickel or may be a duplex layer containing two different layers of nickel, for example, a layer comprised of semi-glossy nickel and a layer comprised of bright nickel. The thickness of the nickel layer is generally an effective thickness for leveling the surface of the article and for providing improved resistance to corrosion. This thickness is generally in the range from about 2.5 μm, preferably about 4 μm, to about 90 μm. As is well known in the art before the nickel layer is deposited on the substrate the substrate is subjected to acid activation by being placed in a conventional acid bath. In a manner as illustrated in Figs. 1 and 2, the nickel layer 13 is in fact comprised of two different nickel layers 14 and 16. The layer 14 is comprised of semi-glossy nickel while the layer 16 is comprised of bright nickel. This duplex nickel deposit provides enhanced corrosion protection to the underlying substrate. The semi-gloss, sulfur-free layer 14 is deposited by conventional electroplating processes directly on the surface of the substrate 12. The substrate 12 containing the semi-glossy nickel layer 14 is then placed in a bright nickel metallization bath and the bright nickel layer 16 is deposited on the semi-glossy nickel layer 14. The thickness of the semi-glossy nickel layer and the bright nickel layer is at least effective thickness to provide improved corrosion protection and corrosion. or leveling the surface of the article. Generally, the thickness of the semi-glossy nickel layer is at least about 1.25 μm (microns), preferably at least about 2.5 μm, and more preferably at least about 3.5 μm. The upper thickness limit is generally not critical and is governed by secondary considerations such as cost. Generally, however, a thickness of about 40 μm, preferably about 25 μm and more preferably about 20 μm should not be exceeded. The bright nickel layer 16 generally has a thickness of at least about 1.2 μm, preferably at least about 3 μm, and more preferably at least about 6 μm. The range of the upper thickness of the bright nickel layer is not critical and is generally controlled by considerations such as cost. Generally, however, a thickness of about 60 μm, preferably about 50 μm, and more preferably about 40 μm should not be exceeded. The bright nickel layer 16 also functions as a leveling layer which tends to cover or fill imperfections in the substrate. In the present invention, as illustrated in the Figs. 1 and 2, a first layer 13 comprised of a polymer is applied to the surface of the article 12 as a base coat layer. A second series of layers is applied on the surface of the polymeric layer by vapor deposition. The polymeric layer serves, among other things, as a base coating which levels the surface of the article and as a corrosion barrier to improve the corrosion resistance. In the present invention a polymeric layer 13 is deposited on the surface of the article. The polymeric coating layer 13 can comprise both thermoplastic and thermosetting polymer or resinous material. These polymeric or resinous materials include conventional and commercially available, well known polycarbonates, polycarbonates, epoxy urethanes, polyacrylates, polymethacrylates, nylons, polyesters, polypropylenes, polyepoxies, alkyd resin and styrene containing polymers such as polystyrene, styrene-acrylonitrile (SAN), styrene-butadiene, acrylonitrile-butadiene-styrene (ABS), and mixtures and copolymers thereof. Polycarbonates are described in U.S. Patent Nos. 4,579,910 and 4,513,037, which are incorporated herein by reference. The nylons are polyamides which can be prepared by the reaction of diamines with dicarboxylic acids. The diamines and dicarboxylic acids which are generally used in the preparation of nylons generally contain from two to about 12 carbon atoms. The nylons can also be prepared by additional polymerization. These are described in "Polyamide Resins", D.E. Floyc, Reinhold Publishing Corp., New York, 1958, which is incorporated herein by reference. Polyepoxies are described in "Epoxy Resins", by H. Lee and K. Neville, McGraw-Hill, New York / 1957, and in U.S. Patent Nos. 2,633,458; 4,988,572; 4,680,076; 4,933,429 and 4,999,388, which are incorporated herein by reference.

The polyesters are polycondensation products of an aromatic dicarboxylic acid and dihydric alcohol. Aromatic dicarboxylic acids include terephthalic acid, 2,6-naphthalene dicarboxylic acid, and the like. The dihydric alcohols include lower alkane diols with from two to about 10 carbon atoms such as, for example, ethylene glycol, propylene glycol, cyclohexanedimethanol, and the like. Some illustrative non-limiting examples of polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene isophthalate, and. poly (1,4-cyclohexanedimethylene terephthalate). These are described in U.S. Patent Nos. 2,645,319; 2,901,466 and 3,047,539, which are incorporated in. the present document for reference. Polyacrylates and polymethacrylates are polymers or resins resulting from the polymerization of one or more acrylates such as, for example, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylexyl acrylate, etc., as well as methacrylates such as, for example, methyl methacrylates, ethyl methacrylate, butyl methacrylate, hexyl methacrylate, etc. Copolymers of the above acrylate and methacrylate monomers are also included within the term "polyacrylates or polymethacrylates" as it appears herein. Polymerization of the monomeric acrylates and methacrylates to provide the polyacrylate resins useful in the practice of the invention can be accomplished by any of the well-known polymerization techniques. Styrene-acrylonitrile and acrylonitrile-butanediene-styrene resins and their preparation are described, inter alia, in U.S. Patent Nos. 2,769,804; 2,989,517; 2,739,142; 3,991,136 and 4,387,179, which are incorporated herein by reference. Alkyd resins are described in "Alkyd Resin Technology", Patton, Interscience Publishers, NY, NY, 1962 and in U.S. Patent Nos. 3,102,866 '; 3,228,787 and 4,511,692, which are incorporated herein by reference. Epoxy urethanes and their preparation are described, inter alia, in U.S. Patent Nos. 3,963,663; 4,705,841; 4,035,274; 4,052,280; 4,066,523; 4,159,233; 4,163,809; 4,229,335 and 3,970,535 which are incorporated herein by reference. Particularly useful epoxy urethanes are those that are electrocoated on the article. Such electrodepositable epoxy urethanes are described in U.S. Patent Nos. 3,963,663; 4,066,523; 4,159,233; 4,035,274 and 4,070,258. These polymeric materials may optionally contain conventional and well-known fillers such as mica, talcum and glass fibers. The polymeric coating layer 13 can be applied to the surface of the substrate by any of the well-known and conventional methods such as dipping, spraying, lacquering-with brush and electrodeposition. The polymeric layer 13 functions, among other things, to level the surface of the substrate, cover any scrapes or imperfections in the surface of the article and provide a smooth and smooth surface for the. deposition of the following layers such as the layers deposited in the vapor phase. The polymeric basecoat layer 13 has a thickness that is at least effective for leveling the surface of the article or substrate. Generally, this thickness is at least about 0.12 μm, preferably at least about 2.5 μm, and more preferably at least about 5 μm. The range of the upper thickness should not exceed approximately 250 μm. In some cases, depending on the material of the substrate and the type of polymeric base coating, the polymeric base coat does not adhere sufficiently to the substrate. In such a situation a primer layer is deposited on the substrate to improve the adhesion of the polymeric base coat to the substrate. The primer layer may be comprised, among other things, of halogenated polyolefins. These halogenated polyolefins are conventional and well known polymers which are generally commercially available. The preferred halogenated polyolefins are chlorinated and brominated polyolefins, with chlorinated polyolefins being most preferred. Halogenated polyolefins, particularly chlorinated, are described, along with methods for their preparation, inter alia, in U.S. Patent Nos. 5,319,032; 5,840,783; 5,385,979; 5,198,485; 5,863,646; 5,489,650 and 4,273,894, which are incorporated herein by reference. The thickness of the primer layer is an effective thickness to improve the adhesion of the polymeric coating layer to the substrate. Generally this thickness is at least about 0.25 μm. The superior thickness is not critical and is generally controlled by secondary considerations such as cost and appearance. Generally, a thickness greater than about 125 μm should not be exceeded. In one embodiment, as illustrated in FIG. 2, arranged between the base coating layer 13 and the vapor deposited shock layer 22 which functions, inter alia, as a reinforcing layer. This additional metal layer 22 can be deposited by electroplating or vapor deposition such as physical deposition in the vapor phase. This additional metallic layer includes but is not limited to chromium. When the layer 22 is comprised of chromium it may be deposited on the basecoat layer 13 by conventional and well-known chromium plating techniques or well-known and conventional physical vapor deposition techniques. The techniques of electroplating together with various chrome plating baths are described in Brassard, "Decorative Electroplating - A Process in Transition", Metal Finishing, pp. 105-108, June 1988; Zaki, "Chromium Metalization", PF Directory, pp. 146-160; and in U.S. Patent Nos. 4,460,438; 4,234,396; and 4,093,522, which are incorporated herein by reference. Chromium plating baths are well known and commercially available. A typical chromium plating bath contains chromic acid or salts thereof, and catalyst ions such as sulfate or fluoride. The catalyst ions can be provided by sulfuric acid or its salts and fluosilicic acid. The baths can be operated at a temperature of approximately 44.4-46.70C (112 ° -116 ° F). Typically in chromium metallization a current density of about 150 amps per 10.40 square meters (square foot) is used, at about 5 to 9 volts. The chromium layer generally has a thickness at least sufficient to function as a reinforcing layer. Generally this thickness is at least about 0.05 μm, preferably at least about 0.12 μm, and more preferably at least about 0.2 μm. Generally, the upper range of thickness is not critical and is determined by secondary considerations such as cost. However, the thickness of the chromium layer should generally not exceed about 1.5 μm, preferably about 1.2 μm, and more preferably about 1 μm. Instead of the layer 22 being comprised of chromium it can be comprised of tin-nickel alloy, palladium-nickel alloy or nickel-tungsten-boron alloy. The tin-nickel alloy layer can be deposited on the surface of the substrate by conventional and well-known tin-nickel electroplating processes. These processes and the metallization baths are conventional and well known and are described, inter alia, in U.S. Patent Nos. 4,033,835; 4,049,508; 3,887,444; 3,772,168 and 3,940,319 which are incorporated herein by reference. The tin-nickel alloy layer is preferably comprised of about 60-70 weight percent tin and about 30-40 weight percent nickel, more preferably about 65% tin and 35% nickel representing the SnNi atomic composition. . The plating bath contains sufficient amounts of nickel and tin to provide a tin-nickel alloy of the composition mentioned above. A commercially available tin-nickel metallization process is the NiColloy ™ process available from ATOTECH and described in its Technical Information Sheet No: NiColloy, Oct. 30, 1994, incorporated herein by reference. The thickness of the tin-nickel alloy layer 22 is generally at least about 0.25 μm, preferably at least about 0.5 μm, and more preferably at least about 1 μm. The range of the upper thickness is not critical and is generally dependent on economic considerations. Generally, a thickness of about 50 μm, preferably about 25 μm, and more preferably about 15 μm should not be exceeded. The nickel-tungsten-boron alloy layer can be deposited by metallization such as electroplating or vapor deposition such as physical vapor deposition. If the nickel-tungsten-boron alloy layer is deposited by electroplating, it is deposited by conventional and well-known nickel-tungsten-boron electroplating processes.The plating bath is normally operated at a temperature of approximately 45.1 to 51.7 ° C (115 ° to 125 ° F) and a range of PH from about 8.2 to about 8.6 The well-known soluble nickel, tungsten and boron salts, preferably soluble in water, are used in the metallization bath or solution to provide of nickel, tungsten and boron The amorphous nickel-tungsten-boron alloy layer generally contains at least 50, preferably at least about 55, and more preferably at least 57.5 percent by weight of nickel, at least about 30, preferably at least about 35, and more preferably at least 37.5 weight percent tungsten, and at least about 0.05, preferably at least about 0.5, and more preferably at least about 0.75 weight percent boron. Generally the amount of nickel does not exceed about 70, preferably about 65, and more preferably about 62.5 percent by weight, the amount of tungsten does not exceed about 50, preferably about 45, and more preferably about 42.5 percent by weight, and the amount of boron does not exceed about 2.5, preferably about 2, and more preferably about 1.25 percent by weight. The plating bath contains sufficient amounts of the salts, preferably soluble salts, of nickel, tungsten and boron to provide a nickel-tungsten boron alloy of the composition described above. A nickel-tungsten-boron metallization bath effective to provide a nickel-tungsten boron alloy of which a composition is available . commercially, such as the Ampíate ™ system from Amorphous Technologies International of Laguna Niguel, California. A typical nickel-tungsten-boron alloy contains about 59.5 weight percent nickel, about 39.5 weight percent tungsten, and about 1% boron. The nickel-boron-tungsten alloy is an alloy of amorphous / nanocrystalline compound. Such an alloy layer is deposited by the AMPLATE metallization process marketed by Amorphous Technologies International. The palladium-nickel alloy layer can be deposited by metallization such as electroplating or vapor deposition such as physical vapor deposition. If the palladium-nickel alloy layer is deposited by electroplating, it is deposited by the conventional and well known nickel-plating electroplating process. Generally, these include the use of palladium salts or complexes such as nickel amine sulfate, organic brighteners, and the like. Some illustrative examples of palladium / nickel electroplating processes and baths are described in U.S. Patent Nos. 4,849,303; 4 / 463,660; 4,416,748; 4,428,820 and 4,699,697 which are incorporated for reference. The weight ratio of palladium to nickel in the palladium / nickel alloy depends, among other things, on the concentration of palladium (in the form of its salt) in the plating bath. The higher the palladium salt concentration or the relative proportion of the nickel salt concentration in the higher bath is the ratio of palladium in the palladium / nickel alloy. The palladium / nickel alloy layer generally has a weight ratio of palladium to nickel from about 50:50 to about 95: 5, preferably from about 60:40 to about 90:10, and more preferably from about 70:30 to about 85:15. On the reinforcing layer 22, by deposition in vapor phase such as physical deposition in vapor phase or chemical vapor deposition, a layer with protective and decorative color 34 is deposited. The color layer 34 is comprised of layers 36 of a carbon-rich refractory metal carbonitride or alternating refractory metal alloy carbonitride with layers 38 of refractory-metal refractory refractory metal carbonitride or refractory metal alloy carbonitride, such as, for example, zirconium carbonitride, titanium carbonitride, carbonitride hafnium and tantalum carbonitride, and the carbonitrides of refractory metal alloys such as a titanium-zirconium alloy. These carbonitride layers may contain a small percentage of oxygen to increase the dark appearance of the coating. This small amount of oxygen has a range from about 2 to about 15 atomic percent. For zirconium, in the carbon-rich zirconium carbonitride layer, the carbon content is generally, between about 25 to about 50 atomic percent, nitrogen content between about 5 to about 35 atomic percent, providing this layer with a color dark gray. In the nitrogen-rich zirconium carbonitride layer, the nitrogen content is between about 25 to about 50 atomic percent, carbon content between about 5 to about 35 atomic percent, giving this layer a dark yellow color with a dye light reddish It is understood that in the practice of the present invention each of the layers 36 and 38 is very thin, or not thick enough, to provide or form the color of the individual layer. However, the layers 36 and 38 are used in combination with each other and, when several layers are present, they form a color and provide the protective stack layer 34. As a result, the overall color of the stack layer 34 mimics or is an antique bronze color of two shades dark gray and dark yellow. The number of layers 36 and 28 in the stack layer 34 is generally from about 4 to about 50, preferably from about 8 to about 36. Each of the layers 36 and 38 generally has a thickness from about 30 A to about 200 A , preferably from about 50 A to about 150 A. The thickness of this color and the protective pile layer 34 is a thickness which is at least effective to provide bronze color, particularly antique bronze, and to provide resistance to abrasion , scratch resistance, and resistance to use. Generally, the thickness is at least about 1,000 A, preferably at least about 1,500 A, and more preferably at least about 2,500 A. The range of the upper thickness is generally not critical and is dependent on secondary considerations such as cost. Generally a thickness of about 7500 A, preferably of about 5000 A should not be exceeded. Layer 34 is deposited by conventional and well-known techniques including vapor deposition techniques such as cathode arc evaporation (CAE) or cathodic bombardment, and the like. The techniques of cathodic bombing and CAE and equipment are described, among other things, in J. Vossen and W. Kern "The Fine Film Processes II", Academic Press, 1991; R. Boxman et al, - "Manual of Science and Technology of Vacuum Arc", Noyes Pub., 1995; and U.S. Patent Nos. 4,162, -954 and 4,591,418, which are incorporated herein by reference. A deposition method of layer 34 is by physical deposition in the vapor phase using reactive cathodic bombardment or reactive cathodic arc evaporation. Reactive cathodic arc evaporation and reactive cathodic bombardment are generally similar to ordinary cathodic bombardment and cathode arc evaporation except that a reactive gas is introduced into the chamber which reacts with the displaced target material. Thus, in the case where zirconium carbonitride is layer 34, the cathode is comprised of zirconium and nitrogen and carbon containing gas, such as methane or acetylene, are reactive gases introduced into the chamber. When the carbon-rich zirconium carbonitride layer '36 is produced, the flow of carbon gas increases momentarily while the nitrogen gas decreases momentarily. When the nitrogen-rich zirconium carbonitride layer is produced, the flow of nitrogen gas increases momentarily while the carbon gas decreases momentarily. When a layer of carbonitride 36 is formed, the flow of carbon gas increases and the flow of nitrogen gas ends. When a nitride layer 38 is formed, the flow of nitrogen gas increases and the flow of carbon gas ends. In addition to the protective color stack layer 34, additional vapor deposited layers may optionally be present. These additional vapor deposited layers may include a layer 32 comprised of refractory metal or refractory metal alloy. Refractory metals include hafnium, tantalum, zirconium and titanium.

Refractory metal alloys include zirconium-titanium alloy, zirconium-hafnium alloy and titanium-hafnium alloy. The refractory metal layer or refractory metal alloy layer 32 generally functions, inter alia, as a shock layer which improves the adhesion of the colored layer 34 to the electroplated upper layer. As illustrated in Fig. 1, the shock layer of refractory metal or refractory metal alloy 32 is generally arranged intermediate to the color layer 34 and the electroplated upper layer. As illustrated in Fig. 2, the shock layer is disposed in the reinforcement layer 22. The layer 32 has a thickness which is generally at least effective for the layer 32 to function as a shock layer. Generally, this thickness is at least about 60A, preferably • at least about 120A, and more preferably at least about 250A. 'The higher thickness range is not critical and is generally dependent on considerations such as cost. Generally, however, layer 32 should not be thicker than about 1.2 μm, preferably about 0.5 μm, and more preferably about 0.25 μm. The shock layer of refractory metal or refractory metal alloy 32 is deposited by conventional and well-known vapor deposition techniques-such as cathodic arc evaporation (CAE) or cathodic bombardment. Briefly, in the cathodic bombardment deposition process a target of refractory metal (such as titanium or zirconium), 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 ionize and accelerate towards the target to displace titanium or zirconium atoms. The displaced 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 hits the surface of a metal cathode such as zirconium or titanium. The arc vaporizes the cathode material, which is then condensed on the substrates to form a coating. In a preferred embodiment of the present invention the refractory metal is comprised of titanium or zirconium, preferably zirconium, and the refractory metal alloy is comprised of zirconium-titanium alloy. Additional vapor deposited layers may also include refractory metal compounds and refractory metal alloy compounds in addition to the carbonitrides described above. These refractory metal compounds and refractory metal alloy compounds include the refractory metal oxides and the refractory metal alloy oxides; refractory metal nitrides and refractory metal alloy nitrides; reaction products of (a) refractory metal or refractory metal alloy, (b) oxygen, and (c) nitrogen; and the refractory metal oxynitrides and refractory metal alloy oxynitrides.

In one embodiment of the invention as illustrated in Figs. 1 and 2 a layer 40 comprised of reaction products of a refractory metal or metal alloy, oxygen containing gas such as oxygen, and nitrogen is deposited on layer 34. The metals that can be employed in the practice of this invention are those which are capable of both forming a metal oxide and a metal nitride under appropriate 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. The reaction products of the metal or metal alloy, oxygen and nitrogen are generally comprised of metal oxide or metal alloy, metal nitride or metal alloy and oxy-nitride metal or metal alloy. Thus, for example, the reaction products of zirconium, oxygen and nitrogen comprise zirconium oxide, zirconium nitride and zirconium oxynitride. These metal oxides and metal nitrides including zirconium oxide and zirconium nitride alloys and their preparation and deposition are conventional and well known, and are described, inter alia, in U.S. Patent No. 5,367,285, the disclosure of which is incorporated herein by reference. the present document for reference. The layer 40 can be deposited by conventional and well-known vapor deposition techniques, including reactive cathodic bombardment and cathodic arc evaporation. In another embodiment, instead of layer 40 being comprised of the reaction products of a refractory metal or refractory metal alloy, oxygen and nitrogen, it is comprised of refractory metal oxide or refractory metal alloy oxide. The refractory metal oxides and refractory metal alloy oxides of which the layer 40 is comprised include, but are not limited to, hafnium oxide, tantalum oxide, zirconium oxide, titanium oxide, and zirconium oxide. titanium, preferably titanium oxide, zirconium oxide, and zirconium-titanium alloy oxide, and more preferably zirconium oxide. These oxides and their preparation are conventional and well known. Layer 40 is effective in providing improved chemistry, such as acid or base, resistance to coating. Layer 40 containing (i) the reaction products of the refractory metal or refractory metal alloy, oxygen and nitrogen, or (ii) refractory metal oxide or refractory metal alloy oxide generally has a thickness at least effective to provide strength improved chemistry but is not too thick to darken the color of the stack layer with color 34. Generally this thickness is at least about 10 Á, preferably at least about 25 Á, and more preferably at least about 40 A. Layer 34 should be thin enough such that it does not obscure the color of the underlying color layer 34. That is, the layer 40 should be thin enough that it is non-opaque or substantially transparent. Generally layer 40 does not it should be thicker of about 0.10 μm, preferably about 250 Á, and more preferably about 100 Á. In order that the invention can be more easily understood, the following example is provided. - The example is illustrative and does not limit the invention to it. EXAMPLE 1 Brass taps are placed in a conventional soap cleaner bath containing standard and well known soaps, detergents, deflocculants and the like which are maintained at a pH of 8.9-9.2 and at a temperature of 82. 2-93.3 ° C (180-200 ° F) for approximately 10 minutes.

The brass faucets are then placed in a conventional ultrasonic alkaline cleaner bath. The ultrasonic cleaning bath has a pH of 8.9-9.2, is maintained at a temperature of 71.1-82.2 ° C (160-180 ° F) and contains conventional and well-known soaps, detergents, deflocculants and the like. After the ultrasonic cleaning the taps are rinsed and placed in a conventional alkaline electro-cleaning bath. The electro-cleaning bath is maintained at a temperature of approximately 140-180 ° F, a. a pH of approximately 10.5-11.5, and contains standard and conventional detergents. The taps 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 room temperature, and contains sodium fluoride based on acid salt. The faucets are then rinsed twice and placed in a bright nickel plating bath for approximately 12 minutes. The bright nickel bath. it is generally a conventional bath which is maintained at a temperature of about 54.4-65.6 ° C (130-150 ° F), a pH of about 4.0, contains NiS04,? iCl2, boric acid, and brighteners. A bright nickel layer with an average thickness of approximately 10 μm is deposited on the surface of the tap. The bright nickel metallized faucets are rinsed three times and then placed in a commercially available hexavalent chromium plating bath using equipment. of conventional chrome plating for approximately seven minutes. The hexavalent chromium bath is a conventional and well known bath which contains approximately 947.2 milliliters / 3.8 liters (32 oz / gal) of chromic acid. : The bath also contains conventional and well known chrome plating additives. The bath is maintained at a temperature of approximately 44.4 ° -46.7 ° C (112 ° -116 ° F), and uses a mixed sulphate / fluoride catalyst. The chromic acid to sulfate ratio is approximately 200: 1. A chromium layer of approximately 0.25 μm is deposited on the surface of the bright nickel layer. The faucets are completely rinsed in deionized water and then dried. Chromium-plated faucets are placed in a cathode-arc evaporation metalized container. The container is generally a cylindrical housing containing a vacuum chamber which is adapted to be evacuated by means of pumps. An argon gas source is connected to the chamber by an adjustable valve to vary the flow velocity of the argon within the chamber. In addition, sources of nitrogen, methane and oxygen gas are connected to the chamber by adjustable valves to vary the flow rates of nitrogen, methane and oxygen within the chamber. A cylindrical cathode mounts in the center of the chamber and connects to negative outputs of a power source D.C. variable. The positive side of the power source is connected to the wall of the chamber. The cathode material comprises zirconium. Metallic faucets are mounted on spindles, 16 of which are mounted on a ring around the outer side of the cathode. The complete 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 towards. the cathode for the multiple taps 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 are provided with rotatable contacts such that a voltage change can be applied to the substrates during the coating. The vacuum chamber is evacuated to a pressure of approximately 10"s to 10" 7 torr and heats up to approximately 150 ° C. Electroplated faucets are then subjected to a high polarized arc plasma cleanup in which a voltage (negative) bias of approximately -600 volts is applied to the electroplated faucets while an arc of approximately 500 amps strikes and rests on the cathode. The duration of cleaning is approximately five minutes.

The argon gas is introduced at a sufficient rate to maintain a pressure of about 1 to 5 millitorr. A layer of zirconium having an average thickness of approximately 0.1 μm is deposited on the metallized cocks. with chromium for a period of three minutes. The process of cathodic arc deposition involves applying DC power to the cathode to achieve a current flow of approximately 500 amps, ._ introducing argon gas into the vessel to maintain the pressure in the vessel at approximately 1 to 5 millitor and rotate the taps in the planetary mode described above. After the zirconium layer is deposited a layer with zirconium carbonitride color is deposited on the zirconium layer. Nitrogen and methane flows are introduced into the vacuum chamber while the arc discharge continues at approximately 500 amperes. To increase the darkening of the coating, a small flow of oxygen, in quantity from 5 to 10 percent of the total gas flow, can also be introduced into the chamber. To produce the dark gray carbon-rich zirconium carbonitride, the flow velocity of methane increases momentarily while the nitrogen flow velocity decreases, and thus the resulting layer contains a carbon content between 25 to 50 atomic percent and nitrogen content between 5 to 35 atomic percent. To produce the dark yellow nitrogen-rich carbonitride, the flow velocity of the nitrogen increases momentarily while the flow velocity of the methane is decreased, and the resulting layer contains the nitrogen content between 25 to 50 atomic percent and carbon content between 5 to 35 percent • atomic. Neither of these two layers is thick enough to make the coating produce its own color. As a result, the overall color of the pile layers mimics an antique bronze appearance of two shades of dark gray and dark yellow. After this layer of zirconium carbonitride is deposited, the nitrogen flow is terminated and an oxygen flow of about 100 to 500 standard liters per minute is introduced for a time of about 10 to 60 seconds. A thin layer of zirconium oxide is formed with a thickness of about 20 to 100 Á. The arch is extinguished, the vacuum chamber vented and the coated articles removed. EXAMPLE II Other brass faucets were prepared in accordance with the procedures of Example I except that the polymer base coatings were used in place of nickel base coatings. The initial cleaning procedures of Example I were followed. After the ultrasonic cleaning the taps were rinsed and dried. A basecoat polymeric composition was applied over the clean and dry faucets with a standard and conventional high volume low pressure gun. The polymer is comprised of 35 weight percent styrenated acrylic resin, 30 weight percent formaldehyde melamine resin, and 35 weight percent epoxy A bisphenol resin. The polymer is dissolved in solvents sufficient to provide a polymer composition containing about 43 weight percent solids. After the base coat was applied over the faucets, the faucets were allowed to stand for 20 minutes to vaporize the solvent in the environment. The faucets were then baked at 190.6 ° C (375 ° F) for two hours. The resulting cured polymeric basecoat has a thickness of about 20 μm. The polymeric coated faucets were rinsed three times and then placed in a conventional commercially available hexavalent chromium plating bath using conventional chrome metallization in accordance with the procedures of Example I. The remaining procedures of Example I were followed for producing coated articles having the same colored stack layer of Example I. Although certain embodiments of the invention have been described for purposes of illustration, it should be understood that there are several embodiments and modifications within the general scope of the invention. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (28)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property: 1. An article having on at least a portion of its surface a multi-layered coating having a bronze color characterized in that it comprises: colored and protective stack comprised of carbon-carbon refractory metal carbonitride or carbide layers, or carbon-rich refractory metal alloy carbonitride or carbide alternating with nitrogen-rich refractory metal carbonitride nitride layers or refractory metal alloy carbonitride rich in nitrogen or nitride.
2. 2. The article in accordance with the claim 1 characterized in that the color stack layer is comprised of layers of carbon-rich refractory metal carbide, or carbon-rich refractory metal alloy carbide alternating with layers of refractory-rich refractory metal carbonitride or refractory metal alloy carbonitride. rich in nitrogen.
3. 3. The article in accordance with the claim 1 characterized in that the colored pile layer is comprised of layers of carbon-rich refractory metal carbide, or carbon-rich refractory metal alloy carbide alternating with layers of refractory nitrogen-rich metal nitride or refractory metal alloy nitride. rich in nitrogen.
4. 4. The article according to claim 1, characterized in that the colored pile layer is comprised of layers of carbon-rich refractory metal carbonitride or carbon-rich refractory metal alloy carbonitride alternating with carbonitride layers. of refractory metal rich in nitrogen or carbonitride of refractory metal alloy rich in nitrogen.
5. 5. The article according to claim 1, characterized in that the colored pile layer is comprised of layers of carbon-rich refractory metal carbonitride or carbon-rich refractory metal alloy carbonitride alternating with rich refractory metal nitride layers. in nitrogen or nitrogen-refractory refractory metal alloy nitride.
6. 6. The article according to claim 1, characterized in that the base coating layer comprised of nickel or a polymer is intermediate to the article and the pile layer with color.
7. The article according to claim 6, characterized in that a shock layer comprised of refractory metal or refractory metal alloy is intermediate to the base coating layer and the colored pile layer.
8. 8. The article in accordance with the claim 7 characterized in that a reinforcing layer is on the base coating layer.
9. 9. The article in accordance with the claim 8 characterized in that the reinforcing layer is comprised of chromium.
10. 10. The article according to claim 7, characterized in that a reinforcement layer is intermediate to the base coating layer and the shock layer 11.
11. The article according to claim 10, characterized in that the reinforcing layer is comprised of: 12.
12. The article according to claim 10, characterized in that an oxide layer comprised of refractory metal oxide or refractory metal alloy oxide is on the colored pile layer 13.
13. The article according to claim 10 characterized in that an oxy-nitride layer comprised of reaction products of refractory metal or refractory metal alloy, oxygen and nitrogen is on the colored stack layer 1.
14. The article according to claim 7 characterized in that an oxide layer comprised of refractory metal oxide or refractory metal alloy oxide is on the pile layer with color
15. 15. The article according to claim 7, characterized in that an oxy-nitride layer -comprehensive of reaction products of refractory metal or refractory metal alloy, oxygen and nitrogen is on the pile layer with color.
16. 16. The article according to claim 7, characterized in that an oxide layer comprised of refractory metal oxide or refractory metal alloy oxide is on the colored pile layer.
17. 17. The article according to claim 1, characterized in that an oxy-nitride layer comprised of reaction products of refractory metal or refractory metal alloy, oxygen and nitrogen is on the colored pile layer.
18. 18. The article according to claim 6, characterized in that the base coating layer is comprised of two layers of nickel.
19. 19. The article according to claim 18, characterized in that two layers of nickel comprise a layer of semi-gloss nickel on the article and a layer of bright nickel on the layer of semi-gloss nickel.
20. 20. The article according to claim 1, characterized in that the layer of carbonitride of refractory metal alloy rich in carbon contains a small amount of oxygen.
21. 21. The article according to claim 1, characterized in that the nitrogen-rich refractory metal carbonitride layer or nitrogen-rich refractory metal alloy carbonitride contains a small amount of oxygen.
22. 22. The article according to claim 1 characterized in that the carbon-rich carbonitride contains, a carbon content between 25 to 50 atomic percent and a nitrogen content between 5 to 35 atomic percent, and wherein the carbonitride rich in Nitrogen contains a nitrogen content between 25 to 50 atomic percent and carbon content between 5 to 35 atomic percent.
23. 23. A method for coating a substrate with a multi-layered coating having a bronze color characterized in that it comprises: providing a colored and protective stack layer comprised of layers of carbon-rich refractory metal carbonitride or carbide, or alloy carbonitride of high-carbon refractory metal or carbide alternating with layers of nitrogen-rich refractory metal carbonitride nitride or refractory metal alloy carbonitride rich in nitrogen or nitride.
24. 24. A method according to claim 23, characterized in that the colored pile layer is comprised of layers of carbon-rich refractory carbon carbide, or carbon-rich refractory metal alloy carbide alternating with layers of refractory metal carbonitride. rich in nitrogen or carbonitride of refractory metal alloy rich in nitrogen.
25. 25. A method in accordance with the claim 23 characterized in that the colored pile layer is comprised of layers of carbon-rich refractory metal carbide, or carbon-rich refractory metal alloy carbide alternating with layers of nitrogen-rich refractory metal nitride or metal alloy nitride refractory rich in nitrogen.
26. 26. A method according to claim 23, characterized in that the colored pile layer is comprised of layers of carbon-rich refractory metal carbonitride or carbon-rich refractory metal alloy carbonitride alternating with layers of refractory metal carbonitride rich in carbon. nitrogen or carbonitride of refractory metal alloy rich in nitrogen.
27. 27. A method according to claim 23, characterized in that the colored pile layer is comprised of layers of carbon-rich refractory metal carbonitride or carbon-rich refractory metal alloy carbonitride alternating with layers of refractory metal nitride rich in carbon. nitrogen or refractory metal alloy nitride rich in nitrogen.
28. 28. A method in accordance with the claim 23 characterized in that it includes the step of providing a base coating layer comprised of nickel or a polymer is intermediate to the article and the pile layer with color.