MXPA96006389A - Articles revesti - Google Patents

Abstract

The present invention describes an article coated with a multilayer coating, comprising a layer of bright nickel deposited on the surface of the article, a layer of semi-gloss nickel deposited on the bright nickel layer, a layer providing palladium adhesion , deposited on the semi-glossy nickel layer, a layer of ruthenium deposited on the layer that provides palladium adhesion, a layer that provides adhesion of refractory metal, preferably zirconium, deposited on the ruthenium layer, and a refractory metal compound , preferably zirconium nitride, deposited on the layer providing refractory metal adhesion. The coating provides the polished bronze color to the article, and also provides protection against abrasion and corrosion.

Description

FIELD OF THE INVENTION The present invention is directed to metallic coatings of multiple protective layers, for metal substrates. BACKGROUND OF THE INVENTION Currently it is the practice with various bronze articles, such as lamps, trivets, candlesticks, door knobs and door handles and similar articles to prime and polish and burnish the surface of the article to a high gloss, and then apply an organic protective coating, such as one comprising acrylics, urethanes, epoxies, and the like, on this polished surface. While this system is generally very satisfactory, it has the disadvantage that the polishing and burnishing operation, particularly if the article is of a complex shape, is labor intensive. Also the known organic coatings are not always as durable as desired, particularly in outdoor applications, where the articles are exposed to the elements and ultraviolet radiation. Therefore, it would be very advantageous if the brass articles, or indeed other metal articles, could be provided with a coating that would give the articles the appearance of highly polished brass, and also provide wear resistance and protection against corrosion. The present in- REF: 23607 -? - Vention provides such a coating. SUMMARY OF THE INVENTION The present invention is directed to a metal substrate having a coating of multiple layers disposed or deposited on its surface. More particularly, it is directed to a metallic substrate, particularly bronze, which has deposited on its surface multiple metallic layers superimposed on certain specific types of metals or compounds of metals or metal alloys. The re-dressing is decorative and protective, for example, it provides resistance to wear and corrosion. The coating simulates the appearance of highly polished bronze, that is, it has a bronze color tone. Thus, a surface of the article, which has the coating on it, simulates a highly polished bronze surface. A first layer, deposited directly on the surface of the substrate consists of nickel. The first layer preferably consists of two different layers of nickel, such as a semi-glossy nickel layer, deposited directly on the surface of the substrate, and a layer of bright nickel, superimposed on the semi-glossy nickel layer. Arranged on the nickel layer is a layer composed of palladium. This layer of palladium is thinner than the nickel layer. On the palladium layer is a layer comprising ruthenium. On the ruthenium layer is a layer comprising a non-precious refractory metal, such as zirconium, titanium, hafnium or tantalum, preferably zirconium or titanium. An upper layer, comprising a zirconium compound, titanium compound, hafnium compound or tantalum compound, preferably a titanium compound or a zirconium compound, such as a zirconium nitride, is disposed on the refractory metal layer, preferably a zirconium layer. The nickel, palladium and ruthenium layers are pre-ferred by electrode coating. The refractory metal layer, such as the zirconium layer and the refractory metal composite layer, such as the zirconium compound layer are applied by vapor deposition, such as ion spray deposition. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-sectional view of a portion of the substrate, which has the multilayer coating deposited on its surface. DESCRIPTION OF THE PREFERRED MODALITY The substrate 12 can be any metal or metal alloy substrate, such as copper, steel, bronze, tungsten, nickel alloys, and the like. In a preferred embodiment, the substrate is bronze. The nickel layer 13 is deposited on the surface of the substrate 12 by conventional and well-known electrocoating processes. These processes include using a conventional electrocoating bath, such as, for example, a Watts bath as the electrocoating solution. Typically, such baths contain nickel nickel chloride, nickel chloride, and boric acid dissolved in water.

Solutions for electrocoating chloride, ulfamate and fluoroborate can also be used. These baths may optionally include a number of well-known and conventionally used compounds, such as homogenous and uniform deposition agents, brighteners, and the like. To produce a specularly bright nickel layer, at least one class I brightener and at least one class II brightener are added to the electrocoat solution. Class I brighteners are organic compounds that contain sulfur. Class II polishes are organic compounds that do not contain sulfur. Class II brighteners can also cause homogeneous and uniform deposition and, when added to the electrocoat bath without the sulfur-containing class I brighteners, result in semi-briquetting nickel deposits. These class I brighteners include alkyl naphthalene and benzene sulphonic acids, benzene and naphthalenic acid di- and tri-sulphonic acids, benzene and naphthalene sulfonamides, and sulfonamides such as saccharine, vinyl and allyl sulfonamides 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 polishes are well known to those skilled in the art, and are readily available commercially. They are described, inter alia, in the U.S. Patent. No. 4,421,611, incorporated herein by reference. The nickel layer preferably comprises a double layer containing a layer comprising semi-briquet nickel, and a layer comprising bright nickel. The thickness of the nickel layer is usually in the range of about 2.54 microns (100 millionths [0.000100] of an inch), preferably about 3.81 microns (150 millionths [0.000150] of an inch) to about 88.9 microns (3,500 millionths [0.0035] inch.) As is well known in the art, before the nickel layer is deposited on the substrate, the substrate is subjected to activation by being placed in a well-known conventional bath of acid. In a preferred embodiment, illustrated in the Figure, the nickel layer 13 comprises two different nickel layers 14 and 16. The layer 14 comprises semi-glossy nickel, while the layer 16 comprises bright nickel.This double nickel deposit provides a Improved corrosion protection to the underlying substrate Semi-gloss, sulfur-free plate 14 is deposited, by conventional reverse-electrode process, directly onto the surface of substrate 12. substrate 12, which contains layer 14 of sepi-gloss nickel, is then placed in a bright nickel electrocoating bath, and layer 16 of bright nickel is deposited on layer 14 of semi-gloss nickel. The thickness of the semi-glossy nickel layer and the bright nickel layer is an effective thickness to provide improved protection against corrosion. Generally, the thickness of the semi-glossy nickel layer is at least about 1.27 microns (50 millionths [0.00005] of an inch), preferably at least about 2.54 microns (100 millionths [0.000100] of an inch), and more preferably at least about 3.81 microns (150 millionths [0.00015] of an inch). The upper thickness limit is usually not critical, and is governed by secondary considerations, such as cost. Generally, however, it should not exceed a thickness of about 38.1 microns (1,500 millionths [0.0015] of an inch), preferably about 25.4 microns (1,000 millionths [0.001] of an inch), and more preferably near 19.05 microns (750 millionths [0.00075] of an inch). The layer 16 of bright nickel usually has a thickness of at least about 1.27 microns (50 millionths [0.00005] of an inch), preferably at least about 3,175 microns (125 ill-millionths [0.000125] of an inch), and more preferably at least about 6.35 microns (250 millionths [0.000250] of an inch). The upper range of the thickness of the bright nickel layer is not critical, and is usually rolled by considerations such as cost. Generally, however, a thickness of about 63.5 microns (2,500 millionths [0.0025] of an inch), preferably about 50.8 microns (2,000 millionths [0.002] of an inch), and more preferably about 38.1 should not be exceeded. micras (1,500 million [0.0015] of an inch). The bright nickel layer 16 also functions as a leveling layer, which tends to cover or fill imperfections in the substrate. Arranged on the layer 16 of bright nickel is a relatively thin layer, comprising palladium. The layer 18 providing palladium adhesion can be deposited on the layer 16 by well-known and conventional palladium electrocoating techniques. Thus, for example, the anode may be inert platinized titanium, while the cathode is the substrate 12, which has layers 14 and 16 of nickel thereon. Palladium is present in the bath as a salt or complex palladium ion. Such palladium baths are conventional and well known. Some of the complexing agents include the polyamines, such as those described in the U.S. Patent. No. 4,486,274, incorporated herein by reference. Some other palladium complexes, such as the palladium tetraamine complex, used as the source of pal dioxide in a number of palladium electrocoating processes are described in the U.S. Patent. Nos. 4,622,110; 4,552,628; and 4,628,165, all of which are incorporated herein by reference. Some electrocoating processes with a paddle are described in the patents of E.U.A. Nos. 4,487,665; 4,491,507 and 4,545,869, incorporated herein by reference. The adhesion-providing layer 18 functions, inter alia, as a primer layer, to improve adhesion of the ruthenium layer 20 to the nickel layer, such as the bright nickel layer 16 in the embodiment illustrated in the Figure. This layer that provides palladium adhesion 18 has a thickness that is at least effective in improving the adhesion of the ruthenium layer 20 to the nickel layer. The layer that provides palladium adhesion usually has a thickness of at least about 0.00635 microns (0.25 millionths [0.00000025] of an inch), preferably at least about 0.0125 microns (0.5 millionths [0.0000005] of an inch), and more preferably at least about 0.0254 microns (one millionth [0.000001] of an inch). In general, the upper range of rosor is not critical, and is determined by secondary considerations, such as cost. However, the thickness of the layer that provides palladium adhesion generally should not exceed about 1.27 microns (50 millionths [0.00005] of an inch), preferably 0.331 microns (15 millionths [0.000015] of inch, and more preferably 0.254 microns (10 millionths [0.000010] of an inch) The ruthenium layer 20 is deposited on the palladium layer 18 in a variety of conventional and well known manners, such as for example by electrolytic deposition, ion deposition, vacuum deposition , and deposition of the ruthenium metal as a finely divided dispersion in an organic vehicle.Ruthenium is preferably deposited by electrolytic deposition, preferably electrocoating.The ruthenium electrocoating process and electrolytic deposit baths are conventional and well known. example, in the Journal of the Chemical Society of London, 1971 edition, page 839, by CD Burke and J. 0. 0'Meardi, and in Electrodeposition of Alloys, Vol. II, pages 4-29, Abner Brenner (1963). The electroless coating baths with ruthenium can be acidic or non-acidic. Some illustrative examples of electroless coating baths with non-acidic ruthenium are described in U.S. Pat. Nos. 4,297,178 and 4,507,183, both incorporated herein by reference. Some illustrative examples of acid electrolytic deposition baths are described in the U.S. Patent. No. 3,793,162, incorporated herein by reference. Some other baths for electrolytic deposition with ruthenium are described in U.S. Patents. Nos. 3,576,724 and 4,377,448, both are incorporated herein by reference. Baths for electrolytic deposition with ruthenium include baths with nitrous salt and baths with sulfa ate. Ruthenium can be electrocoated by the use of continuous direct current densities, or by the use of electrolytic deposition by impulse current, that is, where a current is generated for a first period of time, and is absent during a second period. of time, the first and second periods of time reoccur in a cyclical way. Electrolytic deposition by ruthenium pulse current is described, for example, in the Patent of E.U.A. No. 4,082,622, incorporated herein by reference. The thickness of the ruthenium layer 20 is at least about 0.0508 microns (2 millionths [0.000002] of an inch), preferably at least about 0.127 microns (5 millionths [0.000005] of an inch), and more preferably at least about 0.2032 microns (8 millionths [0.000008] of an inch). The upper range of thickness is not critical, and is usually dependent on economic considerations. Generally, a thickness of about 2.54 microns (100 millionths [0.0001] of an inch), preferably about 1905 microns (75 millionths [0.000075] of an inch), and more preferably about 1.27 microns (50 millionths of an inch) should not be exceeded. [0.00005] inch). Arranged on the ruthenium layer 20 is a layer 22, comprising a non-precious refractory metal, such as hafnium, tantalum, zirconium or titanium, preferably zirconium or titanium, and more preferably zirconium. The layer 20 serves, inter alia, to improve or increase the adhesion of the layer 24 to the layer 20. The layer 22 is deposited on the ruthenium layer 20 or conventional and well-known techniques, such as vacuum coating, physical deposition of steam - such as ion spray deposition, and similar techniques. The techniques and equipment for ion spray deposition are described, inter alia, in T. Van Vorous, "Planar Magnetron Sputtering, A New Industrial Coating Technique", Solid State Technology, Dec. 1976, pages 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. Techn. Conf., Philadelphia, E.U.A., 1991, 48-61, and the Patents of E.U.A. Nos. 4,162,954 and 4,591,418, all incorporated herein by reference. Briefly, in the ion spray deposition process, the refractory metal, such as titanium or target zirconium, which is the cathode, and the substrate are placed in a vacuum chamber. The air that is 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 accelerated to the target, to dislodge titanium or zirconium atoms. The evicted target material is typically then deposited as a reversal film on the substrate. The layer 22 has a thickness that is at least effective to improve the adhesion of the layer 24 to the layer 20. Generally, this thickness is at least about 0.00625 microns (0.25 millionths [0.00000025] inch), preferably at least about 0.0125 microns (0.5 millionths [0.0000005] of an inch), and more preferably at least about 0.0254 microns (one millionth [0.000001] of an inch). The upper thickness range is not critical, and is usually dependent on considerations such as cost. Generally, however, layer 22 should not be thicker than about 1.27 microns (50 millionths [0.00005] of an inch), preferably about 0.381 microns (15 millionths [0.000015] of an inch), and more preferably close to 0.254 microns (10 millionths [0.000010] of an inch). In a preferred embodiment of the present invention, the layer 22 comprises titanium or zirconium, preferably zirconium, and is deposited by ion spray deposition. The layer 24 comprises a hafnium compound, a tantalum compound, a titanium compound or a zirconium compound, preferably a titanium compound or a zirconium compound, and more preferably a zirconium 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 24 provides resistance to abrasion and wear, and the desired color or appearance, such as, for example, polished brass. The layer 24 is deposited on the layer 22 by any of the well known and conventional coating or deposition processes, such as vacuum coating, reactive ion spray deposition, and similar processes. The preferred method is reactive ion spray deposition. Reactive ion deposition is generally similar to ion spray deposition, except that a reactive gas is introduced into the chamber, which reacts with the target evicted material. Thus, in the case where the zirconium nitride is the upper layer 24, the objective comprises zirconium and the gaseous nitrogen is the reactive gas introduced into the chamber. By controlling the amount of nitrogen available to react with the zirconium, the color of zirconium nitride can be made to be similar to that of various shades of bronze. The layer 24 has a thickness at least effective to provide resistance to abrasion. Generally, this thickness is at least 0.0508 microns (2 millionths [0.000002] of an inch), preferably at least 0.1016 microns (4 millionths [0.000004] of an inch), and more preferably at least 0.1524 microns (6 millionths [0.000006] of an inch). The upper thickness range is usually not critical, and is dependent on considerations such as cost. Generally, a thickness of about 0.762 microns (30 millionths [0.00003] of an inch) should not be exceeded, preferably about 0.635 microns (25 millionths [0.000025] of an inch), and more preferably about 0.508 microns ( 20 millionths [0.000020] of an inch). Zirconium nitride is the preferred coating material, since it more closely provides the appearance of polished bronze. In order that the invention can be understood more easily, the following example is provided. The example is illustrative and does not limit the invention to it. EXAMPLE 1 Door key shields, bronze, were placed in a conventional impregnation cleaning bath, containing standard and well-known soaps, detergents, deflocculants and the like, which is maintained at a pH of 8.9-9.2, and a temperature of 82.2-93.3 ° C (180-200 ° F) for 30 minutes. The brass keyhole d-r shields were then installed for six minutes in a conventional ultrasonic alkaline cleaner bath. The ultrasonic cleaning bath had a pH of 8.9-9.2, was maintained at a temperature of about 72-82 ° C (160-180 ° F), and contained conventional and well-known soaps, detergents, deflocculants and the like. . After the ultrasonic cleaning, the keyhole shields were rinsed and placed in a conventional electro-cleaned alkaline bath for about two minutes. The electro-cleansing bath contained an insoluble submerged steel anode, maintained at a temperature of about 60-82.2 ° C (140-180 ° F), a pH of about 10.5-11.5, and contained standard and conventional detergents. The keyhole shields were then rinsed twice, and placed in a conventional acid activator bath for about one minute. The acid activator bath had a pH of about 2.0-3.0, was room temperature, and contained an acid salt with sodium fluoride base. The keyhole shields were then rinsed twice, and placed in a semi-bright nickel electrolytic deposit bath for about 10 minutes. The semi-glossy nickel bath was a conventional and well-known bath, which had a pH of about 4.2-4.6, was maintained at a temperature of about 54.4-65.5 ° C (130-150 ° F), contained NiS04 >; NiCl, boric acid, and brighteners. A layer of semi-gloss nickel was deposited on the surface of the keyhole shields, with an average thickness of about 6.35 mm (250 millionths [0.00025] of an inch). The key shields containing the semi-glossy nickel layer were then rinsed twice, and placed in a briquetting electrolytic deposit bath for about 24 minutes. The bright nickel bath is usually a conventional bath, which was maintained at a temperature of about 54.4-65.5 ° C (130-150 ° F), a pH of about 4.0-4.8, containing NiSO,, NiCl2. boric acid, and brighteners. A layer of bright nickel of an average thickness of about 19.05 microns (750 millionths [0.00075] of an inch) was deposited on the semi-glossy nickel layer. The key shields coated with semi-glossy and bright nickel were rinsed three times, and placed for about a minute and a half in a conventional palladium electrolyte de-positioner bath. The palladium bath used an insoluble platinized niobium anode, was maintained at a temperature of about 35-60 ° C (95-140 ° F), a pH of about 3.7-4.5, contained from about 1-5 grams per liter of palladium (as metal), and about 50-100 grams per liter of sodium chloride. A layer of palladium of an average thickness of about 0.0762 microns (three millionths [0.000003] of an inch) was deposited on the bright nickel layer. The palladium coated key shields were then rinsed twice. The palladium-coated palladium shields were then placed in a conventional ruthenium electrolytic deposit bath, for about ten minutes. The ruthenium bath used insoluble platinized titanium anodes, was maintained at a temperature of about 65.5-76.6 ° C (150-170 ° F), a pH of about 1.0-2.0, and contained about 3 grams per liter of ruthenium. A layer of ruthenium with an average thickness of about 0.254 microns (10 millionths of an inch) was deposited on the palladium layer. The key shields were then rinsed carefully, and dried. The ruthenium-coated key shields were placed in a container for ion spray deposition. This container is a stainless steel vacuum vessel sold by Leybold A. G. of Germany. The container is usually a cylindrical tank containing a vacuum chamber that is adapted to be evacuated by means of pumps. A source of argon gas is connected to the chamber by an adjustable valve, to vary the flow rate of argon to the chamber. In addition, two sources of nitrogen gas are connected to the chamber by an adjustable valve, to vary the flow velocity of nitrogen to the chamber. Two pairs of magnetron-type target mounts are mounted in a spaced apart relationship in the chamber, and are set to negative outputs from C.D. variable. The targets constitute cathodes, and the chamber wall is an anode common to the target cathodes. The target material comprises zirconium. A substrate carrier, which carries the substrates, i.e., the keyhole shields provided, for example, can be suspended from the top of the chamber, and is rotated by a variable speed motor, to carry the substrates between each pair of magnetron-type target mounts. The carrier is conductive, and is electrically connected to the negative output of a power source of C.D. variable The ruthenium-coated key shields are mounted on the carrier of the substrate in the ion spray deposition container. The vacuum chamber is evacuated to a pressure of about 5 x 10 millibars, and heated to about 400 ° C via a radiant electric resistance heater. The target material is cleaned by spraying, to remove contaminants from its surface. The spray cleaning is carried out for about a minute and a half, applying energy to the cathodes, enough to achieve a current flow of about 18 amps, and introducing argon gas at the speed of about 200 standard cubic centimeters per minute. A pressure -3 of about 3 x 10 millibars is maintained during spray cleaning. The keyhole shields are then cleaned by a low pressure pickling process. The low pressure pickling process was carried out for about five minutes, and involved applying a potential of C.D. negative, which increases over a period of one minute from about 1200 to close to 1400 volts to keyhole shields, and apply energy from C.D. to the cathodes, to achieve a current flow of about 3.6 amps. Argon gas was introduced at a rate that increased over a period of one minute, from about 800 to about 1000 standard cubic centimeters per minute, and the pressure remained at about 1.1 x 10 -2 milli-bars. The keyhole shields were rotated between the magnetron type objective mounts, at a rate of one revolution per minute. The keyhole shields were then subjected to a cleaning process by high pressure pickling for about 15 minutes. In the high-pressure pickling process, argon gas was introduced into the vacuum chamber, at a rate that increased over a period of 10 minutes from about 500 to 650 standard cubic centimeters per minute (ie, at the start of the velocity) flow rate is 500 ccem, and after ten minutes the flow rate is 650 ccem, and remains at 650 ccem for the remainder of the high-pressure pickling process), the pressure remained at about 2 x 10 mbar, and a negative potential that increased over a period of ten minutes, from about 1400 to 2000 volts was applied to the keyhole shields. The keyhole shields were rotated between the magnetron-type target assemblies, at about one revolution per minute. The pressure in the container was maintained at about 2 x 10 millibars. The keyhole shields were then attached to another cleaning process by low pressure pickling for about five minutes. During this process of cleaning by low pressure pickling, a negative potential of about 1400 volts is applied to the keyhole shields, C.D. to the cathodes, to get a current flow of about 2.6 amps. , and argon gas was introduced to the vacuum chamber, at a rate that increased over a period of five minutes, from about 800 ccem (standard cubic centimeters per minute) to about 1000 ccem. The pressure was maintained at about 1.1 x 10 millibars, and the key shields were rotated at about one rpm. The target material was spray cleaned again for about one minute, applying energy to the cathodes, enough to achieve a current flow of about 18 amps, introducing argon gas at a rate of about 150 ccem, and maintaining a pressure of about 3 x -3 10 millibars. During the cleaning process, screens were interposed between the keyhole shields and the magnetron-type objective assemblies, to prevent the deposition of the target material on the key shields. The screens were removed, and a layer of zirconium, which had an average thickness of about 0.0762 microns (3 millionths [0.000003] of an inch), was deposited on the ruthenium layer of the keyhole shields for a period of four minutes. This spray deposition process comprises applying energy of C.D. to the cathodes, to achieve a current flow of about 18 amps, introduce argon gas to the vessel, to about 450 ccem, maintain the preion in the vessel at about 6 x 10 mbar, and rotate the shields from keyhole to about 0.7 revolutions per minute. After the zirconium layer was deposited, a layer of zirconium nitride, which had an average thickness of about 0.3556 microns (14 millionths [0.000014] of an inch) was deposited on the zirconium layer by reactive ion spray, during a 14 minute period. A negative potential of about 200 volts C.D. to the keyhole shields, while applying C.D. to the cathodes, to achieve a current flow of about 18 amps. Argon gas was introduced at a flow rate of about 500 ccem. Nitrogen gas was introduced into the vessel from two sources. A source introduced the nitrogen at a flow rate usually constant of about 40 ccem. The other source was variable. The variable source was regulated to maintain a partial ionic current of 6.3 x 10 amps, and the variable flow of nitrogen was increased or decreased when necessary, to maintain the partial ionic current at this predetermined value. The pressure in the container remained at about 7.5 -3 x 10 millibars. The key shields coated with zirconium nitride were then subjected to cooling at low pressure, where the heating was discontinued, the pressure was increased from about 1.1 x 10 millibarea to about 2 x. millibars, and argon gas was introduced at a rate of about 950 ccem. Although the present invention has been described in conjunction with the preferred embodiments, it is to be understood that modifications and variations may be made thereto without departing from the spirit and scope of the invention, as will be readily understood by those skilled in the art. Such modifications and variations are considered within the scope and scope of the invention and the appended claims.

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.

Having described the invention as above, property is claimed as contained in the following:

Claims (21)

1. CLAIMS 1. An article characterized in that it comprises a metal substrate having on it at least a portion of its surface a multi-layered coating, simulating bronze, comprising: a layer comprising semi-glossy nickel on at least a portion of the surface of the substrate; a layer comprising bright nickel on at least a portion of the layer comprising semi-briliant nickel; a layer comprising palladium on at least a portion of the layer comprising bright nickel; a layer comprising ruthenium on at least a portion of the layer comprising palladium; a layer comprising zirconium or titanium on the roots a portion of the layer comprising ruthenium; and a layer comprising a zirconium compound or a titanium compound, on at least a portion of the layer comprising zirconium or titanium.
2. 2. The article in accordance with the claim 1, characterized in that the layer comprising zirconium or titanium comprises zirconium.
3. 3. The article according to claim 2, characterized in that the layer comprising a zirconium compound or a titanium compound comprises a zirconium compound.
4. 4. The article according to claim 3, characterized in that the zirconium compound comprises zirconium nitride.
5. 5. The article in accordance with the claim 1, characterized in that the metallic substrate comprises bronze.
6. 6. An article, characterized in that it comprises a substrate having on at least a portion of its surface a coating having a bronze color, and comprising a first layer comprising semi-glossy nickel; a second layer on at least a portion of the first layer, comprising bright nickel; a third layer on at least a portion of the second layer, comprising palladium; a fourth layer on at least a portion of the third layer, comprising ruthenium; a fifth layer on at least a portion of the fourth layer, comprising zirconium; and a sixth layer on at least a portion of the fifth layer, comprising a zirconium compound.
7. 7. The article according to claim 6, characterized in that the substrate comprises bronze.
8. 8. The article according to claim 7, characterized in that the sixth layer comprises zirconium nitride.
9. 9. The article according to claim 6, characterized in that the sixth layer comprises zirconium nitride.
10. 10. An article, characterized in that it comprises a metallic substrate, which has arranged on at least a portion of its surface a multi-layer coating comprising: a layer comprising semi-glossy nickel; a layer comprising bright nickel; a layer comprising palladium; a layer comprising ruthenium; a layer comprising zirconium or titanium; and a layer comprising a zirconium compound or a titanium compound.
11. 11. The article according to claim 10, characterized in that the layer comprising zirconium or titanium comprises zirconium.
12. 12. The article according to claim 11, characterized in that the layer comprising a zirconium compound or a titanium compound comprises a zirconium compound.
13. 13. The article according to claim 12, characterized in that the zirconium compound comprises zirconium nitride.
14. 14. The article in accordance with the claim 13, characterized in that the metallic substrate comprises bronze.
15. 15. The article according to claim 11, characterized in that the metallic substrate comprises bronze.
16. 16. An article characterized in that it comprises a substrate having on at least a portion of its surface a coating comprising a first layer comprising semi-glossy nickel; a second layer on at least a portion of the first layer, comprising bright nickel; a third layer on at least a portion of the second layer, comprising palladium; a fourth layer on the memos a portion of the third layer, which comprises ruthenium; a fifth layer on at least a portion of the fourth layer, comprising zirconium or titanium; and a sixth layer on at least a portion of the fifth layer, comprising a zirconium compound or a titanium compound.
17. 17. The article according to claim 16, characterized in that the substrate comprises bronze.
18. 18. The article according to claim 16, characterized in that the fifth layer comprises zirconium.
19. 19. The article in accordance with the claim 18, characterized in that the sixth layer comprises a zirconium compound.
20. 20. The article in accordance with the claim 19, characterized in that the sixth layer comprises zirconium nitride.
21. 21. The article in accordance with the claim 20, characterized in that the substrate comprises bronze.