MXPA96001824A - Article that has a coat that simulates the lat - Google Patents

Abstract

The present invention relates to an article that is coated with a multilayer coating comprising a layer of the nickel tin alloy, deposited on the surface of the article, a layer for improving the adhesion of the refractory metal, preferably zirconium, deposited on the tin-nickel alloy layer, and a refractory metal compound, and preferably zirconium nitride, deposited on the layer to improve the adhesion of the refractory metal. The coating provides the color of the polished bronze to the article and also provides protection against abrasion.

Description

Ref. 22451 ARTICLE THAT HAS A COAT THAT SIMULATES THE BRONZE FIELD OF THE INVENTION The present invention relates to substrates, in particular to bronze substrates, coated with a decorative and protective coating that simulates bronze.

BACKGROUND OF THE INVENTION It is a very common practice with several bronze items such as lamps, placemats, candlesticks, door knobs, door handles, shields or ornamental plates for doors and the like, which first smooth and polish the surface of the item until a shine and then apply a protective organic coating, such as one comprised of acrylics, urethanes, epoxies, and the like, on this polished surface. Although this system in general is quite satisfactory, it has the disadvantage that the operation of smoothing and polishing, particularly if the article is of a complex shape, is of an intense work. Also, known organic coatings are not always as durable as desired, particularly in external applications where articles are exposed to the elements and ultraviolet radiation. Therefore, it could be quite advantageous if the brass articles, or indeed other metal articles, could be provided with a coating which gives the article the appearance of polished brass and also provides resistance against wear and corrosion protection. The present invention provides such a coating.

BRIEF DESCRIPTION OF THE INVENTION The present invention is directed to a metal substrate having a multi-foot layer coating placed or deposited on its surface. More particularly, it is directed to a metallic substrate, particularly the bronze, which has deposited on its surface multiple overlapping metallic layers of certain specific types of metals or metal compounds. The coating is decorative and also provides resistance against abrasion and wear. The coating provides the appearance of polished bronze. Accordingly, a surface of the article having the coating thereon simulates a polished bronze surface.

A first layer deposited directly on the surface of the substrate is comprised of a tin-nickel alloy. On the layer of the tin-nickel alloy is a layer comprised of a non-precious refractory metal such as zirconium, titanium, hafnium or tantalum, preferably zirconium or titanium. A top layer comprised of a non-precious refractory metal compound, preferably a zirconium compound, a titanium compound, a hafnium compound or a tantalum compound, more preferably a titanium compound or a zirconium compound such as nitru-ro of zirconium, is placed on the layer of the refractory metal, preferably the zirconium layer. The tin-nickel alloy layer is applied by electroplating. Layers of the refractory metal such as zirconium and the refractory metal compound such as the zirconium compound are applied by vapor deposition, such as ion spray deposition and reactive ion spray deposition.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-sectional view of a portion of the substrate having the multilayer coating deposited on its surface.

DESCRIPTION OF THE PREFERRED MODALITY The substrate 12 can be any metal or metal alloy, venerable substrate, such as copper, steel, bronze, tungsten or, nickel alloys, and the like. In a preferred embodiment, the substrate is bronze. Placed on the surface of the substrate 12 is a layer 20 comprised of the tin-nickel alloy. More specifically, the layer 20 is comprised of a nickel-tin alloy. The layer 20 is deposited on the surface of the substrate by conventional and well-known nickel-tin electroplating processes. These processes and plating baths are conventional and well known and are described, inter alia, in U.S. Pat. Nos. 4,033,835; 4,049,508; 3,887,444; 3,772,168 and 3,940,319 and corpora-das here for reference. The tin-nickel alloy layer is preferably comprised of about 60-60 weight percent tin and about 30-40 weight percent nickel, more preferably about 65% tin and 35% nickel. represents the atomic composition of SnNi. The plating bath contains sufficient amounts of nickel and tin to provide a tin-nickel alloy of the composition described above. A commercially available tin-nickel plating process is the NiColloy process available from ATOTECH, and described in its Technical Information Sheet No: NiColloy, 10-30-94, incorporated herein for reference. The thickness of the layer 20 of the tin-nickel alloy is generally at least about 2.54 x 10"cm (10 millionths (0.00001) of an inch), preferably at least about 5.08 x 10" cm (20 millionths (0.00002 ) of one inch), and more preferably at least about 1.27 x 10 -4 cm (50 millionths (0.00005) of an inch).

The range of the upper thickness is not critical and generally depends on economic considerations. In general, a thickness of about 0.00508 cm (2,000 millionths (0.002) of an inch), preferably about 0.00254 cm (1,000 millionths (0.001) of an inch), and more preferably about 0.00127 cm (500 millionths (0.0005) ) of one inch), should not be exceeded. Placed on layer 20 of the tin-nickel alloy, there is a layer 22 comprised of a non-precious refractory metal such as hafnium, tantalum, zirconium or titanium, preferably zirconium or titanium, and more preferably zirconium. The layer 22 serves, inter alia, to increase or improve the adhesion of the layer 24 to the layer 20. The layer 22 is deposited on the layer 20 by conventional and well known techniques such as vacuum coating, physical deposition or in phase steam such as ion spray, and the like. Ion spraying techniques and equipment are described, inter alia, in T. Van Vorous, "Planar Magnetron Sputtering, A New Industrial Coating Technique," Solid State Technology, December 1976, p. 62-66; U. Kapacz and S. Schulz, "Industrial Application of Decorative Coatings - Principle and Advantages of the Sputter Ion Platmg Process", Soc. Vac. Coat., Proc. 34 / a. Arn. Techn. Conf., Philadelphia, E.U.A., 1991, 48-61; and U.S. Patents Nos. 4,162,954, and 4,591,418, all of which are incorporated herein by reference. Briefly, in the ion spray deposition process, the refractory metal such as the titanium or zirconium target or 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 accelerated to the target or target to dislodge the titanium or zirconium atoms. The target or evacuated target material is then typically deposited as a coating film on the substrate. The layer 22 has a thickness which is at least effective for improving the adhesion of the layer 24 to the layer 20. In general, this thickness is at least about 6.35 x 10 cm (0.25 millionths (0.00000025) of an inch ), preferably at least about 1.27 x 10"cm (0.5 millionths (0.0000005) of an inch), and more preferably at least about 2.54 x 10" cm (one millionth (0.000001) of a flea-day). The range of the upper thickness is not critical and generally depends on economic considerations such as cost. In general, however, layer 22 should not be thicker than approximately 1.27 x 10 -4 cm (50 millionths (0.00005) of an inch), preferably approximately 3.81 x 10"cm (15 millionths) of an inch), and more preferably approximately 2.54 x 10 ~ cm (10 millionths (0.000010) in one preferred embodiment of the present invention, the layer 22 is comprised of titanium or zirconium, preferably zirconium, and is deposited by ion spray plating.The layer 24 is preferably deposited on the layer 22 by spray deposition. Reactive ionic deposition Reactive ion spray deposition is generally similar to ion spray deposition except that a reactive gas which reacts with the target material dislodged is introduced into the chamber. wherein the zirconium nitride is the top layer 24, the target or target is comprised of zirconium and the nitrogen gas is the reactive gas introduced into the chamber. the amount of nitrogen available to react with zirconium, the color of zirconium nitride can be made to be similar to that of bronze of various shades or shades. The layer 24 is comprised of 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 the titanium nitride being preferred. The zirconium compound is selected from zirconium nitride, zirconium carbonytride, and zirconium carbide, with the zirconium nitride which is preferred. The layer 24 provides resistance against abrasion and wear and the desired color or appearance, such as, for example, polished bronze.

The layer 24 is deposited on the layer 22 by any well known and conventional deposition or plating processes, such as vacuum coating, reactive ion plating, and casting. The preferred method is reactive ion spray plating. The layer 24 has a thickness at least effective to provide resistance to abrasion. In general, this thickness is at least 5.08 x 10"cm (2 millionths (0.000002) of an inch), preferably at least 1016 x 10" cm (4 millionths (0.000004) of an inch), and more preferably at least 1.524. x 10 cm (6 millionths (0.000006) of an inch). The range of the upper thickness in general is not critical and depends on considerations such as cost. In general, a thickness of about 7.62 ex 10"cm (30 millionths (0.00003) of an inch), preferably about 6.35 x 10" cm (25 millionths (0.000025) of an inch), and more preferably about 5.08 x 10"5 cm (20 millionths (0.000020) of an inch should not be exceeded.) Zirconium nitride is the preferred coating material because it provides the appearance that is closest to or similar to that of polished brass.

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 itself.

EXAMPLE 1 The bronze door shields or ornamental plates are placed in a conventional soaking bath containing soaps, detergents, deflocculants and the like, standard and well known, 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 shields or ornamental bronze plates are then placed for six minutes in an alkaline, ultrasonic, conventional cleaning bath. The ultrasonic cleaning bath has a pH of 8.9-9.2, is maintained at a temperature of about 71.11-82.2 ° C (160-180 ° F), and contains conventional and well-known soaps, detergents, deflocculants, and the like. After the ultrasonic cleaning, the shields or ornamental plates are rinsed and placed in an electrical, alkaline, conventional cleaning bath for about two minutes. The electric cleaning bath contains a submerged, insoluble steel anode, is maintained at a temperature of approximately 60-82.2 ° C (140-180 ° F), a pH of approximately 10.5-1.1.5, and contains standard and conventional detergents . The shields or ornamental plates are then rinsed twice and placed in a conventional acid activator bath for about one minute. The acid activator bath has a pH of about 2.0-3.0, is at room temperature, and contains an acid salt based on sodium fluoride. The shields or ornamental plates are rinsed twice and placed in a tin-nickel plating bath for approximately 7 1/2 minutes. The bath is maintained at a temperature of about 48.88-60 ° C (120-140 ° F) and a pH of about 4.5-5.0. The bath contains stannous chloride, nickel chloride, ammonium bifluoride, and other conventional and well-known complexing and wetting agents.

A layer of tin-nickel of an average thickness of approximately 5.08 x 10 -4 cm (200 millionths (0.0002) of an inch) is deposited on the surface of the shields or ornamental plates. The plated ornamental plates of the tin-nickel alloy are placed in an ion spray plating container. This container is a stainless steel vacuum vessel sold or marketed by Leybold A.G. from Germany. The container in general is 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 means of an adjustable valve to vary the flow velocity of the argon towards the chamber. further, two sources of nitrogen gas are connected to the chamber by an adjustable valve, to vary the flow velocity of the nitrogen towards the chamber. Two pairs of magnetron target or target mounts are mounted in a spaced relationship far into the chamber and connected to the negative outputs of the C.C. variable. The targets or targets constitute the cathodes and the wall of the chamber is a common anode for the target or target cathodes. Target or target material comprises zirconium. A carrier or carrier of the substrate, which transports the substrates, i.e., the ornamental plates or shields, is already provided, for example, it can be suspended from the top of the chamber, and is rotated by a speed motor variable to transport the substrates between each pair of target or magnetron target mounts. The conveyor is conductive and is electrically connected to the negative output of a power supply of C. C. variable. The veneered ornamental boards or plates are mounted on the substrate conveyor in the ion spray plating container. The vacuum chamber is evacuated to a pressure of approximately 5 x 10"millibars and heated to approximately 400 ° C by means of a radiant electric resistance heater.The target or target material is spray cleaned to remove contaminants from its Surface Spray cleaning is carried out for approximately half a minute by applying a sufficient amount of energy to the cathodes to achieve a current flow of approximately 18 amps and introducing argon gas at the rate of approximately 200 standard cubic centimeters per A pressure of approximately 3 x 10"ilibars is maintained during spray cleaning. The shields or ornamental plates are then cleaned by a process of attack with acid under pressure ba a. The acid attack process at low pressure is carried out for approximately five minutes and involves the application of a C.C. Negative which is increased during a period of one minute from approximately 1200 to approximately 1400 volts to ornamental.es shields and plates, and applying an energy of C.C. to the cathodes to achieve a flow current of approximately 3.6 amps. The argon gas is introduced at a rate which is increased over a period of one minute from about 800 to about 1000 standard cubic centimeters per minute, and the pressure is maintained at about 1.1 x 10 millibars. The shields or ornamental plates are rotated between the target or magnetron target mounts at a rate of one revolution per minute. The shields or ornamental plates are then subjected to a cleaning process by acid attack at high pressure, for approximately 15 minutes. In the high pressure acid attack process, the argon gas is introduced into the vacuum chamber at a rate which is increased over a period of 10 minutes from about 500 to 650 standard cubic centimeters per minute (i.e. start the flow rate is 500 sccm and after 10 minutes the flow rate is 650 sccm and remains at 650 sccm for the remainder of the acid attack process at high pressure), the pressure is maintained at approximately 2 x 10 millibars, and a negative potential which is increased over a period of ten minutes from about 1400 to 2000 volts is applied to the shields or ornamental plates. The shields or ornamental plates are rotated between the target or magnetron target mounts at about one revolution per minute. The pressure in the container is maintained at approximately 2 x 10"millibars.The ornamental boards or plates are then subjected to another cleaning process by acid attack at low pressure., for approximately five minutes. During this cleaning process by acid attack at low pressure, a negative potential of approximately 1400 volts is applied to the shields or ornamental plates, the energy of C. C. is applied to the cathodes to achieve a flow current of approximately 2.6 amps, and the argon gas is introduced into the vacuum chamber at a rate which increases over a period of five minutes from approximately 800 sccm (standard cubic centimeters per minute) ) to approximately 1000 sccm. The pressure is maintained at _2 about 1.1 x 10 millibars and the shields or metal plates are rotated at about one rpm. The target or target material is cleaned again by spraying for about one minute by applying a sufficient amount of energy to the cathodes to achieve a flow of about 18 amps, introducing argon gas at a rate of approximately 150 sccm, and maintaining a pressure of approximately 3 x 10 millibars. During the cleaning process, protections are interposed between the shields or ornamental plates and the target or magnetron mounts, to prevent the deposition of target material on the shields or ornamental plates. The protections are removed and a zirconium layer having an average thickness of approximately 7.62 x 10 ~ cm (3 millionths (0.000003) of an inch) is deposited on the tin-nickel layer for a period of four minutes. The spray deposition process comprises the application of energy or current of C.C. to the cathodes to achieve a current flow of approximately 18 amps, introducing the argon gas into the vessel at approximately 450 sccm, maintaining the pressure in the vessel at approximately 6 x 10"millibars, and rotating the shields or ornamental plates at about 0.7 revolutions per minute After the zirconium layer is deposited, a layer of zirconium nitride having an average thickness of about 3.55 x 10"cm (14 millionths (0.000014) of an inch) is deposited on the layer of zirconium by reactive ion spray for a period of 14 minutes. A negative potential of approximately 200 volts of C.C. it is applied to the shields or ornamental plates while the energy of C.C. It is applied to the cathodes to achieve a current flow of approximately 18 amps. The argon gas is introduced at a flow rate of approximately 500 sccm. Nitrogen gas is introduced into the vessel from two sources. A source introduces nitrogen at a generally steady flow rate of about 40 sccm. The other source is variable and is regulated so as to maintain a partial ionic co-current of 6.3 x 10 ~ amperes, with the variable flow of nitrogen being increased or decreased when necessary to maintain the partial ionic current at this predetermined value. The pressure in the vessel is maintained at approximately 7.5 x 10"millibars.The ornamental plates coated with zirconium nitride are then subjected to cooling at low pressure, where the heating is interrupted, the pressure is increased from about 1.1 x 10 -2 _1 millibars to about 2 x 10 millibars, and the argon gas is introduced at a rate of 950 sccm This invention can be further developed within the scope of the following claims In accordance with this, the above specification is so that is interpreted as illustrative only of a single operative modality of the present invention, instead of being interpreted in a strictly limitative sense.

It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates. Having described the invention as above, property is claimed as contained in the following

Claims (8)

R E I V I N D I C A C I O N S

1. An article comprising a metallic substrate having on it at least a portion of its surface a multi-layered coating that simulates bronze, characterized in that it comprises: a layer comprised of the tin-nickel alloy; a layer comprised of zirconium or titanium; and a top layer comprised of a zirconium or titanium compound.

2. The article according to claim 1, characterized in that the layer comprised of zirconium or titanium, is comprised of zirconium.

3. The article according to claim 2, characterized in that the layer comprised of the zirconium compound or the titanium compound is comprised of the zirconium compound.

4. The article according to claim 3, characterized in that the zirconium compound is comprised of zirconium nitride.

5. The article according to claim 1, characterized in that the metallic substrate is comprised of bronze.

6. An article comprising a substrate having on at least a portion of its surface a multi-layered coating having a bronze color, characterized in that it comprises: a first layer comprised of the tin-nickel alloy; a second layer on at least a portion of the first layer, comprised of zirconium; and a top layer on at least a portion of the second layer, comprised of a zirconium compound.

7. The article according to claim 6, characterized in that the substrate is comprised of bronze.

8. The article according to claim 7, characterized in that the upper layer is comprised of zirconium nitride. . The article according to claim 6, characterized in that the upper layer is comprised of zirconium nitride.