METALLIC COATING AND METHOD

Abstract

The invention is a metallic coating comprising a first metal, a second metal, phosphorus, and carbon nanoparticles, wherein the carbon is in the form of graphene. In one example, the carbon nanoparticles are selected from a group consisting of graphene nanoplatelets, graphene oxide, and carbon nanotubes. The first metal may preferably be nickel and the second metal may preferably be a refractory metal. The refractory metal may be selected from a group consisting of tungsten, rhenium, molybdenum, niobium, tantalum, and mixtures thereof, and may preferably be tungsten. The metallic coating may include crystallites having a columnar structure. Crystallites comprising the columnar structure precipitate to form grain structures that improve the mechanical strength of the coating through heat treatment.

Claims

1. A metallic coating comprising: a first metal; a second metal; phosphorous; and carbon nanoparticles; wherein the carbon is in the form of graphene.

2. The metallic coating according to claim 1, wherein the carbon nanoparticles are selected from a group consisting of graphene nanoplatelets, graphene oxide, and carbon nanotubes.

3. The metallic coating according to claim 1, wherein the carbon nanoparticles include graphene nanoplatelets.

4. The metallic coating according to claim 3, wherein the graphene nanoplatelets have a stack thickness in the range of 1 to 10 nanometers.

5. The metallic coating according to claim 3, wherein the graphene nanoplatelets have a particle diameter in the range of 1 to 20 nanometers.

6. The metallic coating according to claim 3, wherein the graphene nanoplatelets include terminated graphene nanoplatelets and non-terminated graphene nanoplatelets.

7. The metallic coating according to claim 3, wherein the graphene nanoplatelets are terminated.

8. The metallic coating according to claim 7, wherein the graphene nanoplatelets are terminated by attachment of a functional group, wherein the graphene nanoplatelets have a minimum resulting net zeta potential of +40 mv.

9. The metallic coating according to claim 8, wherein the graphene nanoplatelets are terminated with amino, carboxylate, hydroxylate, or hydrogenate functional groups.

10. The metallic coating according to claim 3, wherein the graphene nanoplatelets exhibit a positive net zeta potential.

11. The metallic coating according to claim 1, wherein: the first metal is nickel; and the second metal is a refractory metal.

12. The metallic coating according to claim 11, wherein the second metal is selected from a group consisting of tungsten, rhenium, molybdenum, niobium, tantalum, and mixtures thereof.

13. The metallic coating according to claim 11, wherein the refractory metal is tungsten.

14. The metallic coating according to claim 13, wherein the composition of the metallic coating includes crystallite structures selected from a group comprising nickel phosphorous, nickel, nickel phosphorous, mixtures thereof.

15. The metallic coating according to claim 14, wherein the crystallite structures include columnar structures.

16. The metallic coating according to claim 1, further comprising: a third metal.

17. The metallic coating according to claim 16, wherein the third metal is selected from the group consisting of molybdenum, rhenium, and mixtures thereof.

18. The metallic coating according to claim 16, wherein the third metal is boron.

19. The metallic coating according to claim 11, wherein: the carbon nanoparticles include graphene nanoplatelets; and the composition of the metallic coating includes graphene nanoplatelets in the range of 0.01% to 5.0% by weight of the metallic coating.

20. The metallic coating according to claim 19, wherein the composition of the metallic coating includes tungsten in the range of 1.0% to 40.0% by weight of the metallic coating.

21. The metallic coating according to claim 20, wherein the composition of the metallic coating includes phosphorous in the range of 1.0% to 20.0% by weight of the metallic coating.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0044] FIG. 1 is a flowchart of an exemplary method for preparing a metal plating solution as further described herein;

[0045] FIG. 2 is a flowchart of an exemplary method for coating a surface of a substrate with a metallic coating deposited from the metal plating solution prepared by the exemplary method of FIG. 1; and

[0046] FIG. 3 is a flowchart of an exemplary method for heat treatment of the coated substrate plated using the exemplary method of FIG. 2.

DETAILED DESCRIPTION

[0047] While the present disclosure may be described with respect to specific applications or industries, those skilled in the art will recognize the broader applicability of the disclosure. Those having ordinary skill in the art will recognize that terms such as above, below, upward, downward, etc., are used descriptively of the figures, and do not represent limitations on the scope of the disclosure, as defined by the appended claims. Any numerical designations, such as first or second are illustrative only and are not intended to limit the scope of the disclosure in any way.

[0048] The terms comprising, including, and having are inclusive and therefore specify the presence of stated features, steps, operations, elements, or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, or components. Orders of steps, processes, and operations may be altered when possible, and additional or alternative steps may be employed. As used in this specification, the term or includes any one and all combinations of the associated listed items. The term any of is understood to include any possible combination of referenced items, including any one of the referenced items. The term any of is understood to include any possible combination of referenced claims of the appended claims, including any one of the referenced claims.

[0049] The terms a, an, the, at least one, and one or more are used interchangeably to indicate that at least one of the items is present. A plurality of such items may be present unless the context clearly indicates otherwise. All numerical values of parameters (e.g., of quantities or conditions) in this specification, unless otherwise indicated expressly or clearly in view of the context, including the appended claims, are to be understood as being modified in all instances by the term about whether or not about actually appears before the numerical value. About indicates that the stated numerical value allows some slight imprecision (with some approach to exactness in the value; approximately or reasonably close to the value; nearly). If the imprecision provided by about is not otherwise understood in the art with this ordinary meaning, then about as used herein indicates at least variations that may arise from ordinary methods of measuring and using such parameters. In addition, a disclosure of a range is to be understood as specifically disclosing all values and further divided ranges within the range. Each value within a range and the endpoints of a range are hereby all disclosed as separate embodiments.

[0050] Features shown in one figure may be combined with, substituted for, or modified by, features shown in any of the figures. Unless stated otherwise, no features, elements, or limitations are mutually exclusive of any other features, elements, or limitations. Furthermore, no features, elements, or limitations are absolutely required for operation. Any specific configurations shown in the figures are illustrative only and the specific configurations shown are not limiting of the claims or the description.

[0051] The following discussion and accompanying figures disclose various configurations of an electroless metal plating solution, a method of producing the electroless metal plating solution, a metallic coating deposited from the metal plating solution, and a method for coating a substrate with the metallic coating, using the metal plating solution. The components and compositions of the disclosed embodiments, as described and illustrated herein, may be arranged and designed in a variety of different configurations. Thus, the following detailed description is not intended to limit the scope of the disclosure, as claimed, but is merely representative of possible embodiments thereof. For example, although the metallic coating and metal plating solution is depicted as being composed of nickel, tungsten, phosphorous and graphene nanoplatelets in the example descriptions and associated Figures, other configurations and compositions may be applied to provide various properties and characteristics in the resulting metallic coating. For example, refractory metals in addition to or other than tungsten can be included in the composition. Additional metals can be added to contribute and/or enhance properties such as heat resistance of and grain formation in the metallic coating. Further, in addition to graphene nanoplatelets, other forms of graphene-based nanoparticles, such as graphene oxide and/or carbon nanotubes may also be included in the compositions discussed herein.

[0052] In addition, while numerous specific details are set forth in the following description in order to provide a thorough understanding of the embodiments disclosed herein, some embodiments can be practiced without some of these details. Moreover, for the purpose of clarity, certain technical material that is understood in the related art has not been described in detail in order to avoid unnecessarily obscuring the disclosure. For example, the formation and production of graphene nanoplatelets is well understood in the art, as illustrated at least by Kim (U.S. Pat. No. 8,263,843B2) and Sanchez (U.S. Pat. No. 8,641,998B2). For example, the termination of graphene oxide using different types of termination is well understood in the art, as illustrated at least by Ho (U.S. Pat. No. 9,156,701B2). For example, the method for separation and functionalization of carbon nanotubes is well understood in the art, as illustrated at least by Strano (U.S. Pat. No. 7,887,774B2). Furthermore, the disclosure, as illustrated and described herein, may be practiced in the absence of an element that is not specifically disclosed herein.

[0053] A metal plating solution is described herein, the metal plating solution includes a first source of first metal ions, a second source of second metal ions, a reducing agent containing phosphorous, and carbon nanoparticles where the carbon is in the form of graphene, e.g., where the carbon nanoparticle is a graphene-based nanoparticle. The carbon nanoparticles made from carbon in the form of graphene can also be referred to herein as graphene nanoparticles, thus differentiating the graphene nanoparticles included in the metal plating solution described herein from non-graphene nanoparticles made from other non-graphene allotropes of carbon such as carbide and diamond. For example, it would be understood that carbide nanoparticles and diamond nanoparticles are made from non-graphene allotropes of carbon, and as such, are specifically not included in the group of carbon nanoparticles referred to herein as graphene nanoparticles. By way of illustrative example, the graphene nanoparticles included in the metal plating solution and metallic coating described herein are selected from the group consisting of graphene nanoplatelets (also referred to herein as graphite nanoplatelets), graphene oxide, and carbon nanotubes.

[0054] Referring to the figures, FIG. 1 illustrates an example method 100 for producing the metal plating solution. FIG. 2 illustrates an example method 200 for forming a metallic coating on a substrate, using the metal plating solution produced by the method 100 shown in FIG. 1 and a process of electroless plating for depositing the metallic coating. The metallic coating deposited from the metal plating solution on to the substrate includes a first metal from the first source of metal ions, a second metal from the second source of metal ions, phosphorous sourced from the reducing agent of the metal plating solution, and graphene nanoparticles. The method 200 illustrated by FIG. 2 further includes steps 205 through 220 for preparing a substrate prior to depositing the metallic coating, heat treatment at 240 of the coated substrate, and applying an auxiliary coating to the coated substrate at optional steps 245 through 250. By way of non-limiting example, FIG. 3 details the method 240 of applying a heat treatment to the coated substrate. The metal plating solution can also be referred to herein as a plating bath and/or as a plating solution.

[0055] In a non-limiting example, the metal of the first source of metal ions is nickel, which can be provided to the metal plating solution as nickel sulfate, nickel chloride, and/or a mixture thereof. In a non-limiting example, the metal of the second source of metal ions is a refractory metal and/or mixture of refractory metals. For example, the metal of the second source of metal ions can be a refractory metal selected from a group consisting of tungsten, rhenium, molybdenum, tantalum, and mixtures thereof. In one example, the metal of the second source of metal ions is tungsten, which is advantaged by a more affordable cost, for example, relative to rhenium, due to a wider range of stable supply of tungsten worldwide. In a non-limiting example, the reducing agent includes sodium hypophosphite, which in the electroless plating solution reacts with the first and second sources of metal ions to deposit ultra-fine metal phosphorous crystallites on the surface of a substrate immersed in the plating solution, to form a metallic coating on the surface of the substrate. The metal plating solution described herein is composed such that, as the bath concentration increases in sodium hypophosphite, the structure of the metal phosphorous coating can change in structure, preventing intergranular corrosion in the metallic coating formed in the substrate. In conjunction with corrosion resistance, the metal phosphorous coating has a multitude of other benefits, including high hardness and hot hardness, high melting temperature, high thermal and electrical conductivity, and a low thermal expansion coefficient.

[0056] In one example, the introduction of the second source of metal ions in the form of sodium tungstate into an electroless nickel bath alters the structure of the crystallites deposited in the metallic coating. The sodium hypophosphite reductions with nickel occurring in the plating solution described herein are accompanied by sodium tungstate reductions to create three main crystallite structures in the metallic coating, specifically, nickel phosphorous, nickel tungstate, and nickel phosphorous tungstate, where the phosphorous reduces tungsten preferentially to reducing nickel during forming of the metallic coating. The introduction of these new constituents creates a columnar coating structure. These columnar crystallites formed in the deposited metallic coating substantially improve the corrosion resistance, melting temperature, and hardness of the metallic coating, such that the metallic coating described herein is substantially advantaged by the columnar structure of the refractory crystallites formed therein.

[0057] In an illustrative example, the metal coating deposited from the metal plating solution on to a substrate is a multi-material composite comprised of organic and metal elements alloyed together, where the organic materials are phosphorous and carbon in the form of graphene nanoparticles and the metal elements include tungsten and nickel. The size distribution of the graphene nanoparticles is preferably in a range from about 1 nanometer to about 10 nanometers and in a shape that is consistent within the native material of the nanoparticle. By way of example, the graphene nanoparticles include graphene nanoplatelets (GNPs), comprised of stacked layers of graphene having a stack thickness in the range of about 1 to 20 nanometers, or more preferably, having a stack thickness of equal to or less than 4 nanometers. The stack thickness can also be referred to herein as the stack height or particle height. The size of the graphene nanoparticles, defined for example, by a particle width or particle diameter, is preferably in the range of about 1 to 20 nanometers, or more preferably in the range of about 1 to 10 nanometers.

[0058] Each metal is supplied in a metal salts form or another form donating the appropriate metal ions to the plating bath. In a non-limiting example, the source of nickel ions in the metal plating solution is one of nickel chloride and nickel sulfate, and the source of tungsten ions is sodium tungstate. In the metallic coating, the constituent components can range in percent by weight composition. For example, the graphene nanoparticles are present in the metallic coating in a percent by weight composition ranging from 0.01% to 5.0% by weight, with a preferable range between 0.05% and 1.5% by weight of the metallic coating, and in a more preferable range between 0.05% and 0.25% by weight of the metallic coating. The phosphorous is present in the metallic coating in a percent by weight between 1.0% and 15.0%, with a preferable range between 1.0% and 6.0% by weight of the metallic coating. Tungsten is the second most prevalent material within the deposited metallic coating, with a percent by weight composition between 1.0% and 40.0%, and a preferable range between 1.0% and 20.0%. The most prevalent material within the deposited metallic coating is nickel, which comprises the remainder of the 100% by weight composition of the coating. For example, nickel can be present in the deposited metallic coating in a range between about 30% and 97.99% by weight of the metallic coating.

[0059] Referring to FIG. 1, shown is an example method 100 for producing the metal plating solution described herein. The metal plating solution, to be used for electroless plating of a substrate to deposit the metallic coating described herein, requires multiple sources of metal ions and reactive organic materials to form varying alloy grains. Phosphorous is typically added to the solution as the reducing agent, in the form of sodium hypophosphite. The metal plating solution must be heated to an operating temperature ranging between about 170 to 210 degrees Fahrenheit (77 to 99 degrees Celsius). In a non-limiting example, the pH of the metal plating solution is controlled within a range between 2 and 10, is controlled preferably to a pH between 4 and 9, and most preferably, to a pH of 9 or about 9. The pH of the metal plating solution can be controlled in a multitude of ways, with the preferred method being the addition of ammonium to the metal plating solution.

[0060] The purity of the nickel metal ions added to the metal plating bath, in a non-limiting example, is in a range between 97% and 100%, with a preferable purity of at least 99.9%, and with a more preferable purity of 99.99%. These nickel metal ions can be added in a variety of forms, with the preferable being nickel sulfate. Tungsten metal ions, of similar purity ranges, can be added in a variety of forms, with the preferable being sodium tungstate.

[0061] By way of a non-limiting example, additional sources of metal ions can be added to the metal plating solution, such that the metals of these additional sources are included in the metallic coating deposited from the metal plating solution. These additional sources of metal ions can be added to promote the formation of the metallic coating deposit and/or to enhance and/or contribute to certain properties and/or characteristics of the metallic coating deposit. In one example, at least one of molybdenum or rhenium can be added to the metal plating solution and be deposited to the metallic coating to modify, for example, increase, the hardness of the deposited alloys and/or the melting temperature of the metallic coating. In one example, boron can be added to the metal plating solution and be deposited to the metallic coating, to act as a binder in the metal plating bath, and to contribute to increased smoothness of the resulting metallic coating deposit. In one example, boron can be added to the metal plating bath in the form of boron hydride metal salts having a particle size at 100 mesh, e.g., equal to or less than 100 mesh. and at a concentration of 20 grams per liter (g/l).

[0062] Graphene-based carbon nanoparticles are added to the metal plating solution in a form selected from a group consisting of graphene nanoplatelets, graphene oxide, or functionalized carbon tubes, or mixtures thereof. In a preferred example, graphene nanoplatelets are added to the plating solution, where the graphene nanoplatelets are non-terminated graphene nanoplatelets, terminated graphene nanoplatelets, and/or a mixture thereof.

[0063] By way of non-limiting example, the use of terminated graphite nanoplatelets is preferred as providing advantages to the metal plating process described herein. For example, terminated graphite nanoplatelets have a residual charge which allows the nanoplatelets to disperse within the metal plating solution preventing agglomeration of the nanoplatelets in the metal plating solution and creating a more uniform deposit structure. Advantageously, preferred termination of the graphite nanoplatelets creates a positive electrical potential which prevents precipitation within the metal plating solution of metal cations, and as such, prevents coagulation of the precipitated metal cations within the metal plating solution. If allowed to occur, the coagulation and agglomeration of these precipitants can result in a tremendous loss in efficiencies of the plating process, and can result in an unstable metal plating solution. As such, the inclusion of terminated graphite nanoplatelets in the metal plating solution to prevent precipitation of metal cations in the solution is advantageous. Additionally, terminated graphitic nanoplatelets with positive charge bias support bonding to the solutions metal cations.

[0064] By way of non-limiting example, any termination providing a net electrical charge on the graphene nanoparticles is usable within the described methods, metal plating solution, and metallic coating. Non-limiting examples of forms of termination which can be used to produce terminated graphene nanoparticles include the attachment of carboxylic acids (COOH), dinitrogen (N2), amino radical (NH2), fluorine (F), oxygen (O+), and silicon (SI), with any functional group developing a net positive zeta potential, including O+, being preferable, such that the terminated nanoparticles exhibit a positive net zeta potential in the metal plating solution. In a non-limiting example, the nanoparticle size distribution is between 1 and 20 nanometers, with the preferred size distribution between 2 and 10 nanometers. The graphene nanoparticles can be delivered to the metal plating solution in either a dry powder form or suspended in solution, with the preferred method being suspended in an aqueous dispersing agent.

[0065] Referring to FIG. 1, shown is an example method 100 for producing a metal plating solution as described herein. At 105, a base solution is prepared, which in a non-limiting example is an electroless nickel plating bath as is known in the art. In an illustrative example, a nickel plating bath such as a Meta-Plate electroless nickel (EN) plating bath sold by Metal Chem, Inc., can be used. The base solution includes a first source of metal ions, which in the present example are nickel ions, and further includes a reducing agent including phosphorous, which can be included in the base solution in the form of sodium hypophosphite.

[0066] At step 110, a second source of metal ions is added to the base solution, where the metal of the second source of metal ions includes one or more refractory metals. The concentration of the second source of metal ions in the metal plating solution is about 60 g/l. The particle size of the refractory metal is preferred at 100 mesh, e.g., equal to or less than 100 mesh. In a preferred example, the refractory metal particles have a spherical shape. In one example, the refractory metal particles are prepared using molten gas atomization to provide particles which are substantially spherical. As previously described, the refractory metal in a preferred example is tungsten.

[0067] Optionally, at step 115, one or more additional sources of metal ions such as boron, molybdenum, rhenium and/or mixtures thereof can be added to the bath, as previously described herein.

[0068] At step 120, graphene nanoparticles are added to the base solution, where in a preferred example, the graphene nanoparticles are graphene nanoplatelets, also referred to herein as graphite nanoplatelets. The concentration of graphene nanoplatelets in the metal plating solution is in a range of 0.01 grams/liter (g/l) to 5 g/l, and preferably about 0.05 g/l. In a preferred example, the graphene nanoplatelets are terminated and exhibit a positive zeta potential. The base solution including the source of nickel ions and phosphorous, the source of refractory metal ions, such as tungsten, additional metals if added, and graphene nanoparticles, is thoroughly mixed such that the constituents of the solution are uniformly dispersed to produce the metal plating solution.

[0069] The metal plating solution, at step 125, is loaded into the plating equipment at ambient temperature, and at step 130, is heated to an operating temperature in the range of 185 to 190 degrees Fahrenheit (85 to 88 degrees Celsius). In an alternative method, the plating solution can be prepared directly in the plating equipment such that the equipment can support this process. The pH of the metal plating solution is measured and adjusted as needed, for example, by the addition of ammonium, to a pH range of 2 to 11, or preferably, to a pH range of 4 to 9 with a target pH of 9. In use, the operating temperature, pH and composition of the metal plating solution are periodically measured and/or monitored, and adjustments are made as needed to maintain the operating temperature, pH, and composition of the metal plating solution, including, for example, the concentrations of metal ions and graphene nanoparticles in the solution, within the ranges described herein.

[0070] Referring now to FIG. 2, shown is an exemplary method 200 for coating a surface of a substrate with a metallic coating deposited from the metal plating solution prepared by the exemplary method of FIG. 1. A substrate, as that term is used herein, refers to any object having a surface onto which a coating can be deposited from the metal plating solution disclosed herein. A substrate can include, by way of non-limiting example, a sheet of material, a component part, an assembly, etc. The substrate can be made of one or more of a metal-based material, a non-metallic material, a polymer, a ceramic, and/or a combination thereof. In one example, the substrate includes and/or is made of a metal-based material, wherein the metal-based material is selected from a group comprising iron, aluminum, magnesium, titanium, zinc, copper, nickel, chromium, trace elements, and mixtures thereof. In one example, the metal-based material is a steel alloy. In one example, the steel alloy is comprised of iron, carbon, chrome, molybdenum, and vanadium along with other elements and trace elements. In one example, substrates made of iron-carbon-chrome-molybdenum-vanadium steel alloys have been coated using the metal plating bath and methods described herein.

[0071] Referring to FIG. 2, the method 200 includes a step 205 for receiving and inspecting the substrate, for example, to determine whether cleaning of the substrate is required at step 210, prior to immersion of the substrate in the metal plating solution. At step 210, if required, the substrate undergoes a cleaning process, where the cleaning method used will depend on the material from which the substrate is made, the condition of the substrate, and the nature of any materials to be cleaned or removed from the substrate. In an illustrative example, the substrate may be made from a metal-based material, such as steel, to which a protective coating and/or corrosion resistant agent, such as a protective oil or other corrosion inhibiting material has been applied to prevent corrosion of the substrate, for example, during transport of the substrate to the coating facility. The cleaning method selected will depend on the type of the metal-based material and the type of the protective coating to be cleaned from the substrate. For example, a degreasing agent can be used to remove protective oil from a steel surface. For example, the cleaning method can be selected to accomplish cleaning of the substrate without toxification of the substrate material.

[0072] As shown at step 220, preparation of the substrate for coating can include preparing and/or activating the surface upon which the coating will be deposited from the metal plating bath. Preparing the substrate surface can include, for example, removal and/or etching of an oxide layer on the surface of the substrate, to activate the substrate surface for receiving the deposited metallic coating. For example, the preparation and/or activation method can be selected to accomplish this step without toxification of the substrate material.

[0073] At optional step 215, a plating mask or masking material can be applied to one or more portions of the surface of the substrate, prior to immersion of the substrate in the metal plating solution at 225. The plating mask and/or masking material is applied to an unplated portion and is configured such that the unplated portion remains unplated, e.g., is shielded or masked from receiving a deposit of the metallic coating on the masked portion of the surface. In one example, a masking material can be selectively applied to the portion of the substrate to be masked, for example, by painting, spraying or otherwise applying the masking material to the selected portion to form the plating mask, prior to immersing the substrate in the plating bath. In one example, the plating mask can be configured to be selectively attached to the substrate such that when attached, the plating mask shields the masked portion from receiving a deposit of the metallic coating when the substrate is immersed in the metal plating bath. For example, the plating mask can be configured as a cap, sleeve, cover, etc. which can be fitted to and/or selectively attached to the masked portion of the substrate. In one example, the plating mask is configured to be reusable, such that the plating mask can be selectively attached to the substrate prior to coating the substrate in the metal plating bath, removed from the unplated portion of the substrate after the substrate has been removed from the metal plating bath, and reapplied to another substrate. The example shown in method 200 is non-limiting, such that the masking step 215 can occur at various points in the process, for example, after step 220, prior to step 210, etc., depending on the configuration and composition of the substrate, the surface(s) to remain unplated, etc.

[0074] At step 225, the cleaned and/or activated substrate, including the plating mask, if applicable, is immersed in the metal plating solution for a period of plating time as required to deposit the metallic coating on the substrate at a desired thickness. The metal plating solution can be prepared as described herein, and/or as illustrated by method 100 shown in FIG. 1. Deposition of the metallic coating on the substrate, as previously described, can include deposition of crystallite structures including, for example, crystallite structures comprised of nickel, tungsten, phosphorous, graphene and mixtures thereof. In one example, the crystallite structures formed in the metallic coating can include columnar structures which can contribute, for example, to the stability, strength, and/or wear resistance of the deposited metallic coating. After immersion in the plating solution for the desired plating time, the coated substrate is removed from the plating solution at step 230. In one example, step 230 can include rinsing residual plating solution from the coated substrate after removal from the plating solution, by means appropriate to the composition and configuration of the coated substrate, which can include, for example, immersion of the coated substrate in a rinsing bath, or spray rinsing of the coated substrate. If a plating mask has been applied, the plating mask is removed at step 235. In one example, a plurality of substrates can be processed through the method 200 as a batch, including, for example, concurrently immersing multiple substrates into the metal plating solution, using fixturing and/or tools designed for that purpose.

[0075] At step 240, a heat treatment can be applied to the coated substrate and/or to the batch of coated substrates. FIG. 3 illustrates an example heat treatment in additional detail. As shown in FIG. 3, at option step 241 the coated substrate can be subjected to a drying step, for example, to dry any residual plating solution, rinsing solution, and/or moisture from the coated substrate prior to loading the coated substrate into the heated chamber. The drying step can include, for example, air drying the coated substrate using ambient and/or pressurized air. At step 242, a heat treatment chamber, also referred to herein as a baking oven which in an illustrative example can be configured as an industrial oven or furnace, is prepared by preheating the heat treat chamber to a baking temperature in the range of about 93 to 1022 degrees Fahrenheit (200 to 550 degrees Celsius), where the baking temperature is selected based on one or more factors including the composition of the substrate, the cycle time of the baking cycle, the desired post-heat treatment grain structure in the metallic coating, and the susceptibility of the coated substrate to heat distortion or deformation. The minimum baking cycle time is the time required to uniformly heat the plated coating to the baking temperature and hold for a minimum cycle time predicated by the target temperature. The baking temperature and cycle time can be adjusted to precipitate new grain structures in the metallic coating, to optimize mechanical properties of the metallic coating including hardness and wear resistance. The cycle time can be increased for lower baking temperatures, for example, to achieve the desired grain structure in the metallic coating while minimizing heat distortion of the substrate. In one example, the atmosphere in the heat treat chamber is ambient air. In a preferred example, a protective atmosphere is maintained in the heat treat chamber, which can be, for example, argon gas. In one example, a batch of coated, e.g., plated, substrates are positioned in the heat treat chamber such that each plated substrate is spatially separated in the chamber from each other plated substrate of the plurality of plated substrates, for example, by fixturing or position, to provide uniform heating of each of the plated substrates in the chamber.

[0076] At steps 245 and 246, the baked coated substrate is removed from the heat treat chamber and cooled. In one example, the baked coated substrate is cooled in air. In a preferred example, the substrate is cooled in a protective environment such as in argon gas, where in the latter example, the substrate can be cooled in the baking chamber and/or in a cooling chamber in which the atmosphere can be controlled. The example of step 240 is non-limiting, and it would be understood that heat treatment of the coated substrate can be optional. In this case, the metallic coating will exhibit mechanical properties determined by the structure of the metallic coating as deposited on the substrate from the metal plating solution.

[0077] Referring again to FIG. 2, at steps 245 and 250, an auxiliary coating can be applied to the plated substrate, where the auxiliary coating can be applied, for example, to an unplated portion of the substrate surface, to the entire substrate surface, to the plated surface, and/or to a combination of the unplated and plated portions of the surface, where the type of auxiliary coating, the surface or surface portion of the plated substrate to which the auxiliary coating is applied, and the method of application are dependent on the requirements of the finished substrate. In one example, the auxiliary coating can be selected from a group consisting of a liquid paint, a conversion coating, an organic coating, and an electrophoretic deposition coating (e-coating). In one example, multiple auxiliary coatings can be applied, either as a single layer in selected portions of the surface of the substrate or as layered coatings on the substrate and/or on the metallic coating, and/or in various and/or selected portions of the surface of the substrate, to provide functional and/or decorative characteristics and/or properties to the substrate.

[0078] In a non-limiting example, the unplated portions of the substrate may be coated with an organic coating, such as a liquid paint or e-coat, for appearance, emittance, wear, scratch resistance, corrosion protection, etc., or other affects. In one example, the plated portions of the surface can be masked, by applying and/or attaching a coating mask to the plated portions, to prevent the application of the auxiliary coating to the plated portion. The coating mask is removed after application of the auxiliary coating, to provide a finished substrate. The coating mask can be configured as a reusable mask, for example, as a cap, sleeve or other cover, or as a stencil mask for applying an auxiliary coating in a stenciled pattern. The examples provided herein are non-limiting and illustrative.

[0079] The compositions and methods of the appended claims are not limited in scope by the specific compositions and methods described herein, which are intended as illustrations of a few aspects of the claims and any compositions and methods that are functionally equivalent are intended to fall within the scope of the claims. Various modifications of the compositions and methods in addition to those shown and described herein are intended to fall within the scope of the appended claims. The appended claims, in their entirety, are incorporated by reference into this description, such that the various alternative designs and embodiments defined in the appended claims should be considered supplementary to that of the present description. Further, while only certain representative materials and method steps disclosed herein are specifically described, other combinations of the materials and method steps also are intended to fall within the scope of the appended claims, even if not specifically recited. Thus, a combination of steps, elements, components, or constituents and observations derived therefrom may be explicitly mentioned herein; however, other combinations of steps, elements, components, and constituents and observations derived therefrom are included, even though not explicitly stated.

[0080] When an amount, concentration, or other value or parameter is given as either a range, preferred range, or a list of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether ranges are separately disclosed. Where a range of numerical values is recited herein, unless otherwise stated, the range is intended to include the endpoints thereof, and all integers and fractions within the range. It is not intended that the scope of the presently disclosed subject matter be limited to the specific values recited when defining a range.

[0081] The detailed description and the drawings or figures are supportive and descriptive of the disclosure, but the scope of the disclosure is defined solely by the claims. While some of the best modes and other embodiments for carrying out the claimed disclosure have been described in detail, various alternative designs and embodiments exist for practicing the disclosure defined in the appended claims. Furthermore, the embodiments shown in the drawings or the characteristics of various embodiments mentioned in the present description are not necessarily to be understood as embodiments independent of each other. Rather, it is possible that each of the characteristics described in one of the examples of an embodiment can be combined with one or a plurality of other desired characteristics from other embodiments, resulting in other embodiments not described in words or by reference to the drawings. Accordingly, such other embodiments fall within the framework of the scope of the appended claims.