WO2012145750A2 - Electroplated lubricant-hard-ductile nanocomposite coatings and their applications - Google Patents

Abstract

Disclosed herein is a non-line-of-sight ("NLOS") process for electroplating nanocomposite coatings onto a substrate. This coating reveals a combination of lubricant-hard-ductile nanocomposite coating compositions. Applications of the coatings are disclosed herein. In one embodiment, the plating process uses a nickel electrode, or an electroless plating process. In another embodiment, the obtained coating is a nanocomposite coating composition that comprises a lubricant/soft phase for providing lubrication to a surface; a hard ceramic phase for providing structural integrity and wear resistance to the surface; and a ductile metal phase for providing ductility to the surface. In a third embodiment, this coating composition has applications in mating parts where a combination of high lubricity, wear resistance and ductility is important, including hydraulic cylinders and sleeves, copper mold in steel making industry, rollers in printing, and gear geometries.

Description

ELECTROPLATED LUBRICANT-HARD-DUCTILE NANOCOMPOSITE COATINGS AND THEIR APPLICATIONS

BACKGROUND

[0001] Disclosed herein are electroplated lubricant nanocomposite coatings and their applications. Disclosed herein too are electroplated-hard-ductile-lubricant nanocomposite coatings and their applications.

[0002] Engineered tribological coatings offer a significant opportunity in the field of coatings as they enhance component reliability and reduce life-cycle cost. These coatings are thermally sprayed and use chromium or tungsten carbide or they are electroplated and use hard chrome. Electrolytic hard chrome, however, suffers from severe environmental problems due to the emission of hexavalent chromium ions, which are carcinogenic. Hard chrome coatings are now being replaced by High Velocity Oxy Fuel (HVOF) coatings. It is estimated that at least 20-30% of the department of defense's chromium plated parts have complex geometries and fall in the category of no-line-of- sight (NLOS) applications that are not amenable to HVOF technology. Therefore, an environmentally friendly electrodeposited tribocoating having properties similar to those of hard chrome will satisfy this NLOS market need and achieve the EPA's goal by offering a clean deposition technology.

[0003] Black oxide coatings result from a conversion of the existing alloys to a black form of rust. Coatings are deposited primarily on components where tight tolerances are useful in mating surfaces, e.g., rotary gears, and may also be used as a decorative coating. These suffer from the drawback that only very limited corrosion protection is afforded under mildly corrosive conditions.

[0004] For moving parts that cannot tolerate the dimensional change of a more corrosion-resistant finish black oxide coating should normally be given a supplementary treatment (i.e., oil displacement per Mil-C-16173 Grade 3 or protective treatments of Mil-C-16173). Techniques of depositing black oxide coatings including (1) alkaline oxidizing on wrought iron, cast and malleable irons, common carbon, and low alloy steels, as well as on certain corrosion resistant steel alloys tempered at less than 900°F, and (2) fused salt oxidizing on corrosion resistant steel alloys which are tempered at 900°F (482°C) or higher. A black finish is produced by immersing tool in a hot oxidizing salt solution. During this treatment all grinding stresses are relieved to improve the toughness of tool. Finish is rust resistant and helps prevent metal to metal contact in machining operations. This finish reduces galling and chip welding and enables tool surface to absorb more lubricant.

[0005] Solid lubricants are thin films composed of a single solid or combination of solids introduced between two rubbing surfaces for the purpose of reducing friction and wear. Two requirements must be met to achieve effective solid film lubrication, including (1) strong coating to substrate adhesion, and (2) low resistance to crystalline slip during shear. Graphite and M0S₂ are the two most common solid lubricants, used in applications involving severe temps., pressures, and environments, which preclude the use of organic fluids. The development in solid lubricants has been motivated by aerospace requirements and performed at NASA's Glenn Research Ctr. at Lewis Field (Cleveland, OH).

[0006] Solid lubricant coatings share certain material properties. Specifically, direct microscopic observations of the dynamics of solid lubrication show that sliding is accompanied by severe ductile shear of the solid lubricant film. Hence, low shear strength is critical for lubricity. If the lubricant is crystalline, this occurs by slip along preferred crystallographic planes. Low shear strength alone does not ensure lubrication if the material does not adhere to the lubricated surface. Other important properties include low abrasivity (ratio of hardness of lubricant and substrate) and thermodynamic stability.

[0007] Layer lattice is a term used to describe crystal structures that consist of basal planes parallel to each other and consist of hexagonally oriented atoms. The spacing between the planes is the c-spacing. The spacing between the atoms within the basal plane is the a-spacing. Compounds with a high c/a ratio have very anisotropic shear properties with preferred shear parallel to the basal planes or perpendicular to the c-axis of the crystal structure. The dichalcogenides (sulfides, selenides, and tellurides) of molybdenum and tungsten have this structure, So does FeS₂, which along with MoS₂ and WS₂, is an intrinsic solid lubricant in that, unlike graphite, it does not require adsorbed materials or additives for lubricating capability, and is therefore attractive for vacuum appls. FeS, in distinction, has demonstrated viability in air. Table 1 lists some of these compounds (other sulfides) and their decomposition temperatures (onset of decomposition as determined by TGA). All the disulfides have coefficients of friction > 0.2. In distinction, Inframat's thermal sprayed FeS/Fei__xS coatings revealed coefficients of friction < 0.08.

Table 1. Salient physical properties of solid lubricants [4-5]

Material Mol. Wt. M.P. BJ*. Stable to Temp

WS₂ 247.97 - decompose 1250°C

MoS₂ 160.06 1185°C sublime 450°C

FeS 87.91 1193-1199°C decompose 1050°C

[0008] MoS₂ is normally applied to surfaces by several methods, e.g., simple rubbing or burnishing, air spraying of resin-bonded or inorganically bonded coatings, and PVD (e.g., sputtering). Burnished films have limited wear life. Resin-bonded aerosol spray coatings have good wear life in air, likely due to the oxidation protection from the resin binder. The endurance life and friction coefficients of sputtered MoS₂ are not as good in air as in vacuum (where 0.01 has been achieved). Moreover, Spalvins has reviewed the field and points out that sputtered MoS₂ forms columnar-fiber-like structure networks. These columns fracture after a single pass sliding. Lubrication is then provided by the residual film (0.18-0.22 micrometers (Dm)). Hence, thick films are not possible by sputtering. Brushed or painted coatings provide weak bonding to the substrate.

[0009] Iron sulfide, FeS, has a layered structure hexagonal close packed lattice similar to the graphite lattice, yet maintains lubricating properties at high load or high speed in air as well as in vacuum. The salient physical properties of sulfides are listed in Table 1. Typically, FeS is stable up to 1050°C. Because of its relatively low melting temperature and its layered lattice structure, FeS has good lubricating properties. This process, although not

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popular in the U.S. due to the environmental concerns of the SULF-BT technology, is widely use in major industrial applications in many other parts of the world, including, Europe, Japan, and China. These applications include anti-scuffing on cylinder liners, gears, CV joints, heavy duty rear axle spider, textile machinery parts, especially in hot rollers. It had also shown that a monolayer of strongly chemisorbed atoms of sulfur atoms at the steel surface can act as a lubricant, remarkably decreasing the frictional coefficient of the surface. The good lubricating properties of sulfur compounds derive from the strong sulfur-metal bonds formed at the surface. The strength of these bonds is such that sulfur-covered surfaces are chemically passivated against chemical attack, even when the new bonds to be formed by the reactive species are stronger than those formed by sulfur. The reason for this is kinetics, not thermodynamic equilibrium.

[0010] The earliest sulfur treatments for steel parts to deposit FeS solid lubricants were performed by employing solid (pack), liquid (salt bath) or gaseous media. However, these techniques are not used any more due to their high treatment temperatures (usually at 540 - 570°C or higher); their long duration of the processing (1 - 3 hours); and their production of harmful gases and wastes which cause air and water pollution.

[0011] A low temperature sulfurizing method is currently under license from HEF France and is utilized in industries in Japan, France, India and China. This method is called

SULF-BT" or Caubet process and is an anodic sulfurization performed in a suitable molten bath. Its aim is the formation of a thin (a few microns thick) pyrrhotite (Fei__xS, a metal-deficient iron sulfide) film on steel. An example of the SULF-BT process is that the parts or specimens to be coated will undergo an electrolytic sulfurizing after degreasing and pickling. Electrolytic sulfurizing is carried out in a molten salt bath with a bath composition of 75% KSCN + 25% NaSCN, at temperatures of 190°C and a duration of about 20 minutes. Treated specimens are used as anodes; while the cathode is stainless steel. The density of the anodic current is 2.5 Amperes/square decimeter. After sulfurizing and rinsing the specimens in running water to dissolve the frozen salt crust, they are then put into engine oil. A thin (several micron thick) iron sulfide (FeS) film can be formed on the surface of specimens after the electrolytic sulfurizing at 190°C for 10 to 30 minutes. The FeS film possesses a cloud layer-like, or scale-like morphology. Because the SULF-BT process decreases the coefficient of friction and increase the wear resistance of steel, the method has received much attention.

[0012] However, almost all the bath compositions used for the SULF-BT process are harmful substances, such as NaCNS, KNCS, KCN, and NaCN. The SULF-BT^® process also generates some harmful gases or liquid, even during operation at temperatures below 200°C. After sulfurizing, the parts or specimens have to be rinsed in running water for a long period of time to dissolve the frozen salt crust, thus producing a lot of harmful waste water, as well as leaving a residue of un-removed corrosion products. It should be noted that the molten salt will lose efficacy after a few cycles and the waste salt cannot be regenerated or recycled, thus, creating a major environmental problem. Moreover, sulfurized parts are easily corroded by retained salt due to residual corrosion products.

Furthermore, the SULF-BT process is not appropriate for stainless steels whose chromium content is higher than 12%. It is not suitable to treat nonferrous metals or other materials. Table 2 summarizes salient features of these different coating approaches for solid lubricants.

Table 2. Salient performance properties of solid lubricant coating processes

[0013] Plasma spray tribological coatings were first reported by Sliney at NASA Lewis and were composites of CaF₂, sodium-free glass, and a nickel-chromium alloy binder, with (PS101) and without (PS100) silver to improve low-temperature friction. The PS200 series of coatings were subsequently developed by Sliney and Dellacorte, where the lubricating solids are distributed throughout a wear-resistant matrix of Ni-Co alloy-bonded chromium carbide (Cr₃C₂). For example, PS200 contains 10 wt% each of Ag and CaF₂-BaF₂ eutectic, and PS212 contains each at 15 wt%. These coatings have been developed for aerospace applications and are too expensive and not versatile for the all applications as well as being unsuitable for terrestrial applications. Recent patents examine both DC arc plasma processes to spray solid lubricants based on agglomerates of solid lubricant particles and steel particles and HVOF processes to spray composites of a ceramic, metal, and self-lubricant. None of these approaches yields a pure self lubricant as the end product.

[0014] Hard chrome plating is a technique that has been in commercial production for over 60 years and is a useful NLOS process for applying protective hard coatings in military as well as commercial applications. Hard chrome plating utilizes carcinogenic hexavalent-Cr. Hence, there are severe environmental problems associated with hard chrome electroplating, including the release into the air of a fine mist containing hexavalent-Cr ions

[0015] Consequently, the EPA has issued air emission standards for hexagonal-Cr under the MACT Standards, and OSHA has established permissible exposure limits (PEL) for hex-Cr in the work place. For most metals, the concentrations have been drastically reduced (e.g., in shops, 30-day average for Cr was reduced from the current 1.71 mg/L to 0.55 mg/L for existing sources and 0.07 mg/L for new sources, including major upgrades). The metal finishing industry anticipates, if new limits stand, many shops will go out of business and costs will skyrocket. The Aug. 2000 issue of the American Journal of Industrial Medicine published a report on study of 2,357 workers over a 30-year period, which correlated the incidence of cancer with hex-Cr exposure. Analysis of a study by the Navy Environmental Health Center

3 3 appears to support lowering of PEL to less than 0.001 mg/m from current 0.1 mg/m . It appears likely that OSHA will have to act in the near future to lower PEL, with major impact on chrome plating.

[0016] Under the new regulations, the cost of hard chrome plating will significantly increase and the turnaround time for processing of components will also significantly increase, impacting mission readiness for military equipment. In general, hard chrome plating would no longer be economically viable at those exposure levels and an acceptable alternative will be essential.

[0017] The concept of codeposited wear resistant particles during electroplating was first patented by Grazen for improving wear, corrosion and abrasion resistance by using materials such as silicon carbide, aluminum oxide, tungsten carbide, chromium carbide and the like. The process involves simultaneous electrodeposition of a metal and settling of electrically inert particles under controlled conditions to produce a composite structure in which the additive particles retain their discrete identity and more or less homogeneously dispersed within an electroplated metal deposit. [0018] The co-deposition is achieved by carefully balancing settling of inert particles and electrodeposition of metal ions. The article to be coated (cathode) is rotated slowly in the bath, with agitation not severe enough to cause turbulence. As the hard particles tend to collect on the workpiece, the metal being deposited by electrodeposition tends to trap these particles and cause them to adhere to freshly plated surfaces. Excess particles are continuously removed during this cycle of rotation when the article is at an angle exceeding the angle of repose of unattached particles. A delicate balance of trapping and removal of particles has to be maintained to yield good quality coatings.

[0019] Similar electrolytic co-deposition processes have been disclosed by a number of other patents particularly for wear resistant coatings applications. Current tribological coatings are, however, thermal sprayed rather than codeposited using electroplating. The difficulty, it is hypothesized, stems from the lack of control of settling micrometer size particles and their entrapment by metal ions. If the particles are small enough to be in a colloidal solution, the probability of entrapment at the cathode surface through electrophoresis is expected to be equal from all directions irrespective of the angle of repose of the nanophase particles. The availability of colloidal solutions containing nanoparticles offers a new opportunity for a more robust electroplating process involving co-deposition of composite coatings.

[0020] More recently, fine particles of SiC, several μπι in diameter, were codeposited with Ni using a nickel sulphamate bath, or an electroless nickel deposition process. In these co-deposition processes, the electrochemically mobile nickel ions capture or entrap the suspended inert particles in suspension and form the coating. Because of their size, it was difficult to keep SiC particles in suspension. Larger SiC particles tended to settle out on the horizontal surfaces along with the deposition of metal ions, leading to nonuniform coatings on various surfaces.

[0021] Despite their many advantages, and there nonetheless remains a need for an NLOS nanocomposite coating process that is capable of forming a coating to provide improved mechanical properties that may offer three basic functions of high wear resistance, lubricity, and ductility. SUMMARY OF THE INVENTION

[0022] This invention relates to electroplating coating method for the formation of a tenacious film that consists of three components, including (1) a solid lubricant phase having low coefficient of friction or high lubricity, (2) a hard ceramic phase responsible for the structural integrity and wear resistance, (3) ductile metal phase for material toughness. The applications of this coating composition is used in mating parts where a combination of high lubricity, wear resistance and ductility is important, including hydraulic cylinders and sleeves, copper mold in steel making industry, rollers in printing, and gear geometries, as well as for critical hard chrome replacement coating applications.

[0023] The above-described drawbacks and disadvantages are overcome or alleviated by the use of a colloidal solution bath comprises of: solid-lubricant phase and a hard phase nanocomposite nanoparticles uniformly dispersed into a metallic phase electrolyte.

[0024] In another embodiment, this nanoparticle colloidal solution bath which consists of hard phase and lubricant phase nanoparticles composite, and metallic electrolyte, under the right processing conditions will form a coating that consists of the following functions:

(1) . The solid lubricant phase provides the necessary lubrication required for contact or wear surfaces;

(2) . The hard ceramic phase provides the structural integrity and wear resistance;

(3) . The ductile matrix phase provide the toughness or ductility required the mating surfaces;

[0025] The deposition process to convert the nanocomposite bath solution into coatings can be either an electroplating process or electroless deposition process. In either deposition process, the workpiece can either be LOS (line of sight) or NLOS (non line of sight) surface geometries.

[0026] The applications of this coating composition is in mating parts where a combination of high lubricity, wear resistance and ductility is important, including hydraulic cylinders and sleeves, copper mold in steel making industry, rollers in printing, and gear geometries, as well as for critical hard chrome replacement coating applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG. 1. Schematic diagram showing a triphasic material that has a solid lubricant phase, hard-phase, and a ductile phase;

[0028] FIG. 2. Schematic diagram showing the wear mechanism of a triphasic material that has a solid lubricant phase, hard-phase, and a ductile phase;

[0029] FIG. 3. Schematic diagram of the electrolytic co-deposition of (a) mtallic, and lubricant and ceramic nanoparticles, and (b) tribological coating containing high lubricity lubricant and wear resistant ceramic nanoparticles in a metallic matrix;

[0030] FIG. 4. Effect of particle size on wear track; a rougher wear track resulting from a larger particle or grain size will exhibit a higher friction coefficient and wear rate, while nanometer sized grains will exhibit a low friction coefficient and smooth wear track with low wear rate;

[0031] FIG. 5. Schematic illustration of the wear mechanisms of triphase composite coatings having different amounts of the solid lubricant phase;

[0032] FIG. 6. SEM micrographs showing the microstructures of the as-coated BN-Si0₂/Ni nanocomposite coatings (a) tilted top surface, and (b) higher resolution of the surface view;

[0033] FIG. 7. Cross-sectional view of the nanocomposite coating;

[0034] FIG. 8. Coefficient of friction vs time temperature relationship in the as-coated BN-Si0₂/Ni nanocomposite coatings;

[0035] FIG. 9. Coating of Bush/sleeve complex surfaces showing (a) schematic drawing of the electrode and the bush internal surface need to be coated, and (b) photographs of the coated parts;

[0036] FIG. 10. Schematics shown electroplating connections for a simple a simple rod-type shape shock absorber; and

[0037] FIG. 11. Photograph of a partial electrode/gear teeth assembly showing the relationships of the gear teeth, tip-shaped electrode, plastic insulator, and electrical connector.

DETAILED DESCRIPTION OF THE INVENTION

[0038] Disclosed herein are coatings comprising nanometer size particles, which form a true colloidal solution. The use of nanometer sized particles promotes an increase in the surface hardness and ultimately wear resistance of the coating. The coating comprises about 5 to about 50 volume percent of hard ceramic nanoparticles along with about 5 to about 50 vol% of a lubricant. The coating can be incorporated into a nanocomposite electroplating bath and disposed upon a substrate.

[0039] Schematics for the electroplating of nano-colloidal solution are shown in FIG, la, and the coated part is shown in FIG. lb. This colloidal solution are mixed with Ni or Co or other ionic electrolyte solutions to co-deposit a metal matrix containing the lubricant-hard nanoparticles dispersion. The resultant coating will consist of a finely dispersed wear resistant hard phase and lubricant phase nanocomposite in a metal matrix. The metal matrix will comprise a metal that is dependent upon the ionic electrolyte solutions. In an exemplary embodiment, the metal comprises nickel or cobalt.

[0040] In one embodiment, the novel lubricant-hard-ductile nanocomposite coating comprises lubricant nanoparticles and hard ceramic nanoparticles embedded in a ductile metal matrix as shown in FIG. 2. Specifically, in a contacting mating surface, (1) the solid lubricant phase provides the necessary lubrication required for contact or wear surfaces, (2) the hard ceramic phase provides the structural integrity and wear resistance, and (3) the ductile metal matrix phase provides the toughness or ductility required the mating surfaces.

[0041] To incorporate small particles into an electroplated process uses an electrophoresis process step. Ideally, this process step should be incorporated into the electroplating procedure. This is however difficult, because the electrical and chemical parameters for electroplating and electrophoresis are quite different.

[0042] In electroplating, the electrolyte concentration is high, the current densities are low, the electric fields are small, and the ionic conductivity is high. In electrophoresis, the electrolyte concentration is low, current densities are high, electric fields are high, and electrolyte ionic conductivity is low. Of these parameters, the high electric field is the most important for electrophoresis. If one can produce a high electric field at or very near the surface to be plated, the current density, concentration, and ionic conductivity for electrophoresis are of secondary importance.

[0043] The process that is used for electroplating of a species onto a conducting substrate has several process regions. These regions are, (1) the bulk electrolyte, the major volume of electrolyte and occupies most of the volume of the plating bath, (2) the diffusion layer - close to the substrate surface where plating is occurring, there is a concentration gradient that is established by the depletion of the ionic species being plated, and diffusion from the bulk electrolyte replenishes the depleted ionic species close to the substrate, (3) the electrical double layer, and (4) the charge transfer interface where electron transfer to metal ions occurs, and metal is plated onto the conducting substrate.

[0044] The electrical double layer resides in the area adjacent to the conducting substrate that is being plated. Simplistically described (and ignoring ionic solvation), the substrate is negatively charged and attracts positive ions immediately adjacent to the substrate. The combination of the layer of positive ions next to the negative substrate is called the compact, or Helmholtz Electrical Double Layer (HEDL). Just beyond the HEDL, there are negative ions attracted to the layer of positive ions of the HEDL. Beyond this, there are positive ions attracted to the negative ions, and so on. However, because the solution is dynamic due to factors such as Brownian motion, the replication of multiple layers outwards from the substrate decreases as the distance increases from the substrate. The multiple layers become more diffuse. This is called the diffuse double layer, or the Gouy-Chapman Diffuse Electrical Double Layer (GCDEDL). Both the HEDL and the GCDEDL have strong electric fields associated with them. This property provides the core technology for concomitant electrophoresis with electrodeposition. Relationships between the HEDL, GCDEDL, electrolytes, and BE are schematically illustrated in FIG. 3.

[0045] Without going into a lot of theoretical detail, the charge transfer interface is the plane at which electrons neutralize positive (metal) ions at the substrate surface and then deposit the metal on the conducting substrate. This is the electrodeposition step.

[0046] During electroplating, if there are nano- sized particles present and suspended in the plating electrolyte, then the smallest nano-particles can enter the region of the GCDEDL and HEDL. If the nano-particles have a positive surface charge (either intrinsic or imparted by additives), then they will be preferentially attracted to the cathode (the negatively charged electrode) in the GCDEDL and HEDL. During electroplating, these particles will be driven onto the substrate surface and incorporated into the electroplated metal. This process provides a method of forming a matrix of nano-particles embedded in an electroplated metal. For larger particles, incorporation mechanism will be dominated by trapping due to agitation of the electrolyte/particle impinge onto the electrodes, thus the amount of trapped small particles onto the matrix phase will be statistical.

[0047] In this invention, we have a colloidal bath of two types of nanoparticles: solid lubricant nanoparticles, and hard ceramic nanoparticles. These nanoparticles are uniformly distributed in a metal ion electrolyte bath, along with bath additives. Ideally, this design is anticipated to obtain a coating with the function of: a lubricant/soft phase for providing lubrication to a surface; a hard ceramic phase for providing structural integrity and wear resistance to the surface; and a ductile metal phase for providing ductility to the surface.

[0048] This unique combination of low-friction and low-wear rates nanocoatings will minimize heat generation at contact surfaces and will enhance component life and reliability. The integrity of electrodeposited nanocoating will be superior as the bonding will be metallurgical, and the coating will be 100% dense. For examples, in the current black oxide coatings practice, the coating usually exhibit high porosity and low bond strength, which exhibit severe coating delamination and grain pull-out during service. Because of the small lubricant and hard grain characteristics, which are finely dispersed in the metal matrix, we expect that all interphase interfaces of the lubricant/hard/metal nanocoatings will have superior metallurgical bonds preventing coating delamination and lubricant nanoparticle pull-out. The effect of particle size is schematically illustrated in FIG. 4. The coefficient of friction has been found to decrease with grain size. The wear tracks of nanocoatings are expected to have a lower surface roughness compared to black oxide coatings and electrodeposited coatings containing 0.5-2 μπι silicon carbide particles, currently being used. Also, these particles are generally not metallurgically bonded to the coating matrix causing particle pull-out, and both of these phenomena are expected to increase the friction coefficient and wear rate of the coating.

[0049] In a typical room temperature wear mechanism, microfracture-controlled wear process is dominant wear mechanism for most ceramic coatings due to their inherent high brittleness and low strain tolerance. In the case of lubricant-hard-ductile nanocoating, the electroplated nanocomposite coating is verified to have a high toughness, cohesive and adhesive bonding strength. As a result, the improved ductility and integrity of the nanostructured coating was responsible for improved friction and wear properties due to nanoscale plastic deformation, reduced microfracture, delamination and grain tearing-out. It is generally accepted that the wear behavior of a materials is directly related to its microhardness, toughness, grain size, mating material properties.

[0050] To further elucidate the wear mechanism, the close observation on the friction tracks of lubricant-hard/ductile surface nanocoating. A transferred lubricant film was formed and thereafter covered the wear surface partially or completely as schematically shown in FIG. 5. From the viewpoint of microstructure and coating integrity, the presence of "soft" lubricant phase should promote perfect microstructure and so resulted in the improvement in coating toughness, strain tolerance and cohesion strength. With a low lubricant content, the worn surface will consist mostly of "hard" and an adhesive and/or abrasive wear occurred between the ceramic and the mating surface. With the optimal lubricant content, part of the wear surface will occupied by lubricant additive and also smoothed by smeared filling of transferred lubricant. The combined surface of the "hard" ceramic and major "soft" oxide are confirmed to be beneficial for improving friction and wear properties. When further increasing lubricant content, the whole surface will be covered by lubricant and the situation became similar to pure lubricant coating.

[0051] Suitable lubricant materials include but are not limited to compositions of a family of layered hexagonal lattice structures, boron nitride (BN), graphite (C), tungsten disulfide (WS₂), molybdenum disulfide (M0S₂), iron sulfide Fei__xS, calcium fluoride (CaF₂), diamond or diamond-like nanoparticles, and others such as Fe₃0₄, and Teflon.

[0052] Suitable hard ceramic phase include but are not limited to (1) metal oxide family of aluminum oxide A1₂0₃, silica Si0₂, chromium Cr₂0₃, zironia Zr0₂, ceria Ce0₂, yttria Y₂0₃, (2) carbide family of tungsten carbide WC, titanium carbide TiC, vanadium carbide VC, chromium carbide Cr₃C₂, tantalum carbide TaC, silicon carbide SiC, (3) nitride family of aluminum nitride A1N, silicon nitride Si₃N₄, zirconium nitride, zirconia nitride ZrN, and (4) boride family of titanium diboride TiB₂, and zirconium boride. The hard phase can also be diamond nanoparticles.

[0053] Suitable metal matrix phase include but are not limited to transition metals or their alloys of Co, Ni, Fe, Mo, Cr. Thus, the electrolyte in the bath solution will comprise, but not limited to metallic salts of cobalt, nickel, chromium, iron, and molybdenum. The coating deposition process can be either LOS or NLOS processes of electroplating or electroless plating.

[0054] For complicated shapes, especially, NLOS coatings, special electrodes have to be designed. As shown in FIG. 9, when coating internal diameters of bushes/sleeves, a male-type electrode need to be designed that will be inserted into the ID of the sleeve in order to achieve uniform electrical field of the sleeve during electroplating.

[0055] In the case of gears, although it is the line-of-sight LOS geometry, since complicated geometry of the gear teeth makes extremely non-uniform electrical field during plating. To accommodate this type of geometry, pairs of replica shape of the gears need to be designed. For this design, the key is the gear tip shape, which is exact from the shape of space profile between the two gear tips as shown in FIG. 11.

[0056] The invention is further illustrated by the following non-limiting examples. EXAMPLES

Example 1 - Making the electroplating bath

BN-Si0₂/Ni solution: 200 grams of BN and 220 grams of Si0₂ nanoparticles were mixed with 100 grams of nickel sulphamate solution, 880 ml DI water and desired amount of surfactants. This mixture is then transferred into a ball milling jar and milled overnight. Different amounts of the solution mixture were added to the electroplating vessel of 11 liters so as to have 4400 grams of nickel sulphamate in the solution mixture. Other plating additives such as phosphor and brightener were then added into the bath, and DI water was finally added to make up a 11 -liter plating solution. The BN-Si0₂ compositions of the electroplating bath is 40g/l for electroplating.

An exemplary plating bath is shown in Table 3. Table 3. Current Inframat plating bath solution composition for plating BN-Si0₂/Ni nanocomposite coatings (using 11 liters of solution)

BN-Cr₂0₃/Ni solution: 220 grams of BN and 220 grams of Cr₂0₃ nanoparticles were mixed with 220 grams of nickel sulphamate solution, 880 ml DI water and desired amount of surfactants. This mixture is then transferred into a ball milling jar and milled overnight. Different amounts of the solution mixture were added to the electroplating vessel of 11 liters so as to have 4400 grams of nickel sulphamate. Other plating additives such as a phosphor and a brightener were then added into the bath, and DI water was finally added to make up an 11-liter plating solution. The BN-Cr₂0₃ composition of the electroplating bath is 40g/l for electroplating.

BN-SiC/Ni solution: 220 grams of BN and 220 grams of SiC nanoparticles were mix with 220 grams of nickel sulphamate solution, 880 ml DI water and desired amount of surfactants. This mixture is then transferred into a ball milling jar and milled overnight. Different amount of the solution mixture were added to the electroplating vessel of 11 liters so as to have a 4400 grams of nickel sulphamate. Other plating additives such as phosphor and brightener were then added into the bath, and DI water was finally added to make up an 11 -liter plating solution. The BN-SiC compositions of the electroplating bath is 40g/l for electroplating.

BN-diamond/Ni solution: 220 grams of BN and 220 grams of diamond nanoparticles were mix with 220 grams of nickel sulphamate solution, 880 ml DI water and desired amount of surfactants. This mixture is then transferred into a ball milling jar and milled overnight. Different amount of the solution mixture were added to the electroplating vessel of 11 liters so as to have a 4400 grams of nickel sulphamate. Other plating additives such as phosphor and brightener were then added into the bath, and DI water was finally added to make up an 11 -liter plating solution. The BN-Diamond compositions of the electroplating bath is 40g/l for electroplating.

Other baths: In the procedure of electroplating nanocomposite coatings to electroplate nanocomposite coatings, Inframat has develop a prototype plating line that consists of:

(1) . Degreasing cell. A bath for substrate cleaning, containing the 30% sodium hydroxide in DI water, and connected to a power supply.

(2) . Neutralizing cell. A bath for substrate treatment after cleaning, containing the 30% hydrochloric acid in DI water.

(3) . Activation cell. Commercial grade Wood Strike obtained from technical for substrate activation prior to electroplating, and it is connected to a power supply.

(4) . Rinsing cells. DI water only

The bath sequence is schematically illustrated in the flow diagram below. The electrolytic bath has capabilities to vary and control different factors such as temperature, agitation, current density, pH and other process parameters.

Flowchart of the electroplating procedure for nanocoatings Example 2 - Coating of BN-Si0₂/Ni on coupons

[0057] The base metal substrate used at this point is carbon steel and copper alloy for uses in bush /sleeves in steel mill applications. We use a standard size of donut type discs with ID: 15 mm, OD: 30 mm, and height: 10 mm. These are the typical sliding wear testing coupons used in the Chinese academic standards.

[0058] The first step is to remove the surface dirt by rubbing against sandpaper, followed by acetone washing and rinsed with DI water. The fresh surface is the immersed in the degrease bath for 10 min., and rinsing thoroughly in the rinse bath. The next step is to immerse the sample in the neutralize bath for 10 min., followed by rinsing. This sample is then immersed in the activation bath for 10 min., followed by rinsing. The sample is now ready for plating.

[0059] In the plating bath, the anode is Ni, and the cathode is the substrate coupon (or gear specimen). The electrodeposition current can be monitored using an amperometer with an accuracy of 0.1 mA, under a controlled temperature and acid concentration. The deposition parameters include: these parameters, 4.2-4.5 plating pH, mechanical stirring, and 20-40 amp/ft current density. Detailed electroplating steps are described below:

Degreasing Procedure

Step 1. Following removal of obvious loose particles from the sample surface (e.g., by light san blasting), connect the sample to the degreasing bath sample holder

Step 2. Anodize the samples for 20 to 30 minutes in the degreasing bath between porous nickel cathodes. Current typically should be about 1.6 A for a sample of about 6 square inches. This should be "tuned" depending on the iron based alloy. Successful "cleaning" should show faint cloud of dark particles surrounding the sample. 20 A per square foot is a good value to start with. Step 3. Disconnect, remove sample from the degreasing bath Rinsing after Degreasing

Step 1. Immerse the components into the rinsing bath and shake for 10 times Neutralizing Procedure

Step 1. Immerse the components into the neutralizing bath and shake for 10 times Rinsing before Activation

Step 1. Immerse the components into the rinsing bath and shake for 10 times Activation Procedure

Step 1. Mount the sample as cathode in the activation bath between porous nickel anodes.

Step 2. Plate samples between nickel electrodes at current densities in the range 20 to 100 A/sq-dm (150 to 900 A/sq-ft). You only need a very thin layer of "strike" nickel, barely enough to give the sample a "color." Plating only takes minutes. Also, gassing is normal. This plating process in relatively inefficient. Focus a bright light on the sample (a good flashlight will do) so that the color change can be observed.

Step 3. Transfer the "strike" plated sample immediately to the main plating bath and immerse the sample in the electrolyte. Allow a film of strike electrolyte to "carry-over" with the sample, i.e., don't shake off excess electrolyte. The carry-over electrolyte protects the sample from air oxidation.

Electroplating Procedure

Step 1. Adjust the plating current density to be somewhere in the range 20 to 50 A/ft². Try to keep the current as high as possible to help the electrophoresis effect on the Si0₂/BN nanoparticles. Plating time will depend on how thick you need the plate has to be. Make sure the plating power supply will cope with the upper limit of current. Step 2. When you have everything ready to start plating (electrolyte up to temperature, stirring on, but out of the way of where the sample will be, hooks/suspension clips ready to receive the sample, power supply on, but turned to a low value - about 10% of your estimated plating current, etc), transfer the sample quickly from the "Strike" bath. Remember, you need to maintain a film of strike electrolyte on the sample to prevent air oxidation of the sample surface. Immediately immerse the sample in the plating bath electrolyte so that all surfaces to be plated are below the electrolyte surface. While you are arranging the positioning of the sample, keep the sample well covered with electrolyte. Make sure there is a good flow of electrolyte at, and by the sample. Try to keep all the slurry particles in suspension.

Step 3. When you are satisfied with the positioning of the sample, slowly raise the plating current to the value that you have chosen. Raise the current over a period of 15 to 30 seconds. Plate for the desired time and reduce the current to close to zero. Remove the sample. Wash and inspect.

Example 3 - Properties of the electroplated nanocomposite coatings

[0060] The plated BN-Si0₂/Ni nanocoatings for are smooth, uniform, dense, and with metallic or satin finishing. Most importantly, there is no evidence of non-uniformity in sharp-cornered angles. Without nanoparticulate additives, the pure nickel plated surface is bright, smooth, dense, and has uniform thickness throughout all sections of the coated surfaces. As the percentage of both Si0₂ and BN nanoparticles increased in the plating solution, the gloss appearance of the coating gradually starting to disappear in a order of 5g/l, lOg/1, 15g/l, 20g/l, 25g/l, 30g/l, 40g/l, and 50g/l. At a 40g/l nanoparticles solution, the coating is being a satin finish, with high density and other desirable characteristics.

[0061] Surface morphology of the as plated BN-Si0₂/Ni nanocomposite coating is shown in FIG. 6. Cross-sectional scanning electron microscopy (SEM) revealed that the coating has a very uniform structure throughout the coating cross-section, with an excellent coating to substrate interface, shown in FIG. 7. Look at the coating-substrate intersections using transmission electron microscopy techniques, it revealed the perfect bonding between the substrate and the coating, all atomic bonding of the coating has been achieved. [0062] Microhardness is measured at cross-section surface of the coated specimen using Vickers hardness machine. In the optimization experiments, hardness is one of the most important parameters used to determine the coating quality, as it relates to coating density, and strength. In the analysis, we have plotted the coating hardness values as a function of BN/S1O₂ ratio, as a function of particulate (BN:Si0₂ ratio of 1:1), and as a function of heat treatment temperature. Depending on the concentration of BN-Si0₂ nanoparticles in the bath, the hardness of the coating varies ranges from 400 up to 1,000 VHN. With pure BN, the hardness of the coating is about 250 VHN.

[0063] Samples from the electrodeposited coupons were subjected to "pin on disk" friction measurements. Measurements were taken using ¼" silicon nitride balls or tool steel balls pressed to the sample surface with a 50 - 100 N force. A transducer measured the friction drag and the coefficient of friction was calculated from these data.

[0064] FIG. 8 shows the friction coefficient of the BN-Si0₂/Ni nanocomposites under different lubricating conditions. Samples were measured with (1) no oil (completely dry), and (2) with a thin oil film (carefully wiped dry with tissue) lubrication in Castrol SAE 10W-40 oil. The data show that boron nitride provides a dry lubricity when incorporated in nickel matrix. It is of note that the coefficient of friction values of the "oil film" are close to the full lubrication values. Tests for coated pieces with different conditions are shown in Table 4 below.

Table 4. Coefficient friction measurement of electroplated nanocoatings compared with different materials, friction of coefficient varies from low to high.

[0065] The corresponding coating coefficient for the BN-Si0₂/Ni coating is in the neighborhood of 0.15 to 0.20 range, either have a lubricant film or not. In this set of experiments, the BN-Si0₂/Ni coating seems to have the lowest value of coefficient of friction, with reasonable good hardness>400 VHN, and the best wear resistance. It should be noted that during the wear experiments, both the tool steel and silicon nitride balls were worn, while the was even a notice scar or wear track appeared on the coated specimen.

Example 4 - Coating of BN-Cr₂0₃/Ni on coupons

[0066] The experimental conditions are similar as compared to the coating of BN-Si0₂/Ni on coupons. Briefly, carbon steel or copper alloy were used as coupons, with size of ID: 15 mm, OD: 30 mm, and height: 10 mm. The plating procedures used as, degrease, rinse, neutralize, rinse, activation, and plating. In this case the plating bath is a BN-Cr₂0₃/Ni colloidal solution as described in Example 2. The plating parameters are also similar to the BN-Si0₂/Ni plating parameter as described in Example 3, except, here the pH is around 2 to 2.5 for the best coating. [0067] The corresponding coating coefficient is 0.063 with full oil lubrication, 0.079 with a thin oil film (wiped off), and 0.118 in absolute dry for the coated gear substrate. The property of this coating is not stable, thus, we changed the pH to a range of 2.0 to 4.0, and the coefficient of friction also ranges from 0.08 to 0.5, almost a 10 folds of difference. The exact reason for this property instability is currently unknown, but we believe it could be related to the double layer effect or the GCDEDL and HEDL phenomena associated in the coating process, due to the fact that Cr₂0₃ nanoparticles maybe conductors in the presence of nickel electrolyte, thus significantly complicate the electroplating process.

Example 5 - Coating of BN-SiC/Ni on coupons

[0068] The experimental conditions are similar as compared to the coating of BN-SiC/Ni on coupons. Briefly, carbon steel or copper alloy were used as coupons, with size of ID: 15 mm, OD: 30 mm, and height: 10 mm. The plating procedures used as, degrease, rinse, neutralize, rinse, activation, and plating. In this case the plating bath is a BN-SiC/Ni colloidal solution as described in Example 2. The plating parameters are also similar to the BN-Si0₂/Ni plating parameter as described in Example 3, except, here the pH is around 4.0 for the best coating. Coating of about 20 micron thick coating takes about 30 minutes.

[0069] The corresponding coating coefficient is 0.6-0.8 with a thin oil film (wiped off). The coating also have a hardness in the neighborhood of 650 to 700 VHN.

Example 6 - Coating of BN-Si0₂/Ni on Bush/Sleeve Components for Steel Mill Equipment Applications

[0070] In this case, the component has a size of ID: 70 mm, OD: 85 mm, and height: 70 mm. To coat this component, first, a male electrode (anode) is fabricated that uses either a carbon conductor or a nickel metal. The relative relationship between the electode, sleeve, and the electrical connector is shown in FIG. 9. Note, in the degrease procedure, the male electrode is reversed (or acted as the cathode). It should be noted that during plating, the uncoated surfaces are masked with tapes. The plating current density are then calculated according to the effective area of the component. [0071] The plating procedures used as, degrease, rinse, neutralize, rinse, activation, and plating. The deposition parameters include: These parameters, 4.2-4.5 plating pH, mechanical stirring, and 20-40 amp/ft current density. Coating of about 100 micron thick coating takes about 240 minutes. The obtained coating has a smooth surface, characteristics of the coating is similar to as those described in Example 2. A photograph of the coated components are shown in FIG. 10.

Example 7 - Coating of BN-Si0₂/Ni on Shock Absorbers for Automotive Applications

[0072] In this case, the component has a size of φ 15.81x290.75 mm. To coat this component, first, an electrical connector is attached at each end of the shock absorber, as schematically shown in FIG. 10. The uncoated surfaces are masked with tapes. The plating current density is then calculated according to the effective area of the component.

[0073] The plating procedures used as, degrease, rinse, neutralize, rinse, activation, and plating. The deposition parameters include: These parameters, 4.2-4.5 plating pH, mechanical stirring, and 20 amp/ft current density. Coating of about 15-20 micron thick coating takes about 30 minutes.

Example 8 - Coating of BN-Si0₂/Ni on Gear Shaped Geometries

[0074] Inframat had sent its previously obtained auto transmission gears to Shilin for coating. A gear-tip shaped individual electrodes with respect to the gear are assemblied as shown in FIG. 11. The uncoated surfaces are masked with tapes. The plating current density is then calculated according to the effective area of the component.

[0075] The plating procedures used as, degrease, rinse, neutralize, rinse, activation, and plating. The deposition parameters include: These parameters, 4.2-4.5 plating pH, mechanical stirring, and 20 amp/ft current density. Coating of about 15-20 micron thick coating takes about 30 minutes. The obtained coating has a smooth surface, with uniform coatings on both valley tips, and slopes.

Claims

What is claimed is:

1. A slurry or near colloidal bath, comprising of at least one of the following:

(1) . an electrolyte solution,

(2) . a solid lubricant nanoparticle,

(3) . a hard phase ceramic nanoparticle

2. The slurry of Claim 1, wherein the electrolyte solution is selected from a group of at least one of the metallic salts of nickel, cobalt, chromium, iron, zinc, molybdenum, tungsten, tatanlum; or a combination thereof and wherein the amount of this electrolyte is from 50 to 100 weight percent of the colloidal bath.

3. The slurry of Claim 1, wherein the lubricant nanoparticles comprises molybdenum disulfide (MoS₂), tungsten sulfide (WS₂), iron sulfide (Fei_xSx), iron oxide (Fe₃0₄), calcium flouride (CaF₂), boron nitride (BN), chromium oxide (Cr₂0₃), polytetrafluoroethylene, carbon graphite, polyolefins, polysiloxanes, carbon nanotubes/bulky balls, silicon oxide, titanium oxide; a fluoropolymer, or a combination comprising at least one of the foregoing and wherein the lubricant nanoparticles are present in an amount of 1 to 50 weight percent of the colloidal bath.

4. The slurry of Claim 1, wherein the hard phase nanoparticles comprises of tungsten carbide (WC), silicon carbide (SiC), boron carbide (B₄C), titanium carbide (TiC), tantalum carbide (TaC), vanadium carbide (VC), silicon nitride (Si₃N₄), aluminum nitride (A1N), cubic boron nitride (BN), zirconium nitride (ZrN), aluminum oxynitride (Α10χΝι_χ), silicon oxynide (Si₃0xN₄_x), titanium boride (TiB₂), and zirconium boride (ZrB₂), diamond, silicon dioxide (Si0₂), aluminum oxide (A1₂0₃), titanium oxide (Ti0₂), chromium oxide (Cr₂0₃), cerium oxide (Ce0₂), zirconium oxide (Zr0₂), yttrium oxide (Y₂0₃); diamond, or a combination comprising at least one of the foregoing and wherein the amount of the hard nanoparticle phase is from 1 to 50 weight percent of the colloidal bath.

5. The slurry of Claim 1, further comprising bath additives; wherein the bath additives may be selected from the group consisting of surfactants and plating additives; the surfactants and plating additives consisting of at least one of Darvin C (ammonium polymethylacrylate), 75% aqueous solution of tetrakis(hydroxymethyl) phosphonium sulfate (phosphorus source and cataphoretic additive), boric acid H₃B0_3; sodium saccharin, 1,4-butyne 2-diol, dow corning T2 7604, Dow Corning 2210, 2-propanol, and/or a combination of and wherein the amount of this bath additive phase is from 0.01 to 40 weight percent of the colloidal bath.

6. The slurry of Claim 1, comprising nickel sulfamate, boron nitride, silicon dioxide (and/or chromium oxide), with bath additives of 75% aqueous solution of tetrakis(hydroxymethyl) phosphonium sulfate, boric acid H₃B0_3; sodium saccharin, 1,4-butyne 2-diol, and 2-propanol.

7. The slurry of Claim 1, being used as a electroplating or electroless plating solution.

8. A method comprising:

disposing a substrate in an electroplating solution to form on the substrate a composite coating comprising:

(a) , a lubricant phase for providing lubrication to the composite coating;

(b) . a hard ceramic phase for providing structural integrity and wear resistance to the composite coating; and

(c) . a ductile metallic phase for providing ductility to the composite coating.

9. The method of Claim 8, wherein composite coating is nanostructured or superfine.

10. The method of Claim 8, wherein the lubricant phase and the hard ceramic phase comprises nanoparticles or superfine particles distributed in the ductile metal phase.

11. The method of Claim 8, wherein the lubricant phase comprises molybdenum disulfide (M0S₂), tungsten sulfide (WS₂), iron sulfide (Fei__xSx), iron oxide (Fe₃0₄), calcium floride (CaF₂), boron nitride (BN), chromium oxide (Cr₂03), Teflon, carbon graphite, carbon nanotubes/bulky balls, silicon oxide, titanium oxide; a fluoropolymer, or a combination comprising at least one of the foregoing.

12. The method of Claim 8, wherein the hard particle phase comprises of tungsten carbide (WC), silicon carbide (SiC), boron carbide (B₄C), titanium carbide (TiC), tantalum carbide (TaC), vanadium carbide (VC), silicon nitride (Si₃N₄), aluminum nitride (A1N), cubic boron nitride (BN), zirconium nitride (ZrN), aluminum oxynitride (Α10χΝι_χ), silicon oxynide (Si₃0xN₄_x), titanium boride (TiB₂), and zirconium boride (ZrB₂), diamond, silicon dioxide (Si0₂), aluminum oxide (AI₂O₃), titanium oxide (Ti0₂), chromium oxide (Cr₂03), cerium oxide (Ce0₂), zirconium oxide (Zr0₂), yttrium oxide (Y₂O₃), diamond; or a combination comprising at least one of the foregoing.

13. The method of Claim 8, wherein the ductile metal phase comprises a transition metal, Co, Ni, Fe, Mo, Cr, an alloy of transition metals, or a combination comprising at least one of the foregoing.

14. The method of Claim 8, wherein the composite coating is a nano structured or superfine coating comprising a BN phase, a Cr₂C«3 phase, and a Ni, Ni-Cr, Ni-Co, Co-Cr, or NiFe phase.

15. The method of Claim 8, wherein the composite coating is a nano structured or superfine coating comprising a BN phase, a Si0₂ phase, and a Ni, Ni-Cr, Ni-Co, Co-Cr, or NiFe phase.

16. The method of Claim 8, wherein the composite coating is a nano structured or superfine coating comprising a BN phase, a diamond phase, and a Ni, Ni-Cr, Ni-Co, Co-Cr, or NiFe phase.

17. The method of Claim 8, wherein the composite coating is a nanostructured or superfine coating comprising a BN phase, or a Si0₂ phase, and a Ni, Ni-Cr, Ni-Co, Co-Cr, or NiFe phase.

18. The method of Claim 8, wherein the composite coating is a nanostructured or superfine coating comprising a CaF₂ phase, or a Si0₂ phase, and a Ni, Ni-Cr, Ni-Co, Co-Cr, or NiFe phase.

19. An electroplating method, comprising:

combining lubricant particles and hard ceramic particles with an ionic metal electroplating solution;

electroplating a substrate using the electroplating solution to form a composite coating on the substrate; and

performing an electrophoresis procedure to cause the lubricant particles and the hard ceramic particles to be incorporated into the metal coating and thereby form the lubricant-hard-ductile composite coating.

20. The method of Claim 20, wherein the composite coating is disposed upon a surface of mating parts that undergo wear.

21. The method of Claim 20, wherein the mating part comprises a gear.

22. The method of Claim 20, wherein the mating part comprises a copper mould surface in steel mills

23. The method of Claim 20, wherein the mating part comprises a bush or a sleeve.

24. The method of Claim 20, wherein the mating part comprises a hydraulic cylinder.

25. The method of Claim 20, wherein the mating part comprises a shock absorber in automobile or other moving vehicles that improve component wear life.

26. The method of Claim 20, wherein the mating part comprises a down hole/or bottom hole drilling in petroleum or other mining applications for improve component wear life.

27. An article comprising:

a substrate upon which is disposed a nanocomposite coating; the nanocomposite coating comprising:

(a) , a lubricant phase for providing lubrication to the composite coating;

(b) . a hard ceramic phase for providing structural integrity and wear resistance to the composite coating; and

(c) . a ductile metallic phase for providing ductility to the composite coating.

28. The article of Claim 27, wherein the composite coating is nanostructured or superfine.

29. The article of Claim 27, wherein the lubricant phase and the hard ceramic phase comprises nanoparticles or superfine particles distributed in the ductile metal phase.

30. The article of Claim 27, wherein the lubricant phase comprises molybdenum disulfide (M0S₂), tungsten sulfide (WS₂), iron sulfide (Fei_xSx), iron oxide (Fe₃0₄), calcium flouride (CaF₂), boron nitride (BN), chromium oxide (Cr₂0₃), Teflon, carbon graphite, carbon nanotubes/bulky balls, silicon oxide, titanium oxide; a fluoropolymer, or a combination comprising at least one of the foregoing.

31. The article of Claim 27, wherein the hard particle phase comprises tungsten carbide (WC), silicon carbide (SiC), boron carbide (B₄C), titanium carbide (TiC), tantalum carbide (TaC), vanadium carbide (VC), silicon nitride (Si₃N₄), aluminum nitride (AIN), cubic boron nitride (BN), zirconium nitride (ZrN), aluminum oxynitride (Α10χΝι_χ), silicon oxynide (Si₃0xN₄_x), titanium boride (TiB₂), and zirconium boride (ZrB₂), diamond, silicon dioxide (Si0₂), aluminum oxide (AI₂O₃), titanium oxide (T1O₂), chromium oxide (C^Ch), cerium oxide (Ce0₂), zirconium oxide (Zr0₂), yttrium oxide (Y₂0₃), diamond; or a combination comprising at least one of the foregoing.

32. The article of Claim 27, wherein the ductile metal phase comprises a transition metal, Co, Ni, Fe, Mo, Cr, an alloy of transition metals, or a combination comprising at least one of the foregoing.

33. The article of Claim 27, wherein the composite coating is a nano structured or superfine coating comprising a BN phase, a Cr₂0₃ phase, and a Ni, Ni-Cr, Ni-Co, Co-Cr, or NiFe phase.

34. The article of Claim 27, wherein the composite coating is a nano structured or superfine coating comprising a BN phase, a S1O₂ phase, and a Ni, Ni-Cr, Ni-Co, Co-Cr, or NiFe phase.

35. The article of Claim 27, wherein the composite coating is a nano structured or superfine coating comprising a BN phase, a diamond phase, and a Ni, Ni-Cr, Ni-Co, Co-Cr, or NiFe phase.

36. The article of Claim 27, wherein the composite coating is a nano structured or superfine coating comprising a BN phase, or a S1O₂ phase, and a Ni, Ni-Cr, Ni-Co, Co-Cr, or NiFe phase.

37. The article of Claim 27, wherein the composite coating is a nano structured or superfine coating comprising a CaF₂ phase, or a S1O₂ phase, and a Ni, Ni-Cr, Ni-Co, Co-Cr, or NiFe phase.

38. The article of Claim 27, wherein the substrate is a mating part that undergoes wear.

39. The article of Claim 38, wherein the mating part comprises a gear.

40. The article of Claim 38, wherein the mating part comprises a copper mold surface in a steel mill.

41. The article of Claim 38, wherein the mating part comprises a bush or a sleeve.

42. The article of Claim 38, wherein the mating part comprises a hydraulic cylinder.

43. The article of Claim 38, wherein the mating part comprises a shock absorber in an automobile or other moving vehicles that improve component wear life.

44. The article of Claim 38, wherein the mating part comprises a down hole/or bottom hole drill for use in petroleum or other mining applications for improving component wear life.