ELECTROPLATED COATINGS FOR HYDRAULIC COMPONENTS

Abstract

An example hydraulic system component of a machine includes a protective coating deposited by electroplating in a multi-anodic plating tool. The plating tool allows for independent control of the anodic current, voltage, and/or waveform of each of the anodes to provide a uniform, hard, and dense protective coating along a length of an elongated component, such as a rod, cylinder, or piston. The electroplating process may allow for independent control of rectifiers providing power to the electrically isolated anodes to achieve a high level of uniformity over the length of the components being electroplated. The coating may include a layer of trivalent chromium electroplated over an electroplated layer of nickel to protect the component from wear, oxidation, and/or corrosion. The bi-layer coating may be relatively thin, with a thickness less than 125 microns.

Claims

1. A hydraulic component, comprising: a steel surface; and a coating disposed over the steel surface, wherein: the coating includes a first layer of nickel (Ni) provided directly on the steel surface, the coating includes a second layer of trivalent chromium (Cr) provided directly on the first layer, the coating has a thickness of less than 125 micrometers (m), the coating having a uniformity of 15 m or less along its length, and the coating is characterized by a hardness exceeding 800 Vickers Hardness (Hv).

2. The hydraulic component of claim 1, wherein the hydraulic component comprises at least one of: (i) a rod, (ii) a cylinder, or (iii) a piston.

3. The hydraulic component of claim 1, wherein the coating has a thickness less than 50 m.

4. The hydraulic component of claim 1, wherein the second layer is characterized by a hardness greater than 1300 Hv.

5. The hydraulic component of claim 1, wherein the second layer has a thickness in a range of about 3 m to about 50 m.

6. The hydraulic component of claim 1, wherein the hydraulic component has a length of greater than 6 feet and the coating has a uniformity within about 5 m over the length of the hydraulic component.

7. A plating tool, comprising: a reservoir configured to hold an electroplating bath; an electroplating chamber fluidically coupled to the reservoir and configured to receive the electroplating bath from the reservoir; a first annular anode disposed within the electroplating chamber; a second annular anode disposed within the electroplating chamber and axially aligned with the first annular anode; a first rectifier electrically coupled to the first annular anode and configured to provide a first current to the first annular anode; and a second rectifier electrically coupled to the second annular anode and configured to provide a second current to the second annular anode.

8. The plating tool of claim 7, wherein the first current is different from the second current.

9. The plating tool of claim 7, further comprising: a spacer electrically isolating the first annular anode from the second annular anode.

10. The plating tool of claim 7, wherein the electroplating chamber includes high density polyethylene (HDPE).

11. The plating tool of claim 7, wherein the first annular anode includes at least one of: (i) graphite, (ii) titanium (Ti), (iii) a mixed metal oxide, or (iv) platinum (Pt) coated Ti.

12. The plating tool of claim 7, further comprising: a controller to control the first rectifier to provide the first current.

13. The plating tool of claim 7, further comprising: a third annular anode disposed within the electroplating chamber and axially aligned with the first annular anode; and a third rectifier electrically coupled to the third annular anode and configured to provide a third current to the third annular anode.

14. A method, comprising: providing an electroplating bath in an electroplating chamber; providing a first annular anode immersed in the electroplating bath; providing a second annular anode immersed in the electroplating bath such that the first annular anode and the second annular anode are substantially axially aligned; immersing a component into the electroplating bath such that the first annular anode conformally surrounds a first part of the component and the second annular anode conformally surrounds a second part of the component; providing first power from a first rectifier electrically coupled to the first annular anode to electroplate a first coating substantially onto the first part of the component; and providing second power from a second rectifier electrically coupled to the second annular anode to electroplate a second coating substantially onto the second part of the component, wherein the first rectifier and the second rectifier are electrically isolated.

15. The method of claim 14, further comprising: determining, based at least in part on a length of the component, that the first rectifier and the second rectifier are to be energized.

16. The method of claim 14, further comprising: forming the component from steel; and hardening the component.

17. The method of claim 14, wherein the component is a preexisting component that is to be remanufactured by deposition of a protective coating.

18. The method of claim 14, the electroplating bath is a nickel electroplating bath and the method further comprising: electroplating a first layer of nickel on the component; and electroplating a second layer of chromium over the first layer of nickel.

19. The method of claim 18, further comprising: rinsing the component after electroplating the second layer of chromium.

20. The method of claim 14, further comprising: providing a third annular anode immersed in the electroplating bath such that the first annular anode and the third annular anode are substantially axially aligned; and providing third power from a third rectifier electrically coupled to the third annular anode to electroplate a third coating substantially onto a third part of the component, wherein the second rectifier and the third rectifier are electrically isolated.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0009] FIG. 1 is a schematic illustration of an example machine with one or more hydraulic components formed in accordance with examples of the disclosure.

[0010] FIG. 2 is a schematic illustration of an example electroplating system to form the hydraulic components of the machine as depicted in FIG. 1, according to examples of the disclosure.

[0011] FIG. 3 is a flow diagram depicting an example method for forming the hydraulic components with electroplated coatings of the machine as depicted in FIG. 1, according to examples of the disclosure.

[0012] FIG. 4 is a sectional illustration of an example component surface with the steel surface and the coating(s) thereon, according to examples of the disclosure.

DETAILED DESCRIPTION

[0013] Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. FIG. 1 is a schematic illustration of an example machine 100 with one or more components formed in accordance with examples of the disclosure. Although the machine 100 is depicted as a dozer, it should be understood that the machine 100 may be of any suitable type, such as those used in construction, farming, mining, paving, transportation, or the like. In other examples, the machine 100 may be any suitable machine 100, such as, a loader, an excavator, a tank, a backhoe, a drilling machine, a trencher, a combine, or any other on-highway or off-highway vehicle.

[0014] The machine 100 includes a frame 102 on which other elements of the machine 100 are mounted. The machine 100 includes a propulsion system 104, such as a track chain assembly, as shown. Alternatively, the machine 100 may have any other suitable type of propulsion system 104, such as wheels and tires. The machine 100 further includes an engine 106, such as an internal combustion engine using hydrocarbon fuels. Alternatively, the machine 100 may be an electrically powered machine. The machine 100 includes an exhaust system 108 and/or one or more work systems 110 with cutting edges 112 that are movable by one or more hydraulic systems 114. The machine 100 also includes a transmission system (not shown) that mechanically couples the engine 106 to the propulsion system 104. According to examples of the disclosure, any component of the machine 100, including any variety of components of the propulsion system 104, the engine 106, the exhaust system 108, the work systems 110, the hydraulic systems 114, the transmission, etc., may be formed by the processes disclosed herein. Additionally, any of the aforementioned components of the machine 100 may have the structure and the resultant material properties as disclosed herein, when formed by the processes disclosed herein.

[0015] The hydraulic system 114 may include a cylinder 116, as shown in sectional view, and a piston 118 that is rigidly coupled to a piston rod, or rod 120. The piston 118 and rod 120 are movably coupled to the cylinder 116. The piston 118 is mechanically coupled to the work system 110 to perform work tasks, such as lifting dirt or redistributing gravel. The cylinder 116, piston 118, and/or rod 120, during operation may have relatively high level of stresses imparted on them, such as by pressurized hydraulic fluids. Additionally, the piston 118 and/or rod 120 may impact the cylinder 116 during operation of the hydraulic system 114. Further still, the rod 120 may slide along portions of the cylinder 116 during operation of the hydraulic system 114, resulting in frictional forces, such as along the length of the rod 120. Thus, the cylinder 116 and/or the rod 120 are prone to tribological failures, such as wear and tear on the outer diameter of the rod 120. Additionally, due to the conditions under which they operate, the cylinder 116, piston 118, and/or the rod 120 may be subject to oxidation and/or other forms of corrosion. These types of oxidative defects, such as on the rod 120, may lead to excessive frictional forces, leakage of lubrication oil, leakage of hydraulic fluid, and/or other operational failures and/or degradations of the hydraulic systems 114. The processing mechanisms and material compositions, as disclosed herein, when applied to the rod 120, cylinder 116, and/or the piston 118, results in components that are corrosion resistant, leading to longer lifetimes and/or more optimal operations of the hydraulic systems 114.

[0016] In examples of the disclosure, the rod 120, piston 118, and/or the inner diameter of the cylinder 116 may be coated with a coating, such as a thin film, to protect these components from oxidation and/or corrosion, as well as to provide an ideal, or at least improved, surface topology for the functioning of the hydraulic system 114. For example, the rod 120 may be coated with a coating that provides a surface topology that retains a desired level of surface lubrication on the surface of the rod 120, such that the rod 120 can move in a reciprocating and/or telescopic manner within the cylinder 116. Furthermore, the coating may protect the rod 120, or other components of machine 100, from any variety of oxidation and/or corrosion. The coating may be more uniformly coated, contain fewer pinhole defects, provide superior coverage, provide improved adhesion strength, allow for thinner coatings, provide a larger processing window, provide greater hardness, result in greater durability, provide a greater operational lifetime, provide an improved roughness profile, and/or be coated at a reduced cost compared to conventional coatings for the rod 120 or other components of the machine 100.

[0017] In some cases, conventional coatings on the rod 120 may have poor and/or incomplete coverage that results in moisture incursion to the underlying steel of the rod 120 and subsequent oxidation (e.g., formation of rust) on the steel surface. These surface oxidation locations on the rod 120 may lead to expansion and/or protrusions (e.g., rust bubbles) on the surface of the rod 120. During operation of the hydraulic system 114, the oxidation induced protrusion may be sheared off as the rod 120 moves in and out of the cylinder 116 while in contact with the cylinder 116. This shearing of oxidized regions may lead to additional frictional forces during operation of the hydraulic system 114. Additionally, the increased surface topography resulting from the oxidation sites may result in additional leakage of lubricants and/or hydraulic fluid during operation. These and other issues are avoided and/or mitigated by use of the coatings and/or processes disclosed herein.

[0018] In some cases, components other than those associated with the hydraulic systems 114 may be coated with the coatings and the processes disclosed herein. For example, the cutting edge 112 and/or other components of the work systems 110 may also be subject to tribologically and/or thermally harsh operating environments, such as in moving gravel, picking up stones, redistributing asphalt, etc. In many cases, the cutting edge 112 is exposed to repeated impact with hard objects (e.g., rocks) and in some cases may also be subject to relatively high temperatures (e.g., when distributing hot asphalt and/or tar, from frictional heating, etc.). Aspects of the present application enable forming cutting edges 112 and/or other components of the work systems 110 with coatings, such as protective coatings, as disclosed herein. This may allow the cutting edge 112 to have a longer lifetime in use. The engine 106 may include a variety of components that can also be enhanced with the coatings and/or processes, as disclosed herein, to improve the surface properties and/or lifetime of those components.

[0019] As another example, the propulsion system 104 may include one or more components, such as track shoes and bushings, that may be exposed to harsh environments with high levels of stresses and frictional forces imparted thereon. For example, the track shoes engage the ground, or other surface, and propel the machine 100 thereon. Thus, the track shoes hold the weight of the entire machine 100, which can be on the order of 10's or even 100's of tons, as it travels over an abrasive surface. Similarly, the bushings grind, with extremely high loading, against other metallic components of the propulsion system 104. This can lead to a variety of issues, such as cracking, galling, and/or other defects. The propulsion system 104, in the form of a track propulsion system, includes other components, such as rolling elements, sprockets, front idlers, rear idlers, track rollers, etc., that operate under harsh conditions where heavy loads and/or high levels of abrasion are imparted thereon. Thus, the propulsion system 104 may include a variety of components that can also be enhanced with the coatings and/or processes as disclosed herein to improve the durability and/or lifetime of those components.

[0020] According to examples of the disclosure, the rod 120, the cylinder 116, and/or other components of the hydraulic system 114 and/or the machine 100 may be coated with an electroplated coating. This electroplated coating may be a single element, multiple elements, and/or multiple different layers of coating. The coatings, in some cases, may be harder than the bulk material of construct of the rod 120 or other component. For example, the bulk material of construct of the rod 120 may be steel and one or more harder materials, such as in the form of thin films, may be deposited on the bulk steel. In some cases, the protective coating may include a layer of chromium (Cr), a layer of nickel (Ni), a bi-layer of Ni and Cr, and/or any other similar materials. The protective coating may be electroplated. In multilayer coatings, such as bi-layer coatings, both coated layers may be deposited by electroplating in some cases. In other cases, multilayer coatings may include at least one electroplated coating and at least one non-electroplated coating, such as an electroless plated coating, a high velocity air fuel (HVAF) coating, high velocity oxygen fuel (HVOF) coating, or the like. In some cases, the protective coating may include a layer of Ni over the bulk steel of the component and a layer of trivalent Cr over the layer of Ni.

[0021] The protective coating, as disclosed herein, may be relatively uniform over the length of an elongated component, such as a rod 120 and/or cylinder 116. Additionally, due to its conformal nature, the protective coating, as disclosed herein, may be relatively thin compared to conventional coatings used for similar applications. In other words, due to the dense and uniform nature of the electroplated coating(s) discussed here, the electroplated coatings can be made relatively thin without undue risk of pinhole and other defects therein. Further, the plating tool used to electroplate coatings may be configured to provide a highly uniform coating along the length of an elongated component, such as the rod 120 and/or cylinder 116. Further still, the plating tool used to electroplate coatings may be configured to electroplate a protective coating onto elongated components of various lengths. For example, the plating tool may be able to electroplate trivalent Cr onto rods 120 that are 12 inches long or rods 120 that are 12 feet long, and any length in between.

[0022] As disclosed herein, a plating tool may include a process chamber fluidically coupled to a reservoir holding a plating bath. The plating bath may include electrolytic chemistry that is used to plate the coatings on a component, such as rod 120 or cylinder 116. The process chamber may be filled with electrolytic chemistry from the reservoir prior to the electroplating process. The component, such as rod 120, may be immersed into the plating bath. The process chamber may include one or more anodes that are electrically isolated from each other. For example, the process chamber may include three different anodes that are electrically isolated from each other, such that the different anodes can be energized independently with different voltages, currents, and/or waveforms. The component being electroplated is the cathode where a reduction reaction takes place to deposit material onto the component.

[0023] The anodes of the process chamber may be a round cage like shape, which is well suited for providing a uniform coating on cylindrical components, such as rod 120 and/or cylinder 116. The round shape of the anodes allows for maintaining a consistent distance between the anode and the surface of the rod 120 or cylinder 116 being coated. Each of the anodes may be separated, both physically and electrically, by spacers. The anodes may be electrically coupled to a corresponding rectifier that can provide a particular current, voltage, and/or waveform to its respective anode within the process chamber.

[0024] During operation, the various anodes of the process chamber may be selectively energized to electroplate the regions of the component proximal to each of the anodes. The number of anodes that are energized during processing may depend on the length of the component being electroplated. For example, a relatively long rod 120 may require a greater number of energized anodes, compared to a relatively shorter rod 120, to electroplate. For example, each of the anodes may have a cylindrical or annular shape and a length of 2 feet. The anodes may be axially aligned with each other, such that a component to be electroplated can be conformally surrounded by multiple anodes. Thus, if a 4 feet long rod 120 is to be electroplated, two anodes may be energized during the electroplating process. However, if an 8 feet long rod 120 is to be electroplated, then four anodes may need to be energized. The preceding dimensions are illustrative examples and the disclosure herein contemplates any suitable shape and size of the anodes.

[0025] It should be understood that the various anodes may receive different type of power from their respective rectifiers during plating the rod 120 to achieve a highly uniform coating along the length of the rod 120. For example, the rectifiers may provide different levels of current, voltage, and/or waveform along the length of the rod 120 and/or the cylinder 116 to provide a relatively uniform coating along the component's length. By partitioning the function of a single anode to multiple separately controllable anodes, the current density and deposition rates can be optimized to provide a uniform electroplated coating over the entire length of the component being plated.

[0026] The coating may be provided using trivalent chromium electroplating on the rod 120 with a thickness in the range of about 3 microns (m) to about 50 m. In other cases, the coating thickness range may be between about 5 m to about 40 m. In yet other cases, the coating thickness range may be between about 8 m to about 35 m. In still other cases, the coating thickness range may be between about 10 m to about 30 m. In yet further cases, the coating thickness range may be between about 13 m to about 27 m. In still further cases, the coating thickness range may be between about 15 m to about 25 m. For example, in some cases, the thickness of the coating may be about 20 m.

[0027] In some cases, trivalent Cr may be plated on top of an electroplated layer of Ni. The Ni electroplated coating on the rod 120 and under the Cr coating may have a thickness in the range of about 1 m to about 75 m. In other cases, the Ni coating thickness range may be between about 3 m to about 65 m. In yet other cases, the Ni coating thickness range may be between about 5 m to about 60 m. In still other cases, the Ni coating thickness range may be between about 10 m to about 50 m. In yet further cases, the Ni coating thickness range may be between about 13 m to about 40 m. In still further cases, the Ni coating thickness range may be between about 15 m to about 30 m. For example, in some cases, the thickness of the Ni coating may be about 25 m.

[0028] The total thickness of a bilayer coating with trivalent Cr film over a Ni film may be in the range of about 4 m to about 125 m. In other cases, the bilayer coating thickness range may be between about 8 m to about 105 m. In yet other cases, the bilayer coating thickness range may be between about 13 m to about 95 m. In still other cases, the Ni coating thickness range may be between about 20 m to about 80 m. In yet further cases, the Ni coating thickness range may be between about 26 m to about 67 m. In still further cases, the Ni coating thickness range may be between about 30 m to about 55 m. For example, in some cases, the thickness of the Ni coating may be about 45 m. In many cases, the combined thickness of the bilayer coating of Cr over Ni may be less than 100 m, less than 75 m, or even less than 50 m. The relatively thin protective layer(s) can be electroplated relatively quickly and provide similar or improved protection of the hydraulic system 114 compared to conventional protective coatings. The improvements gained by the bilayer coating as disclosed herein are a result of the relatively high level of control over the uniformity of the films, as afforded by the multiple electrically isolated anodes of the plating tool.

[0029] In some cases, the bilayer coating (a Cr layer over a Ni layer) may have a uniformity of 20 m or less for a 12 foot long rod 120. In other cases, the bilayer coating may have a uniformity of 15 m or less for a 12 foot long rod 120. In yet other cases, the bilayer coating may have a uniformity of 10 m or less for a 12 foot long rod 120. In still other cases, the bilayer coating may have a uniformity of 5 m or less for a 12 foot long rod 120.

[0030] The hardness of the bilayer coating may be in the range of about 800 Vickers Hardness Number (Hv) to about 1900 Hv. In other cases, the bilayer coating may have a hardness in the range of about 1000 Hv to about 1700 Hv. In yet other cases, the bilayer coating may have a hardness in the range of about 1200 Hv to about 1600 Hv. The hardness of the Cr layer may be in a range of about 800 Hv to about 1900 Hv. In other cases, the hardness of the Cr layer may be in the range of about 1000 Hv to about 1850 Hv. In yet other cases, the hardness of the Cr layer may be in the range of about 1300 Hv to about 1700 Hv. For example, in some cases, the hardness of the Cr layer may be approximately 1650 Hv. The hardness of the outer layer of the component allows for reduced wear and tear of the component. For example, as the rod 120 reciprocates within the cylinder 116, there are frictional forces between the rod 120 and/or the piston 118 and the cylinder 116. If the respective contacting surfaces are coated with a hard material, such as the bilayer coating of Cr over Ni, then there will be reduced wear and tear of the contacting surfaces of the hydraulic system 114.

[0031] According to examples of the disclosure, the coating may have a surface finish, as measured by R.sub.z, less than about 2 m. As used herein, R.sub.z defines a peak-to-valley depth, as determined by a surface finish measurement tool, such as a profilometer, an optical roughness measurement tool, a scanning tunneling microscope (STM), an atomic force microscope (AFM), or the like. In some cases, the R.sub.z of the coating may be in the range of about 0.6 m to about 1.8 m. In other cases, the coating may have a R.sub.z value in the range of about 1 m to about 1.4 m. The coatings with R.sub.z values, as discussed herein, may result in superior performance in lubricant (e.g., oil) retention on the surfaces of the components of the hydraulic systems 114 (e.g., rod 120, cylinder 116, piston 118, etc.), while reducing the amount of lubricant and/or hydraulic fluid leakage as the rod 120 is stroked within the cylinder 116. In some cases, a post-electroplating polish process may be used to achieve a desired surface roughness.

[0032] The rod 120, piston 118, cylinder 116, and/or any other components of the machine 100 that is coated with electroplating, as described herein, may be formed with any suitable material, such as any variety of steel or other metallic materials. For example, the rod 120, piston 118, cylinder 116, and/or any other components of the machine 100 may be formed using American Iron and Steel Institute (AISI) 4140 steel, AISI 4130 steel, AISI 4330 steel, AISI 4141 steel, any variety of low-carbon steel, any variety of medium carbon steel, any variety of high-carbon steel, any variety of alloy steel, or the like. The electroplating process, as described herein, for forming the coating is able to be deposited directly on these materials, without roughening the component, resulting in reduced pre-deposition and/or post-deposition processing. In other words, one advantage of the electroplating process, as disclosed herein, may not require a pre-roughening process, as conventional coating process use. This reduces the number of process steps for providing the coatings disclosed herein, which in turn reduces cost of fabricating and/or manufacturing the coated components, such as rod 120.

[0033] Although discussed in the context of electroplating protective coatings on new components, it should be understood that the apparatus, systems, and methods disclosed herein may be applied to refurbishing preexisting components, such as hydraulic components. Thus, rods 120, pistons 118, and/or cylinders 116 that are already in use, may be remanufactured according to a maintenance timetable or when inspections indicate that the old protective coatings are close to being worn out. When remanufacturing, any old residual coating may be stripped by any suitable process, such as in an acid bath.

[0034] The electroplating processes, in example embodiments, may result in minimal increase on the surface temperature of the components on which the coating is to be deposited, compared to conventional processes, such as HVOF or HVAF. This results in relatively high adhesion strength of the coating to the underlying steel and relatively reduced levels of distortion and/or warping compared to other coating processes, such as HVOF. Because the electroplating process, such as the Ni and trivalent Cr bilayer, results in a denser coating, with reduced pinholes therein, the coating can be made significantly thinner compared to conventional HVOF and/or HVAF coating techniques. Additionally, the reduction in the number of different operations in forming the coating, along with the ability to use thinner and/or higher quality coating films, results in cost savings compared to conventional techniques for coating the hydraulic system 114 components.

[0035] The electroplating process may also allow relatively high coating speed, as well as high surface adhesion. Because the Ni layer, described herein, results in a relatively high adhesion strength to the underlying steel surface of the component being coated, as well as the Cr overlayer, the component does not need to be roughened prior to electroplating the Ni layer, unlike with conventional processes that typically require a roughening process, such as grit blasting. The coating rate of the trivalent Cr may be in a range of about 1 m/min to about 10 m/min. In other cases, the coating rate of the trivalent Cr may be in the range of about 2 m/min to about 8 m/min. In yet other cases, the coating rate of the trivalent Cr may be in the range of about 3 m/min to about 7 m/min.

[0036] Additionally, the electroplating process may be used to deposit a relatively thin film, such as a bilayer (Cr over Ni) coating that is less than 100 m thick. A thin coating may be sufficient due to the dense and highly uniform coating enabled by the multi-anodic apparatus and methods, as disclosed herein. After coating the component, such as rod 120, a post-grind process may not be needed, as is typically used when coating using HVOF and/or HVAF. Thus, the elimination/reduction of the pre-roughening process, along with the elimination/reduction of the post-grinding process, and further along with the need to deposit a thinner coating on the component may result in reduced processing time, and therefore, reduced cost of forming the component with the coating described herein.

[0037] FIG. 2 is a schematic illustration of an example electroplating system 200 to form the hydraulic components 116, 118, 120 of the machine 100 as depicted in FIG. 1, according to examples of the disclosure. The electroplating system 200 includes a plating chamber 202 that is configured to hold an electroplating bath 204 filled to a particular level 206. The plating chamber 202 may be fluidically coupled to an electroplating bath reservoir or reservoir 208 configured to hold electroplating bath 210 filled to a particular level 212. In some cases, the level 212 may correspond to a volume of electroplating bath 210 that might be needed to bring the level 206 to a completely full state within the plating chamber 202. Although a single reservoir 208 is shown as coupled to the plating chamber 202, it should be understood that there may be any number of different reservoirs 208 fluidically coupled to the plating chamber 202.

[0038] The reservoir 208 may be configured to provide electroplating bath 204 to the plating chamber 202 via conduit 214. Similarly, the reservoir 208 may be configured to receive used electroplating bath 204 from the plating chamber 202 via conduit 216. Although not shown here, it will be understood that the conduit 214 and/or conduit 216 may have one or more valves (not shown) and/or pumps (not shown) disposed therein to control the flow of electroplating bath 204, 210 between the plating chamber 202 and the reservoir 208. In cases, where there are multiple reservoirs 208 fluidically coupled to the plating chamber 202, there may be valves to control the flow of plating bath between those additional reservoir(s) 208 and the plating chamber 202. It will be understood that by having more than one reservoir 208 fluidically coupled to the plating chamber 202, different electroplating baths may be dispensed into the plating chamber 202 to plate different materials.

[0039] The plating chamber 202 may have therein one or more anodes 218(1), 218(2), 218(3), . . . , 218(M), hereinafter referred to in the singular as anode 218 or in the plural as anodes 218. Although four separate anodes 218 are depicted here, the disclosure herein contemplates any suitable number of anodes 218, such as two anodes 218, three anodes 218, five anodes 218, or the like. Furthermore, although the anodes 218 are depicted as cylindrical and/or annular cages, it should be understood that the anodes 218 may be of any suitable shape and/or length. For example, in some cases, the anodes 218 may be shorter discs, rather than longer cylinders. In other cases, the anodes may have a patter that is different from the crisscross cage pattern depicted here. Further still, in some cases, the anodes 218 may have a scam that allows the anodic cage to be folded upon itself to allow a variable radius of the cylinders of the anodes 218. This may allow for mare accurate and precise control of the distance between the anode 218 and the component being plated. The anodes 218 may be formed from any suitable material, such as titanium (Ti) and mixed metal oxides (MMO) (Ti-MMO), graphite, platinum (Pt) covered Ti, and/or the like.

[0040] Each of the anodes 218 may be electrically isolated from each other using spacers 220. The spacers 220 may be formed of any suitable electrically insulative material that can withstand relatively long term exposure to the electroplating bath 204. The spacers 220 may physically separate the anodes 218 from each other enough that there is substantially no current flow between anodes 218 resulting from relatively small differences in potential between adjacent anodes. In other words, the spacers 220 may have a sufficient thickness such that there is negligible or no current flow and/or electrical coupling between adjacent anodes 218, either through the spacers 220 and/or the electroplating bath 204 between the anodes 218.

[0041] The spacers 220 may have a thickness, corresponding to the distance between adjacent anodes 218, in the range of about 1 millimeter (mm) to about 20 mm. In other cases, the spacers 220 may have a thickness, corresponding to the distance between adjacent anodes 218, in the range of about 2 mm to about 15 mm. In yet other cases, the spacers 220 may have a thickness, corresponding to the distance between adjacent anodes 218, in the range of about 3 mm to about 10 mm. The spacers 220 may be constructed of any suitable material, such as polyethylene, high density polyethylene (HDPE), polyvinylchloride (PVC), polytetrafluoroethylene (PTFE), polystyrene, silicate glass, other types of glass, nitrile, rubber, any variety of plastics, any variety of polymers, or the like.

[0042] The anodes 218 may each be electrically coupled to its own respective rectifier 122(1), 122(2), 122(3), . . . , 122(N), hereinafter referred to in the singular as rectifier 222 or in the plural as rectifiers 222. The rectifiers 222 may alternatively be referred to, without limitation, as a signal generator, a power source, a current source, or the like. Each of the rectifiers 222 may be coupled to its corresponding anode via wire 224. Each of the rectifiers may also be electrically coupled to the component to be plated, shown here as rod 120, via wires 226. In other words, the rod 120 may be the cathode for each of the rectifiers 222. A negative terminal of each of the rectifiers 222 may be electrically connected to the rod 120 and a positive terminal of each of the rectifiers 222 may be electrically connected to its respective anode 218. Although four separate rectifiers 222 are depicted here, it should be understood that there may be any suitable number of rectifiers 222. In some cases, there may be the same number of rectifiers 222 as there are anodes 218 (e.g., M=N). In alternate cases, one or more of the anodes 218 may have more than one rectifier 222 associated therewith, such that the number of rectifiers 222 and anodes 218 are not matched.

[0043] The rectifiers 222 may provide power to cause a non-spontaneous reduction-oxidation (redox) reaction that results in the electroplating of the cathode, in the form of the component being plated, shown here as rod 120. A half-cell oxidation reaction may occur at the anode 218 and a half-cell reduction reaction may occur at the component being plated, such as rod 120. Although the rod 120 is shown as being electroplated here, it should be understood that any suitable component may be electroplated using the electroplating tool 200 and/or techniques disclosed herein. For example, any suitable component of the hydraulic system 114, such as cylinder 116, piston 118, and/or rod 120, may be plated using the electroplating tool 200. The electroplating tool 200 and methods, as disclosed herein, may be particularly well suited for elongated components, both associated with the hydraulic system 114 or otherwise. The rectifiers 222 may provide any suitable type of power, such as continuous direct current (DC), pulsed current, alternating current (AC), pulsed-reverse pulsed current, pulse-width modulated (PWM) current, or the like. Because the plating current can be closely controlled along the length of an elongated component, due to the multiple independently controlled anodes 218 of the electroplating tool 200, a high degree of plating rate and/or thickness control can be maintained along the length of the elongated component.

[0044] During use, the individual operations of the electroplating tool 200 may be controlled by a controller 228 of the electroplating tool 200. The controller 228 may perform operations autonomously and/or responsive to operator inputs via human-machine interfaces (HMI) (not shown). During operation, the plating chamber 202 may be filled with cleaning and/or activating fluids to clean and/or activate the surface of the rod 120, such that new material (e.g., Ni, Cr, etc.) may be plated thereon. The rod 120, or other component to be coated, may be immersed into the cleaning and/or activating bath, as indicated by arrow 230, such that the rod 120 is conformally surrounded by one or more anodes 218. The controller may control one or more motors and/or robots to immerse the rod 120 into the cleaning and/or activating bath. The cleaning and/or activating baths may degrease and remove oxides, nitrides, or other passivating layers from the surface of the rod 120. Any suitable acidic and/or basic cleaning and/or activation bath may be used to prepare the surface of the rod 120. In some cases, an electrocleaning process may be used, where current is used to passed through the rod 120 and one or more anodes 218 to clean and/or deoxidize the surfaces to be plated with the assistance of current from the rectifiers. During the electroclean process, the rod 120 may be biased as the anode and the anodes 218 may be biased as cathodes for the purposes of cleaning.

[0045] Once the surface of the rod 120 is cleaned, the cleaning and/or activating baths may be drained from the plating chamber 202 to any suitable location, such as another reservoir 208. The plating chamber 202 may next be filled with electroplating bath, such as from reservoir 208. For example, a Ni plating bath may be introduced into the plating chamber 202 and Ni may be plated onto the rod 120, as current is delivered to one or more anodes 218 from their respective rectifiers 222. Alternatively, Cr may be directly plated on the steel surface of the rod 120. If Ni is electroplated on the steel, trivalent Cr may be plated over the Ni layer. In this case, the Ni electroplating bath may be drained from the plating chamber 202, such as to its reservoir 208, and trivalent Cr plating bath may be introduced to the plating chamber 202. Next, trivalent Cr may be plated over the Ni plating. In alternate cases, hexavalent Cr may be plated instead of trivalent Cr, although trivalent Cr has advantages over hexavalent Cr, including the use of less toxic and less volatile chemistries that are easier to use and dispose.

[0046] During the electroplating process of either Ni or Cr, the number of anodes 218 used and the level 206 of filling the plating chamber 202 may depend on the length of the rod 120. For example, if a relatively short rod 120 is being electroplated, such as one that may be use on a skid loader and may have a length of around 2 feet, the electroplating may only require a relatively small volume of plating bath in the plating chamber 202, such that the level 206 is relatively low. The rod 120 may be immersed all the way to the bottom of the plating chamber 202 and only one anode 218(M) or two anodes 218(M), 218(3) may be used to electroplate thereon. On the other hand, if a relatively long rod 120 is being electroplated, such as one that may be use on a mining truck and may have a length of around 12 feet, the electroplating may require a relatively large volume of plating bath in the plating chamber 202, such that the level 206 is relatively high. The rod 120, when immersed, may span from all the way to the bottom of the plating chamber 202 to all the way to the top of the plating chamber 202 and may need all of the anodes 218 to be energized to electroplate over the full length of the relatively long rod 120.

[0047] During the electroplating processes more than one anode 218 may be energized. Additionally, each of the anodes may be independently controlled, such that the rod 120 has a high level of plating uniformity over its surface, particularly its length. Conventional electroplating, with a single long anode may not be suitable for plating highly uniform films over the length of the rod 120. In some cases, single long anodes may have resistive drops along its length resulting in non-uniform plating along the length of the rod 120. Additionally, in some cases, a single anode can result in non-uniform field lines/flux at the ends (e.g., top end, bottom end) of the anode, again resulting in non-uniformity and lack of uniformity control near the ends of the rod 120 relative to the middle of the rod 120. However, with the use of multiple anodes 218, as disclosed herein, different zones along the length of the rod 120 can be electroplated with different parameters (e.g., current, voltage, waveform, pulse duty cycle, reverse-pulse duty cycle, etc.) at different rectifiers 222 to achieve a greater level of coating uniformity along the length of the rod 120. For example, the controller 228 may control each of the rectifiers 222 to provide a similar amount of current density over the entire surface of the rod 120.

[0048] In some cases, the rod 120 may be rinsed between the Ni layer being electroplated and the Cr layer being electroplated. Similar to filling the plating chamber 202 with plating bath 204, the plating chamber may be filled with deionized water or other solvent for the rinse processes. After the final electroplating process (e.g., trivalent Cr layer), the rod 120 may again be rinsed. After the final rinse, the bilayer coating of Ni and Cr may be polished to improve its surface texture and/or improve its uniformity.

[0049] The electroplating process, in some aspects, may result in minimal increase on the surface temperature of the components being coated, compared to other mechanisms of coating, such as thermal spray, leading to relatively reduced levels of distortion and/or warping compared to other coating processes. For example, the electroplating processes may be performed in electroplating baths with a temperature in a range of about 100 C. to about 200 C. In some other cases, the electroplating temperature may be between about 160 C. and about 180 C. The plating chamber 202 and/or reservoir may include heater(s) (not shown) to control the temperature of the electroplating bath 204, 210. Additionally, the lower electroplating temperature promotes good adhesion between the Ni plated and/or Cr plated coating and the underlying steel surface of the component.

[0050] Because of the good adhesion characteristics, the electroplating process may obviate the need for grit-blasting the component surface prior to coating. Grit-blasting is often needed with conventional coating techniques, such as HVOF, to roughen the surface of the component to promote adhesion of the coating to the roughened steel surface of the component. When grit-blasting is used in conventional techniques for providing protective coatings, the steel surface is often roughened in a non-uniform manner. Additionally, grit often gets embedded on the steel surface of the components. To compensate for such surface non-uniformities, conventional techniques often provide a much thicker coating than what is need for the techniques disclosed herein. The techniques disclosed herein provide the ability to deposit the coating directly on the smooth steel surface of the component without a pre-roughening process (e.g., grit-blasting). As a result, thinner coatings can be deposited, as disclosed herein, such as under 100 m, and as low as 15 m or so. Thus, the elimination of the grit-blasting process, resulting from the disclosure herein, reduces the cost of coating machine 100 components that further result in reduced cost of the end components.

[0051] It should further be appreciated that the electroplating tool 200 with its multiple anodes 218 allow for electroplating different sizes of hydraulic components in the same tool. For example, 2 feet long hydraulic components may be electroplated in the same electroplating tool 200 as 12 feet long hydraulic components. This wide range of processing in a single tool is enabled by the ability to use a variable number of anodes 218, the combined length of which corresponds to the length of the hydraulic components being electroplated. In some cases, if only a portion of a hydraulic component is to be coated, then the electroplating tool 200 enables the operation of a limited number of anode(s) 218 corresponding to the portions of the hydraulic component that are to be coated. The plating chamber 202, as disclosed herein, allows for improved control of plating thickness, plating uniformity, plating crack pattern, deposition rates, and a variety of other quality improvements in the coating protected hydraulic components.

[0052] FIG. 3 is a flow diagram depicting an example method for forming the hydraulic components with electroplated coatings of the machine as depicted in FIG. 1, according to examples of the disclosure. The method 300 may be performed using any suitable component, as discussed herein. In examples of the disclosure, the component may be any variety of components associated with the hydraulic systems 114, such as the cylinder 116, piston 118, and/or rod 120. In other examples, the components may be any other part of the machine 100, such as elongated components from the engine 106 and/or the propulsion system 104.

[0053] At block 302, the rough component is formed with steel. This is a formation of the component, such as the cylinder 116, the piston 118, the rod 120, etc., prior to subsequent processing. The component may be formed using any suitable type of steel, such as AISI 4140 steel, AISI 4130 steel, AISI 4330 steel, AISI 4141 steel, any variety of low-carbon steel, any variety of medium carbon steel, any variety of high-carbon steel, any variety of alloy steel, or the like. The component may be formed by any suitable mechanism such as any suitable hot formation mechanism and/or machining technique. For example, any type of casting, rolling, hot rolling, cold rolling, extrusion, combinations thereof, or the like may be used to form the rough component. Additionally or alternatively, the rough component may be formed by any variety of machining techniques suitable for forming the component, such as any type of shaping, turning, milling, drilling, grinding, chiseling, lathing, and/or other machining techniques.

[0054] The component, during rough formation, may be any suitable crystal structure, such as ferrite, pearlite, bainite, cementite, martensite, and/or austenite. In some cases, the starting steel may have a relatively high level of relatively softer ferrite and/or pearlite crystal structure. The initial low, medium, or high carbon steel may be relatively soft and ductile, allowing for easier formation of the rough component, such as the cylinder 116. For example, the steel may have an initial hardness in the range of about 35 Rockwell Hardness Scale C (HRC) to about 50 HRC. In some cases, if the starting steel is not sufficiently soft, then a tempering process may be performed to soften the steel prior to machining.

[0055] At block 304, the rough component may optionally be hardened. After forming the shape of the component, the component may be subjected to any variety of operations to provide a suitable hardness, grain structure, and/or stress/strain profile. For example, any variety of hardening operations may be performed, such as a furnace heating and quenching process to harden the steel. Alternatively, other surface hardening operations, such as carburization, hardfacing, or the like may be performed. As a result of any post-formation hardening techniques, the hardness of the surface regions of the component may be in the range of about 45 HRC to about 65 HRC. For example, the component, such as the rod 120, may have a hardness of about 50 HRC. After hardening, the crystal structure of the component may be primarily martensitic and/or austenitic.

[0056] In some cases, an induction heating operation is performed for case hardening the component. The induction heating process may be performed on the surface of the component. For example, in the case of the cylinder 116, induction heating may be performed from the inner surface within the cylinder 116. The induction heating process may heat a relatively small depth from the surface of the component to temperatures that harden the steel. After induction heating, the component may be quenched, such as by forced air quenching, oil quenching, or the like, to harden a region proximal to the surface of the component. The depth of the hardening, in some cases, may be about 2 mm to about 5 mm in from the surface of the component. Thus, the component may have a hardness profile such that the region proximal to the surface is relatively hard and the rest of the component is relatively soft compared to the surface. Additionally, the relatively hard portion of the component and the rest of the component have substantially the same carbon concentrations and composition. In some examples, the hard portion of the component at the surface may be under compressive stress, while the rest of the component may be under tensile stress. The hardness of the surface of the component, after the hardening process may be in the range of about 45 HRC to about 65 HRC. For example, the component, such as the cylinder 116, may have a hardness of about 50 HRC.

[0057] It should be understood that when remanufacturing a preexisting hydraulic component, the rough component would not need to be formed or hardened. Rather, inspection processes may be used to verify that the preexisting hydraulic components are suitable for remanufacturing and/or refurbishing. Additionally, any residual coatings on the preexisting hydraulic components may need to be stripped, such as in an acid bath.

[0058] At block 306, the surface of the rough component may be cleaned and/or activated. The plating chamber 202 may be filled with cleaning and/or activating fluids to clean and/or activate the surface of the rough component, such that new material (e.g., Ni, Cr, etc.) may be plated thereon. The rough component, such as cylinder 116, may be immersed into the cleaning and/or activating bath, such as under the control of controller 228. For example, the controller 228 may control one or more motors and/or robots to immerse the cylinder 116 into the cleaning and/or activating bath. When immersed, the cylinder 116 is conformally surrounded by one or more anodes 218. The distance between the surface of the rough component and the anode 218 may be relatively consistent along the length of the rough component. In some cases, the distance between the surface of the rough component and one or more anodes 218 may be in the range of about 2 centimeters (cm) to about 20 cm. In other cases, the distance between the surface of the rough component and the one or more anodes 218 may be in the range of about 5 cm to about 10 cm.

[0059] The cleaning and/or activating baths may degrease and remove oxides, nitrides, or other passivating layers from the surface of the rough component, such that the surface is clean and ready to be electroplated upon. Any suitable acidic and/or basic cleaning and/or activation bath may be used to prepare the surface of the rough component. The cleaning/activating bath may include any variety of additives, such as chelating agents, surfactants, inhibitors, emulsifiers, buffers, etc. In some cases, an electrocleaning process may be used, where reverse current is used to clean and/or deoxidize the surfaces to be plated with the assistance of current from the rectifiers 222. During the electroclean process, the rough component may be biased as the anode and the anodes 218 may be biased as cathodes for the purposes of cleaning. After the cleaning and/or activating process is performed, the cleaning and/or activating bath may be drained, such as to a reservoir 208 that is fluidically coupled to the plating chamber 202 in which the cleaning and/or activating process was performed. An optional deionized water rinse may be performed after the cleaning/activating process.

[0060] At block 308, the rough component may be electroplated with Ni in a Ni electroplating bath to form a Ni plated component. In some case, the Ni electroplating process may be performed in the same plating chamber 202 that the cleaning/activating process of block 306 was performed. In this case, the rough component may remain immersed within the plating chamber 202 while the cleaning and/or activating bath is drained and the Ni electroplating bath is introduced into the plating chamber 202. In other cases, if the cleaning and/or activating process was performed in a different chamber than the Ni electroplating chamber, then the rough component may be moved to the Ni electroplating chamber, such as plating chamber 202. In some alternate cases, this process may be optional and the Cr may be plated directly on the rough component.

[0061] The plating chamber 202 may be filled with Ni electroplating bath, such as from reservoir 208. For example, a Ni plating bath may be introduced into the plating chamber 202 and Ni may be plated onto the rough component, as current is delivered to one or more anodes 218 from their respective rectifiers 222. The Ni electroplating bath may include any suitable chemistry, such as nickel sulfate, nickel chloride, nickel sulfamate, and/or boric acid. The Ni electroplating chemistry may be at any suitable pH level and/or temperature.

[0062] During the Ni electroplating process, the number of anodes 218 used and the level 206 of filling the plating chamber 202 may depend, in part, on the length of the rough component. For example, if a relatively short cylinder 116 is being electroplated, such as one that may be used on a small back hoe and may have a length of around 4 feet, the electroplating may only require a relatively small volume of plating bath in the plating chamber 202, such that the level 206 is relatively low. The cylinder 116 may be immersed all the way to the bottom of the plating chamber 202 and only two anodes 218(M), 218(3) may be used to electroplate thereon. On the other hand, if a relatively long cylinder 116 is being electroplated, such as one that may be use on a large dozer and may have a length of around 10 feet, the electroplating may require a relatively large volume of plating bath in the plating chamber 202, such that the level 206 is relatively high. The cylinder 116, when immersed, may span from all the way to the bottom of the plating chamber 202 to all the way to the top of the plating chamber 202 and may need all of the anodes 218 to be energized to electroplate over the full length of the relatively long cylinder 116.

[0063] During the Ni electroplating processes more than one anode 218 may be energized. Additionally, each of the anodes may be independently controlled, such that the rough component has a high level of plating uniformity over its surface, particularly its length. Conventional electroplating, with a single long anode may not be suitable for plating highly uniform films over the length of the rod 120. In some cases, single long anodes may have resistive drops along its length resulting in non-uniform plating along the length of the rough component. Additionally, in some cases, a single anode can result in non-uniform field lines/flux at the ends (e.g., top end, bottom end) of the anode, again resulting in non-uniformity and lack of uniformity control near the ends of the rough component relative to the middle of the rough component. However, with the use of multiple anodes 218, as disclosed herein, different zones along the length of the rough component can be electroplated with different parameters (e.g., current, voltage, waveform, pulse duty cycle, reverse-pulse duty cycle, etc.) at different rectifiers 222 to achieve a greater level of coating uniformity along the length of the rough component, such as the cylinder 116. For example, the controller 228 may control each of the rectifiers 222 to provide a similar amount of current density over the entire surface of the rough component. In some cases, an optional rinse may be performed prior to the Cr electroplating. In alternate cases, Ni may be plated in an electroless manner.

[0064] At block 310, the Ni plated component may be immersed in a Cr electroplating bath. Alternatively, Cr may be directly plated on the steel surface of the rough component, skipping the processes of block 308. If Ni is electroplated on the steel, trivalent Cr may be plated over the Ni layer. In this case, the Ni electroplating bath may be drained from the plating chamber 202, such as to its reservoir 208, and trivalent Cr plating bath may be introduced to the plating chamber 202. Next, trivalent Cr may be electroplated over the Ni plating. In other cases, the Ni plated component may be moved to a different plating chamber 202 to be plated thereon. In alternate cases, hexavalent Cr may be plated instead of trivalent Cr, although trivalent Cr has advantages over hexavalent Cr, including the use of less toxic and less volatile chemistries that are easier to use and dispose. The Cr bath may include any suitable chemistry, such as chromium sulfate, chromium chloride, or the like. The Cr bath may include any variety of additives, such as chelating agents, surfactants, inhibitors, emulsifiers, buffers, etc. In some cases, the Cr bath may not include chromic acid, which is a difficult material to use and dispose due to its toxicity.

[0065] At block 312, power is provided to one or more anodes to electroplate Cr on the surface of the Ni plated component to form a chromium plated component. The Cr electroplating process, in some cases, may use the same number of anodes 218 as were used for the Ni electroplating process. Again, the controller 228 may independently control the power characteristic from individual rectifiers 222 to maintain a high level of uniformity of plating of the Ni plated component.

[0066] During the Cr electroplating processes more than one anode 218 may be energized. Additionally, each of the anodes may be independently controlled, such that the rough component has a high level of plating uniformity over its surface, particularly its length. For example, a first current level may be provided via a first rectifier 222 to a first anode 218, while a second current level may be provided via a second rectifier 222 to a second anode 218. Similarly, a different power level, current level, voltage, waveform, duty cycle, reverse pulse level, reverse pulse duty cycle, or the like may be provided via any of the rectifiers 222 to any of the anodes 218. Conventional electroplating, with a single long anode may not be suitable for plating highly uniform films over the length of the Ni plated component. In some cases, single long anodes may have resistive drops along its length resulting in non-uniform plating along the length of the rough component. Additionally, in some cases, a single anode can result in non-uniform field lines/flux at the ends (e.g., top end, bottom end) of the anode, again resulting in non-uniformity and lack of uniformity control near the ends of the rough component relative to the middle of the rough component. However, with the use of multiple anodes 218, as disclosed herein, different zones along the length of the rough component can be electroplated with different parameters (e.g., current, voltage, waveform, pulse duty cycle, reverse-pulse duty cycle, etc.) at different rectifiers 222 to achieve a greater level of coating uniformity along the length of the Ni coated component, such as the cylinder 116. For example, the controller 228 may control each of the rectifiers 222 to provide a similar amount of current density over the entire surface of the Ni plated component.

[0067] At block 314, the Cr plated component is rinsed. The plating chamber 202 may be filled with water, deionized water, or other solvent for the rinse processes. In some cases, the rinse may be performed in a separate chamber than the plating chamber 202. After the final electroplating process (e.g., trivalent Cr layer), the rod 120 may again be rinsed. In some cases, the rod 120 may be rinsed between the Ni layer being electroplated and the Cr layer being electroplated.

[0068] At block 316, the Cr plated component is polished to form the final component. The polishing process can be performed by any suitable mechanism, such as tape polishing. For example, a diamond superfinishing tape/belt may be used to polish the surface of the component. Due to the relatively high as-deposited smoothness, only a few passes of the tape may be needed to polish the surface of the component. In other words, the polish may be a relatively quick and inexpensive process compared to what is needed for conventional techniques of depositing protective coating. In some cases, the polish may include wax and/or lubricant buff process. Such a process may mitigate any corrosion and/or oxidation in any cracks on the surface of the coating.

[0069] After the polish operation, the coating may have a surface finish, as measured by R.sub.z, less than about 2 m. In some cases, the R.sub.z of the coating may be in the range of about 0.6 m to about 1.8 m. In other cases, the coating may have a R.sub.z value in the range of about 1 m to about 1.4 m. The coatings with R.sub.z values, as discussed herein, may result in superior performance in lubricant (e.g., oil) retention on the surfaces of the components of the hydraulic systems 114 (e.g., rod 120, cylinder 116, piston 118, etc.), while reducing the amount of lubricant and/or hydraulic fluid leakage as the rod 120 is stroked within the cylinder 116.

[0070] It should be appreciated that the method 300 does not include a roughening (e.g., grit blasting) operation prior to electroplating the component, as is often used with conventional techniques. Furthermore, because a relatively thick coating was not deposited, as is often the case with conventional techniques, a post-grind process is also not needed. The elimination of these relatively time-consuming operations, may reduce the cost of manufacturing the component, as described herein, relative to conventional methods of manufacturing these components. The use of the muti-anodic electroplating tool 200 in method 300 results in relatively high levels of plating uniformity over the surface of the component being electroplated. Additionally, the method 300 results in components with preferred surface morphology, hardness, and stress profiles, compared to conventional techniques. Further still, the use of trivalent Cr, rather than hexavalent Cr, results in health and human safety, as well as environmental benefits.

[0071] It should be noted that some of the operations of method 300 may be performed out of the order presented, with additional elements, and/or without some elements. Some of the operations of method 300 may further take place substantially concurrently and, therefore, may conclude in an order different from the order of operations shown above.

[0072] FIG. 4 is a sectional illustration of an example component surface 400 with the steel surface 402 and the coating(s) 404, 406 thereon, according to examples of the disclosure. The Ni electroplated coating 404 on the rod 120 and under the Cr coating 406 may have a thickness (T.sub.Ni) in the range of about 1 m to about 75 m. In other cases, the Ni coating thickness (T.sub.Ni) range may be between about 3 m to about 65 m. In yet other cases, the Ni coating thickness (T.sub.Ni) range may be between about 5 m to about 60 m. In still other cases, the Ni coating thickness (T.sub.Ni) range may be between about 10 m to about 50 m. In yet further cases, the Ni coating thickness (T.sub.Ni) range may be between about 13 m to about 40 m. In still further cases, the Ni coating thickness (T.sub.Ni) range may be between about 15 m to about 30 m. For example, in some cases, the thickness (T.sub.Ni) of the Ni coating may be about 25 m.

[0073] The trivalent Cr 406 may be plated on top of an electroplated layer of Ni 404. The coating may be provided using trivalent chromium electroplating on the component with a Cr thickness (T.sub.Cr) in the range of about 3 m to about 50 m. In other cases, the Cr coating thickness (T.sub.Cr) range may be between about 5 m to about 40 m. In yet other cases, the Cr coating thickness (T.sub.Cr) range may be between about 8 m to about 35 m. In still other cases, the Cr coating thickness (T.sub.Cr) range may be between about 10 m to about 30 m. In yet further cases, the Cr coating thickness (T.sub.Cr) range may be between about 13 m to about 27 m. In still further cases, the Cr coating thickness (T.sub.Cr) range may be between about 15 m to about 25 m. For example, in some cases, the thickness (T.sub.Cr) of the Cr coating may be about 20 m.

[0074] For remanufacturing processes, a slightly thicker coating may be disposed on the hydraulic component. For example, one or both of the Ni and/or Cr layers may be thicker than the ranges discussed above. In some cases, the thickness of the coating may be in the range of about 45 m to about 200 m. In other cases, the coating thickness may be in the range of about 45 m to about 100 m. In some cases, the coating thickness may be in the range of about 45 m to about 55 m. The thicker thickness of the protective coating may be to compensate for overgrinding and/or over polishing when residual prior coating is stripped from the hydraulic component.

INDUSTRIAL APPLICABILITY

[0075] The present disclosure describes systems, structures, and methods to electroplate coatings on components of machine 100, such as components of the hydraulic system 114, using independently controlled and electrically isolated anodes and respective corresponding rectifiers. The components of the hydraulic system 114 may include, for example, a cylinder 116, a piston 118, and/or a rod 120. The coatings may be provided on the component of the machine 100 to provide a hard protective layer that prevents and/or reduces oxidation and/or corrosion of the steel with which the bulk component is formed. The coating also provides a preferred surface morphology that promotes adhesion of lubricants on the surface of the component, while reducing the leakage of oil and/or hydraulic fluids. The coatings and the processing thereof, as disclosed here, using electroplating of Ni and/or Cr provides a dense coating with strong adhesion strength to the underlying steel of the component with a high level of uniformity along its length, compared to conventional HVOF or HVAF techniques. Furthermore, the electroplating-based coatings result in the elimination and/or reduction of processing steps, such as pre-roughening step, that lead to a reduction in the cost of providing this protective coating on the surface of the components.

[0076] As a result of the systems, apparatus, and methods described herein, parts of machines 100, such as cylinder 116, piston 118, and/or rod 120, may have a greater operational lifetime. For example, the hydraulic system 114 components described herein may have greater service lifetime than traditional hydraulic system 114 components that do not have the protective coating, as described herein. In some cases, components, such as the rod 120, may allow for a significant improvement in the wear lifetime of parts of the machines 100. For example, the coated rods may have operational lifetimes exceeding 1000 hours or more, which is longer than conventionally coated rods. This reduces field downtime, reduces the frequency of servicing and maintenance, and overall reduces the cost of heavy equipment, such as machines 100. The improved reliability and reduced field-level downtime also improves the user experience such that the machine 100 can be devoted to its intended purpose for longer times and for an overall greater percentage of its lifetime. Improved machine 100 uptime and reduced scheduled maintenance may allow for more efficient deployment of resources (e.g., fewer, but more reliable machines 100 at a construction site). Thus, the technologies disclosed herein improve the efficiency of project resources (e.g., construction resources, mining resources, etc.), provide greater uptime of project resources, and improves the financial performance of project resources.

[0077] In addition to the improved lifetimes of coated components, the coated components may have preferred surface morphology that result in improved operational performance. For example, the rod 120 may have a surface morphology that promote lubrication adhesion during operation and further results in low levels oil leakage or hydraulic fluid leakage. Thus, the preferred surface morphology of the coatings described herein result in improved performance of the coated components.

[0078] Although the processes of forming protective coatings are discussed in the context of various hydraulic system 114 components, it should be appreciated that the mechanisms discussed herein may be applied to a wide array of mechanical parts in a wide variety of systems used in any variety of industries. For example the protective coatings discussed herein may be applied to industrial fabrication equipment, like metal working equipment, construction equipment, or automotive parts.

[0079] While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.

[0080] Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein.