Hybrid cathodes for ion plasma deposition systems and methods

Abstract

To provide an ion plasma deposition (IPD) cathode useful for reducing a process cost related to an IPD process, capable of operating the IPD process for a long time without replacing the cathode, and / or useful for improving a film deposited on a substrate and enhancing uniformity.SOLUTION: A cathode (200) for use in an ion deposition process includes a main body (202) defining a working surface (204) of the cathode and at least one insert (218) coupled to the main body. The main body includes a first deposition material and the at least one insert includes a second deposition material that is incompatible with the first deposition material. The at least one insert is at least partially exposed at the working cathode surface. The first and second deposition materials are vaporizable in response to an electric arc generated at the working cathode surface for depositing a coating including the first and second deposition materials on a substrate.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The field of the disclosure relates broadly to ion plasma deposition, and more specifically to cathodes for use in ion plasma deposition systems and methods. [Background technology]

[0002] Ion plasma deposition (IPD) processes (also called cathodic arc deposition or vacuum arc deposition) typically involve placing a cathode in a vacuum environment, providing a substrate or workpiece within the vacuum environment, and inducing a current through the cathode to generate an electric (cathodic) arc at the cathode's working surface. The cathodic arc is formed at the cathode working surface after placing the cathode and anode in the vacuum environment and supplying sufficient current to the cathode to create a potential between the cathode and anode sufficient to generate an electric discharge. The anode may be a conductive surface in the vacuum chamber or may be another structure within the vacuum chamber. The function of the anode is to sink electrons from the cathode to maintain the discharge. The arc briefly forms, extinguishes, and then quickly reforms, creating the appearance of an arc moving continuously across the cathode working surface.

[0003] The cathode is fabricated (e.g., cast, forged, or powder pressed) from a deposition material (e.g., a metal or metal alloy) to be included in the coating to be deposited on the substrate. The cathodic arc erodes or vaporizes the deposition material at the cathode working surface. The erosion or vaporization of the deposition material from the cathode working surface forms a cloud of coating material containing high-energy ions, charged particles, vapor, and neutral droplets in a vacuum environment. This coating material is available for deposition in a vacuum environment. The coating material may be deposited on a cooler surface by condensation in a vacuum environment and / or on an anode surface by condensation and electrical attraction. A workpiece provided in a vacuum environment also serves as the surface on which the coating material is deposited. A voltage bias may be applied to the workpiece to affect material deposition by increasing the attraction of ions and charged particles to the surface.

[0004] Cost and material constraints associated with cathode fabrication and operation can significantly limit the IPD process and its ability to deposit relatively complex coating compositions. For example, cathodes made from compositions or alloys that do not provide adequate strength and / or ductility as solid structures can prematurely degrade during fabrication or use, potentially resulting in unacceptable yield loss, reduced coating quality, and / or non-transfer of material from the cathode during the IPD process. As such, IPD processes involving a single cathode are limited in the types of compositions that can be practically used to fabricate and then deposit from the cathode without increasing the risk of cathode failure. Depositing coatings with complex compositions may require multiple cathodes, increasing fabrication and / or equipment cost and complexity.

[0005] Thus, a need exists for an IPD cathode that can increase the variety and flexibility of coating compositions that can be incorporated into and deposited using the cathode, help reduce processing costs associated with the IPD process, allow the IPD process to operate for extended periods without cathode replacement, and / or help improve and increase the uniformity of the coating deposited on the substrate.

[0006] This Background section is intended to introduce various aspects of the art that may be related to various aspects of the disclosed technology, which are described in the Detailed Description and Claims below. The statements in this section are believed to be helpful in providing background information to facilitate a better understanding of various aspects of the disclosed technology. As such, the statements in this section should be construed in this light, and not as admissions of prior art. Summary of the Invention

[0007] In one aspect, a cathode for use in an ion deposition process is provided. The cathode includes a body defining a cathode working surface, the body including a first deposition material. The cathode also includes one or more inserts coupled to the body. The one or more inserts are at least partially exposed at the cathode working surface, and the one or more inserts include a second deposition material incompatible with the first deposition material. The first and second deposition materials are vaporizable in response to an electric arc generated at the cathode working surface to deposit a coating including the first and second deposition materials on a substrate.

[0008] In another aspect, an apparatus for depositing a film on a substrate is provided. The apparatus includes a deposition chamber sized to accommodate the substrate therein and a cathode disposed within the deposition chamber. The cathode includes a body defining a cathode working surface, the body including a first deposition material. The cathode also includes one or more deposition inserts coupled to the body. The one or more deposition inserts are at least partially exposed at the cathode working surface, and the one or more deposition inserts include a second deposition material incompatible with the first deposition material. The apparatus also includes a power source coupled to the cathode. The power source is operable to generate an electric arc at the cathode working surface to vaporize the first and second deposition materials and deposit a coating including the first and second deposition materials on the substrate.

[0009] In another aspect, a method for depositing a coating on a substrate is provided, the method including the steps of: providing a cathode including a body defining a cathode working surface, the body including a first deposition material, coupling one or more inserts to the body including a second deposition material incompatible with the first deposition material such that the one or more inserts are at least partially exposed to the cathode working surface, generating an electric arc at the cathode working surface to vaporize the first and second deposition materials, and depositing the vaporized first and second deposition materials on a substrate.

[0010] These and other features, aspects, and advantages of the present disclosure will become better understood by reference to the following detailed description taken in conjunction with the accompanying drawings, in which like reference numerals represent like elements throughout. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram of an exemplary ion plasma deposition (IPD) apparatus. [Figure 2] 2 is a perspective view of an exemplary cathode that may be used in the IPD device shown in FIG. 1. [Figure 3] An exploded view of the cathode shown in Figure 2. [Figure 4] 4 is an exemplary top view of a first alternative embodiment of the cathode of FIGS. 2 and 3. FIG. [Figure 5] FIG. 4 is an exemplary top view of a second alternative embodiment of the cathode of FIGS. 2 and 3. [Figure 6] FIG. 4 is an exemplary top view of a third alternative embodiment of the cathode of FIGS. 2 and 3. [Figure 7] FIG. 4 is an exemplary top view of a fourth alternative embodiment of the cathode of FIGS. 2 and 3. [Figure 8] FIG. 4 is an exemplary top view of a fifth alternative embodiment of the cathode of FIGS. 2 and 3. [Figure 9] 1 is a flow diagram of an exemplary method for depositing a film on a substrate.

[0012] Reference numerals used in the drawings indicate corresponding parts. Unless otherwise indicated, the drawings accompanying this application illustrate features of embodiments of the disclosed technology. It is contemplated that these features may be applicable to a wide variety of systems incorporating one or more embodiments of the disclosed technology. As such, the drawings may not include all conventional features known to those skilled in the art that are required to practice the embodiments disclosed herein. DETAILED DESCRIPTION OF THE INVENTION

[0013] Exemplary embodiments described herein relate to systems and methods for depositing coatings on substrates using an ion plasma deposition (IPD) process (also known as cathodic arc deposition or vacuum arc deposition). The IPD process can be used to deposit metallic and / or non-metallic coatings. In some embodiments, the IPD process can be used to deposit coatings on components for turbine engines (e.g., hot gas path components such as turbine blades or nozzle vanes). Turbine engine components may be used in high-temperature and highly oxidizing environments, and the components may be fabricated from nickel-, cobalt-, and / or iron-based alloys or refractory metal-based alloys that are resistant to such environments. The IPD process can be used to deposit additional heat- and / or wear-resistant coatings on turbine engine components to protect the underlying alloy from oxidation and hot corrosion. Additionally / alternatively, the deposited coating can also function as a bond coat used to hold the corrosion-resistant coating. Suitable deposited corrosion-resistant coatings for use in turbine engine applications include, but are not limited to, nickel aluminide-based coatings, which may be formed with the addition of platinum to form platinum-nickel aluminide-based coatings, and / or coatings comprising alloys of chromium, aluminum, and one or more of iron, nickel, and cobalt. IPD processes may be a suitable alternative for depositing such corrosion-resistant coatings over known physical vapor deposition techniques, such as electron beam physical vapor deposition (EBPVD) and chemical vapor deposition techniques, both of which have limited ability to achieve and maintain compositional control over the complex compositions required for these corrosion-resistant coatings.

[0014] The IPD process is a physical vapor deposition process that confines an electric (or cathodic) arc to the working surface of a cathode. The cathode is placed in a vacuum chamber, which acts as the anode when an electric current is applied to the cathode, generating an electric arc. As the electric arc crosses the cathode working surface, high-energy ions are emitted from the working surface and accelerated toward the substrate to be coated. Solids evaporated from the cathode working surface turn into vapor and recondense on the substrate, depositing as a coating. The cathode is manufactured (e.g., cast, forged, or powder pressed) from a deposition material (e.g., a metal or metal alloy) and has a composition selected to achieve the desired composition of the deposited coating. However, significant technical challenges can arise associated with the manufacture and / or use of cathodes. For example, depending on the composition of the coating, it may be difficult or impossible to manufacture a cathode from the deposition material required to produce the coating. The composition of the required deposited material may be such that cathodes fabricated from the deposited material do not have sufficient strength and / or ductility to withstand the mechanical loads and stresses encountered during cathode fabrication and / or use without premature decomposition, which may result in unacceptable yield loss, reduced coating quality, and / or non-transfer of material from the cathode during the IPD process.

[0015] Exemplary systems and methods described herein include using a "hybrid" cathode including a body fabricated from a first deposition material and one or more inserts bonded to the body, the inserts being fabricated from a second deposition material, where the second deposition material is different from the first deposition material. The first and second deposition materials each suitably vaporize in response to an electric arc generated at the cathode's working surface, depositing a coating comprising the first and second deposition materials on a substrate. The first and second deposition materials may be incompatible with each other, and a cathode otherwise fabricated (e.g., cast, forged, or powder pressed) from a mixture of the first and second deposition materials may have insufficient strength and / or ductility to withstand the mechanical loads and stresses encountered during cathode fabrication and / or use without premature decomposition. Bonding one or more inserts fabricated from the second deposition material to the body fabricated from the first deposition material keeps the incompatible deposition materials contained in the cathode separated until they vaporize and deposit on a substrate. Thus, exemplary hybrid cathodes allow for the “tuning” of the deposition material composition contained in the cathode for deposition on a substrate by allowing different, incompatible materials to be mechanically coupled to the cathode body. In some embodiments, the cathode body can be machined (e.g., drilled) to form openings or holes in the cathode working surface. Inserts (rods, poles, studs, etc.) made of different materials are inserted into and retained in the openings. The inserts may be pressed into the corresponding openings and retained there by a friction fit. Additionally / alternatively, the inserts may be retained in the corresponding openings using threads. Such inserts can also be easily removed from the body and replaced with other inserts made of other materials for deposition. Because the cathode can be used to quickly and precisely tune the chemical composition without waiting for additional cathodes to be manufactured, such cathodes may be particularly useful for research and other applications where using a wide variety of materials in a single cathode is advantageous. In some embodiments, hybrid cathodes may also be configured in a manner that allows for control over the cathode arc as it orbits the cathode working surface.For example, the cathode working surface may be "dish-shaped" or "sunken" to drive the cathode arc toward a central region of the cathode working surface, ensuring uniform erosion or vaporization or otherwise preventing the cathode arc from concentrating in undesired locations on the cathode working surface. Additionally / alternatively, the movement of the cathode arc may be controlled using an insulating insert coupled to the body and strategically positioned to control the movement of the arc. The insulating insert may be fabricated from an insulating material that the cathode arc avoids and thus shifts toward other areas on the cathode working surface. The insulating material may be alumina, boron nitride, or another suitable insulating material that does not support the cathode arc. In this manner, the hybrid cathode can "force" the cathode arc to align to uniformly and efficiently vaporize the desired material contained in both the body and the deposition material insert.

[0016] The exemplary hybrid cathode overcomes at least some of the current limitations of the IPD process, including facilitating cost reduction and overcoming the inability to deposit compositionally complex coatings. Furthermore, the exemplary hybrid cathode significantly impacts the costs associated with the IPD process by making additional deposition material available for the coating process and enabling the IPD process to operate for extended periods without cathode replacement. Additionally, by configuring the cathode to control the movement of the cathodic arc at the working surface, more uniform and improved coating material can be deposited.

[0017] When introducing elements of various embodiments of the disclosed technology, the singular "a," "an," or "an" means that there are one or more of the element, unless the context clearly dictates otherwise. The terms "optional" or "optionally" mean that the described event or circumstance may or may not occur, and such a description encompasses both the occurrence of the event and the absence of the event. Furthermore, reference to "one embodiment" should not be interpreted as excluding the existence of additional embodiments that also comprise the recited features. Furthermore, unless expressly stated otherwise, the terms "including," "comprising," and "having" are inclusive and mean that there may be additional elements other than the recited elements.

[0018] Unless otherwise specified, approximate expressions such as "approximately," "substantially," and "about" used herein indicate that the modified terms are not absolute or precise, but are merely approximations that would be obvious to one skilled in the art. Thus, values modified by terms such as "approximately," "substantially," and "about" are not limited to the exact numerical values. In at least some cases, approximate expressions correspond to the accuracy of the instrument used to measure the value.

[0019] Unless otherwise specified, the terms "first," "second," etc. are used herein merely as labels and do not impose any numerical, positional, or hierarchical requirements on what they refer to. Furthermore, a reference to, for example, "second" does not require or exclude the presence of, for example, a "first" or more, or a "third" or more.

[0020] Referring now to the drawings, FIG. 1 is a schematic diagram of an exemplary ion plasma deposition (IPD) apparatus 100, which may include additional or other components than those shown and described with reference to FIG. 1 such that the IPD apparatus 100 functions as described herein. The IPD apparatus 100 may also be referred to as a cathodic arc deposition apparatus or a vacuum arc deposition apparatus. In the exemplary embodiment, the IPD apparatus 100 includes a vacuum chamber 102 in fluid communication with a vacuum system 104. The vacuum system 104 may be operable to generate a vacuum within the vacuum chamber 102, i.e., to create a subatmospheric partial pressure within the vacuum chamber.

[0021] The IPD apparatus 100 also includes a cathode 106 disposed within the vacuum chamber 102. The cathode 106 is fabricated from a suitable material (e.g., a metal or metal alloy) for deposition onto a workpiece 108 (also referred to herein as a substrate 108) using the IPD apparatus 100. The workpiece 108 is disposed within the vacuum chamber 102 at a distance from the cathode 106. In the exemplary embodiment, the cathode 106 is above the workpiece 108, although in other embodiments, the relative positions of the cathode 106 and the workpiece 108 within the vacuum chamber 102 may be different. In addition to the cathode 106 and the workpiece 108, the vacuum chamber 102 may include an anode (not shown). The anode may be a conductive surface of the vacuum chamber 102 or may be a separate anode within the vacuum chamber. The anode may be provided to sink electrons from the cathode 106 to maintain a discharge generated at the cathode during the IPD process. In some embodiments, the workpiece 108 may function as an anode within the vacuum chamber 102 .

[0022] The workpiece 108 may be any article or component on which a coating (e.g., a metal or metal alloy coating) can be deposited using the IPD apparatus 100. The workpiece 108 may be suitably fabricated from a metal or metal alloy material. The coating deposited on the workpiece 108 from the cathode 106 using the IPD apparatus 100 may provide a protective layer or other function on the surface of the workpiece. In some embodiments, the workpiece 108 is a component used in a high-temperature and / or oxidizing environment of a rotary machine, and the coating deposited from the cathode 106 provides a corrosion-resistant layer on the surface of the component. For example, the workpiece 108 may be a component used in the combustion chamber or hot gas path of a turbine engine, such as a turbine blade, vane, nozzle, liner, or transition piece. In such embodiments, the workpiece 108 may comprise one or more of a nickel alloy, an iron alloy, a cobalt alloy, and a nickel-iron alloy, including, but not limited to, high-strength, heat-resistant alloys known in the art as "superalloys." Such superalloys may contain about 50% or more by weight of nickel, cobalt, iron, or nickel-iron, in addition to alloying elements added to help improve the mechanical and physical properties of these alloys. For example, in some embodiments, the workpiece 108 may be fabricated from a nickel-based superalloy such as CMSX-4®, Rene N4™, Rene N5™, Rene 108™, GTD-111®, GTD-222®, GTD-444™, and IN-738. Rene N4™, Rene N5™, Rene 108™, and / or GTD-111®. GTD-222® and / or GTD-444® are gamma-prime strengthened nickel-based superalloys. In some embodiments, the workpiece 108 may be fabricated from a cobalt-based superalloy such as FSX-414. In other embodiments, the workpiece 108 may comprise a refractory metal-based alloy, such as, for example, an alloy containing one or more of niobium, molybdenum, tantalum, tungsten, rhenium, titanium, vanadium, chromium, zirconium, hafnium, ruthenium, rhodium, osmium, and iridium.Although particular alloys are described herein for the workpiece 108, these are by way of example only and are not intended to be limiting. The materials used may vary depending on the intended use of the workpiece 108.

[0023] The IPD apparatus 100 can be used to deposit a coating on a newly manufactured workpiece 108 and / or to deposit a coating on a workpiece that has already been used in service. For example, the IPD apparatus 100 is suitable for use in repair processes for workpieces 108 that have previously been placed and used in high temperature and / or oxidizing environments, such as turbine components that have previously been used in the hot gas path or combustion chamber of a turbine engine. Thus, in some embodiments, the workpiece 108 may already include one or more coatings before the workpiece 108 is placed in the vacuum chamber 102. Depending on the composition and condition of the existing coating on the workpiece 108, the existing coating may be removed before the apparatus 100 is used to perform the IPD process, or the workpiece may be subjected to the IPD process without removing the previous coating.

[0024] Exemplary cathodes for use as cathode 106 are described in further detail below (see FIGS. 2-8). Generally, in exemplary embodiments, cathode 106 comprises a material suitable for depositing a coating on workpiece 108 having a composition that enables the coating to perform as desired. The material included in cathode 106 is also referred to herein as the cathode material or deposition material. The specific composition of cathode 106 can depend on several factors, including, but not limited to, the type of workpiece 108 and the type of environmental exposure the workpiece 108 is expected to endure during use. In various examples, cathode 106 may comprise one or more elements selected from, but not limited to, nickel, aluminum, cobalt, chromium, molybdenum, tungsten, rhenium, ruthenium, zirconium, hafnium, tantalum, silicon, yttrium, titanium, lanthanum, cerium, niobium, vanadium, platinum, iridium, osmium, palladium, rhodium, and / or combinations thereof. Cathode 106 may include additional and / or alternative elements such as carbon and boron depending on the desired application of the coating.

[0025] The cathode 106 may be formed in any suitable shape for use in the IPD device 100, such as, but not limited to, a cylindrical shape. The cathode 106 is formed with an end surface 118 from which cathode material is eroded or evaporated to deposit a coating on the workpiece 108. The end surface 118 may also be referred to as the working surface 118 of the cathode 106. For example, metallurgical and manufacturing processes, such as casting and powder metallurgy processing, are suitably used to fabricate the body (e.g., primary cylindrical portion) of the cathode 106 from a mixture of cathode materials for deposition. However, such techniques are often limited in that the materials incorporated into the cathode 106 from the mixture must be compatible with each other. If the materials are incompatible, the cathode 106 may lack sufficient strength and / or ductility and may be susceptible to premature disassembly (failure) during or before the IPD process.

[0026] Thus, as described in more detail below, the exemplary cathode 106 used in the exemplary IPD apparatus 100 includes one or more inserts (e.g., insert 218 in FIG. 3 ) fabricated from an additional deposition material (e.g., insert 218 in FIG. 3 ) that is incompatible with the deposition material included in the body of the cathode 106. Such inserts 218 are coupled to the body of the cathode 106, allowing the incompatible deposition material included in the insert 218 and the body of the cathode 106 to simultaneously deposit a coating without premature degradation (failure) of the cathode 106. The exemplary cathode 106 described herein thereby facilitates the deposition of a wide variety of coating compositions, increasing the amount of flexibility in the IPD process. Furthermore, the inserts 218 can be selectively attached and detached from the body of the cathode 106, allowing this portion of the cathode 106 to be salvaged and reused with inserts fabricated from other deposition materials. In this manner, the exemplary cathode 106 not only contributes to reducing costs and overcoming limitations in known IPD devices, but also contributes to the controlled incorporation of incompatible materials into a single cathode having suitable strength and / or ductility for manufacture and use in an IPD process.

[0027] In an exemplary embodiment, the cathode 106 may be supported within the vacuum chamber 102 by an evaporator plate 110. The evaporator plate 110 may be cooled via a cooling fluid supply system 112 that channels cooling fluid to and from the evaporator plate 110. The cooling fluid supplied to the evaporator plate 110 may be circulated through internal passages (not shown) formed in the evaporator plate 110 to facilitate cooling during operation of the IPD device 100.

[0028] The IPD device 100 also includes one or more power sources 114, 116 (or current sources) operative to generate a cathode (or electric) arc at the cathode working surface 118. The power sources 114, 116 may be any suitable power source for generating a cathode arc at the cathode working surface 118, such as a direct current (DC) power source (e.g., an arc welder). In an exemplary embodiment, a cathode 106 containing the material to be deposited on the workpiece 108 is coupled to a first DC power source 114. The amount of current supplied to the cathode 106 using the DC power source 114 may be determined, at least in part, by the cathode material and the desired rate of erosion or evaporation of the coating material from the cathode working surface 118. The melting point of the cathode material may be a factor in determining the appropriate current to supply to the cathode 106. The current applied to the cathode 106 may be increased or decreased to selectively increase or decrease the erosion or evaporation rate.

[0029] A negative voltage bias may be induced on the workpiece 108 using a second DC power supply 116 coupled to the workpiece. In other embodiments, the second DC power supply 116 may be coupled to an anode (not shown) included in the vacuum chamber 102 or may be omitted from the IPD apparatus 100. In some embodiments, the cathode 106 and the workpiece 108 (or other anode) may be coupled to opposite terminals of a single power supply, such as the DC power supplies 114 or 116. A negative voltage bias may be applied to the workpiece 108 to affect material deposition by increasing the attraction of ions and charged particles to the workpiece 108 from the cathode working surface 118. Applying a negative voltage bias may additionally and / or alternatively heat the workpiece 108, potentially increasing the temperature of the workpiece 108 during the IPD process. Such heating of the workpiece 108 may cause interdiffusion and reaction between the deposited material and the workpiece material, forming an in-situ coating composition on the workpiece. The particular value selected for the voltage bias may depend on a variety of factors, including, for example, the amount and type of interaction desired to occur between the deposited material and the material of the workpiece 108 .

[0030] In operation of the IPD apparatus 100, as shown in FIG. 1, a cathode 106 and a workpiece 108 are placed within a vacuum chamber 102. A vacuum system 104 operates to create a vacuum within the vacuum chamber 102. The cathode 106 is supplied with current, for example, from a first DC power supply 114, to create a sufficient electrical potential between the cathode 106 and the workpiece 108 (and / or an anode disposed within the vacuum chamber 102). The workpiece may also be provided with a negative voltage bias, for example, using a second DC power supply 116. An electric (or cathodic) arc is generated at the cathode working surface 118, eroding or vaporizing cathode material from the cathode working surface. The cathode current is concentrated into a fine, very high-energy cathode arc spot, which generates a highly ionized metal plasma from the erosion or vaporization of the cathode material at the cathode working surface 118. The cathode arc briefly forms, then rapidly extinguishes and reforms, appearing as a continuous arc moving across the cathode working surface 118. Erosion or evaporation of the cathode material at the working surface 118 forms a cloud of ions and droplets of coating material within the vacuum chamber 102 (indicated by arrows 120 in FIG. 1 ). The cloud of coating material 120 contains ions, charged particles, vapor, and neutral droplets in the vacuum environment. The coating material 120 is deposited from the cloud onto the surface of the workpiece 108 via condensation and / or electrical attraction. The electrical attraction can be controlled (e.g., increased) using a negative voltage bias applied to the workpiece 108 to facilitate attracting the charged particles in the cloud of coating material 120 to the workpiece surface. In this manner, a coating is deposited on the workpiece 108, the desired thickness of which may be determined by various factors, such as the intended use of the coated workpiece 108. The thickness of the coating deposited on the workpiece 108 can be controlled based on various IPD process parameters, such as the duration of the IPD process, the pressure in the vacuum chamber, the current supplied to the cathode 106, the material contained in the cathode, the ground potential or negative voltage bias applied to the workpiece 108, and / or other process parameters. The cathode 106 and / or the workpiece 108 may be rotated on a planet (not shown) to provide a uniform coating on the workpiece.

[0031] 2 and 3 illustrate an exemplary cathode 200 that may be used as the cathode 106 in the IPD device 100 (shown in FIG. 1). FIG. 2 is a perspective view of the exemplary cathode 200, and FIG. 3 is an exploded view of the cathode 200. In the exemplary embodiment, the exemplary cathode 200 includes a body 202 that is cylindrical and defines two end faces 204 and 206, and a peripheral edge 208 extending between the end faces 204 and 206. In other examples, the body 202 of the cathode 200 may have any other suitable shape that enables the cathode to function as described herein. For example, the body 202 of the cathode 200 may have any suitable cross-sectional shape (e.g., oval, square, rectangular, or another polygonal shape) and may be another prismatic shape including a pair of end faces 204 and 206 and a side edge 208 extending therebetween. The cathode 106 may be appropriately dimensioned depending, for example, on the desired thickness of the deposited coating.

[0032] The first end surface 204 defines a cathode working surface of the cathode 200 and functions as the cathode working surface 118 when the cathode 200 is used in the IPD apparatus 100 (shown in FIG. 1 ). Thus, during an IPD process using the cathode 200, a cathode arc is generated at the cathode working surface 204, as described above, to erode or vaporize material at the cathode working surface 204 for deposition on the workpiece 108. The second end surface 206 may be coupled to a component of the IPD apparatus 100 (e.g., the evaporator plate 110) for positioning the cathode 200 within the vacuum chamber 102. The second end surface 206 may be substantially flat or may have features (e.g., contours, slots, etc.) that enable the cathode 200 to be coupled to the IPD apparatus 100 within the vacuum chamber 102.

[0033] As shown in FIG. 2 , the cathode working surface 204 may be “dish-shaped” or “depressed.” In particular, the cathode working surface 204 of the exemplary cathode 200 includes an outer edge 210 adjacent a peripheral edge 208 of the body 202 and a concave surface 212 recessed from the outer edge 210. A downwardly extending surface 214 may extend between the concave surface 212 and the outer edge 210. Any suitable machining technique may be used to form the concave surface 212 and the downwardly extending surface 214 between the peripheral edge 208 and the concave surface 212. Suitable machining techniques include, but are not limited to, hand grinding, milling, electrical discharge machining, and the like. The concave surface 212 forms a major area of the cathode working surface 204 and extends more than about 50% of the radial distance (or diameter) of the cathode working surface. In other words, the distance extending between the downwardly extending surface 214 between the concave surface 212 and the peripheral edge 208 and the outer edge 210 may be less than about 50% of the radial distance (or diameter) of the cathode working surface 204.

[0034] Surface 214 may be a chamfer between outer edge 210 and concave surface 212, and may also be referred to as chamfer 214. The angle of chamfer 214 may vary and may be selected depending on the desired "sink" of concave surface 212 from outer edge 210. In various embodiments, chamfer 214 may extend at an angle ranging from about 10° to about 80°. A relatively steep angle of chamfer 214 provides greater sink of concave surface 212, while a relatively gentle angle of the chamfer results in less sink of the concave surface.

[0035] The concave surface 212 may be substantially flat between the peripheral edge 208 and the downwardly extending surface 214, except for holes or openings 216 (shown in FIG. 3 ) formed in the concave surface 212 to receive corresponding inserts 218 fabricated from additional cathode or deposition material, as described in more detail below. The outer edge 210 may be substantially flat between the peripheral edge 208 and the downwardly extending surface 214. In some embodiments, the downwardly extending surface 214 may be omitted, and the cathode working surface 204 may be generally recessed to form a dished or sunken shape. In still other embodiments, the cathode working surface 204 may be substantially flat between the peripheral edge 208 of the body 202, except for openings 216 formed in the cathode working surface to receive corresponding inserts 218. The desired shape of the cathode working surface 204 may be provided by any suitable machining technique, such as hand grinding, milling, electrical discharge machining, etc. Such machining techniques may also be used to form the openings 216.

[0036] Preferably, the dished or depressed shape of the cathode working surface 204 is provided to help control the movement of the cathode arc during the IPD process. In particular, the shape of the cathode working surface 204 can drive the cathode arc toward a central region of the cathode working surface 204 (e.g., the concave surface 212), control erosion or evaporation of the cathode working surface, and / or facilitate concentrating the cathode arc to a spot along the periphery of the cathode working surface, closer to the peripheral edge 208 of the body 202. This can facilitate extending the life of the cathode 200 and / or improving material transfer from the cathode during the IPD process.

[0037] The body 202 of the cathode 200 can be manufactured using any suitable technique, including, but not limited to, metallurgical and manufacturing processes such as casting and powder metallurgical processing. For example, suitable machining techniques, such as hand grinding, milling, and electrical discharge machining, can be used to machine the body 202 to a desired shape and dimensions and / or to machine the surfaces of the body 202 (e.g., first and second end faces 204 and 206 and peripheral edge 208) to a desired shape and / or end finish.

[0038] The body 202 of the cathode 200 is fabricated from a first deposition material that is vaporizable in response to an electric arc generated at the cathode working surface 204 and is suitable for deposition onto a substrate using an IPD process. The first deposition material can include one or more elements selected from, but not limited to, nickel, aluminum, cobalt, chromium, molybdenum, tungsten, rhenium, ruthenium, zirconium, hafnium, tantalum, silicon, yttrium, titanium, lanthanum, cerium, niobium, vanadium, platinum, iridium, osmium, palladium, rhodium, carbon, boron, and / or combinations thereof. In examples where the first deposition material includes a combination of elements (e.g., an alloy), the elements are suitably compatible with each other in their respective amounts. As used herein, the term "compatible" refers to elements and / or alloys that can be mixed in their respective amounts and used to fabricate (e.g., by casting, forging, or powder pressing) a solid structure of cathode 200 (e.g., body 202 or insert 218 of cathode 200) that has sufficient strength and / or ductility to withstand the mechanical loads experienced during cathode manufacture and / or use without premature decomposition (failure). As used herein, "incompatible" elements and alloys cannot be mixed in their respective amounts and used to fabricate (e.g., by casting, forging, or powder pressing) a solid structure of cathode 200 (e.g., body 202 or insert 218 of cathode 200) that has sufficient strength and / or ductility to withstand the mechanical loads experienced during cathode manufacture and / or use without premature decomposition (failure). Thus, when body 202 is fabricated from a first deposition material that includes a mixture of compatible elements, body 202 has sufficient strength and / or ductility to prevent failure of body 202, but when body 202 is fabricated from a first deposition material that includes a mixture of incompatible elements, body 202 has an increased tendency to fail.

[0039] In the exemplary embodiment, the cathode 200 also includes one or more inserts 218 coupled to the body 202. The inserts 218 may also be referred to herein as deposition inserts. Each insert 218 is fabricated from a deposition material that, like the first deposition material, is vaporizable in response to an electric arc generated at the cathode working surface 204 and suitable for deposition on a substrate using an IPD process. Preferably, the deposition material used to fabricate each insert 218 is different (e.g., a different element or alloy) from the first deposition material. The deposition material used to fabricate each insert may include one or more elements selected from, but not limited to, nickel, aluminum, cobalt, chromium, molybdenum, tungsten, rhenium, ruthenium, zirconium, hafnium, tantalum, silicon, yttrium, titanium, lanthanum, cerium, niobium, vanadium, platinum, iridium, osmium, palladium, rhodium, carbon, boron, and / or combinations thereof. In instances where the deposition material used to manufacture one or more of the inserts 218 includes a combination of elements (eg, an alloy), the elements are suitably compatible with one another.

[0040] In an exemplary embodiment, the deposition material used to fabricate one or more of the inserts 218 may be incompatible with the first deposition material included in the body 202 of the cathode 200. For example, the deposition material used to fabricate each insert 218 may be an element or alloy that provides sufficient strength and / or ductility to prevent failure of the insert 218, but if mixed with the first deposition material and the mixture is used to fabricate the body 202 (e.g., by casting, forging, or powder pressing), the body 202 may be more prone to failure. The deposition material used to fabricate the inserts 218 mechanically coupled to the body 202 of the cathode 200 remains separate (or is not mixed) from the first deposition material of the body 202 until vaporized and deposited in the IPD process. This allows the inserts 218 to simultaneously deposit incompatible deposition materials (e.g., incompatible elements and / or incompatible alloys) with the first deposition material via the IPD process using the cathode 200. This allows for a wide variety of deposited coating compositions by providing inserts 218 mechanically coupled to body 202, increasing the amount of flexibility in the IPD process.

[0041] The inserts 218 may each include the same deposition material, or the inserts 218 may include different deposition materials. In some embodiments, one or some of the inserts 218 may be manufactured from a deposition material that is incompatible with the deposition material of another insert 218. The inserts 218 may be manufactured and machined to the desired size and shape using techniques similar to those described above for the body 202. For example, the inserts 218 may be manufactured from the desired deposition material using casting or power metallurgy processes and subsequently machined to the desired size and shape using hand grinding, milling, electrical discharge machining, etc. Additionally / alternatively, the inserts 218 may be supplied as a solid stock of the deposition material from a commercial supplier and further machined to the desired size and shape as appropriate.

[0042] In the example shown in FIGS. 2 and 3 , three inserts 218 are included in the cathode 200. In other embodiments, such as those described below with reference to FIGS. 4-8 , the number of inserts 218 may vary. Any suitable number of inserts 218 may be included in the cathode 200, and the number of inserts 218 may vary depending on the deposition material included in the cathode 200, the desired composition of the coating deposited using the IPD process, and the size of the inserts 218. In various examples, the cathode 200 may include one insert 218 or more than one insert 218, such as two, three, four, five, six, seven, eight, nine, ten, or more than ten inserts 218. When relatively small inserts 218 are used, a relatively large number of inserts 218 (e.g., more than 10, more than 20, or more than 50) may be included.

[0043] In the exemplary embodiment, each insert 218 is coupled to the body 202 of the cathode 200 by placing the insert 218 in a corresponding opening 216 formed in the cathode working surface 204. The openings 216 may also be referred to as bores 216. The inserts 218 are inserted into the corresponding bores or openings 216 and retained therein to couple the insert to the body 202. The inserts 218 may also be forcefully inserted (or pressed) into the corresponding openings 216 and retained therein via a friction fit (or press fit). In these examples, each insert 218 and the corresponding opening 216 are appropriately sized so that the insert is retained within the corresponding opening and does not prematurely separate from the body 202. Additionally / alternatively, the inserts 218 may be retained in the corresponding openings 216 using threads (i.e., via a threaded engagement between the insert and the threads in the corresponding opening). In these examples, each insert 218 and corresponding opening 216 is appropriately sized and has corresponding threads so that the insert is threaded and retained within the corresponding opening and does not prematurely separate from the body 202. Any suitable attachment means may be used to couple the insert 218 to the body 202. In some examples, the insert 218 is suitably coupled to the body 202 without the use of additional mechanical elements, adhesives, or the like. This may facilitate reducing the tendency of any external elements used to couple the insert 218 to the body 202 to interfere with the cathode arc during the IPD process.

[0044] As shown in FIG. 3 , each insert 218 may be cylindrical rod-shaped and have opposing end faces 220, 222. The length of each insert 218 (measured between the opposing end faces 220, 222) may be substantially equal to or less than the length of the body 202 of the cathode 200. The inserts 218 may vary in size and shape (see, e.g., FIG. 6 ). For example, the inserts 218 may have different cross-sectional shapes, diameters, and / or lengths. The size and shape of each insert 218 may depend on the desired amount of deposition material for each insert to be included in the deposited coating. Alternatively, inserts 218 containing deposition material to be incorporated into the deposited coating in larger amounts may be larger in size than inserts containing deposition material to be incorporated into the deposited coating in smaller amounts. The size and shape of the corresponding openings 216 may also vary depending on the size and shape of the corresponding insert 218 to allow the inserts to be coupled to the body 202, as described herein.

[0045] When each insert 218 is coupled to the body 202 of the cathode 200, a first end face 220 of the insert 218 is exposed at the cathode working surface 204. The first end face 220 of the insert 218 may also be referred to as the exposed surface 220 or exposed portion 220 of the insert 218. Each exposed surface 220 is eroded or evaporated by the cathode arc generated at the cathode working surface 204 during the IPD process. The opposite second end face 222 of each insert 218 may extend to the second end face 206 of the body 202 of the cathode 200, or may terminate short of the second end face of the body where the insert has a shorter length than the body.

[0046] Each insert 218 may be machined (e.g., by hand grinding, milling, electrical discharge machining, etc.) so that the exposed surface 220 matches the contour of the cathode working surface 204. In an exemplary embodiment, as shown in FIG. 2 , each exposed surface 220 of the insert 218 lies on the concave surface 212 and may be machined to be substantially flat and flush with the concave surface. Preferably, in embodiments in which the cathode working surface 204 is dished or depressed, the exposed surface 220 of the insert 218 is located radially inward from the downwardly extending surface 214 and is located in the path of the cathode arc such that the exposed portion is controlled by the dished or depressed shape of the cathode working surface. In other embodiments, when the cathode working surface 204 is dished or depressed, the exposed surface 220 of the insert 218 may be located at least partially on the downwardly extending surface 214 and / or the outer edge 210. In these embodiments, the surface 220 may be machined to match the contour (e.g., chamfer) of the radially outer portion of the cathode working surface 204. In yet other embodiments, the cathode working surface 204 may be generally concave to form a dished or sunken shape, and the exposed surface 220 of the insert 218 may be machined to match the concave shape of the cathode working surface. In yet other embodiments, the cathode working surface 204 may be substantially flat between the peripheral edge 208 of the body 202 and the exposed surface 220 of the insert 218 may be machined to match the substantially flat shape of the cathode working surface. In embodiments in which the cathode working surface 204 is generally concave or substantially flat, one or a portion of the insert 218 may be located at a radially outer portion of the cathode working surface proximate the peripheral edge 208 of the body 202.

[0047] 4-8, various exemplary alternative embodiments of the cathode 200 shown in FIGS. 2 and 3 are described having different exemplary configurations of the insert 218. Each of FIGS. 4-8 illustrates a top view of an embodiment of the cathode 200 showing the cathode working surface 204 of the body 202 and the exposed surface 220 at the cathode working surface of the insert 218. The insert 218 is coupled to the body 202 as described above. In exemplary embodiments, the insert 218 is received within a corresponding opening 216 (shown in FIG. 3) formed in the cathode working surface 204 and retained therein via a friction (or press) fit or using threads. It is understood that the exemplary embodiments of the cathode 200 in FIGS. 2-8 are exemplary only, and that the cathode 200 may include more, fewer, or other features than those shown and described. The insert 218 may be coupled to the body 202 using any suitable attachment means. The features of the cathode 200 described in each embodiment herein can be combined in any combination or subcombination.

[0048] In each alternative embodiment, the cathode working surface 204 may include a dished or depressed shape as described above, an example of which is shown in FIG. 2 . In these embodiments, the exposed surfaces 220 of the inserts 218 may be located at and substantially flush with the concave surface 212, radially inward from the downwardly extending surface 214. Additionally / alternatively, the exposed surfaces 220 of the inserts 218 may be located at least partially at the downwardly extending surface 214 and / or the outer edge 210. In other embodiments, the cathode working surface 204 may be substantially flat or generally concave. The exposed surfaces 220 of the inserts 218 may be machined as described above to match the contours (e.g., flat, chamfered, concave) of the portions of the cathode working surface 204 where they are located.

[0049] FIG. 4 illustrates a first exemplary alternative embodiment of a cathode 200, generally designated 200a. In this embodiment, the cathode 200a includes four inserts 218 coupled to the body 202. More or fewer inserts 218 may be included in the cathode 200a. The body 202 and the four inserts 218 each include a deposition material, as described above. The deposition material of each of the four inserts 218 may be the same as or different from the deposition material of the other inserts 218. In some embodiments, one or more of the four inserts 218 include a deposition material that is incompatible with the deposition material included in the body 202 and / or the deposition material included in one or more of the other inserts 218. In the illustrated embodiment of FIG. 4, the four inserts 218 are coupled to the body 202 such that exposed surfaces 220 are circumferentially disposed or spaced apart about the cathode working surface 204. The circumferential arrangement of the exposed surfaces 220 of the inserts 218 may track the path traveled by the cathode arc on the cathode working surface 204 during the IPD process, which may be directed at least in part by the sinking or dishing of the cathode working surface. In other embodiments, the inserts 218 may be arranged in any suitable pattern such that the cathode 200a functions as described herein.

[0050] FIG. 5 illustrates a second exemplary alternative embodiment of the cathode 200, generally designated 200b. In this embodiment, the cathode 200b is coupled to a body 202 and includes four inserts 218 circumferentially arranged or spaced apart on the cathode working surface 204 with exposed surfaces 220, as described above for the cathode 200a of FIG. 4. The body 202 and the four inserts 218 each include a deposition material as described above, and at least one of the inserts 218 may include a deposition material that is incompatible with the deposition material included in the body 202 and / or the deposition material included in one or more of the other inserts 218. Additionally, the cathode 200b of this embodiment includes an additional insert, designated 224, which is fabricated from an electrically insulating material that does not support a cathode arc. In some examples, the additional insert 224 is fabricated from alumina or boron nitride. The additional insert 224 may also be referred to as an electrically insulating insert or an insulating insert. The insulating insert 224 includes an exposed surface 226 at the cathode working surface 204. The insulating insert 224 may be similar in configuration to the other inserts 218, for example, it may be similar in shape to the inserts 218 (e.g., a cylindrical rod). The insulating insert 224 is coupled to the body 202 of the cathode 200b as described above for the inserts 218. For example, the insulating insert 224 may be received in a corresponding opening 216 (shown in FIG. 3) in the cathode working surface 204 and retained there via a friction (or press) fit.

[0051] Preferably, the insulating insert 224 is provided to help control the movement of the cathode arc at the cathode working surface 204 during the IPD process. The insulating insert 224 may be included in addition to, or as an alternative to, a dished or sunken shape of the cathode working surface 204. The electrically insulating material of the insulating insert 224 (e.g., alumina or boron nitride) eliminates the cathode arc at the working surface 204 and drives the cathode arc away from the insulating insert toward other areas of the cathode working surface 204. In this manner, the provision of the insulating insert 224 facilitates control of the movement of the cathode arc at the cathode working surface, for example, allowing for more uniform erosion or evaporation of the cathode working surface and preventing the cathode arc from concentrating at undesired locations along the cathode working surface. This can extend the life of the cathode 200b and improve material transfer from the cathode during the IPD process.

[0052] The illustrated cathode 200b includes a single insulating insert 224 coupled to the body 202 such that an exposed surface 226 of the insulating insert is located in a central region of the cathode working surface 204. The exposed surface 220 of the insert 218 and the deposited material on the body 202 are located radially outward from the insulating insert 224. Thus, during an IPD process, the cathode arc generated at the cathode working surface 204 avoids the insulating material (e.g., alumina or boron nitride) of the insulating insert 224 and circles around the central region of the cathode working surface, eroding or vaporizing the deposited material contained in the insert surrounding the body and the exposed surface 226 of the insulating insert. Circumferential movement of the cathode arc around the insulating insert 224 can be further controlled by the dished or depressed shape of the cathode working surface 204. That is, the dished or depressed shape of the cathode working surface 204 drives the cathode arc radially inward while the insulating insert 224 acts to control the movement of the cathode arc radially outward from the insulating insert. In this manner, the dished or depressed shape of the insulating insert 224 and the cathode working surface 204 control the movement of the cathode arc to concentrate it, for example, along a circumferential path (indicated by arrow 228 in FIG. 5 ) located between the insulating insert and the downwardly extending surface 214. Preferably, the exposed surface 220 of the insert 218 is located in a region of the cathode working surface 204 where the concentration of the cathode arc is controlled.

[0053] The movement controlled by the cathode arc using the insulating insert 224 and cathode working surface 204 as illustrated in FIG. 5 is provided by way of example only. More insulating inserts 224 may be included, or one or more insulating inserts 224 may have exposed surfaces 226 at other locations on the cathode working surface 204 to control the desired movement of the cathode arc. The size and / or shape of the insulating insert 224 may also be adjusted (e.g., by changing the diameter of the exposed surface 226 at the cathode working surface 204) to control the movement of the cathode arc as described herein. Furthermore, the insulating insert 224 may be appropriately sized to optimize the operable surface area of the cathode working surface 204 that contains the evaporable deposition material while still allowing the insulating insert to function as described herein. The configuration of the insulating insert 224 may be adjusted in addition to or as an alternative to adjusting the shape of the cathode working surface 204. In some embodiments, one or more insulating inserts 224 may be included, and the cathode working surface 204 may be substantially flat. In these examples, multiple insulating inserts 224 may be provided that are circular and facilitate concentration of the cathode arc in an annular region located between radially adjacent insulating inserts 224 (see FIG. 8). In this manner, movement of the cathode arc at the cathode working surface 204 may be fine-tuned and controlled using the shape of the insulating inserts 224 and / or the cathode working surface.

[0054] FIG. 6 illustrates a third exemplary alternative embodiment of cathode 200, generally designated 200c. Similar to cathode 200a (shown in FIG. 4), cathode 200c includes four inserts 218 coupled to a body 202 with exposed surfaces 220 circumferentially arranged or spaced apart from the cathode working surface 204. As described above, body 202 and four inserts 218 each include a deposition material, and at least one of the inserts 218 may include a deposition material that is incompatible with the deposition material included in body 202 and / or another one or more of the inserts 218. Cathode 200c is illustrated without insulating insert 224 (shown in FIG. 5), although insulating inserts may be included in other examples. The inserts 218 in this example have different cross-sectional shapes, as shown in FIG. 6. The cross-sectional shapes are provided by way of example only, and the insert 218 may have any suitable cross-sectional shape (e.g., circular, oval, triangular, square, rectangular, or another polygonal shape). The size and shape of the insert 218 may vary depending on the deposition material contained therein and the desired amount of that deposition material contained in the deposited coating.

[0055] FIG. 7 illustrates a fourth exemplary alternative embodiment of the cathode 200, generally designated 200d. In this embodiment, the cathode 200d includes eight inserts 218, each including an exposed surface 220 located radially outward from an insulating insert 224. The insulating inserts 224 are located in a central region of the cathode working surface 204, as described above, and the inserts 218 are arranged such that the exposed surfaces 220 are circumferentially disposed around the insulating inserts. In this example, the body 202 is fabricated from a first deposition material, and the inserts 218 include a first insert 218a fabricated from a second deposition material, a second insert 218b fabricated from a third deposition material, and a third insert 218c fabricated from a fourth deposition material. The inserts 218a-c are arranged in an alternating circumferential arrangement as shown in FIG. 7, although any arrangement of the inserts 218a-c may be used. For example, the first insert 218a, the second insert 218b, and / or the third insert 218c may be grouped by similar material (i.e., adjacent inserts 218a-218c are arranged with similar deposition materials). In the illustrated cathode 200d, the inserts 218 are similarly sized and shaped, and more inserts 218a and 218b are included than insert 218c. As a result, the deposited coating contains more of the second and third deposition materials than the fourth deposition material. The number of each type of insert 218a-218c, along with their relative dimensions, can vary depending on the desired amount of each deposition material in the deposited coating. The second, third, and / or fourth deposition materials may be incompatible with the first deposition material of the body 202. Additionally / alternatively, the second deposition material may be incompatible with the third and / or fourth deposition material, and / or the third and fourth deposition materials may be incompatible.

[0056] FIG. 8 illustrates a fifth exemplary alternative embodiment of the cathode 200, generally designated 200e. In this embodiment, the cathode 200e includes a body 202 fabricated from a first deposition material, two insulating inserts 224 (labeled 224a and 224b), and an insert 218 fabricated from a second deposition material. As noted above, the first and second deposition materials may be incompatible with one another. Each of the insulating inserts 224a and 224b is fabricated from an electrically insulating material that does not support a cathode arc, such as alumina or boron nitride. The insulating inserts 224a and 224b control the movement of the cathode arc at the cathode working surface 204. The first insulating insert 224a is cylindrical and is located in a central region of the cathode working surface 204. The second insulating insert 224b is annularly shaped and positioned between the outer edge 210 of the body 202 and the remaining portion of the cathode working surface 204 located radially between the insulating inserts 224a and 224b. In some embodiments, the annular-shaped insulating insert 224b may surround the body 202 of the cathode 200e, including the peripheral edge 208 (shown in FIGS. 2 and 3). The region of the cathode working surface 204 between the insulating inserts 224a and 224b may be substantially flat. The insulating inserts 224a and 224b may cooperate to control the movement of the cathode arc, which is concentrated along a circumferential path (shown by arrow 228 in FIG. 8 ) located radially between the insulating inserts. Suitably, the insert 218 is fabricated from a second deposition material located between the insulating inserts 224a and 224b and along the region of the cathode working surface 204 where the concentration of the cathode arc is controlled. In the exemplary cathode 200e, the insert 218 is annular. Other embodiments may include more or fewer inserts 218. For example, multiple annular-shaped inserts 218 may be included, and may include the same or different deposition materials. Additionally / alternatively, the insert 218 of the cathode 200e may have any suitable size and / or shape. For example, the insert 218 may be shaped as illustrated in any of Figures 2-7 and described above.The number, size, and / or shape of the inserts 218 may vary depending on the desired composition of the deposited coating, as discussed above.

[0057] FIG. 9 illustrates, with reference to FIG. 1, an exemplary method 300 for depositing a coating material on a substrate, such as the workpiece 108 described above. Note that the method 300 may be performed using the IPD apparatus 100 (shown in FIG. 1). The method includes, at 302, providing a cathode (e.g., cathode 200) including a body (e.g., body 202) defining a cathode working surface (e.g., cathode working surface 204). The body includes a first deposition material that is vaporizable in response to a cathode (or electric) arc generated at the cathode working surface. The method 300 also includes coupling 304 one or more inserts (e.g., one or more inserts 218) to the body. The one or more inserts may define corresponding openings (e.g., opening 216) in the cathode working surface of each insert, and the body 304 may be coupled by placing each insert in the corresponding opening. Each insert may be retained in the corresponding opening via a friction (or press-fit) fit. The one or more inserts include a second deposition material that is vaporizable in response to a cathode (or electric) arc generated at the cathode working surface. The second deposition material may be different from and incompatible with the first deposition material. When the one or more inserts are coupled to the body 304, the one or more inserts are at least partially exposed at the cathode working surface (e.g., have an exposed surface 220).

[0058] The method 300 also includes generating an electric (or cathodic) arc 306 at the cathodic working surface, thereby vaporizing the first and second deposition materials. To generate the cathodic arc 306, the cathode and substrate are placed in a vacuum environment (e.g., within the vacuum chamber 102), and an electric current is supplied to the cathode (e.g., via the DC power supply 114) to create a sufficient electrical potential between the cathode and the substrate. The substrate may also be provided with a ground potential or a negative voltage bias, as described above. The cathodic arc 306 generated at the cathodic working surface erodes or vaporizes the first deposition material of the body and the second deposition material of the one or more inserts from the cathodic working surface. The erosion or evaporation of the first and second deposition materials forms a cloud of droplets and ions of coating material, which are deposited 308 on the surface of the substrate by condensation and / or electrical attraction. The deposited coating includes first and second deposition materials, which may be incompatible and therefore remain separated until the materials evaporate to reduce or prevent premature decomposition of the cathode before or during the deposition process. In some embodiments, method 300 may include controlling the movement of a cathode arc 306 generated at the cathode working surface. For example, method 300 may include coupling an insulating insert (e.g., insulating insert 224) to the body such that the insulating insert is at least partially exposed to the cathode working surface (e.g., has exposed surface 226), and using the insulating insert to control the movement of the electric arc at the cathode working surface. Additionally / alternatively, method 300 may include forming a dished or depressed shape on the cathode working surface and using the shape of the cathode working surface to control the movement of the electric arc at the cathode working surface.

[0059] The above-described systems and methods facilitate overcoming at least some of the limitations and costs associated with current IPD processes by using a "hybrid" cathode that includes one or more inserts coupled to a body fabricated from a first deposition material and a body fabricated from a second, different deposition material. The hybrid cathode enables the deposition of first and second deposition materials onto a substrate. In particular, exemplary hybrid cathodes enable the simultaneous deposition of incompatible materials onto a substrate from a single cathode while reducing or eliminating the tendency of the cathode to prematurely decompose or fail before or during deposition. The second deposition material may be incompatible with the first deposition material, and the incompatible deposition materials remain separate until they are vaporized and deposited onto the substrate.

[0060] The insert coupled to the body can be easily removed from the body and selectively replaced with inserts made of other materials, advantageously allowing a wide variety of materials to be used with a single cathode. The exemplary hybrid cathode can also be configured to control the cathode arc as it orbits the cathode working surface (e.g., by shaping the cathode working surface and / or including one or more insulating inserts). Thus, the exemplary hybrid cathode overcomes at least some of the current limitations of the IPD process, such as promoting cost reductions and overcoming the inability to produce coatings with complex compositions. Furthermore, the exemplary hybrid cathode facilitates the use of additional coating materials available for the coating process, thereby significantly reducing costs associated with the IPD process by enabling the process to operate for extended periods without cathode replacement. Furthermore, the lack of frequent cathode replacement allows for the deposition of more uniform and improved coating materials. [Example]

[0061] The disclosed technology will now be further described with reference to the following non-limiting examples.

[0062] The preparation of monolithic cathodes for the deposition of Nb-Si-Ti-Al-Hf alloy coatings containing various atomic percents of niobium (Nb), silicon (Si), titanium (Ti), aluminum (Al), and hafnium (Hf) was attempted by mixing the respective amounts of elements and casting the cathodes. The solid material was too brittle and broke into multiple pieces during casting. It also could not withstand the mechanical stresses during processing and could not be machined to the appropriate size and shape without cracking and decomposition.

[0063] Therefore, hybrid cathodes capable of depositing the desired chemistry of Nb-Si-Ti-Al-Hf alloy coatings were prepared by casting the cathode body from a Ti-Al-Si alloy containing about 18 to about 22% Si, about 18 to about 22% Ti, and about 58 to about 62% Al, which provided solid strength and ductility suitable for casting and machining the cathode body. Inserts fabricated from a Nb-Si-Ti-Hf alloy containing 100 atomic percent p-doped Si and about 35 to about 38% Nb, about 11 to about 15% Si, about 33 to about 37% Ti, and about 14 to about 17% Hf also possessed adequate strength and ductility to prevent insert failure. The Si and Nb-Si-Ti-Hf alloy inserts were pressed into openings machined into the working surface of the Ti-Al-Si alloy cathode body, leaving the insert partially exposed at the working surface. An insulating insert made of boron nitride (BN) was also obtained and forcefully inserted into a corresponding opening formed in the radially central region of the working surface of the Ti-Al-Si alloy cathode body. The Si and Nb-Si-Ti-Hf alloy inserts were circumferentially arranged around the insulating BN insert, allowing the cathode arc to shift toward the Si and Nb-Si-Ti-Hf alloy inserts while avoiding the BN insert at the working surface during hybrid cathode operation. This resulted in a hybrid cathode that contained the chemistry necessary to deposit the desired Nb-Si-Ti-Al-Hf alloy coating in a single hybrid cathode while reducing the cathode's tendency to fail.

[0064] Additional aspects of the disclosed technology are presented in the following embodiments section. [Embodiment Item 1] 1. A cathode for use in an ion deposition process, the cathode comprising: a body defining an active surface of the cathode, the body comprising a first deposition material; and one or more inserts coupled to the body, the one or more inserts being at least partially exposed at the cathode active surface and the one or more inserts comprising a second deposition material incompatible with the first deposition material, wherein the first and second deposition materials can be evaporated in response to an electric arc generated at the cathode active surface to deposit a coating comprising the first and second deposition materials on a substrate. [Embodiment 2] The cathode of embodiment 1, wherein the one or more inserts include two or more inserts coupled to the body, each insert being at least partially exposed at the cathode working surface. [Embodiment 3] The cathode of embodiment 2, wherein two or more inserts are arranged such that the exposed portions of the inserts are circumferentially spaced apart on the cathode working surface. [Embodiment 4] The cathode of embodiment 2 or embodiment 3, wherein the two or more inserts include a first insert comprising a second deposition material and a second insert comprising a third deposition material that is different from the second deposition material and incompatible with the first deposition material. [Embodiment 5] The cathode of embodiment 2 or embodiment 3, wherein the two or more inserts include a first insert comprising a second deposition material and a second insert comprising a third deposition material incompatible with one of the first and second deposition materials. [Embodiment 6] The cathode of any one of paragraphs 2 through 5, wherein the two or more inserts include an insulating insert comprising an insulating material configured to control the movement of an electric arc generated at the cathode working surface. [Embodiment 7] The cathode of embodiment 6, wherein the insulating material comprises one of alumina and boron nitride. [Embodiment 8] The cathode of any one of embodiments 1 through 7, wherein the first deposition material comprises one or more elements selected from the group consisting of nickel, aluminum, cobalt, chromium, molybdenum, tungsten, rhenium, ruthenium, zirconium, hafnium, tantalum, silicon, yttrium, titanium, lanthanum, cerium, niobium, vanadium, platinum, iridium, osmium, palladium, rhodium, carbon, and boron. [Embodiment Item 9] The cathode of any one of embodiments 1 through 8, wherein the second deposition material comprises one or more elements selected from the group consisting of nickel, aluminum, cobalt, chromium, molybdenum, tungsten, rhenium, ruthenium, zirconium, hafnium, tantalum, silicon, yttrium, titanium, lanthanum, cerium, niobium, vanadium, platinum, iridium, osmium, palladium, rhodium, carbon, and boron. [Embodiment Item 10] The cathode of any one of paragraphs 1 through 9, wherein each insert is held in a corresponding opening formed in the body of the cathode. [Embodiment Item 11] The cathode of embodiment 10, wherein each insert is retained in a corresponding opening by at least one of a friction fit and a threaded engagement. [Embodiment Item 12] 1. An apparatus for depositing a film on a substrate, the apparatus comprising: a deposition chamber sized to accommodate the substrate therein; a cathode disposed in the deposition chamber, the cathode including: a body defining an active surface of the cathode, the body including a first deposition material; and one or more deposition inserts coupled to the body, the one or more deposition inserts being at least partially exposed at the cathode active surface and the one or more deposition inserts including a second deposition material incompatible with the first deposition material; and a power supply coupled to the cathode, the power supply operable to generate an electric arc at the cathode active surface to vaporize the first and second deposition materials and deposit a coating including the first and second deposition materials on the substrate. [Embodiment Item 13] The apparatus of embodiment 12, wherein the cathode further comprises an insulating insert coupled to the body and at least partially exposed at the cathode working surface, the exposed portion of the insulating insert being positioned to help control movement of the electric arc at the cathode working surface. [Embodiment Item 14] The apparatus of embodiment 13, wherein the exposed portion of the insulating insert is positioned in a central region of the cathode working surface to help control circumferential movement of the electric arc at the cathode working surface. [Embodiment Item 15] The apparatus of embodiment 14, wherein the one or more deposition inserts include two or more deposition inserts coupled to the body, each deposition insert being at least partially exposed on the cathode working surface at a position radially outward from the exposed portion of the insulating insert. [Embodiment Item 16] The apparatus of embodiment 15, wherein the two or more deposition inserts comprise a first deposition insert including a second deposition material and a second deposition insert including a third deposition material different from the second deposition material. [Embodiment Item 17] 17. The apparatus of embodiment 16, wherein the third deposition material is incompatible with at least one of the first and second deposition materials. [Embodiment Item 18] 1. A method for depositing a coating on a substrate, the method comprising: providing a cathode including a body defining an active surface of the cathode, the body including a first deposition material; coupling one or more inserts to the body, the inserts including a second deposition material incompatible with the first deposition material, such that the one or more inserts are at least partially exposed at the cathode active surface; generating an electric arc at the cathode active surface to vaporize the first and second deposition materials; and depositing the vaporized first and second deposition materials on the substrate. [Embodiment Item 19] The method of embodiment 18, wherein the step of coupling one or more inserts to the body includes forming a corresponding opening in the cathode working surface of each insert, and positioning each insert in the corresponding opening such that each insert is retained in the corresponding opening by at least one of a friction fit and a threaded engagement. [Embodiment Item 20] The method of embodiment 18, further comprising the steps of: coupling an insulating insert to the body such that the insulating insert is at least partially exposed at the cathode working surface; and using the insulating insert to control movement of the electric arc at the cathode working surface.

[0065] Exemplary embodiments of an ion plasma deposition system and a method for depositing a coating material on a substrate using a hybrid cathode have been described above. The methods and systems described herein are not limited to the specific embodiments described herein. For example, each system component and / or each method step may be utilized independently and separately from other components and / or steps described herein. For example, the systems and methods may be used in combination with a wide variety of components and are not limited to practice with rotating machine (e.g., gas turbine engine) components as described herein. The exemplary embodiments may be implemented and utilized in connection with many other ion plasma deposition applications or applications, including deposition of coating materials from incompatible materials.

[0066] Although specific features of various embodiments of the invention may be shown in some drawings and not in others, this is for convenience only. References to "one embodiment" in this specification should not be interpreted as excluding the existence of additional embodiments that incorporate the recited features. Consistent with the principles of the invention, any feature shown in one drawing may be referenced and / or claimed in combination with any feature shown in any other drawing.

[0067] This specification has used examples to disclose the invention, including the best mode, and to enable any person skilled in the art to practice the invention, including making and using the devices or systems and practicing the methods. The patentable scope of the disclosure is defined by the claims, and may include other examples that would be obvious to those skilled in the art. Such other examples are within the scope of the claims if they have elements that do not literally differ from the claims, or equivalent elements that differ only insubstantially from the literal language of the claims. [Explanation of symbols]

[0068] 100 Ion plasma deposition device 102 Vacuum Chamber 104 Vacuum System 106 cathode 108 workpieces 114 Power supply 200 cathode 202 Cathode body 204 cathode working surface 218 Insert 220 Exposed part of insert 224 Insulation Insert 226 Exposed portion of insulating insert

Claims

1. A cathode (200) for use in an ion deposition process, the cathode (200) comprising: a body (202) defining a cathode working surface (204), the body (202) including a first deposition material; one or more inserts (218) coupled to the body, the one or more inserts being at least partially exposed at the cathode working surface, and the one or more inserts including a second deposition material incompatible with the first deposition material; a cathode (200) comprising: a cathode (200) in which the first and second deposition materials can be evaporated in response to an electric arc generated at the cathode working surface to deposit a coating including the first and second deposition materials on the substrate (108).

2. 10. The cathode (200) of claim 1, wherein the one or more inserts (218) include two or more inserts coupled to the body (202), each insert being at least partially exposed at the cathode working surface (204).

3. two or more inserts are arranged such that the exposed portions (220) of the inserts are circumferentially spaced apart on the cathode working surface (204); and / or the two or more inserts include a first insert comprising a second deposition material and a second insert comprising a third deposition material, optionally the third deposition material being different from the second deposition material and / or incompatible with either the first or second deposition material; and / or 3. The cathode of claim 2, wherein the two or more inserts include an insulating insert comprising an insulating material configured to control movement of an electric arc generated at the cathode working surface, and optionally the insulating material comprises one of alumina and boron nitride.

4. 4. The cathode (200) of any one of claims 1 to 3, wherein the first deposition material comprises one or more elements selected from the group consisting of nickel, aluminum, cobalt, chromium, molybdenum, tungsten, rhenium, ruthenium, zirconium, hafnium, tantalum, silicon, yttrium, titanium, lanthanum, cerium, niobium, vanadium, platinum, iridium, osmium, palladium, rhodium, carbon, and boron.

5. 5. The cathode (200) of any one of claims 1 to 4, wherein the second deposition material comprises one or more elements selected from the group consisting of nickel, aluminum, cobalt, chromium, molybdenum, tungsten, rhenium, ruthenium, zirconium, hafnium, tantalum, silicon, yttrium, titanium, lanthanum, cerium, niobium, vanadium, platinum, iridium, osmium, palladium, rhodium, carbon, and boron.

6. 6. The cathode (200) of claim 1, wherein each insert (218) is retained in a corresponding opening (216) formed in the cathode body (202), and optionally each insert is retained in the corresponding opening by at least one of a friction fit and a threaded engagement.

7. An apparatus (100) for depositing a coating on a substrate (108), the apparatus comprising: a deposition chamber (102) sized to accommodate the substrate therein; A cathode (200) disposed in the deposition chamber, the cathode (200) comprising: a body (202) defining a cathode working surface (204), the body (202) including a first deposition material; one or more deposition inserts (218) coupled to the body, the one or more deposition inserts being at least partially exposed at the cathode working surface, and the one or more deposition inserts including a second deposition material incompatible with the first deposition material; a cathode (200) comprising: a power supply (114) coupled to the cathode, the power supply operable to generate an electric arc at the cathode working surface to vaporize the first and second deposition materials and deposit a coating including the first and second deposition materials on the substrate; An apparatus (100) comprising:

8. 8. The apparatus of claim 7, wherein the cathode further includes an insulating insert coupled to the body and at least partially exposed at the cathode working surface, the exposed portion of the insulating insert positioned to help control movement of the electric arc at the cathode working surface.

9. 9. The apparatus of claim 8, wherein the exposed portion of the insulating insert is disposed in a central region of the cathode working surface to help control circumferential movement of the electric arc at the cathode working surface.

10. 10. The apparatus of claim 9, wherein the one or more deposition inserts include two or more deposition inserts coupled to the body, each deposition insert being at least partially exposed on the cathode working surface at a location radially outward from the exposed portion of the insulating insert.

11. 11. The apparatus of claim 10, wherein the two or more deposition inserts comprise a first deposition insert including a second deposition material and a second deposition insert including a third deposition material different from the second deposition material.

12. The apparatus (100) of claim 11, wherein the third deposition material is incompatible with at least one of the first and second deposition materials.

13. A method (300) for depositing a film on a substrate, the method (300) comprising: Providing (302) a cathode including a body defining a working surface of the cathode, the body including a first deposition material; coupling (304) one or more inserts to the body, the inserts including a second deposition material incompatible with the first deposition material, such that the one or more inserts are at least partially exposed at the cathode working surface; generating an electric arc at the cathode working surface to vaporize the first and second deposition materials (306); depositing (308) the evaporated first and second deposition materials onto a substrate; The method (300).

14. The step of coupling (302) one or more inserts to the body includes: forming a corresponding opening in the cathode working surface of each insert; placing each insert in a corresponding opening such that each insert is retained in the corresponding opening by at least one of a friction fit and a threaded engagement; 14. The method (300) of claim 13, comprising:

15. 14. The method (300) of claim 13, further comprising coupling an insulating insert to the body such that the insulating insert is at least partially exposed at the cathode working surface, and using the insulating insert to control movement of the electric arc at the cathode working surface.

Images