System and method for influencing surface of electrically conductive material

Abstract

Described herein are systems and methods for beneficially affecting the surface morphology of conductive materials using electrochemistry. These systems and methods for beneficially affecting the surface morphology of conductive materials use a bimodal process in which a first current type (alternating or direct current) is applied across the electrolyte between the electrode and the workpiece, followed by a second current type different than the first current type. The bimodal process may be repeated one or more times.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 343,933, filed on May 19, 2022, entitled “SYSTEMS AND METHODS FOR AFFECTING SURFACES OF ELECTRICALLY CONDUCTIVE MATERIALS,” the entire contents of which are hereby incorporated by reference herein. Technical Field

[0003] The technology described herein generally relates to systems and methods for beneficially affecting the surface morphology of conductive materials using electrochemistry. More specifically, the technology described herein relates to systems and methods for beneficially affecting the surface morphology of conductive materials using a bimodal process in which a first current type (AC or DC) is applied across an electrolyte between an electrode and a workpiece, followed by a second current type different from the first current type. The bimodal process can be repeated one or more times. Background Art

[0004] Electrochemical methods of affecting the surface of materials are primarily based on Faraday's law of electrolysis. Essentially, the result of an electrochemical operation is proportional to the charge introduced into the system. When the polarity of the electrodes is kept constant, the changes on the electrodes can be predicted via the charge introduced. In the example of electrodeposition, for the total number of electrons flowing into the system (usually measured in ampere-time units), a fixed number of cationic species will be deposited on the electrode in question. Where these cations will be deposited, how evenly they are distributed, and the functional and aesthetic properties of the deposit are controlled by other factors.

[0005] In practice, these results are rate-limiting steps that are primarily influenced by mass transfer mechanisms around the electrodes. Using the example of electrodeposition again, when metal is deposited onto an electrode, the replenishment of fresh ionic species to the workpiece is constrained to a very thin interfacial layer by diffusion, convection, and migration methods of the actual chemical solution. Diffusion (the random movement of molecules from areas of high concentration to lower concentrations) creates an obstacle to the uniform distribution of chemical species within the layer, resulting in an interference barrier. Similarly, fluid dynamics within the electrochemical cell (whether through mechanical agitation / mixing or through differential heat transfer) can improve mass transfer efficiency, but localized excessive turbulence or laminar flow can also create obstacles that need to be overcome. Finally, the movement of charged particles flowing in a local electric field can lead to concentration gradients of ionic species, which is another component of the interference barrier.

[0006] Due to these constraints around the working electrode, unless operating boundaries are set on the operating parameters, undesirable results will be achieved. Continuing with the example of electrodeposition, if the rate of charge introduction is too high, then an uneven and even uncontrolled deposition of ionic species will occur. Conversely, if the rate of charge introduction is too low, then the chemical properties of the electrolyte itself may cause chemical degradation of the deposit. The typical result is chemical attack, usually in the form of undesirable, harmful pitting of the electrode.

[0007] Since Faraday proposed the laws of electrolysis, advances in the field of electrochemical operations have focused primarily on developing and expanding the properties of the chemicals involved or enhancing mechanical methods to overcome problems within interference barriers. A large number of chemicals have been discovered and introduced to beneficially achieve electrochemical results, such as surfactants and chelating agents. In addition, over time, mechanical methods of solution agitation or the delivery concentration of solution chemicals have also been developed. Specifically, jetting equipment has been designed and added to achieve better solution agitation, as well as electrolyte delivery methods as seen in the field of electrochemical machining (ECM).

[0008] These more recent developments are generally designed to minimize the deleterious effects of slowly replenishing a barrier layer adjacent to the electrode in question. A subset of these methods is intended to improve the "detrimental" (i.e., roughening) surface effects on the electrode. In some results, it can be of practical value to deteriorate or roughen the electrode surface morphology. This is confirmed by the destructive results of "etching" the electrode, making its surface porosity or irregularities an integral part of the adhesion of subsequent layers. This result is favorable when the material in question rapidly forms oxides that interfere with the adhesion of subsequent layers when exposed to air. Aluminum lithographic plates are treated to deleteriously affect (i.e., roughen) the surface morphology, thereby producing a surface that is easily receptive to subsequent application of ink. This roughened surface morphology is generally considered to be deleterious because it causes stress corrosion cracking, shortens fatigue life, or requires subsequent application of an added auxiliary layer to overcome irregularities. There are limited applications in which the roughening of the surface morphology provides benefits for the application.

[0009] In view of the foregoing, it remains desirable to further improve electrochemical processes to beneficially affect the surface of a workpiece. Summary of the invention

[0010] This summary is provided to introduce in simplified form a selection of concepts that will be further described below in the detailed description. This summary and the foregoing background technology are not intended to identify key aspects or essential aspects of the claimed subject matter. In addition, this summary is not intended to be used to help determine the scope of the claimed subject matter.

[0011] In some embodiments, a bimodal method for affecting the surface of a conductive workpiece is disclosed herein. The method may include the following steps: immersing the surface of the conductive metal workpiece in an electrolyte solution; immersing at least the surface of an electrode in the electrolyte solution; initiating a first operating mode, the first operating mode comprising applying a direct current across the electrolyte solution between the conductive metal workpiece and the electrode or applying an alternating current across the electrolyte solution between the conductive metal workpiece and the electrode; terminating the first operating mode; initiating a second operating mode, the second operating mode comprising applying an alternating current across the electrolyte solution between the conductive metal workpiece and the electrode or applying a direct current across the electrolyte solution between the conductive metal workpiece and the electrode, the second operating mode using a different current type than the first operating mode; and terminating the second operating mode. The first operating mode and the second operating mode may be performed sequentially one or more times. The material of the conductive metal workpiece may include: (1) pure Ti, Zr, Nb, Hf, Ta or V, or alloys based on Ti, Zr, Nb, Hf, Ta or V; (2) pure Ni, Ni-based alloys, Co-based alloys or titanium aluminide; (3) austenitic stainless steel; (4) martensitic stainless steel; (5) ferritic stainless steel, carbon steel or alloy steel; (6) pure aluminum or aluminum alloys; or (7) pure copper or copper alloys.

[0012] In some embodiments, a system for affecting the surface of a conductive metal workpiece is disclosed herein. The system may include: an electrolyte solution bath; a conductive metal workpiece, at least one surface of which is immersed in the electrolyte solution bath; an electrode, at least one surface of which is immersed in the electrolyte solution bath; a DC power supply, wherein a first terminal of the DC power supply is connected to the conductive metal workpiece, and a second terminal of the DC power supply is connected to the electrode; and an AC power supply, wherein a first terminal of the AC power supply is connected to the conductive metal workpiece, and a second terminal of the AC power supply is connected to the electrode. The system is configured so that: in a first operating mode, the DC power supply applies only direct current across the electrolyte solution between the conductive metal workpiece and the electrode, or the AC power supply applies only alternating current across the electrolyte solution between the conductive metal workpiece and the electrode; and in a second operating mode, the AC power supply applies only alternating current across the electrolyte solution between the conductive metal workpiece and the electrode, or the DC power supply applies only direct current across the electrolyte solution between the conductive metal workpiece and the electrode. The system is further configured so that the first operating mode uses a different current type than the second operating mode. In operation, the system alternates between the first operating mode and the second operating mode. The material of the conductive metal workpiece may include: (1) pure Ti, Zr, Nb, Hf, Ta or V, or alloys based on Ti, Zr, Nb, Hf, Ta or V; (2) pure Ni, Ni-based alloys, Co-based alloys or titanium aluminide; (3) austenitic stainless steel; (4) martensitic stainless steel; (5) ferritic stainless steel, carbon steel or alloy steel; (6) pure aluminum or aluminum alloys; or (7) pure copper or copper alloys.

[0013] As described above, the methods and systems described herein are applicable to seven separate and different workpiece material categories. Although not wishing to be bound by theory, the ability to affect these different types of materials by applying power through a dual mode as described herein may be attributed to the behavioral properties of the periodic table elements included in the different material categories. When Mendeleev first sorted out the periodic table, he tried to arrange the elements with the most similar properties in vertical columns. In addition, the arrangement of these groups is also related to the number of protons in the elements, and correspondingly to the number of electrons. Since electrons exist in a series of increasingly complex shells, and through the Bohr electron behavior model, the vertical element groups are also arranged so that each column reflects the number of electrons in its valence electron shell. Therefore, the ability to affect these valence electrons and interact with them provides a means of understanding two aspects of the technology described herein. The material categories disclosed herein are arranged in part by valence electron grouping. Metals such as titanium, vanadium, and niobium share similar valence electron configurations, and are therefore grouped together for the purpose of the technology described herein. Secondly, it is believed that the influence on valence electrons can be affected by electrochemical, electrokinetic, and electromagnetic properties by applying external power through a dual mode as described herein.

[0014] These and other aspects of the technology described herein will be apparent after considering the detailed description and accompanying drawings herein. However, it should be understood that the scope of the subject matter claimed should be determined by the issued claims, rather than by whether a given subject matter solves any or all of the problems mentioned in the background technology or includes any features or aspects stated in the summary of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Non-limiting and non-exhaustive embodiments of the disclosed technology, including preferred embodiments, are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified.

[0016] Figure 1 is a schematic diagram of a system for beneficially affecting a surface of an electrically conductive metal workpiece configured in accordance with various embodiments described herein.

[0017] Figure 2 is a flow chart illustrating a method for beneficially affecting a surface of an electrically conductive metal workpiece configured in accordance with various embodiments described herein.

[0018] Figure 3A and Figure 3B Various exemplary operational scenarios of methods and systems configured in accordance with various embodiments described herein are shown.

[0019] Figure 4 is a table summarizing grit finishes along with estimated RMS and Ra values.

[0020] Figure 5A and Figure 5B is a table summarizing data from experimental tests conducted on workpiece material class 1 - reactive metals using systems and methods configured according to various embodiments described herein.

[0021] FIG. 6A to FIG. 6E is a table summarizing data from experimental tests conducted on workpiece material category 2 - high temperature / high strength metals using systems and methods configured according to various embodiments described herein.

[0022] 7A to 7F is a table summarizing data from experimental tests conducted on workpiece material class 3 - austenitic stainless steel using systems and methods configured according to various embodiments described herein.

[0023] Figure 8 is a table summarizing data from experimental tests conducted on workpiece material class 4 - martensitic stainless steel using systems and methods configured according to various embodiments described herein.

[0024] 9A to 9D is a table summarizing data from experimental tests conducted on workpiece material class 5 - ferritic stainless steel, carbon steel, alloy steel using systems and methods configured according to various embodiments described herein.

[0025] Fig.10 is a table summarizing data from experimental tests conducted on workpiece material category 6 - aluminum and aluminum alloys using systems and methods configured according to various embodiments described herein.

[0026] Fig.11 is a table summarizing data from experimental tests conducted on workpiece material class 7 - copper and copper alloys using systems and methods configured according to various embodiments described herein. DETAILED DESCRIPTION

[0027] Embodiments are described more fully below with reference to the accompanying drawings, which form a part of the embodiments and show specific exemplary embodiments in an illustrative manner. These embodiments are disclosed in full detail to enable those skilled in the art to practice the present invention. However, the embodiments can be realized in many different forms and should not be construed as being limited to the embodiments set forth herein. Therefore, the following detailed description should not be construed as restrictive.

[0028] refer to Figure 1 , a system 100 for beneficially affecting the surface of a conductive metal workpiece is shown. The system 100 generally includes an electrolyte solution bath 110, a conductive metal workpiece 120, an electrode 130, a DC power source 140, and an AC power source 150. The system 100 may also optionally include a mixing device 160 (in Figure 1A mechanical mixer is shown in FIG. 1 ) and / or a heating element 170 (shown in FIG. Figure 1 shown as a heat exchanger).

[0029] The system 100 is configured such that at least one surface of the conductive metal workpiece 120 and at least one surface of the electrode 130 are immersed in the electrolyte solution bath 110. In some embodiments, most or all of the conductive metal workpiece 120 and / or most or all of the electrode 130 can be immersed in the bath 110. The minimum distance between the conductive metal workpiece 120 and the electrode 130 is 0.003 inches. Due to practical limitations, a minimum separation distance is provided. As the distance between the workpiece 120 and the electrode 130 approaches zero, there is a corresponding increase in the amount of electrical energy concentrated in an increasingly smaller volume. In theory, the distance can be infinitesimally small, but in practice, distances less than 0.003 inches become unmanageable from a mass and heat transfer perspective. Any distance greater than 0.003 inches can be used, provided that current can pass between the conductive metal workpiece 120 and the electrode 130.

[0030] Configuration of the system 100 also includes electrically connecting each of the conductive metal workpiece 120 and the electrode 130 to a DC power source 140 and an AC power source 150. The specific terminals of the DC power source 140 to which each of the conductive metal workpiece 120 and the electrode 130 is connected are generally not limited and can depend on the specific beneficial process being implemented (electrodeposition, electrochemical removal, etc.). In some embodiments, the positive terminal of the DC power source 140 is connected to the conductive metal workpiece 120, and the negative terminal of the DC power source 140 is connected to the electrode 130. In some embodiments, the negative terminal of the DC power source 140 is connected to the conductive metal workpiece 120, and the positive terminal of the DC power source 140 is connected to the electrode 130. The DC power source 140 can also be configured as a switched pole, but the DC power source 140 is not intended to provide an equivalent or approximation of alternating current. The specific terminals of the AC power source 150 to which each of the conductive metal workpiece 120 and the electrode 130 is connected are generally not limited.

[0031] The system 100 may optionally include a means for mixing / agitation of the electrolyte solution bath. Figure 1 As shown, mixing / agitation device 160 is included as part of system 100 and can be configured to mix / agitation the electrolyte solution bath before, during, and / or after applying current from one or both of DC power source 140 and AC power source 150. In some embodiments, mixing / agitation device 160 is a mechanical mixing / agitation device, such as a propeller or stirring rod, but any suitable mechanical mixing / agitation device can be used. In some embodiments, mixing / agitation device 160 is a thermal mixing / agitation device.

[0032] System 100 may optionally include means for heating the electrolyte solution bath. Figure 1 As shown, heating device 170 is included as part of system 100 and can be configured to change the temperature of the electrolyte solution bath before, during, and / or after applying current from one or both of DC power source 140 and AC power source 150. Heating device 170 can be used to heat and / or cool the electrolyte solution bath. Any suitable heating mechanism can be used for heating device 170, including but not limited to, Figure 1 heat exchanger shown. Although Figure 1 The heating device 170 is shown as being located within the electrolyte bath solution, but the heating element 170 may be located anywhere about the system 100, provided that the location of the heating element 170 allows for heating (or cooling) of the electrolyte bath solution.

[0033] Additional information regarding, for example, the material composition of the workpiece 120 , the electrolyte solution 110 , etc., and the operation of the overall system 100 and individual components of the system 100 is provided below.

[0034] In the application, Figure 1 The illustrated system 100 can be used to beneficially affect the surface of a conductive metal workpiece by operating in at least two modes. In a first mode, the system 100 operates to apply a first type of current (e.g., direct current or alternating current) between the conductive metal workpiece and the electrode across an electrolyte bath, and in a second mode, the system 100 operates to apply a second type of current (which is different from the first type of current) between the conductive metal workpiece and the electrode across an electrolyte bath. For example, if the first operating mode employs direct current, the second operating mode employs alternating current, and if the first operating mode employs alternating current, the second operating mode employs direct current. The system alternates between the first operating mode and the second operating mode one or more times, with no practical limit on the number of times the first and second operating modes are performed sequentially. The operating modes are generally non-overlapping, meaning that alternating current and direct current are generally not applied simultaneously. In other words, the first operating mode is terminated (the first current type is terminated) before the second operating mode is initiated (the second current type is initiated). Although alternating current and direct current are generally not applied simultaneously, it should be understood that the time between the termination of the first operating mode and the initiation of the second operating mode can be extremely short, so that the transition from the first current type to the second current type is substantially instantaneous. Alternatively, there may be a longer period of time between termination of the first operating mode and initiation of the second operating mode in which no current of any type is applied.

[0035] Relative to Figure 2 , a method 200 of beneficially affecting the surface of a conductive metal workpiece is shown, and the method may be used Figure 1The method 200 is implemented by the system 100 shown. The method 200 generally includes: a step 210 of immersing at least a surface of a conductive metal workpiece in an electrolyte solution; a step 220 of immersing at least a surface of an electrode in an electrolyte solution; a step 230 of initiating a first operating mode in which a first type of current (i.e., direct current or alternating current) is applied across the electrolyte solution between the conductive metal workpiece and the electrode; a step 240 of terminating the first operating mode; a step 250 of initiating a second operating mode in which a second type of current (which is different from the first type of current) is applied across the electrolyte solution between the conductive metal workpiece and the electrode; and a step 260 of terminating the second operating mode. Figure 2 As shown via arrow 201, steps 230, 240, 250 and 260 may be performed once or multiple times.

[0036] With respect to steps 210 and 220 of immersing at least the surface of the conductive metal workpiece in the electrolyte solution and at least the surface of the electrode in the electrolyte solution, the immersion of the workpiece and the electrode can be at any level. As previously described, the workpiece can be mostly or completely immersed, or only the surfaces of the workpiece and the electrode can be immersed.

[0037] The size and shape of the workpiece and electrode used in steps 210 and 220, respectively, are generally not limited.

[0038] The electrode immersed in the electrolyte solution can be any material known to be suitable for use as an electrode and substantially compatible with the workpiece material. In some embodiments, the electrode material provides the necessary complementary chemicals required for the desired electrochemical reaction (i.e., the desired manner of favorably affecting the workpiece surface). In some embodiments, the electrode material is a chemically inert material. In embodiments where the purpose of the process is to deposit material on the workpiece, the electrode can be formed of a material that provides a chemical substance for removal from the electrode. In embodiments where the purpose of the process is to remove material from the workpiece, the electrode can be formed of a material that can receive material thereon.

[0039] The workpiece immersed in the electrolyte solution has a material composition that generally belongs to one of seven different and separate categories, wherein each category of material potentially requires different operating parameters and / or provides different results. The seven material categories are workpieces including the following: (1) pure Ti, Zr, Nb, Hf, Ta or V, or alloys based on Ti, Zr, Nb, Hf, Ta or V; (2) pure Ni, Ni-based alloys, Co-based alloys or titanium aluminide; (3) austenitic stainless steel; (4) martensitic stainless steel; (5) ferritic stainless steel, carbon steel or alloy steel; (6) pure aluminum or aluminum alloys; or (7) pure copper or copper alloys.

[0040] The term alloy as used herein generally refers to a metallic substance as a compound or solution composed of two or more elements. When the term alloy is used together with a metal (e.g., Co-based alloys, Ni-based alloys, etc.), the metal specifically mentioned is the main metal present in the alloy. "Mainly" refers to the highest percentage of metallic elements, and does not need to be greater than 50%. The components of an alloy are usually metals themselves, but carbon (non-metal) can be an essential component of some alloys (e.g., carbon is an essential component in steel). The distinction between alloying elements and impurities is sometimes subtle, because depending on the application, some elements (such as oxygen or silicon) can be considered as impurities or valuable components. The commercially recognized common name and / or (if any) metal's associated unified numbering system ("UNS") number is related to a specific metal or alloy in order to define the specific chemical composition of each metal.

[0041] As used herein, the term "pure" means greater than 99% by weight.

[0042] With respect to the first workpiece material category, the workpiece includes reactive metals including Ti, Zr, Nb, Hf, Ta and V. Therefore, the workpiece can be pure Ti, Zr, Nb, Hf, Ta or V, or can be an alloy of any one of Ti, Zr, Nb, Hf, Ta or V. The Ti-based workpiece can be made of pure titanium or titanium alloys. Titanium alloys include ordinary titanium alloys (e.g., Ti-CP, Ti-64, Ti-10-2-3, Ti-5553, Ti-3Al-2.5V, ATI-425, Ti-Beta-C) and titanium alloys including molybdenum and / or tin (e.g., Ti-6242, Ti-6246). Pure titanium and titanium alloys belong to the UNS R5 category and have designations such as UNS R50400 (Ti-CP2) and UNS R56400 (Ti-6Al-4V). Zr-based workpieces can be made of pure Zr or Zr alloys. Pure zirconium and zirconium alloys belong to the UNS R6 category and have designations such as UNS R60802 (Zicraloy-2) and UNS R60702 (Zr 702 alloy). Nb-based workpieces can be made of pure Nb or Nb alloys. Pure niobium and niobium alloys belong to the UNS R04 category and have designations such as UNSR04210 (Niobium Type 2) and UNS R04261 (Niobium Type 4). Hf-based workpieces can be made of pure Hf or Hf alloys. Pure hafnium and hafnium alloys belong to the UNS R02 category and have the primary designation UNS R02001 (for pure hafnium or hafnium used for alloying additions in other metals). Ta-based workpieces can be made of pure Ta or Ta alloys. Pure tantalum and tantalum alloys belong to the UNS R05 category and have designations such as UNS R05255 (Ta-10W) and UNS R05240 (Ta-40Nb). V-based workpieces can be made of pure V or V alloys. Pure vanadium and vanadium alloys belong to UNS category R08. Currently, commercial grades of vanadium or vanadium alloys have not been assigned specific UNS numbers.

[0043] With respect to the second workpiece material category, the workpiece includes high temperature / high strength metals including pure Ni, Ni-based alloys, Co-based alloys, or titanium aluminide. The Ni-based workpiece may be made of pure Ni or Ni alloys (e.g., alloy 400UNS N04400, alloy 600UNS N06600, alloy 625UNS N06625, alloy 685N07001 ("Waspaloy"), alloy 718UNS N07718, alloy X-750UNS N07750, alloy C-276UNS N10276, alloy C-22UNS N06022, alloy 617UNS N06617, Nitinol, Rene alloys such as Rene 41UNS N07041, alloy 825UNS N08825, Nimonic alloys such as Nimonic 90UNS N07090, and variations of each). As used herein, the term Ni-based alloy should be interpreted as including Ni-based single crystal alloys, including but not limited to RR2000, AM1, CMSX-2 to CSMX-10, PWA1484, TMS 75 and TMS113. Co-based alloys include X-45, FSX-414, Haynes-25 UNS R30605, HaynesUltimet UNS R31233 and Co-6 UNS R30006. As used herein, the term Co-based alloy should be interpreted as including Co-based single crystal alloys. Titanium aluminide (TiAl) is usually gamma titanium and is an intermetallic chemical compound, such as the compound used for low-pressure turbine blade applications-alloy Ti-48Al-2Cr-2Nb.

[0044] With respect to the third workpiece material category, the workpiece is composed of austenitic stainless steel. Austenitic stainless steel includes 303UNSS30300, 304UNS S30400, 316L UNS S31603, Incoloy alloys (such as alloy 20UNS N08020 and A-286UNS S66286), Nitronic alloys (such as Nitronic 40UNS S21900 and Nitronic 60), alloy 218UNS S21800, alumina forming austenite (AFA) grade alloys, X4CrNiMo16-5-1EN 1.4418 and X20CrMoV11-1 EN 1.4922, each of which contains Ni; and 420UNS 42000 and 430UNS 43000, each of which does not contain Ni.

[0045] With respect to the fourth workpiece material category, the workpiece is composed of martensitic stainless steel. Martensitic stainless steel includes 431UNSS43100, 17-4PH UNS S17400, X4CrNiMo16-5-1EN 1.4418 and X20CrMoV11-1 EN 1.4922, each of which contains Ni, and 420UNS S42000, which does not contain Ni.

[0046] With respect to the fifth workpiece material category, the workpiece is composed of ferritic stainless steel, carbon steel or alloy steel. Ferritic stainless steel includes 409UNS S40920, 410UNS S41000, 430UNS S43000, 439UNS S43035, 441UNS S44100, 434UNS S43400 and 436UNS S43600 (each of which contains more than 10.5% Cr). Carbon steel includes low carbon steel (0.05 volume % to 0.25 volume % carbon), medium carbon steel (0.3 volume % to 0.5 volume % carbon) and high carbon steel (0.6 volume % to 1.5 volume % carbon). Carbon steel grades include A36 UNS K02600, 1018 UNS G10180, a1011 and 1020 UNS G1020, 1045 UNS G10450 and A516 UNS K02700, etc. Tool steel is a subcategory of carbon steel and alloy steel (usually including 0.5 volume % to 1.5 volume % carbon) in which carbon steel or alloy steel has high hardness and wear resistance and deformation resistance. Tool steel is divided into five categories: hydraulic tool steel, cold work tool steel, impact resistant tool steel, high speed tool steel and hot work tool steel UNS T00001 to UNS T99999.

[0047] With respect to the sixth workpiece material category, the workpiece is composed of pure aluminum or aluminum alloy UNS A00001 to A99999. Al alloys have two main classifications, namely casting alloys and wrought alloys. Both classifications are further subdivided into heat-treatable and non-heat-treatable. Wrought aluminum is identified with four digits, which identify alloying elements. Casting aluminum alloys use four to five digits with decimal points. In cast aluminum alloys, the hundreds digit represents the alloying element, and the digit after the decimal point represents the form (casting shape or ingot). All series in all product forms are considered to fall into the material category. In wrought alloys, 1XXX (substantially pure), 2XXX (alloyed with copper), 3XXX series (alloyed with manganese), 4XXX series (alloyed with silicon), 5XXX series (alloyed with magnesium), 6XXX series (alloyed with magnesium and silicon), 7XXX series (alloyed with zinc), 8XXX series (alloyed with other elements not covered by other series). Included in the casting alloys are the 1xx.x series (minimum 99% aluminum), 2xx.x series (alloyed with copper), 3xx.x series (alloyed with silicon, copper and / or magnesium), 4x.xx series (alloyed with silicon), 5xx.x series (alloyed with magnesium), 7xx.x series (alloyed with zinc), 8xx.x series (alloyed with tin) and 9xx.s series (alloyed with other elements not covered by other series).

[0048] With respect to the seventh workpiece material category, the workpiece is composed of pure copper or copper alloys. There are up to 400 different copper and copper alloy compositions, which are loosely grouped into the following categories: copper, high copper alloys, brass, bronze, copper-nickel alloys, copper-nickel-zinc (nickel silver), lead copper and special alloys. All groupings and categories are considered to fall within the metal category. Copper alloys and brasses (where zinc is the main alloying element) are represented by UNS numbers X1xxx to C4xxxx and C66400 to C69800. Phosphor bronze (where tin is the main alloying element) is represented by UNS number C5xxxx. Aluminum bronze (where aluminum is the main alloying element) is represented by UNS numbers C60600 to C64200. Silicon bronze (where silicon is the main alloying element) is represented by UNS numbers C64700 to C66100. White copper / nickel silver (where nickel is the main alloying element) is represented by UNS number C7xxxx.

[0049] Regardless of the specific workpiece material, the workpiece may be formed or produced by any method including, but not limited to, wrought metal forming, casting, drawing, extrusion, superplastic forming, diffusion bonding, powder metallurgy, sintered products and co-products thereof, welding, explosive bonding, spinning, and additive manufacturing.

[0050] The electrolyte solution in which the workpiece and the electrode are immersed in steps 210 and 220 generally includes any suitable electrolyte solution having a conductivity greater than 0.011649 microSiemens / cm at 0°C (ASTM D1125-95 1999). In order for Faraday's law of electrolysis to be effective, the electrolyte solution must be able to transport any charge introduced therein. Pure water having a conductivity of 0.011649 microSiemens / cm at 0°C will not support the transport of the introduced charge unless the driving force (voltage) is too large and is therefore able to bridge the gap from one electrode to the other. Therefore, the electrolyte solution used herein must have a greater conductivity than pure water.

[0051] The specific composition of the electrolyte solution is not limited, provided that it meets the aforementioned conductivity requirements. The specific composition of the electrolyte solution can be selected based on, for example, the material composition of the workpiece and / or the electrode. For example, the exact chemistry of the electrolyte can be selected based on the metal ions involved in the electrolysis reaction. The electrolyte solution can be aqueous or non-aqueous.

[0052] Various solutes may be included in the electrolyte composition in order to adjust the conductivity of the electrolyte solution. Elements from alkali metals, alkaline earth metals, transition metals and post-transition metals and their compounds form excellent ionic solutes, as do halogens, metalloids, reactive non-metals and their respective salts, acids, bases and oxides. In addition, organic compounds and their complexes such as alcohols, aldehydes, ketones, carboxylic acids, amines, etc. may play a beneficial role in the electrolyte. Suitable organic compounds may be water soluble or water insoluble. Surfactants may also be used in the electrolyte composition.

[0053] In some embodiments, the electrolyte is free or substantially free of nitrogen and nitrogen-containing compounds, such as, but not limited to, nitrates. By providing an electrolyte solution free or substantially free of nitrogen and nitrogen-containing compounds, the processes described herein can avoid NO X Exhaust gas emissions. Due to the NO X Regulatory, environmental, health and human safety issues associated with exhaust emissions generally make it desirable to avoid NO X Emission of exhaust gas.

[0054] In step 230, a first mode of operation is initiated in which a first type of current is applied across an electrolyte solution between a conductive metal workpiece and an electrode. Generally, the first type of current will be either direct current or alternating current. Either type of current may be used in step 230, provided that step 240 uses a type of current not used in step 230. The method is generally not substantially affected whether alternating current or direct current is used first. As discussed in more detail below, the first type of current applied in step 230 is maintained for a period of time, after which step 240 is performed to terminate the first mode of operation. Terminating the first mode of operation generally includes terminating application of the first type of current so that no current is applied across the electrolyte between the workpiece and the electrode.

[0055] In step 250, a second mode of operation is initiated in which a second type of current is applied across the electrolyte solution between the conductive metal workpiece and the electrode. Generally, the second type of current will be direct current or alternating current, as long as the second type of current is not the same type of current used in the first mode of operation. As discussed in more detail below, the second type of current applied in step 250 is maintained for a period of time, after which step 260 is implemented to terminate the second mode of operation. Terminating the second mode of operation typically includes terminating the application of the second type of current so that no current is applied across the electrolyte between the workpiece and the electrode.

[0056] For simplicity, the following discussion will describe an embodiment in which direct current is applied in a first operating mode and alternating current is applied in a second operating mode. However, as previously described, the systems and methods are not limited to this order, and in other embodiments, the first operating mode may include applying alternating current, and the second operating mode may include applying direct current.

[0057] In non-limiting embodiments where the first type of current applied in step 230 as part of the first operating mode is direct current, the direct current may be applied to the workpiece or electrode with a single polarity, or may be applied at both negative and positive voltages within a single operating mode.

[0058] In a unipolar embodiment, during the application of direct current in a given first operating mode, the applied voltage will not switch between positive and negative. That is, during the first operating mode, the specific voltage applied can change in the positive range or in the negative range. For example, in the same operating mode, direct current can be applied for a period of time at a constant voltage, and direct current can be applied for a period of time at a second constant voltage different from the first constant voltage but with the same polarity. However, in some embodiments, it is preferred that the voltage applied during the first operating mode is constant and has the same value whenever direct current is applied. For example, when the first operating mode is first performed, the applied voltage can remain constant at +48V for the duration of the first operating mode or at any time when direct current is applied during the first operating mode. During the time during the first operating mode, DC power can be interrupted (i.e., the voltage is zero), but if and when DC power is restored during the first operating mode, when direct current is applied again, the same constant voltage previously used in the first operating mode is used.

[0059] In a bipolar embodiment, a first operating mode may employ a first constant voltage, e.g., positive, for a first period of time, and later during the same first operating mode, employ a second constant voltage, e.g., negative, for a second period of time. For example, a first operating mode may apply a constant +24 VDC for the first two seconds of the first operating mode, and then change the voltage to a constant -12 VDC for the second two seconds of the first operating mode.

[0060] In some embodiments, the operating voltage range of the DC power is from about -480 VDC to about +480 VDC (including all values ​​contained therein). In some embodiments, a range from +50 VDC to +240 VDC or from -50 VDC to -240 VDC is used. The applied voltage combined with the physical properties of the workpiece and the electrode and the electrolyte will produce a resulting current or amperage that is readily understood by those of ordinary skill in the art.

[0061] As previously described, during a given first operating mode, the duration of the constant voltage from the DC power supply may be applied continuously or in two or more intermediate segments. When intermediate segments are used, the duration of the segments may be as short as 1 millisecond in duration. The length of the intermediate segments may also be constant or variable, and the intermediate segments may be applied symmetrically or cycled asymmetrically. When direct current is applied continuously during the entire first operating mode, the duration of the entire first operating mode may be as short as 1 millisecond in duration.

[0062] When the first mode of operation is repeated after the second mode of operation is terminated, the subsequent first mode of operation may use the same operating parameters as the previous first mode of operation, or may use one or more different operating parameters. In the example of a subsequent first mode of operation using the same operating parameters as the previous first mode of operation, both the previous first mode of operation and the subsequent first mode of operation may adopt a constant voltage of +48 VDC for the entire duration of the corresponding first mode of operation. In the example of a subsequent first mode of operation using different operating parameters from the previous first mode of operation, the previous first mode of operation may adopt a constant voltage of +24 VDC for the entire duration of the previous first mode of operation, while the subsequent first mode of operation may adopt a constant voltage of +48 VDC, wherein the voltage applied in the two intermediate segments has an interruption between the two segments (i.e., a period of time when the voltage remains zero).

[0063] After the first mode of operation is terminated at step 240, a second mode of operation is initiated at step 250, which in an embodiment employs alternating current. As used herein, "alternating current" is intended to mean that the slope (voltage with respect to time) of an alternating current waveform is always changing. Thus, a step-wise change in voltage that would normally simulate alternating current is not considered to fall within the meaning of alternating current as used herein, as a step-wise waveform would include situations where the slope does not change.

[0064] The waveform shape of the alternating current applied in step 250 is generally not limited, provided that the above provisions regarding the continuously changing slope are met. In some embodiments, the alternating current is applied as a symmetrical sinusoidal waveform with a constant maximum voltage, but other waveform shapes may be used, including but not limited to complex waves, "hump" waves, and other irregular and / or asymmetrical wave shapes.

[0065] Regardless of the waveform shape, the voltage range of the AC varies from about -480VAC to about +480VAC (including all values ​​contained therein). In embodiments where a symmetrical sinusoidal waveform is used, the constant maximum voltage can be from greater than 0VAC to about +480VAC. The AC used does not need to switch polarity. For example, all values ​​in the AC waveform can be above 0VAC or below 0VAC.

[0066] Another parameter of the alternating current that can be controlled is the frequency. In some embodiments, the alternating current has a frequency in the range of about 6 Hz to about 600 MHz. The frequency can be applied symmetrically or asymmetrically.

[0067] During a given second operating mode, the duration of the voltage from the AC power source may be applied continuously or in two or more intermediate segments. When intermediate segments are used, the duration of the segments may be as short as 1 millisecond in duration. The length of the intermediate segments may also be constant or variable, and the intermediate segments may be applied symmetrically or cycled disproportionately. When the alternating current is applied continuously during the entire second operating mode, the duration of the entire second operating mode may be as short as 1 millisecond in duration.

[0068] When the second mode of operation is repeated after the first mode of operation is terminated, the subsequent second mode of operation may use the same operating parameters as the previous second mode of operation, or may use one or more different operating parameters. In the example of a subsequent second mode of operation using the same operating parameters as the previous second mode of operation, both the previous second mode of operation and the subsequent second mode of operation may employ a symmetrical sinusoidal alternating current with a constant maximum value of +48VAC at the same frequency for the entire duration of the corresponding second mode of operation. In the example of a subsequent second mode of operation using different operating parameters from the previous second mode of operation, the previous second mode of operation may employ a symmetrical sinusoidal alternating current with a constant maximum voltage of +48VAC for the entire duration of the previous second mode of operation, while the subsequent second mode of operation may employ a symmetrical sinusoidal alternating current with a constant maximum voltage of +24VAC, wherein the voltage applied in the two intermediate segments has an interruption between the two segments (i.e., a period of time when the voltage remains at zero). The previous second mode of operation and the subsequent second mode of operation may also vary in one or more aspects of waveform shape, amplitude, wavelength, and frequency.

[0069] Although the previous paragraph discusses the change of AC between the previous second operating mode and the subsequent second operating mode, it should be understood that one or more of the AC waveform shape, amplitude, wavelength and frequency can be changed within the second operating mode. For example, the second operating mode can adopt a symmetrical sinusoidal waveform during the first part of the second operating mode, but the amplitude of the sinusoidal waveform can increase or decrease midway through the second operating mode.

[0070] In one particular embodiment, an initial first operating mode employs a constant direct current at a first voltage for the duration of the initial first operating mode, and each subsequent first operating mode employs a constant direct current at a voltage that increases with each additional first operating mode. For example, the initial first operating mode employs a constant voltage of +3VDC, the next first operating mode employs a constant voltage of +6VDC, the next first operating mode employs a constant voltage of +9VDC, and so on. Consistent with the increasing DC voltage during the first operating modes, corresponding second operating modes between the first operating modes and employing alternating current can use a symmetrical sinusoidal waveform with a gradually increasing maximum voltage. For example, an initial second operating mode following the initial first operating mode can employ alternating current using a symmetrical sinusoidal waveform with a maximum voltage of +3VAC, the next second operating mode employs a maximum voltage of +6VAC, the next second operating mode employs a maximum voltage of +9VAC, and so on.

[0071] Reference now Figure 3A and Figure 3B , which illustrate various operational schemes that may be used with the methods and systems described herein. Figure 3A An operation scheme is shown, wherein an initial first operation mode and all subsequent first operation modes use the same operation parameters, and an initial second operation mode and all subsequent second operation modes use the same operation parameters. More specifically, the initial first operation mode 301 and the subsequent first operation modes 301' and 301" all apply direct current at the same constant voltage for the duration of each first operation mode, wherein each first operation mode has the same time period, and the initial second operation mode 302 and the subsequent second operation modes 302' and 302" all apply alternating current using a symmetrical sinusoidal waveform having the same maximum voltage, frequency and wavelength, and each second operation mode is executed for the same time period.

[0072] Figure 3BAnother embodiment of an operating scheme that can be used is shown, wherein the constant voltage of the direct current applied in each first operating mode increases with each subsequent first operating mode, and the maximum voltage of the symmetrical sinusoidal waveform used when applying alternating current in the second operating mode increases with each subsequent second operating mode. More specifically, the initial first operating mode 311 applies direct current at a first voltage, and the first subsequent first operating mode 311' (and all subsequent first operating modes thereafter) applies direct current at a second voltage equal to, greater than, or less than the first voltage. The time period of each first operating mode is the same, and direct current is applied for the duration of each first operating mode. At the same time, the initial second operating mode 312 applies alternating current using a symmetrical sinusoidal waveform with a first maximum voltage, and the first subsequent second operating mode 312' (and all subsequent second operating modes thereafter) applies alternating current using a symmetrical sinusoidal waveform with a second maximum voltage equal to, greater than, or less than the first maximum voltage. All other operating parameters of the second operating mode (e.g., duration, frequency, wavelength, etc. of the second operating mode) are the same.

[0073] As previously mentioned, the methods and systems described herein can be used to beneficially affect the surface of a conductive metal workpiece. The term "affect" as used herein is intended to be broad, as the methods described herein may require depositing material on or removing material from a workpiece. Measurement of such improvements can be made via a surface profiler. In some embodiments, a reduction in surface finish measurement from 1 Ra to 500 Ra is achieved. Figure 4 A table is provided that relates Ra values ​​to industry-determined grit values ​​(those used to classify sandpaper). With respect to beneficially affecting the surface of a workpiece via removal of material from the surface of the workpiece, it should be understood that removal of material from the surface of the workpiece includes, but is not limited to, performing electrochemical pickling (or its functional equivalent) and chemical milling (or its functional equivalent) using the systems and methods described herein. When electrochemical pickling and chemical milling (or its functional equivalent) are performed using embodiments of the systems and methods described herein, improved measurement of the workpiece surface can be achieved via thickness or gauge measurement using a tool such as a micrometer or ultrasonic thickness gauge. In some embodiments, a precise reduction in gauge from 0.0005" to 0.5000" or greater is achieved.

[0074] In some embodiments, the beneficial effect on surface morphology produced by the systems and methods described herein is to produce a localized change in surface morphology. The specific type of localized change in surface morphology is generally not limited and can include any type of difference in surface morphology from the remainder of the workpiece. Exemplary but non-limiting localized changes in surface morphology that can be produced by the systems and methods described herein include the presence of crystals in a limited area on the workpiece, and the production of a localized mark that can be identified by a color change (e.g., a black line formed on a specific portion of the workpiece).

[0075] Local changes in surface morphology, such as those described above, can be beneficial because they generally indicate the presence of an anomaly in the workpiece near the local change. The specific anomaly associated with local changes in surface morphology is generally not limited, and can include, for example, changes in surface chemistry, or the presence of subsurface defects, such as subsurface voids. Identifying these local changes on the workpiece, which can be viewed as "marks," can provide opportunities for subsequent remedial or beneficial processing (e.g., mechanical polishing) of the workpiece. Therefore, the system 100 described herein can be expanded to include one or more devices capable of identifying these local changes in surface morphology, thereby identifying opportunities for further workpiece processing. Any device suitable for identifying local changes can be used, such as an optical scanner.

[0076] In addition, it should be understood that the beneficial effects obtained by the methods and systems described herein may not include changes in surface morphology. For example, the beneficial effects obtained may involve changes in the surface chemistry of the workpiece. For example, when foreign iron on the surface is removed, stainless steel is passivated and a barrier layer of metal oxide is enhanced on the surface of the metal material. In this case, no measurable improvement in surface finish is achieved, but the change in surface chemistry still provides benefits to the workpiece. Therefore, beneficially affecting the workpiece via a change in surface chemistry may include, for example, removing metallic material, adding oxygen (e.g., via the formation of an oxide layer), removing hydrogen, preventing or inhibiting the attachment of hydrogen, or any combination thereof.

[0077] In some embodiments, the beneficial effect on the surface of the conductive metal workpiece produced by the systems and methods described herein is the charging of hydrogen to at least the surface of the metal workpiece. In this way, the metal workpiece can be used to store hydrogen, which can be beneficial for applications in which hydrogen is used as an energy source. When hydrogen is charged to the metal workpiece using the methods and systems described herein, the surface and internal portions of the workpiece can be filled with hydrogen. For example, hydrogen can be stored on the surface of the workpiece and along the grain boundaries located within the metal workpiece.

[0078] Although Figure 1Other process parameters are not shown, but can be adjusted and / or manipulated as part of the system 100 to improve the performance of the method described herein. In one example, the thermal activity of the electrolyte can be an important component of the molecular activity, and can therefore be controlled to affect the ability of the electrolyte to transport charge. In some embodiments, the electrolyte solution used in the system 100 described herein operates within an operating range of about 10°C to about 100°C. In some embodiments, the process described herein is implemented at a controlled processing temperature, but the temperature can be controlled (increased to above room temperature) as a means for accelerating the desired electrochemical reaction. Adding heat to the system 100 to accelerate the electrochemical reaction can be provided by the previously described heating device 170. In other embodiments, the process described herein is implemented while the temperature can be controlled at a reduced processing temperature as a means of reducing the desired electrochemical reaction provided by the previously specified cooling device 170. Precise control of the heating device 170 thereby achieves precise control of the electrochemical reaction and surface treatment. This precise control of the treatment temperature and corresponding precise control of the electrochemical reaction thereby allows the system and process to operate without the need for limited loads, expensive chillers and / or hold times typically required by other surface treatment processes (such as pickling), for example.

[0079] In addition, other externally applied physical forces can be advantageous for the overall performance of the systems and methods described herein. As previously mentioned, the mixing rate of the electrolyte can have a significant impact on the thin barrier layer adjacent to the electrode. Therefore, in some embodiments of the system 100 described herein, additional steps are taken to mix the electrolyte during the above process. Mixing can be implemented by any suitable means, including via physical mixing or thermal mixing. Pumps, mixers, ejectors, equipment configured to move workpieces and / or electrodes, specific fluid delivery methods, etc. combined with heat transfer mechanisms and exothermic and endothermic chemical reactions can produce their respective beneficial effects on the results of the electrolytic reaction.

[0080] In some embodiments, one or more of any of the various operating parameters previously discussed with respect to the operation of the system 100 may be controlled, adjusted, and / or manipulated in order to control the barrier layer formed on the workpiece and / or electrode. The operating parameters of the system 100 that may be controlled for the purpose of controlling the barrier layer may be related to chemical, mechanical, electrical, magnetic, and / or molecular excitation operating parameters. Control of the barrier layer may be related to, for example, controlling the thickness of the barrier layer, controlling the chemical composition of the barrier layer, and / or any other aspect of the barrier layer. Controlling the operating parameters of the system 100 in order to control the barrier layer beneficially enables control of the availability or lack of availability of dissociated ion species obtained from the electrolyte components. This in turn enables precise control of the chemical reactions involved in the electrochemical processes described herein, and therefore enables precise control of the manner in which the workpiece surface is beneficially affected. This is in stark contrast to other previously known methods for modifying the surface of a workpiece, such as pickling, which is notoriously difficult to control because, for example, as part of the pickling process, an exothermic reaction occurs, and the exothermic reaction causes the reaction to proceed at an increasingly faster and uncontrolled rate.

[0081] In some embodiments, the system 100 also includes one or more pieces of equipment that are configured to automatically monitor, analyze, and / or adjust one or more operating parameters that can be used to control the barrier layer, which in turn allows the equipment to control the manner in which the workpiece is beneficially affected. The equipment can be programmed with computer-implemented instructions to achieve automatic control of the systems and processes described herein to obtain the desired results for the workpiece. That is, when the operating parameters are automatically monitored, analyzed, and adjusted by the additional equipment to obtain the desired results for the workpiece, no human intervention may be required. Such equipment can generally operate based on the known relationship between various operating parameters and their associated effects on the barrier layer, and further helps to provide a highly repeatable process, thereby achieving the same or nearly the same results for each individual workpiece processed using the technology described herein.

[0082] Given the precise control of the operation of the system 100 and the various ways of precisely implementing the methods 200 described herein, the techniques described herein are highly repeatable. A single set of precise operating parameters can be used to repeatedly and reliably obtain the same or nearly the same results for the same workpiece, electrode, and / or electrolyte combination.

[0083] Among the benefits provided by the systems and methods described herein is the ability to closely control surface effects in extreme cases of material types. For example, aluminum is generally considered a metal material that is very susceptible to corrosion, thus making it difficult to closely control material removal (e.g., removing very small amounts of material). However, using the systems and methods described herein, it is possible to gently polish aluminum. Similarly, niobium is generally considered a metal material that is very difficult to corrode, thus making it difficult to remove relatively large portions of material. However, using the systems and methods described herein, niobium can be removed vigorously.

[0084] Experimental Results

[0085] In some of the experiments described below, reference is made to a colorimetric chart documented by the Massachusetts Institute of Technology (MIT). The colorimetric chart presents interference colors exhibited by active metals with a relatively thin surface oxide layer formed thereon according to the dissociation voltage. When the surface oxide layer is relatively thin (30 / 50nm), they interfere with light, thereby producing the perception of color by the human eye. These interference colors are related to the oxide thickness. The process is usually carried out via DC electrolysis, which is produced when the metal is anode-charged in a conductive electrolyte. When water is decomposed, nascent oxygen is bonded to the anode metal electrode. These oxides have high resistance to electric current, resulting in the need to increase the potential of the circuit to grow the thickness of the oxide.

[0086] Workpiece Material Category 1 - Reactive Metals

[0087] Experiment 1

[0088] The niobium specimens were acted upon by a dual-mode A / C and D / C power supply configured according to the embodiments described herein in an aqueous electrolyte at 66°C consisting of citric acid (15 g / L) and ammonium bifluoride (8 g / L). The operating scheme of the experiment provided 24 volts (maximum voltage using a symmetrical sinusoidal waveform) 60 Hz AC for 15 seconds, followed by 24 volts DC for 15 seconds, and repeated these two operating modes 5 times for a total operating time of 2.5 minutes. At the completion of the cycle, the material achieved a gauge reduction of 0.074 inches / minute and a modest improvement in surface finish of 5%.

[0089] Experiment 2

[0090] A nuclear grade zirconium alloy Zr-2.5Nb (UNS R60901) sample was acted on by a dual-mode A / C and D / C power supply configured according to the embodiments described herein in a 66°C aqueous electrolyte composed of citric acid (30 g / L) and ammonium bifluoride (10 g / L). The operating scheme of the experiment provided 24 volts (maximum voltage using a symmetrical sine waveform) 60 Hz AC for 15 seconds, followed by 24 volts DC for 15 seconds, and repeated these two operating modes 5 times, with a total operating time of 2.5 minutes. At the completion of the cycle, the material achieved a gauge reduction of 0.056 inches / minute and a reduction in surface finish of 24%.

[0091] Experiment 3

[0092] Commercially pure titanium (Ti-CP, UNS R50400) samples were acted on by a bimodal A / C and D / C power supply configured according to the embodiments described herein in a 40°C aqueous electrolyte consisting of 150 g / l magnesium chloride. The experimental operating scheme provided 3 volts (maximum voltage using a symmetrical sinusoidal waveform) 6 Hz AC for 15 seconds, followed by 3 volts DC for 15 seconds, and repeated these two operating modes 5 times, increasing the voltage in the AC mode and DC mode by 3 volts for the second pairing, and increasing 6 volts for each of the third, fourth and fifth pairings until 24 volts were reached in both the AC mode and the DC mode in the final pairing. The total operating time was 2.5 minutes. This resulted in oxide growth equivalent to the thickness demonstrated by the MIT chart of the conventional 50 VDC process. OSHA regulations require protection of exposed electrical equipment under voltages of 50 volts or less (whether generated by AC or DC methods) in 29 CFR 1910.303 (g) (2) (i). Providing routine results at lower operating voltages provides substantial operating benefits to workers exposed to the operating conditions.

[0093] Experiment 4

[0094] In a 50°C aqueous electrolyte consisting of 50 g / L sodium bisulfate, 150 g / L magnesium chloride, aerospace grade titanium (Ti-6Al-4V, UNS R56400) samples were acted on by a dual-mode A / C and D / C power supply configured according to the embodiments described herein. The experimental operating scheme provided 3 volts (maximum voltage using a symmetrical sine waveform) 6 Hz AC for 15 seconds, followed by 3 volts DC for 15 seconds, and repeated these two operating modes 5 times, increasing the voltage in the AC mode and DC mode by 3 volts for the second pairing, and increasing by 6 volts for each of the third, fourth and fifth pairings until 24 volts were reached in both the AC mode and the DC mode in the final pairing. The total operating time was 2.5 minutes. This resulted in oxide growth equivalent to the thickness demonstrated by the MIT chart of the conventional 115 VDC process, thereby reducing the operating voltage by nearly 5 times.

[0095] Experiment 5

[0096] In a 45°C aqueous electrolyte consisting of 30 g / L citric acid, 10 g / L ammonium bifluoride, a specimen of aerospace grade titanium (Ti-6Al-4V, UNSR56400) covered with scale was acted upon by a bimodal A / C and D / C power supply configured according to the embodiments described herein. The experimental operating scheme provided 24 volts (maximum voltage using a symmetrical sinusoidal waveform) 5 Hz AC for 15 seconds, followed by 24 volts DC for 15 seconds, and repeated these two operating modes 360 times for a total operating time of 180 minutes. Titanium scale is a heavy oxide that exhibits ceramic-like hardness and corrosion resistance properties. Conventional processing requires abrasive blasting or other mechanical tools to break the oxide so that hydrofluoric acid can penetrate the oxide and undercut the chemically inert material to remove it from the metal surface or remove it completely. In the case where the scale is not affected before processing, irregular removal of the scale occurs, so that once completely removed, the underlying material undergoes selective and inconsistent removal, resulting in a rough and often pitted surface. The specimens in this test were not subjected to any pretreatment whatsoever. The material with the oxide scale was directly subjected to the electrochemical operation and at the end of the cycle it was free of oxides and the material was intact. A homogeneous and smooth surface. It is very important that the results were achieved only by electrochemical methods.

[0097] exist Figure 5A and Figure 5B Additional data related to the above experiments and additional experiments conducted on reactive metals are listed in the table presented in .

[0098] Workpiece material category 2 - high temperature / high strength metal

[0099] Experiment 6

[0100] A Nitinol nickel-titanium alloy (Ni-45Ti, UNS N01555) sample was acted on by a bimodal A / C and D / C power supply configured according to the embodiments described herein in a 66°C aqueous electrolyte consisting of citric acid (30 g / L) and ammonium bifluoride (10 g / L). The operating scheme of the experiment provided 24 volts (maximum voltage using a symmetrical sinusoidal waveform) 60 Hz AC for 15 seconds, followed by 24 volts DC for 15 seconds, and repeated these two operating modes 5 times for a total operating time of 2.5 minutes. At the completion of the cycle, the material achieved a 12% improvement in surface finish while experiencing a gauge reduction of 0.037 inches / hour.

[0101] Experiment 7

[0102] Heat treated specimens of austenitic alloy C22 (UNS N06022, Ni-22Cr-13Mo-3Fe-3W) were acted upon by a bimodal A / C and D / C power supply configured according to the embodiments described herein in a 40°C aqueous electrolyte consisting of 50 ml / L fluoroboric acid (50 wt%). The operating scheme of the experiment provided 3 volts (maximum voltage using a symmetrical sinusoidal waveform) 6 Hz AC for 15 seconds, followed by 3 volts DC for 15 seconds, and repeating these two operating modes 5 times, increasing the voltage in both AC and DC modes by 3 volts for the second pairing, and by 6 volts for each of the third, fourth, and fifth pairings, until 24 volts were reached in both AC and DC modes in the final pairing. The total operating time was 2.5 minutes. At the completion of the cycle, the material was oxide-free and smooth, experiencing a 13% reduction in surface finish, while experiencing a 0.019 inch / hour gauge reduction.

[0103] Experiment 8

[0104] Heat treated specimens of nickel alloy Nimonic Alloy 90 (UNS N07090, Ni-20Cr-16Co-3Ti-2Al) were acted upon by a bimodal A / C and D / C power supply configured according to the embodiments described herein in a 40°C aqueous electrolyte consisting of 50 ml / L fluoroboric acid (50 wt%). The experimental operating scheme provided 3 volts (maximum voltage using a symmetrical sinusoidal waveform) 6 Hz AC for 15 seconds, followed by 3 volts DC for 15 seconds, and repeated these two operating modes 5 times, increasing the voltages of the AC mode and DC mode by 3 volts for the second pairing, and by 6 volts for each of the third, fourth, and fifth pairings, until 24 volts were reached in both the AC mode and the DC mode in the final pairing. The total operating time was 2.5 minutes. At the completion of the cycle, the material was smooth, experienced a 19% reduction in surface finish, and experienced a 0.019 inch / hour gauge reduction.

[0105] exist FIG. 6A to FIG. 6E Additional data related to the above experiments and additional experiments conducted on high temperature / high strength alloys are listed in the table presented in.

[0106] Workpiece material category 3 - Austenitic stainless steel

[0107] Experiment 9

[0108] Heat treated specimens of an austenitic creep resistant steel alloy X20CrMoC11-1 (DIN 1.4922, Fe-11Cr-1Mo-1Ni-1Mn) were acted upon by a bimodal A / C and D / C power supply configured according to the embodiments described herein in a 40°C aqueous electrolyte consisting of sodium bisulfate (50 g / L) and magnesium chloride (150 g / L). The operating scheme of the experiment provided 3 volts (maximum voltage using a symmetrical sinusoidal waveform) 60 Hz AC for 15 seconds, followed by 3 volts DC for 15 seconds, and repeating these two operating modes 5 times, increasing the voltage in both AC and DC modes by 3 volts for the second pairing, and by 6 volts for each of the third, fourth, and fifth pairings, until 24 volts were reached in both AC and DC modes in the final pairing. The total operating time was 2.5 minutes. At the completion of the cycle, the material experienced a 2% reduction in surface finish, while experiencing a gauge reduction of 0.034 inches / hour.

[0109] Experiment 10

[0110] A heat treated sample of austenitic stainless steel alloy Nitronic 50 (XM-19, UNS S20910, Fe-21Cr-13Ni-5Mn-3Mo-0.3N-0.2Nb) was acted on by a dual-mode A / C and D / C power supply configured according to the embodiments described herein in a 40°C aqueous electrolyte consisting of 50 ml / L fluoroboric acid (50 wt%). The experimental operating scheme provided 3 volts (maximum voltage using a symmetrical sine waveform) 600 Hz AC for 15 seconds, followed by 3 volts DC for 15 seconds, and repeated these two operating modes 5 times, increasing the voltage of the AC mode and DC mode by 3 volts for the second pairing, and increasing 6 volts for each of the third, fourth and fifth pairings, until 24 volts were reached in both the AC mode and the DC mode in the final pairing. The total operating time was 2.5 minutes. At the completion of the cycle, the material was free of heat treat oxides, bright and smooth, experienced a 23% reduction in surface finish, and a minimal gauge reduction of 0.0024 in / hr.

[0111] Experiment 11

[0112] Heat treated specimens of austenitic stainless steel alloy 316L (UNS S31603, Fe-18Cr-15Ni-3Mo-2Mn) were acted upon by a bimodal A / C and D / C power supply configured according to the embodiments described herein in a 40°C aqueous electrolyte consisting of 50 ml / L fluoroboric acid (50 wt%). The operating scheme of the experiment provided 3 volts (maximum voltage using a symmetrical sinusoidal waveform) 60 Hz AC for 15 seconds, followed by 3 volts DC for 15 seconds, and repeating these two operating modes 5 times, increasing the voltage in both AC and DC modes by 3 volts for the second pairing, and by 6 volts for each of the third, fourth, and fifth pairings, until 24 volts were reached in both AC and DC modes in the final pairing. The total operating time was 2.5 minutes. At the completion of the cycle, the material was free of heat treated oxides, bright and smooth, experienced a 26% reduction in surface finish, and a very small gauge reduction of 0.0048 inches / hour.

[0113] Experiment 12

[0114] Heat treated specimens of boron alloyed austenitic 304 stainless steel (UNS S30463, Fe-19Cr-13Ni-2B) were acted upon by a bimodal A / C and D / C power supply configured according to the embodiments described herein in a 40°C aqueous electrolyte consisting of 50 ml / L fluoroboric acid (50 wt%). The operating scheme of the experiment provided 3 volts (maximum voltage using a symmetrical sinusoidal waveform) 60 Hz AC for 15 seconds, followed by 3 volts DC for 15 seconds, and repeating these two operating modes 5 times, increasing the voltage in both AC and DC modes by 3 volts for the second pairing, and by 6 volts for each of the third, fourth, and fifth pairings, until 24 volts were reached in both AC and DC modes in the final pairing. The total operating time was 2.5 minutes. At the completion of the cycle, the material was free of heat treated oxides, bright and smooth, experienced a 5% reduction in surface finish, and a minimal gauge reduction of 0.0144 inches / hour.

[0115] Experiment 13

[0116] Heat treated samples of austenitic 303 stainless steel (UNS S30300, Fe-18Cr-9Ni-1.8Mn-0.25S) were acted on by a bimodal A / C and D / C power supply configured according to the embodiments described herein in a 40°C aqueous electrolyte consisting of sodium bisulfate (50 g / L) and magnesium chloride (150 g / L). The operating scheme of the experiment provided 3 volts (maximum voltage using a symmetrical sine waveform) 60 Hz AC for 15 seconds, followed by 3 volts DC for 15 seconds, and repeated these two operating modes 5 times, increasing the voltage of the AC mode and DC mode by 3 volts for the second pairing, and increasing by 6 volts for each of the third, fourth and fifth pairings until 24 volts were reached in both the AC mode and the DC mode in the final pairing. The total operating time was 2.5 minutes. At the completion of the cycle, the material achieved a moderate gauge reduction of 0.043 inches / hour.

[0117] exist 7A to 7F The table presented in lists additional data related to the above experiments as well as additional experiments conducted on austenitic stainless steel.

[0118] Workpiece material category 4- Martensitic stainless steel

[0119] Experiment 14

[0120] A sample of 440C martensitic stainless steel (UNS S44004, Fe-17Cr-0.75Mo-0.5Mn-0.5Ni-0.5Si) was acted on by a dual-mode A / C and D / C power supply configured according to the embodiments described herein in a 50°C aqueous electrolyte consisting of 67 volume % phosphoric acid (85 weight %), 33 volume % sulfuric acid (50 weight %), 5 weight % H2O, and 0.1 ml / L of lauraldehyde. The operating scheme of the experiment provided 3 volts (maximum voltage using a symmetrical sinusoidal waveform) 600 Hz AC for 15 seconds, followed by 3 volts DC for 15 seconds, and repeated these two operating modes 5 times, increasing the voltage of the AC mode and DC mode by 3 volts for the second pairing, and increasing by 6 volts for each of the third, fourth, and fifth pairings, until 24 volts were reached in both the AC mode and the DC mode in the final pairing. The total operating time was 2.5 minutes. The material experienced a negligible change in surface finish of 3μ” while experiencing a very small gauge reduction of 0.008” / hr.

[0121] exist Figure 8 The table presented in lists additional data related to the above experiments as well as additional experiments conducted on martensitic stainless steel.

[0122] Workpiece material category 5 - Ferritic stainless steel, carbon steel or alloy steel

[0123] Experiment 15

[0124] A sample of 430 ferritic stainless steel (UNS S43000, Fe-17Cr-0.7Mn-0.60Si) was acted upon by a bimodal A / C and D / C power supply configured according to the embodiments described herein in an aqueous electrolyte at 21°C consisting of 5.0 wt% sodium hydroxide and 2.4 wt% ammonium hydroxide. The operating scheme of the experiment provided 50 volts (maximum voltage using a symmetrical sinusoidal waveform) 60 Hz AC for 15 seconds, followed by 26 volts DC for 15 seconds, and both operating modes were repeated 5 times for a total operating time of 2.5 minutes. The material experienced a gauge reduction of 0.045 inches / hour and became slightly rougher, as indicated by a 17% increase in surface finish.

[0125] Experiment 16

[0126] A sample of 430 ferritic stainless steel (UNS S43000, Fe-17Cr-0.7Mn-0.60Si) was acted on by a bimodal A / C and D / C power supply configured according to the embodiments described herein in an aqueous electrolyte of 53 wt % sulfuric acid, 28 wt % trisodium phosphate, 18 wt % water, and 1 wt % barium sulfate, and 0.1 ml / L of 2-butoxyethanol / propylene glycol at 32°C. The operating scheme of the experiment provided 5 volts (maximum voltage using a symmetrical sinusoidal waveform) 60 Hz AC for 15 seconds, followed by 10 volts DC for 15 seconds, and both operating modes were repeated 5 times for a total operating time of 2.5 minutes. The material exhibited a rapid gauge reduction of 0.295 inches / hour, and an increase in surface finish of 2μ" Ra.

[0127] Experiment 17

[0128] Heat treated specimens of low carbon steel alloy 15CDV6 (DIN 1.7734, Fe-1.4Cr-0.9Mo-0.2V-6Al-2Sn) were acted upon by a bimodal A / C and D / C power supply configured according to the embodiments described herein in a 40°C aqueous electrolyte consisting of 50 ml / L fluoroboric acid (50 wt%). The operating scheme of the experiment provided 3 volts (maximum voltage using a symmetrical sinusoidal waveform) 600 Hz AC for 15 seconds, followed by 3 volts DC for 15 seconds, and repeating these two operating modes 5 times, increasing the voltage in both AC and DC modes by 3 volts for the second pairing, and by 6 volts for each of the third, fourth and fifth pairings, until 24 volts were reached in both AC and DC modes in the final pairing. The total operating time was 2.5 minutes. At the completion of the cycle, the material was bright and smooth, having experienced a 26% reduction in surface finish, while experiencing a 0.024 inch / hour gauge reduction.

[0129] Experiment 18

[0130] Heat treated alloy steel specimens of AISIM2 molybdenum high speed tool steel (UNS T11302, Fe-6W-5Mo-2V-1C-0.4Cr-0.3Ni) were acted on by a dual-mode A / C and D / C power supply configured according to the embodiments described herein in a 40°C aqueous electrolyte consisting of 50 ml / L fluoroboric acid (50 wt%). The experimental operating scheme provided 3 volts (maximum voltage using a symmetrical sine waveform) 6 Hz AC for 15 seconds, followed by 3 volts DC for 15 seconds, and repeated these two operating modes 5 times, increasing the voltage of the AC mode and DC mode by 3 volts for the second pairing, and increasing by 6 volts for each of the third, fourth and fifth pairings until 24 volts were reached in both the AC mode and the DC mode in the final pairing. The total operating time was 2.5 minutes. At the completion of the cycle, the material was free of heat treatment oxides, bright and smooth, experienced a 13% reduction in surface finish, and experienced a 0.060 inch / hour gauge reduction.

[0131] Experiment 19

[0132] Heat treated alloy steel specimens of AISIM2 molybdenum high speed tool steel (UNS T11302, Fe-6W-5Mo-2V-1C-0.4Cr-0.3Ni) were acted on by a dual-mode A / C and D / C power supply configured according to the embodiments described herein in a 40°C aqueous electrolyte consisting of sodium bisulfate (50 g / L) and magnesium chloride (150 g / L). The experimental operating scheme provided 3 volts (maximum voltage using a symmetrical sine waveform) 6 Hz AC for 15 seconds, followed by 3 volts DC for 15 seconds, and repeated these two operating modes 5 times, increasing the voltage of the AC mode and DC mode by 3 volts for the second pairing, and increasing by 6 volts for each of the third, fourth and fifth pairings until 24 volts were reached in both the AC mode and the DC mode in the final pairing. The total operating time was 2.5 minutes. At the completion of the cycle, the material was free of heat treatment oxides, experienced a 25% reduction in surface finish, and experienced a 0.007 inch / hour gauge reduction.

[0133] Experiment 20

[0134] A sample of 1020 carbon steel (UNS G10200, Fe-0.2C-0.5Mn) was acted on by a bimodal A / C and D / C power supply configured according to the embodiments described herein in an 82°C aqueous electrolyte consisting of 53 wt% sulfuric acid, 28 wt% trisodium phosphate, 18 wt% water, and 1 wt% barium sulfate, and 0.1 ml / L of 2-butoxyethanol / propylene glycol. The operating scheme of the experiment provided 2 volts (maximum voltage using a symmetrical sinusoidal waveform) 60 Hz AC for 15 seconds, followed by 1.2 volts DC for 15 seconds, and repeated these two operating modes 5 times for a total operating time of 2.5 minutes. At the completion of the cycle, the material experienced a rapid material removal of 0.342 inches / hour and was polished while experiencing a 28% reduction in surface finish.

[0135] exist 9A to 9D The table presented in lists additional data related to the above experiments as well as additional experiments conducted on ferritic metals.

[0136] Workpiece material category 6 - Aluminum and aluminum alloys

[0137] Experiment 21

[0138] A specimen of precipitation hardened aluminum alloy 6061 (UNS A96061, Al-1Mn-0.6Si-0.28Cu-0.2Cr) was acted upon by a bimodal A / C and D / C power supply configured according to the embodiments described herein in an aqueous electrolyte of 53 wt % sulfuric acid, 28 wt % trisodium phosphate, 18 wt % water, and 1 wt % barium sulfate, and 0.1 ml / L 2-butoxyethanol / propylene glycol at 36°C. The operating scheme of the experiment provided 10 volts (maximum voltage using a symmetrical sinusoidal waveform) 60 Hz AC for 15 seconds, followed by 12 volts DC for 15 seconds, and both operating modes were repeated 5 times for a total operating time of 2.5 minutes. At the completion of the cycle, the material exhibited a bright reflective surface with a corresponding reduction in surface finish of 25%, and a gauge loss of 0.187 inches / hour. This polished surface is desirable for many applications and is conventionally performed with perchloric acid (a potentially explosive chemical if allowed to crystallize in ventilation systems or its industrial logistics from a lack of solution.) It is believed that the bimodal power source acts on and refreshes the bainite layer adjacent to the workpiece to favorably affect the surface of the material.

[0139] Experiment 22

[0140] A sample of non-heat-treatable aluminum alloy 5052 (UNSA95052, Al-2.5Mn-0.25Cr) was acted upon by a bimodal A / C and D / C power supply configured according to the embodiments described herein in an aqueous electrolyte at 24°C consisting of 5.0 wt% sodium hydroxide and 2.4 wt% ammonium hydroxide. The operating scheme of the experiment provided 50 volts (maximum voltage using a symmetrical sinusoidal waveform) 60 Hz AC for 15 seconds, followed by 26 volts DC for 15 seconds, and repeated these two operating modes 5 times for a total operating time of 2.5 minutes. Throughout the cycle, the DC amperage decreased over time as the resistive aluminum oxide grew, while the amperage generated by the AC power supply increased. At the completion of the cycle, the material exhibited a substantial increase in aluminum oxide film thickness equal to 0.141 inches / hour and a corresponding increase in surface finish of 109%. It is believed that the bimodal power supply allows for rapid growth of film thickness by DC, while the AC reactivates or "peels off" the resistive layer of the film in the electrolyte, thereby refreshing the system to achieve additional growth.

[0141] exist Fig.10 Additional data related to the above experiments and additional experiments conducted on aluminum are listed in the table presented in .

[0142] Workpiece material category 7 - Copper and copper alloys

[0143] Experiment 23

[0144] A sample of AMS 4535 beryllium copper (UNS C17200, Cu-1.9Be-0.2Co) was acted on by a dual-mode A / C and D / C power supply configured according to the embodiments described herein in an aqueous electrolyte of 53 wt % sulfuric acid, 28 wt % trisodium phosphate, 18 wt % water and 1 wt % barium sulfate and 0.1 ml / L of 2-butoxyethanol / propylene glycol at 24°C. The operating scheme of the experiment provided 5 volts (maximum voltage using a symmetrical sinusoidal waveform) 60 Hz AC for 15 seconds, followed by 8.5 volts DC for 15 seconds, and both operating modes were repeated 5 times for a total operating time of 2.5 minutes. At the completion of the cycle, the material achieved a substantial removal rate of 0.283 inches / hour, which is very important because the alloy is utilized for its corrosion resistance, especially in downhole applications where resistance to sulfide compounds is critical.

[0145] Experiment 24

[0146] A sample of AMS 4535 beryllium copper (UNS C17200, Cu-1.9Be-0.2Co) was acted upon by a bimodal A / C and D / C power supply configured according to the embodiments described herein in an aqueous electrolyte at 21°C consisting of 5.0 wt. % sodium hydroxide and 2.4 wt. % ammonium hydroxide. The operating scheme of the experiment provided 50 volts (maximum voltage using a symmetrical sinusoidal waveform) 60 Hz AC for 15 seconds, followed by 26 volts DC for 15 seconds, and both operating modes were repeated 5 times for a total operating time of 2.5 minutes. At the completion of the cycle, the material achieved a substantial removal rate of 0.084 inches / hour, which is very important because the alloy is utilized for its corrosion resistance, especially in downhole applications where resistance to sulfide compounds is critical.

[0147] Experiment 25

[0148] A sample of 360 free-cutting brass (UNS C36000, Cu-35.5Zn-3Pb-0.35Fe) was acted upon by a bimodal A / C and D / C power supply configured according to the embodiments described herein in an 18°C ​​aqueous electrolyte consisting of 5.0 wt. % sodium hydroxide and 2.4 wt. % ammonium hydroxide. The operating scheme of the experiment provided 60 volts (maximum voltage using a symmetrical sinusoidal waveform) 60 Hz AC for 15 seconds, followed by 60 volts DC for 15 seconds, and both operating modes were repeated 5 times for a total operating time of 2.5 minutes. At the completion of the cycle, the material had developed a uniform black appearance due to the subdivided surface capturing light and preventing its reflection, giving the perception of a black coating, regardless of the variation in the measured 2μ" Ra surface finish.

[0149] Experiment 26

[0150] A specimen of bearing bronze (UNS C93200, Cu-10Pb-10Sn) was acted upon by a bimodal A / C and D / C power supply configured according to the embodiments described herein in an aqueous electrolyte at 28°C consisting of 53 wt% sulfuric acid, 28 wt% trisodium phosphate, 18 wt% water, and 1 wt% barium sulfate, and 0.1 ml / L of 2-butoxyethanol / propylene glycol. The operating scheme of the experiment provided 50 volts (maximum voltage using a symmetrical sinusoidal waveform) 60 Hz AC for 15 seconds, followed by 26 volts DC for 15 seconds, and both operating modes were repeated 5 times for a total operating time of 2.5 minutes. At the completion of the cycle, the material had developed a uniform black appearance due to the subdivided surface capturing light and preventing its reflection, giving the perception of a black coating, regardless of the measured surface finish variation of 15 μ" Ra.

[0151] exist Fig.11Additional data related to the above experiments and additional experiments conducted on copper are listed in the table presented in .

[0152] It will be appreciated from the foregoing that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without departing from the scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.

[0153] Although the present technology has been described in language specific to certain structures and materials, it should be understood that the invention defined in the appended claims is not necessarily limited to the specific structures and materials described. Instead, these specific aspects are described as forms of implementing the claimed invention. Because many embodiments of the present invention can be practiced without departing from the spirit and scope of the present invention, the present invention is subject to the following claims.

[0154] Unless otherwise stated, all numbers or expressions (such as those expressing dimensions, physical properties, etc.) used in the specification (except claims) should be understood to be modified by the term "approximately" in all cases. At the very least, without attempting to limit the application of the doctrine of equivalents to the claims, each numerical parameter modified by the term "approximately" described in the specification or claims should be interpreted at least in view of the digits of the significant digits described and by applying rounding techniques. In addition, all ranges disclosed herein should be understood to cover and provide support for claims to any and all sub-ranges or any and all single values ​​contained therein. For example, the stated range of 1 to 10 should be considered to include and provide support for claims to any and all sub-ranges or single values ​​between and / or including a minimum value of 1 and a maximum value of 10 (i.e., all sub-ranges starting with a minimum value of 1 or greater and ending with a maximum value of 10 or less (e.g., 5.5 to 10, 2.34 to 3.56, etc.) or any value from 1 to 10 (e.g., 3, 5.8, 9.9994, etc.)).

Claims

1. A dual-modal method for affecting the surface of an electrically conductive metal workpiece, comprising: immersing at least the surface of the conductive metal workpiece in an electrolyte solution; immersing at least the surface of the electrode in the electrolyte solution; initiating a first operating mode, the first operating mode comprising applying a direct current across the electrolyte solution between the conductive metal workpiece and the electrode or applying an alternating current across the electrolyte solution between the conductive metal workpiece and the electrode; terminating the first operation mode; initiating a second operating mode comprising applying an alternating current across the electrolyte solution between the conductive metal workpiece and the electrode or applying a direct current across the electrolyte solution between the conductive metal workpiece and the electrode, wherein the second operating mode is different from the first operating mode; and terminating the second operation mode; The conductive metal workpiece comprises pure Ti, Zr, Nb, Hf, Ta or V, or an alloy based on Ti, Zr, Nb, Hf, Ta or V. 2 . The dual-modal method of claim 1 , wherein the steps of initiating the first operating mode, terminating the first operating mode, initiating the second operating mode, and terminating the second operating mode are sequentially repeated two or more times. The dual-modal method of claim 1 , wherein applying the direct current comprises applying the direct current at a constant voltage. 4 . The dual-modal method of claim 1 , wherein applying an alternating current comprises applying the alternating current as a sinusoidal alternating current having a constant maximum voltage.

5. The dual-modal method of claim 2, wherein applying the direct current comprises applying the direct current at a constant voltage, and applying the alternating current comprises applying the alternating current as a sinusoidal alternating current having a constant maximum voltage.

6. The dual-modality method according to claim 5, wherein: implementing a first iteration of said steps of initiating said first mode of operation, terminating said first mode of operation, initiating said second mode of operation and terminating said second mode of operation using a first value of the DC constant voltage and a first value of the AC constant maximum voltage; performing subsequent iterations of the steps of initiating the first operating mode, terminating the first operating mode, initiating the second operating mode, and terminating the second operating mode using the second value of the DC constant voltage and the second value of the AC constant maximum voltage; and The second value of the DC constant voltage is greater than the first value of the DC constant voltage, and the second value of the AC constant maximum voltage is less than the first value of the AC constant maximum voltage.

7. The bimodal method of claim 1, wherein the electrolyte solution has a conductivity greater than 0.011649 microSiemens / cm at 0°C.

8. The bimodal method of claim 1, wherein the electrolyte solution has a temperature in a range of about 10°C to about 100°C.

9. The bimodal method of claim 1, wherein the electrolyte solution comprises one or more ionic solutes.

10. The bimodal method according to claim 9, wherein the one or more ionic solutes are selected from the group consisting of: alkali metal elements, compounds including alkali metal elements, alkaline earth metal elements, compounds including alkaline earth metal elements, transition elements, compounds including transition elements, post-transition elements and compounds including post-transition elements.

11. The bimodal method of claim 9, wherein the one or more ionic solutes are selected from the group consisting of metalloids, reactive non-metals, salts of non-reactive metals, acids of non-reactive metals, bases of non-reactive metals, oxides of non-reactive metals, and halogens.

12. The bimodal method of claim 1, wherein the electrolyte solution comprises one or more organic compounds.

13. The bimodal method of claim 12, wherein the one or more organic compounds are selected from the group consisting of alcohols, aldehydes, ketones, carboxylic acids, and amines.

14. The bimodal method of claim 1, wherein the electrolyte solution comprises one or more surfactants.

15. The dual-modality method of claim 1, further comprising: The electrolyte solution is agitated during at least a portion of the first operating mode, at least a portion of the second operating mode, or both.

16. The bimodal method of claim 15, wherein agitating the electrolyte solution comprises thermal agitation, physical agitation, or both.

17. The bimodal method of claim 1, wherein applying the direct current across the electrolyte solution between the conductive metal workpiece and the electrode comprises: The direct current is applied from the conductive metal workpiece to the electrode.

18. The bimodal method of claim 1, wherein applying the direct current across the electrolyte solution between the conductive metal workpiece and the electrode comprises: The direct current is applied from the electrode to the conductive metal workpiece.

19. The dual-mode method of claim 5, wherein the constant voltage is in the range of -480V to +480V.

20. The bimodal method of claim 1, wherein applying the direct current across the electrolyte solution between the conductive metal workpiece and the electrode is performed for a period of 1 millisecond or longer.

21. The bimodal method of claim 1, wherein applying the alternating current across the electrolyte solution between the conductive metal workpiece and the electrode is performed for a period of 1 millisecond or longer.

22. The dual-modal method of claim 5, wherein the constant maximum voltage of the sinusoidal alternating current is from greater than 0V to about +480V.

23. The dual-modal method of claim 5, wherein the frequency of the sinusoidal alternating current is in the range of about 6 Hz to about 600 MHz.

24. The dual-modal method of claim 1, wherein the distance between the electrode and the conductive metal workpiece is greater than about 0.003 inches.

25. The bimodal method of claim 1, wherein the method is performed to deposit material on the surface of the conductive metal workpiece.

26. The bimodal method of claim 1, wherein the method is performed to remove material from the surface of the conductive metal workpiece.

27. The dual modal method of claim 26, wherein material is removed from the surface of the conductive metal workpiece to achieve a surface finish measurement in the range of 1 Ra to 500 Ra.

28. The bimodal method of claim 1, wherein the method is performed to change the surface chemistry of the surface of the conductive metal workpiece.

29. The bimodal method of claim 28, wherein altering the surface chemistry of the surface of the conductive metal workpiece comprises: Metal material is removed, an oxide layer is added, or both.

30. The bimodal method of claim 28, wherein altering the surface chemistry of the surface of the conductive metal workpiece comprises: Removing hydrogen, preventing or inhibiting hydrogen attachment, or both.

31. The bimodal method of claim 28, wherein altering the surface chemistry of the surface of the conductive metal workpiece comprises: At least the surface of the conductive metal workpiece is charged with hydrogen.

32. The dual-modal method of claim 1, wherein applying the direct current comprises: The direct current is applied at a first constant voltage for a first period of time, and then applied at a second constant voltage for a second period of time.

33. The dual-modal method of claim 1, wherein applying the direct current comprises: The DC is applied with positive polarity for a first time period and then with negative polarity for a second time period; or the DC is applied with negative polarity for a first time period and then with positive polarity for a second time period.

34. The dual-modal method of claim 1, wherein applying the alternating current comprises: The alternating current is applied in a first waveform for a first period of time and then in a second waveform for a second period of time.

35. The dual-modal method of claim 33, wherein the first waveform differs from the second waveform in one or more of amplitude, frequency, wavelength, and shape.

36. A system configured to affect a surface of an electrically conductive metal workpiece, comprising: electrolyte solution bath; a conductive metal workpiece, at least one surface of which is immersed in the electrolyte solution bath; an electrode, at least one surface of which is immersed in the electrolyte solution bath; a DC power source, wherein a first terminal of the DC power source is connected to the conductive metal workpiece and a second terminal of the DC power source is connected to the electrode; and an AC power source, wherein a first terminal of the AC power source is connected to the conductive metal workpiece and a second terminal of the AC power source is connected to the electrode; wherein in a first operating mode, the DC power source is configured to apply only a direct current across the electrolyte solution between the conductive metal workpiece and the electrode, or the AC power source is configured to apply only an alternating current across the electrolyte solution between the conductive metal workpiece and the electrode; wherein in a second operating mode, the AC power source is configured to apply only an alternating current across the electrolyte solution between the conductive metal workpiece and the electrode, or the DC power source is configured to apply only a direct current across the electrolyte solution between the conductive metal workpiece and the electrode; wherein the first operating mode is different from the second operating mode; wherein the system is configured to alternate between the first mode of operation and the second mode of operation; and The conductive metal workpiece includes Ti, Zr, Nb, Hf, Ta or V, or an alloy based on Ti, Zr, Nb, Hf, Ta or V.

37. The system of claim 36, wherein the first terminal of the DC power source is a positive terminal and the second terminal of the DC power source is a negative terminal.

38. The system of claim 36, wherein the first terminal of the DC power source is a negative terminal and the second terminal of the DC power source is a positive terminal.

39. The system of claim 36, wherein the DC power supply is configured to apply the direct current at a constant voltage during the first operating mode or the second operating mode.

40. The system of claim 36, wherein the AC power source is configured to apply the alternating current as a sinusoidal alternating current having a constant maximum voltage during the first operating mode or the second operating mode.

41. The system of claim 36, wherein the DC power supply is configured to apply the direct current at a constant voltage during the first operating mode or the second operating mode, and the AC power supply is configured to apply the alternating current as a sinusoidal alternating current with a constant maximum voltage during the first operating mode or the second operating mode.

42. The system of claim 36, further comprising: means for agitating the electrolyte solution bath.

43. The system of claim 42, wherein the means for agitating the electrolyte solution bath comprises a mechanical agitation device.

44. The system of claim 42, wherein the means for mixing the electrolyte solution bath comprises a thermal agitation device.

45. The system of claim 41, wherein the constant voltage is in the range of -480V to +480V.

46. ​​The system of claim 41, wherein the first operating mode is implemented for a period of 1 millisecond or longer and the second operating mode is implemented for a period of 1 millisecond or longer.

47. The system of claim 41, wherein the constant maximum voltage of the sinusoidal alternating current is from greater than 0V to about +480V.

48. The system of claim 41, wherein the frequency of the sinusoidal alternating current is in the range of about 6 Hz to about 600 MHz.

49. The system of claim 36, wherein during either the first operating mode or the second operating mode, the DC power supply is configured to apply the DC at a first constant voltage for a first time period and then apply the DC at a second constant voltage for a second time period.

50. A system according to claim 36, wherein during the first operating mode or the second operating mode, the DC power supply is configured to: apply the DC with positive polarity for a first time period, and then apply the DC with negative polarity for a second time period; or apply the DC with negative polarity for a first time period, and then apply the DC with positive polarity for a second time period.

51. The system of claim 36, wherein during the first operating mode or the second operating mode, the AC power source is configured to apply the alternating current with a first waveform for a first time period and then apply the alternating current with a second waveform for a second time period.

52. The system of claim 51, wherein the first waveform differs from the second waveform in one or more of amplitude, frequency, wavelength, and shape.

53. The dual-modality method of claim 1, further comprising: monitoring one or more operating parameters of the method; analyzing the one or more operating parameters to determine whether adjustments to the one or more operating parameters are needed to change an aspect of a barrier layer formed on the workpiece; and When it is determined that adjustment is needed, the one or more operating parameters are automatically adjusted to change an aspect of the barrier layer.

54. The dual-modal method of claim 53, wherein the one or more operating parameters are selected from the group consisting of: the voltage, action, amplitude, pause or form of the direct current; the voltage, action, amplitude, pause or form of the alternating current; the duration of the direct current; the duration of the alternating current; the circulation of the alternating current; the temperature of the electrolyte solution; the agitation of the electrolyte solution; the composition of the electrolyte solution; the conductivity of the electrolyte solution; or any combination thereof.

55. The bimodal method of claim 53, wherein the workpiece is a first workpiece, and the method further comprises: replacing the first workpiece with a second workpiece; and Repeating the steps of initiating the first operating mode, terminating the first operating mode, initiating the second operating mode, terminating the second operating mode, monitoring the operating parameters, analyzing the operating parameters and adjusting the operating parameters in a manner affecting the second workpiece, affects the second workpiece in the same manner as the first workpiece.

56. The bimodal method of claim 1, wherein the electrolyte solution is free or substantially free of nitrogen and nitrogen-containing compounds.

57. The system of claim 36, further comprising: An operating parameter control system, the operating parameter control system being configured to: monitoring one or more operating parameters of the system; analyzing the one or more operating parameters to determine whether adjustments to the one or more operating parameters are needed to change an aspect of a barrier layer formed on the workpiece; and When it is determined that adjustment is needed, the one or more operating parameters are automatically adjusted to change an aspect of the barrier layer.

58. A system according to claim 57, wherein the one or more operating parameters are selected from the group consisting of: the voltage, action, amplitude, intermittence or form of the direct current; the voltage, action, amplitude, intermittence or form of the alternating current; the duration of the direct current; the duration of the alternating current; the circulation of the alternating current; the temperature of the electrolyte solution; the agitation of the electrolyte solution; the composition of the electrolyte solution; the conductivity of the electrolyte solution; or any combination thereof.

59. A bimodal method for affecting the surface of an electrically conductive metal workpiece, comprising: immersing at least the surface of the conductive metal workpiece in an electrolyte solution; immersing at least the surface of the electrode in the electrolyte solution; initiating a first operating mode, the first operating mode comprising applying a direct current across the electrolyte solution between the conductive metal workpiece and the electrode or applying an alternating current across the electrolyte solution between the conductive metal workpiece and the electrode; terminating the first operation mode; initiating a second operating mode comprising applying an alternating current across the electrolyte solution between the conductive metal workpiece and the electrode or applying a direct current across the electrolyte solution between the conductive metal workpiece and the electrode, wherein the second operating mode is different from the first operating mode; and terminating the second operation mode; The conductive metal workpiece includes pure Ni, Ni-based alloy, Co-based alloy or titanium aluminide.

60. A system configured to affect a surface of an electrically conductive metal workpiece, comprising: electrolyte solution bath; a conductive metal workpiece, at least one surface of which is immersed in the electrolyte solution bath; an electrode, at least one surface of which is immersed in the electrolyte solution bath; a DC power source, wherein a first terminal of the DC power source is connected to the conductive metal workpiece and a second terminal of the DC power source is connected to the electrode; and an AC power source, wherein a first terminal of the AC power source is connected to the conductive metal workpiece and a second terminal of the AC power source is connected to the electrode; wherein in a first operating mode, the DC power source is configured to apply only a direct current across the electrolyte solution between the conductive metal workpiece and the electrode, or the AC power source is configured to apply only an alternating current across the electrolyte solution between the conductive metal workpiece and the electrode; wherein in a second operating mode, the AC power source is configured to apply only an alternating current across the electrolyte solution between the conductive metal workpiece and the electrode, or the DC power source is configured to apply only a direct current across the electrolyte solution between the conductive metal workpiece and the electrode; wherein the first operating mode is different from the second operating mode; wherein the system is configured to alternate between the first mode of operation and the second mode of operation; and The conductive metal workpiece includes pure Ni, Ni-based alloy, Co-based alloy or titanium aluminide.

61. A bimodal method for affecting the surface of a conductive metal workpiece, comprising: immersing at least the surface of the conductive metal workpiece in an electrolyte solution; immersing at least the surface of the electrode in the electrolyte solution; initiating a first operating mode, the first operating mode comprising applying a direct current across the electrolyte solution between the conductive metal workpiece and the electrode or applying an alternating current across the electrolyte solution between the conductive metal workpiece and the electrode; terminating the first operation mode; initiating a second operating mode comprising applying an alternating current across the electrolyte solution between the conductive metal workpiece and the electrode or applying a direct current across the electrolyte solution between the conductive metal workpiece and the electrode, wherein the second operating mode is different from the first operating mode; and terminating the second operation mode; The conductive metal workpiece comprises austenitic stainless steel.

62. A system configured to affect a surface of an electrically conductive metal workpiece, comprising: electrolyte solution bath; a conductive metal workpiece, at least one surface of which is immersed in the electrolyte solution bath; an electrode, at least one surface of which is immersed in the electrolyte solution bath; a DC power source, wherein a first terminal of the DC power source is connected to the conductive metal workpiece and a second terminal of the DC power source is connected to the electrode; and an AC power source, wherein a first terminal of the AC power source is connected to the conductive metal workpiece and a second terminal of the AC power source is connected to the electrode; wherein in a first operating mode, the DC power source is configured to apply only a direct current across the electrolyte solution between the conductive metal workpiece and the electrode, or the AC power source is configured to apply only an alternating current across the electrolyte solution between the conductive metal workpiece and the electrode; wherein in a second operating mode, the AC power source is configured to apply only an alternating current across the electrolyte solution between the conductive metal workpiece and the electrode, or the DC power source is configured to apply only a direct current across the electrolyte solution between the conductive metal workpiece and the electrode; wherein the first operating mode is different from the second operating mode; wherein the system is configured to alternate between the first mode of operation and the second mode of operation; and The conductive metal workpiece comprises austenitic stainless steel.

63. A bimodal method for affecting the surface of an electrically conductive metal workpiece, comprising: immersing at least the surface of the conductive metal workpiece in an electrolyte solution; immersing at least the surface of the electrode in the electrolyte solution; initiating a first operating mode, the first operating mode comprising applying a direct current across the electrolyte solution between the conductive metal workpiece and the electrode or applying an alternating current across the electrolyte solution between the conductive metal workpiece and the electrode; terminating the first operation mode; initiating a second operating mode comprising applying an alternating current across the electrolyte solution between the conductive metal workpiece and the electrode or applying a direct current across the electrolyte solution between the conductive metal workpiece and the electrode, wherein the second operating mode is different from the first operating mode; and terminating the second operation mode; The conductive metal workpiece comprises martensitic stainless steel.

64. A system configured to affect a surface of an electrically conductive metal workpiece, comprising: electrolyte solution bath; a conductive metal workpiece, at least one surface of which is immersed in the electrolyte solution bath; an electrode, at least one surface of which is immersed in the electrolyte solution bath; a DC power source, wherein a first terminal of the DC power source is connected to the conductive metal workpiece and a second terminal of the DC power source is connected to the electrode; and an AC power source, wherein a first terminal of the AC power source is connected to the conductive metal workpiece and a second terminal of the AC power source is connected to the electrode; wherein in a first operating mode, the DC power source is configured to apply only a direct current across the electrolyte solution between the conductive metal workpiece and the electrode, or the AC power source is configured to apply only an alternating current across the electrolyte solution between the conductive metal workpiece and the electrode; wherein in a second operating mode, the AC power source is configured to apply only an alternating current across the electrolyte solution between the conductive metal workpiece and the electrode, or the DC power source is configured to apply only a direct current across the electrolyte solution between the conductive metal workpiece and the electrode; wherein the first operating mode is different from the second operating mode; wherein the system is configured to alternate between the first mode of operation and the second mode of operation; and The conductive metal workpiece comprises martensitic stainless steel.

65. A bimodal method for affecting the surface of an electrically conductive metal workpiece, comprising: immersing at least the surface of the conductive metal workpiece in an electrolyte solution; immersing at least the surface of the electrode in the electrolyte solution; initiating a first operating mode, the first operating mode comprising applying a direct current across the electrolyte solution between the conductive metal workpiece and the electrode or applying an alternating current across the electrolyte solution between the conductive metal workpiece and the electrode; terminating the first operation mode; initiating a second operating mode comprising applying an alternating current across the electrolyte solution between the conductive metal workpiece and the electrode or applying a direct current across the electrolyte solution between the conductive metal workpiece and the electrode, wherein the second operating mode is different from the first operating mode; and terminating the second operation mode; The conductive metal workpiece includes ferritic stainless steel, carbon steel or alloy steel.

66. A system configured to affect a surface of an electrically conductive metal workpiece, comprising: electrolyte solution bath; a conductive metal workpiece, at least one surface of which is immersed in the electrolyte solution bath; an electrode, at least one surface of which is immersed in the electrolyte solution bath; a DC power source, wherein a first terminal of the DC power source is connected to the conductive metal workpiece and a second terminal of the DC power source is connected to the electrode; and an AC power source, wherein a first terminal of the AC power source is connected to the conductive metal workpiece and a second terminal of the AC power source is connected to the electrode; wherein in a first operating mode, the DC power source is configured to apply only a direct current across the electrolyte solution between the conductive metal workpiece and the electrode, or the AC power source is configured to apply only an alternating current across the electrolyte solution between the conductive metal workpiece and the electrode; wherein in a second operating mode, the AC power source is configured to apply only an alternating current across the electrolyte solution between the conductive metal workpiece and the electrode, or the DC power source is configured to apply only a direct current across the electrolyte solution between the conductive metal workpiece and the electrode; wherein the first operating mode is different from the second operating mode; wherein the system is configured to alternate between the first mode of operation and the second mode of operation; and The conductive metal workpiece includes ferritic stainless steel, carbon steel or alloy steel.

67. A bimodal method for affecting the surface of an electrically conductive metal workpiece, comprising: immersing at least the surface of the conductive metal workpiece in an electrolyte solution; immersing at least the surface of the electrode in the electrolyte solution; initiating a first operating mode, the first operating mode comprising applying a direct current across the electrolyte solution between the conductive metal workpiece and the electrode or applying an alternating current across the electrolyte solution between the conductive metal workpiece and the electrode; terminating the first operation mode; initiating a second operating mode comprising applying an alternating current across the electrolyte solution between the conductive metal workpiece and the electrode or applying a direct current across the electrolyte solution between the conductive metal workpiece and the electrode, wherein the second operating mode is different from the first operating mode; and terminating the second operation mode; The conductive metal workpiece comprises pure aluminum or an aluminum alloy.

68. A system configured to affect a surface of an electrically conductive metal workpiece, comprising: electrolyte solution bath; a conductive metal workpiece, at least one surface of which is immersed in the electrolyte solution bath; an electrode, at least one surface of which is immersed in the electrolyte solution bath; a DC power source, wherein a first terminal of the DC power source is connected to the conductive metal workpiece and a second terminal of the DC power source is connected to the electrode; and an AC power source, wherein a first terminal of the AC power source is connected to the conductive metal workpiece and a second terminal of the AC power source is connected to the electrode; wherein in a first operating mode, the DC power source is configured to apply only a direct current across the electrolyte solution between the conductive metal workpiece and the electrode, or the AC power source is configured to apply only an alternating current across the electrolyte solution between the conductive metal workpiece and the electrode; wherein in a second operating mode, the AC power source is configured to apply only an alternating current across the electrolyte solution between the conductive metal workpiece and the electrode, or the DC power source is configured to apply only a direct current across the electrolyte solution between the conductive metal workpiece and the electrode; wherein the first operating mode is different from the second operating mode; wherein the system is configured to alternate between the first mode of operation and the second mode of operation; and The conductive metal workpiece comprises pure aluminum or an aluminum alloy.

69. A bimodal method for affecting the surface of an electrically conductive metal workpiece, comprising: immersing at least the surface of the conductive metal workpiece in an electrolyte solution; immersing at least the surface of the electrode in the electrolyte solution; initiating a first operating mode, the first operating mode comprising applying a direct current across the electrolyte solution between the conductive metal workpiece and the electrode or applying an alternating current across the electrolyte solution between the conductive metal workpiece and the electrode; terminating the first operation mode; initiating a second operating mode comprising applying an alternating current across the electrolyte solution between the conductive metal workpiece and the electrode or applying a direct current across the electrolyte solution between the conductive metal workpiece and the electrode, wherein the second operating mode is different from the first operating mode; and terminating the second operation mode; The conductive metal workpiece includes pure copper or a copper alloy.

70. A system configured to affect a surface of an electrically conductive metal workpiece, comprising: electrolyte solution bath; a conductive metal workpiece, at least one surface of which is immersed in the electrolyte solution bath; an electrode, at least one surface of which is immersed in the electrolyte solution bath; a DC power source, wherein a first terminal of the DC power source is connected to the conductive metal workpiece and a second terminal of the DC power source is connected to the electrode; and an AC power source, wherein a first terminal of the AC power source is connected to the conductive metal workpiece and a second terminal of the AC power source is connected to the electrode; wherein in a first operating mode, the DC power source is configured to apply only a direct current across the electrolyte solution between the conductive metal workpiece and the electrode, or the AC power source is configured to apply only an alternating current across the electrolyte solution between the conductive metal workpiece and the electrode; wherein in a second operating mode, the AC power source is configured to apply only an alternating current across the electrolyte solution between the conductive metal workpiece and the electrode, or the DC power source is configured to apply only a direct current across the electrolyte solution between the conductive metal workpiece and the electrode; wherein the first operating mode is different from the second operating mode; wherein the system is configured to alternate between the first mode of operation and the second mode of operation; and The conductive metal workpiece includes pure copper or a copper alloy.

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