Inner surface electrochemically treated electrodes

Abstract

An electrochemical treatment electrode configured to contact an interior surface of a metal article with an electrochemical treatment fluid comprises a flexible conductive body and a plurality of flexible elements connected to the flexible conductive body and extending generally outwardly of the flexible conductive body and configured to position an electrochemical treatment fluid around the flexible conductive body, the plurality of flexible elements including a plurality of conductive or non-conductive fibers extending generally outwardly of the flexible conductive body, the plurality of conductive or non-conductive fibers configured to contact the interior surface of the metal article when the electrode is in use.

Description

[Technical field]

[0001] Priority Cross Reference This application claims priority from Australian Provisional Patent Application No. 2021904085, filed on December 16, 2021, the contents of which are understood to be incorporated herein by reference.

[0002] The present invention generally relates to electrochemical processing electrodes configured to electrochemically process and / or machine the interior or internal surfaces of metal objects, and associated electrochemical processing devices and methods. The present invention is particularly applicable to electrochemical processing, and in particular to electropolishing additively manufactured (3D printed) metal alloys, and it will be convenient to disclose the present invention in relation to its exemplary application hereinafter. However, it should be understood that the present invention is not particularly limited to additively manufactured (3D printed) metals and metal alloys, but can be applied to a wide variety of metallic (metal and metal alloy) articles produced from various manufacturing methods that require electrochemical processing of interior or internal surfaces. [Background technology]

[0003] The following discussion of the background of the invention is intended to facilitate an understanding of the present invention. It should be understood, however, that this discussion is not an acknowledgment or admission that any of the material referred to was published, known, or part of the common general knowledge at the priority date of this application.

[0004] Additive manufacturing of metal articles offers considerable freedom in design and construction. Several techniques are now available for 3D printing metal articles, including electron beam melting (EBM), direct metal laser sintering (DMLS), selective heat sintering (SHS), and selective laser melting (SLM). However, many of these additive manufacturing techniques produce articles with surfaces with high surface roughness that require finishing.

[0005] Electrochemical processing techniques can be used to selectively treat surfaces. For example, electropolishing techniques can be used to reduce the surface roughness of such 3D printed surfaces. One suitable electropolishing system is taught in International Patent Publication WO2020 / 206492. This electropolishing system can use conventional electrodes to electropolish the exterior surfaces of 3D printed metal articles, but the interior surfaces can be problematic due to the size, shape, and inaccessibility of those interior surfaces. This problem can be exacerbated by the design freedom that additive manufacturing offers, where more complex internal structures such as cavities, hollows, channels, or openings can be incorporated into the 3D printing design. As such, finishing these types of internal passages can be very problematic.

[0006] Similar problems in properly treating and fabricating internal structures such as cavities, hollows, channels, or openings are also faced in other electrochemical processes such as electrolytic cleaning, anodizing, parkerizing, and pickling. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] WO2020 / 206492 [Patent Document 2] WO2009 / 105802 [Patent Document 3] AU2013242795A1 [Patent Document 4] AU2017204328A1 Summary of the Invention [Problem to be solved by the invention]

[0008] It would therefore be desirable to provide an alternative or improved electrode that is configured to electrochemically treat interior surfaces / passages of metal articles having internal cavities, spaces, hollows, channels, or openings. [Means for solving the problem]

[0009] The present invention provides an electrode configured to electrochemically treat the interior surfaces of cavities, hollows, channels, or openings in metal articles or metal products, such as heat exchangers or engine parts. The electrochemical treatment can be any electrochemical process in which a power supply (AC or DC) is used to treat the surface. Suitable electrochemical treatment processes include electropolishing, electrolytic cleaning, anodizing, parkerizing, and pickling. In various embodiments, the present invention is particularly applicable to electropolishing the interior surfaces of metal parts, such as additively manufactured (3D printed) metal parts.

[0010] A first aspect of the present invention provides an electrochemical treatment electrode configured to contact an interior surface of a metal article with an electrochemical treatment fluid, comprising: a flexible conductive body; a plurality of flexible elements connected to the flexible conductive body and extending generally outwardly, preferably generally radially outwardly, of the flexible conductive body and configured to position an electrochemical treatment fluid about the flexible conductive body; Equipped with The plurality of flexible elements includes a plurality of conductive or non-conductive fibers extending generally outwardly of the flexible conductive body, the plurality of conductive or non-conductive fibers being an electrochemical processing electrode configured to contact an interior surface of the metal article when the electrode is in use.

[0011] The electrode of the first embodiment comprises a flexible conductive body, and a flexible element including a plurality of conductive or non-conductive fibers is connected to and extends into the flexible conductive body. The flexible conductive body extends along a generally axial axis, and the plurality of flexible elements extend generally outward from the flexible conductive body and its axis, preferably generally radially outward. The flexible element is designed to be flexible enough to elastically deform so that the electrode can be inserted into and moved through a cavity, hollow, channel, or opening in a metal article, such as an additively manufactured metal article. The plurality of flexible elements, preferably a plurality of flexible elements, are used to hold an electrochemical processing fluid, such as an electrolyte, around the conductive body so as to cause the electrolyte to conduct an electric current through itself to facilitate electrochemical processing of an interior surface in a cavity, hollow, channel, or opening in the metal article to be electrochemically processed. More specifically, the flexible elements retain an electrochemical processing fluid, such as an electrolyte, around the conductive body when in a hollow, channel, or opening in the metal article to be electrochemically processed. The flexibility of the flexible elements allows electrodes to be inserted into the internal cavities, spaces, hollows, channels, or openings of the metal article and then pass within and around contours, protrusions, or other features therein while still positioning / retaining the electrochemical processing fluid around the flexible conductive body.

[0012] The flexible element also acts to space the flexible conductive body from the surface of the metal article being electrochemically treated. The current for the electrochemical treatment of the surface is provided through the flexible conductive body and then through an electrochemical treatment fluid, such as an electrolyte, present at or on the surface of the electrode. If the flexible element is non-conductive, it assists in this spacing function. If the flexible element is conductive, it can assist in the transfer of current from the flexible conductive body to the electrolyte and then to the treatment surface. If there is a mixture of non-conductive and conductive elements (e.g., fibers or bristles - see below), the non-conductive elements are typically longer than the conductive elements to help space the conductive elements from the treatment surface.

[0013] Again, it should be understood that the electrochemical treatment of the present invention can be any electrochemical process in which a power supply (AC or DC) is used to treat a surface. Suitable electrochemical treatment processes include electropolishing, electrocleaning, anodizing, parkerizing, and pickling.

[0014] In various embodiments, the present invention is particularly applicable for electropolishing the internal surfaces of metal parts, such as additively manufactured (3D printed) metal parts. The electrodes work particularly well with the applicant's electropolishing system taught in International Patent Publication WO2020 / 206492, the contents of which are to be understood as being incorporated herein by reference. When used in the electropolishing system of WO2020 / 206492, the wire can be designed to carry the large currents required, and the enamel (wire coating) melting point can be managed by the duty cycle and waiting / cooling time.

[0015] The plurality of flexible elements extend generally outwardly of the flexible conductive body, preferably generally radially outwardly. The flexible elements are preferably elastic, i.e., have some mechanical memory, to allow each flexible conductor to bend, twist, or otherwise deform and then recover back to its original extended state. This allows electrodes to be inserted into and around contours, protrusions, or other features (e.g., small flanges) in the cavity and then expand to allow larger passages therein for electrochemical processing.

[0016] The electrochemical processing fluid can be any fluid used in electrochemical processing. The electrochemical processing fluid is preferably a conductive fluid. For example, if the electrode is used for electropolishing, an electropolishing electrolyte can be used. The electropolishing electrolyte can be any suitable conductive liquid, as described in more detail below.

[0017] The flexible elements may include any suitable strips, fibers, etc. In some embodiments, the flexible elements comprise a plurality of wires, strips, cords, filaments, hairs, barbs, fibers, whiskers, or bristles.

[0018] The flexible elements may comprise conductive elements, non-conductive elements, or a mixture thereof. In a specific embodiment, at least some of the flexible elements comprise a plurality of flexible conductive elements, preferably comprising conductive fibers. A variety of fibers may be used. In an embodiment, the plurality of conductive or non-conductive fibers may include conductive fibers comprising a plurality of carbon fibers, metal fibers, or a mixture thereof. It should be understood that any suitable high temperature conductive fibers may be used. In some embodiments, some or all of the flexible elements comprise a plurality of non-conductive elements, such as fibers. Examples of non-conductive fibers include at least one of fiberglass, polyparaphenylene terephthalamide (Kevlar), or a mixture thereof. It should be understood that any suitable high temperature non-conductive fibers may be used. In an embodiment, the plurality of conductive or non-conductive fibers includes a plurality of non-conductive fibers comprising at least one of fiberglass, polyparaphenylene terephthalamide (Kevlar), or a mixture thereof. In some embodiments, the flexible elements may comprise one of conductive or non-conductive fibers. In some embodiments, the flexible element comprises a mix of conductive and non-conductive fibers / elements.

[0019] In an exemplary embodiment, the flexible element comprises a plurality of carbon fibers. One example of a suitable carbon fiber comprises unidirectional 450 gsm carbon fiber.

[0020] In an exemplary embodiment, the flexible element comprises a plurality of fiberglass strands. One example of a suitable fiberglass comprises unidirectional 250 gsm fiberglass.

[0021] In an exemplary embodiment, the flexible element comprises a plurality of Kevlar (polyparaphenylene terephthalamide) fibers. One example of a suitable Kevlar fiber comprises unidirectional 3.2 or aramid (polyparaphenylene terephthalamide-Kevlar).

[0022] The dimensions of the flexible element are typically configured to match the dimensions of the conduit or duct of the metal article undergoing electrochemical treatment. In some embodiments, the flexible element is sized to extend to, and more preferably to extend closely (but not touch) the interior surface to be treated. For example, the length of each flexible conductor is typically selected to have a length that complements the radial dimension of the conduit or duct. In some embodiments, the interior surface is a portion of a conduit or duct having a diameter between 2 mm and 5 mm. In some embodiments, the conduit or duct may have a diameter between 0.5 mm and 5 mm, for example a pipe or a pipeline, such as an oil or gas pipeline. In some embodiments, the interior surface is a portion of a conduit or duct having a diameter between 2 mm and 20 mm, preferably between 4 mm and 10 mm, more preferably between 4 mm and 8 mm. However, it should be understood that processing may be performed down to the width of the fiber. In other embodiments, the length of the flexible element is sized to substantially match the radius of the conduit or duct of the metal article undergoing electrochemical treatment. Here, the length of the flexible element is typically the same as or slightly larger than the radius of the conduit or duct.

[0023] It is important to note that the flexible element, specifically the plurality of conductive or non-conductive fibers, is configured to contact the interior surface of the metal article when the electrode is in use. Therefore, the electrode of the present invention does not need to be electrically isolated from the workpiece during operation. The flexible element, such as the plurality of conductive or non-conductive fibers, is configured to be able to contact the interior surface of the metal article / workpiece during operation, i.e., when electrochemically treating the interior surface of the metal article.

[0024] It should be understood that the internal dimensions / diameters of the metal article conduits or ducts may not be constant, and so the length of each flexible element is designed to fit the largest diameter, or in some cases the substantial / main diameter, and the movement and flexibility of the flexible elements can be used to electrochemically treat surfaces in metal article conduits or ducts of different dimensions / diameters.

[0025] The flexible elements need not have a uniform length extending outwardly of the conductive body. The flexible elements need not have the same length around the circumference of the flexible conductive body or along the axial length of the flexible conductive body.

[0026] In embodiments, the flexible elements can have different lengths relative to the conductive body. For example, when there is a mixture of non-conductive and conductive elements (such as fibers or bristles), the non-conductive elements are typically longer than the conductive elements to help space the conductive elements away from the treatment surface. In some embodiments, a first set of flexible elements, such as conductive elements such as carbon fibers, have a shorter length than a second set of flexible elements, such as non-conductive fibers such as fiberglass or polyparaphenylene terephthalamide (Kevlar) fibers. Again, the longer fiberglass / Kevlar fibers ensure that the shorter carbon fibers are adequately spaced away from the surface being electrochemically treated to reduce spark or short events.

[0027] In some embodiments, the length, preferably the radial length, of the flexible element may vary around the circumference of the conductive body, where a first region or section around the circumference of the conductive body may have a longer length than a second region or section around the circumference of the conductive body. The length may be configured to match the shape or configuration of a particular cavity or internal opening that the electrode is configured to electrochemically process. This may provide the electrode with a shaped radial cross section, such as shaped as a regular or irregular polygon, etc. Examples include triangles, trapezoids, hexagons, etc.

[0028] The flexible element may be connected to the flexible conductive body using any suitable attachment means or configuration. For example, the flexible element may be connected to the flexible conductive body through compressive engagement, weaving, adhering, welding, inlaying, wedging, embedding, bonding, anchoring, or combinations thereof. The compressive engagement can take a variety of forms. In some embodiments, the flexible element is clamped, crimped, pressed, or tied into connection with the flexible conductive body.

[0029] In a specific embodiment, the elongated flexible conductive body comprises at least two elongated wires that are twisted or otherwise intertwined, and the flexible elements are connected to the flexible conductive body through a compressive engagement between the at least two elongated wires. The use of twisted wires allows the flexible element to be quickly secured between the two wires when forming / manufacturing the electrode. In other embodiments, the flexible element is held by a spring. In such an embodiment, the elongated flexible conductive body comprises at least one tension spring, and the flexible element is connected to the flexible conductive body through a compressive engagement between adjacent coils of the spring. In yet other embodiments, the flexible element is soldered, welded, or glued to the flexible conductive body. In still other embodiments, the flexible element is pressed or crimped onto the flexible conductive body.

[0030] The electrodes may include additional features in addition to the flexible element to aid in electrochemically treating the interior surface of the target of the metal article.

[0031] In embodiments of the electrode of the first aspect, the flexible element includes and / or comprises at least one flexible sheet or flexible body. In some embodiments, the electrode further comprises at least one flexible sheet or flexible body connected to a flexible conductive body, preferably extending from or disposed adjacent, between, and / or around a plurality of flexible elements. In some embodiments, the flexible sheet or flexible body comprises a plurality of flexible elements connected to the flexible conductive body and extending generally outwardly of the flexible conductive body and configured to position the electrochemical treatment fluid around the flexible conductive body.

[0032] In a specific embodiment of the invention, an electrochemical treatment electrode is configured to contact an interior surface of a metal article with an electrochemical treatment fluid, the electrode comprising: a flexible conductive body; a plurality of flexible elements connected to the flexible conductive body and extending generally outwardly of the flexible conductive body and configured to position an electrochemical treatment fluid about the flexible conductive body; Equipped with The flexible element comprises at least one flexible sheet or flexible body, or The electrode preferably further comprises at least one flexible sheet or body connected to a flexible conductive body extending from or disposed adjacent to, between, and / or around the multiple flexible elements.

[0033] The flexible sheet or body is typically formed of, positioned adjacent to, disposed within, and / or surrounded by the flexible element, and acts as both an additional conductor and, in some instances, an absorbent for carrying any electrochemical processing fluids, such as electrolytes, used in the electrochemical processing procedure. Any suitable flexible sheet or body may be used, such as, for example, one or more foams, sponges, or fibrous materials. When the flexible sheet / body comprises a foam, any suitable foam may be used, such as natural foam or polymeric foam. In an embodiment, the foam comprises a high temperature foam, such as Intek® PFI-1120 high temperature foam. Similarly, any suitable fibrous material may be used, including woven and non-woven materials. In an embodiment, the fabric may be a fiberglass-based fabric, a carbon fiber-based fabric, or a 1.0 g / cm ZOPIN. 3 The flexible sheet comprises high temperature fibers such as . The flexible sheet is used to carry electrochemical processing fluids and may be preferably conductive to assist in the electrochemical processing of said interior surface of the metal article depending on the metal being processed. For example, the flexible sheet may be conductive for nickel alloys. In other embodiments, the flexible sheet may be non-conductive, for example for aluminum alloys. In one embodiment, the flexible sheet or body comprises a foam element configured to extend over and surround the electrode and the plurality of flexible elements. The foam element preferably comprises a sheath or other surrounding body that extends around the electrode and the plurality of flexible elements. The plurality of flexible elements preferably extend into the foam material, thereby providing conductive paths / elements within the foam material. However, it should be understood that the flexible sheet or body may be configured to extend over and surround the electrode using a variety of other means that may connect to or otherwise position the flexible sheet or body around the flexible conductive body.

[0034] In some embodiments, the electrode further comprises a plurality of conductive particles positioned adjacent and / or between the plurality of flexible elements, the conductive particles providing additional conductor means that can be mixed within an electrochemical processing fluid, such as an electrolyte, to add additional contact points with the interior surfaces being electrochemically processed within the cavity.

[0035] The flexible conductive body may comprise any suitable flexible body onto which the flexible element may be connected.

[0036] In many embodiments, the flexible conductive body comprises an elongate flexible conductive body, such as a wire, that defines a longitudinal axis along its length. Thus, the flexible element is electrically connected to the flexible conductive body and extends generally outward, preferably generally radially outward, from the longitudinal axis of the flexible conductive body. In these embodiments, the conductive body preferably comprises a metal wire, more preferably a magnet wire. In other embodiments, the conductive body comprises a carbon fiber wire or elongate body. However, it should be understood that any conductive metal may be used for the wire, such as, for example, stainless steel, gold, copper, aluminum, or any other metal or conductive material that exhibits good conductivity and corrosion resistance.

[0037] When the conductive body comprises a metal wire or the like, the conductive body may include an insulating coating or sleeve over the non-electrically connected surfaces. The insulating coating or sleeve may comprise a dielectric coating, preferably a polymeric coating, and more preferably an enamel or urethane coating. A variety of dielectric coatings can be used on the wire. Some conventional wire coatings are suitable because they are already inert to most electrochemical processing fluids, such as electropolishing electrolytes. It should be understood that if the coating or sleeve is inappropriate, the wire can be recoated with a suitable coating. In other embodiments, a suitable metal wire, such as a magnet wire, can be supplemented with a suitable dielectric coating or sleeve, such as an inert urethane or the like, as needed.

[0038] The conductive body does not necessarily comprise an elongated wire in all embodiments of the invention. In some embodiments, the conductive body may comprise a flexible body such as a sphere, ball, rod, or pipe including a flexible element extending outward from a surface of the flexible body. The flexible body may be formed from any suitable flexible material such as foam, sponge, or fiber. The conductive body may include an internal cavity and may therefore be hollow. In some embodiments, the conductive body comprises a sphere and the multiple flexible elements include at least one rib, flange, or strip extending from the conductive body. In other embodiments, the flexible body comprises a sphere, ball, rod, or pipe with a flexible element including multiple flexible conductive fibers extending outward from a surface of the flexible body. The multiple flexible conductive fibers may be connected to the flexible body using any suitable means including fitting, gluing, clamping, fastening, crimping, or the like.

[0039] A second aspect of the present invention provides an apparatus for electrochemically treating an internal surface of a metal article, comprising: At least one electrochemical treatment electrode according to the first aspect of the invention; an electrochemical treatment fluid source configured to provide an electrochemical treatment fluid to the flexible element of the electrode and to an interior surface of the metal article; Power supply and Equipped with An apparatus in which an electrochemical process electrode is connected to one terminal of a power supply and a metal article is connected to the other terminal of the power supply.

[0040] This second aspect of the invention provides an electrochemical treatment apparatus including the electrochemical treatment electrode of the first aspect of the invention. In this configuration, the metal article provides one electrode, such as the anode, of the electrochemical treatment circuit, and the electrochemical treatment electrode of the first aspect of the invention provides the other electrode, such as the cathode, to complete the electrical circuit. An electrochemical treatment fluid acts as a conductive medium around the conductive body of the electrode within the flexible element of the electrode facilitating electrochemical treatment of a selected surface.

[0041] Again, it should be understood that the electrochemical treatment of the present invention can be any electrochemical process in which a power supply (AC or DC) is used to treat a surface. Suitable electrochemical treatment processes include electropolishing, electrocleaning, anodizing, parkerizing, and pickling.

[0042] The apparatus preferably further comprises an electrochemical processing fluid source configured to provide an electrochemical processing fluid onto the flexible element of the electrode and onto the interior surface of the metal article. An electrochemical processing fluid, such as an electrolyte, is preferably pumped onto at least the interior surface of the metal article. In embodiments, the electrochemical processing fluid source may be a fluid pump or other fluid conveyor that pumps the electrochemical processing fluid onto the electrode and onto the interior surface of the metal article. However, in some embodiments, the electrochemical processing fluid source may be a reservoir in which the metal article may be immersed, such as a container or other fluid-holding receptacle that holds the electrochemical processing fluid.

[0043] The electrochemical processing fluid may be any fluid used in electrochemical processing. The electrochemical processing fluid is preferably a conductive fluid. For example, when the apparatus of this second aspect comprises an electropolishing apparatus, an electropolishing electrolyte may be used. The electropolishing electrolyte may be any suitable conductive liquid. In a preferred form, the electropolishing electrolyte is H 3 PO 4 The electropolishing electrolyte is water or C 1 ~C 4 The electropolishing electrolyte preferably comprises a solution containing phosphoric acid in an alcohol-based solution. The electropolishing electrolyte contains phosphoric acid (H 3 PO 4 For example, an embodiment of the electropolishing electrolyte may comprise a solution of sulfuric acid (H 2 SO 4 ), hydrochloric acid (HCl), and water or C 1 ~C 4It may include phosphoric acid in combination with one or more of the alcohols. In one form, the electrolyte comprises an 85% aqueous solution of phosphoric acid. However, the composition depends on the ion content and other variables including the voltage, current, and temperature of the electropolishing electrolyte.

[0044] In an exemplary embodiment, the electropolishing electrolyte is a food grade (safety) electrolyte bath. Any suitable conductive liquid may be used. In an embodiment, the electropolishing electrolyte is water or C 1 ~C 4 The electropolishing electrolyte comprises an aqueous phosphoric acid solution in combination with one of the alcohols.

[0045] The acid solution concentration, specifically the phosphoric acid solution concentration, can vary from 1% to 90% (i.e. 1 g to 90 g of compound in 100 ml of water), preferably 10% to 90%, in the electrolyte. The solution concentration depends on the type of metal article to be treated (e.g. stainless steel, cobalt-chromium alloy, Ni-Cr alloy, aluminum or Al alloy, titanium or Ti alloy, etc.) and the electrolytic treatment time. In one embodiment, an 85% phosphoric acid solution is used.

[0046] The electrochemical treatment fluid may be applied to the interior surface of the metal article of interest from an electrochemical fluid source by any useful means. In some embodiments, the metal article is immersed in the electrochemical treatment fluid. In some embodiments, the electrochemical treatment fluid is pumped onto the interior surface through a pipe or conduit. In these embodiments, the apparatus further includes an electrochemical treatment fluid feed conduit including at least one fluid outlet positioned in the electrode. This can pump the electrochemical treatment fluid onto the interior surface of the interest and in close proximity to the electrode. The apparatus may also include a coolant conduit including at least one fluid outlet positioned in the electrode. Again, this can pump the coolant onto the interior surface of the interest and in close proximity to the electrode. In embodiments, the electrolyte or solution for the coolant is pumped to the electrode through a conduit, such as a silicone tube, preferably connected in parallel with the flexible conductive body. For example, if the flexible conductive body includes a spring, each conduit may be positioned at or below the center of the spring system.

[0047] The coolant and electrochemical processing fluid may be pumped using any suitable fluid movement system, including, but not limited to, a pump, a syringe, a piston, or the like. In some embodiments, the electrochemical processing fluid or the solution for cooling is pumped into the conduit or passageway with a pump, a syringe, a piston, or the like.

[0048] The electrochemical treatment electrode is typically pulled or otherwise moved through a cavity in the metal article to gradually electrochemically treat the interior surface. In many embodiments, this movement can be actuated or driven using a suitable attractive device to drive the movement of the electrode across the interior surface of the metal article. Examples of attractive devices include a linear actuator or a winch.

[0049] An electrochemical processing power supply or electrochemical processing generator typically involves the use of a suitable AC, DC, or pulsed power supply (controlled voltage or current) to electrically connect both electrodes (i.e., the cathode / electrochemical processing electrode and the anode / metal article).

[0050] The specific current and current density used for electrochemical processing will depend on the specific application and processing regime intended, and it should be understood that a person skilled in the art can apply the most appropriate parameters based on their ordinary general knowledge in the art of electrochemical processing.

[0051] The current may be only direct current, only alternating current, square wave pulsed direct current, sinusoidal pulsed direct current, or a mixture thereof. It should be understood that when a pulsed direct current waveform is used, the applied current waveform is not classical alternating current, and is not exactly direct current. The waveform may be characterized as a square waveform current, which is either an alternating current or a pulsed direct current square wave. In some embodiments, a pulsed direct current square waveform has a longer zero current phase compared to the peak or phase of the applied current. In some embodiments, the current comprises a direct current.

[0052] The shaped waveform of the voltage can be one of square wave, sinusoidal, pulsed, or a combination thereof. In some embodiments, the shaped waveform current comprises a pulse width modulated (PWM) waveform, preferably a square wave pulse, preferably with a variable dead time. In some embodiments, the square wave pulse has a variable dead time. In some embodiments, the pulsed square waveform has a longer zero current phase compared to the peak or phase of the applied voltage.

[0053] A third aspect of the present invention provides a method of electrochemically treating an interior surface of a metal article, comprising the steps of: electrically connecting an electrochemical processing electrode according to the first aspect of the present invention to terminals of a power supply; electrically connecting the metal article to the other terminal of the power source; contacting at least an interior surface of the metal article with an electrochemical processing fluid; moving an electrochemical treatment electrode across an interior surface of the metal article while an electrochemical treatment current is applied between terminals of a power source, whereby at least a portion of the plurality of conductive or non-conductive fibers contact the interior surface of the metal article; thereby electrochemically treating the interior surface. The method includes:

[0054] This third aspect of the invention provides a method of electrochemically treating a metal article using the electrochemical treatment electrode of the first aspect. Again, it should be understood that the electrochemical treatment of the invention can be any electrochemical process in which a power supply (AC or DC) is used to treat a surface. Suitable electrochemical treatment processes include electropolishing, electrolytic cleaning, anodizing, parkerizing, and pickling.

[0055] In a specific embodiment, a third aspect of the invention provides a method of electropolishing a metal article using the electropolishing electrode of the first aspect, the method comprising: electrically connecting an electrochemical treatment electrode according to the first aspect of the present invention to the negative terminal of an electropolishing power supply; electrically connecting the metal article to a positive terminal of an electropolishing power supply; contacting at least an interior surface of a metal article with an electropolishing electrolyte; moving an electrode across the interior surface of the metal article while an electropolishing current is applied between the positive and negative terminals; thereby electropolishing the interior surface. The present invention relates to electrolytic polishing of the interior surface of a metal article, comprising:

[0056] This electropolishing technique can be applied to metal articles with rough internal surfaces to achieve a reduction in surface roughness. Electropolishing aims to present a resulting surface finish free of uneven texture and / or a significantly lower surface roughness value compared to the initial surface roughness value. Suitable metrology methods for quantifying surface roughness include surface stylus profilometry (where the parameters Ra and Rz can be derived from the shape (lines)) and 3D optical surface profilometry (where the parameters Sa and Sz can be derived from the surface area).

[0057] Any suitable metal article can be treated using the electrochemical treatment method of this third aspect of the invention, including a variety of metals. Examples include iron, iron-containing alloys (e.g., tool steel H13, carbon steel (plain), and stainless steel), aluminum and aluminum-containing alloys, titanium and titanium-containing alloys, chromium and chromium-containing alloys, copper alloys, brass alloys, and niobium. In some embodiments, a suitably manufactured metal article treated in the present invention can comprise a chromium-containing metal alloy. As indicated above, these alloys include iron-chromium alloys such as stainless steel, nickel-chromium (nickel-chromium) and its alloys, cobalt-chromium alloys, and cobalt-chromium-molybdenum alloys. In a preferred embodiment, the manufactured metal article comprises a cobalt-chromium alloy.

[0058] In an embodiment, the metal article provides the anode of the electrochemical treatment circuit, and the electrochemical treatment electrode of the first aspect of the invention provides the cathode to complete the electrical circuit. Electrical connection to the electrochemical treatment electrode is typically via the flexible conductive body of the electrochemical treatment electrode, which is connected to the negative terminal of a power source. However, it should be understood that the polarity can be reversed for metal cleaning or parkerizing.

[0059] The electrodes are configured to electrochemically treat an interior surface of a cavity, hollow, channel, or opening in the metal article or product. The interior cavity may have a variety of configurations. In this sense, the interior surface may include at least one surface of any one or more of a channel, hollow, cavity, opening, opening, conduit, tunnel, duct, tube, pipe, flume, slit, chasm, chamber, rut, vessel, groove, valley, through-hole, funnel, or trough, etc.

[0060] As explained above, the flexible element is sized and configured to suit the shape and configuration of the internal cavity being electrochemically processed. For example, if the internal surface is part of a conduit or duct, the length of the flexible element is selected to have a length that complements the radial dimension of the conduit or duct. The conduit or duct can have any dimension. Again, the flexible element does not need to have the same length around the circumference of the flexible conductive body or along the axial length of the flexible conductive body.

[0061] It should be understood that the electrodes can be configured to electrochemically treat the internal surface of any specific dimension of conduit, hollow, or cavity in the metal article. In some embodiments, the internal surface is a portion of a conduit or duct having a diameter between 2 mm and 5 mm. In some embodiments, the conduit or duct can have a diameter between 0.5 mm and 5 mm, for example, a pipe or a pipeline, such as an oil or gas pipeline. In some embodiments, the internal surface is a portion of a conduit or duct having a diameter between 2 mm and 20 mm, preferably between 4 mm and 10 mm, and more preferably between 4 mm and 8 mm. In a specific embodiment, internal conduits as small as 2 mm in diameter and as large as 8 mm in diameter have been electrochemically treated with electrodes made to fit the conduit dimensions. Again, it should be understood that processing can be done as small as the width of the fiber.

[0062] The electrochemical treatment electrode is typically attracted or otherwise moved through the cavity in the metal article to electrochemically treat the interior surface gradually. In embodiments, the electrochemical treatment electrode is moved across the interior surface through the pulling engagement of the flexible conductive body. The electrochemical treatment electrode is preferably in contact with or in close proximity (i.e., in close proximity) to the interior surface as it moves across the interior surface of the metal article. However, it should be understood that in some embodiments, the electrode may be configured to be moved away from the surface during said movement, for example, when the electrode is moved laterally, turned, or otherwise maneuvered within the cavity. Similarly, electrochemical treatment is possible when the electrode and / or flexible element is in close proximity to, but not in direct contact with, the interior surface / treatment surface. An electrolyte is used in these examples to provide a medium through which an electrical connection is made between the electrode and the interior surface / treatment surface of the metal article. Again, in many embodiments, a flexible element, particularly a non-conductive flexible element, is used to space the flexible conductor body and (where applicable) the conductive flexible element from the interior surface / treatment surface of the metal article. The electrochemical treatment electrode can be moved in a single pass across the interior surface. In some embodiments, the electrochemical treatment electrode is moved in at least two passes, and preferably multiple passes, across the interior surface of the metal article to electrochemically treat the interior surface to a desired degree and / or properties. Here, the movement of the electrochemical treatment electrode across the interior surface can include being pulled back across the interior surface during each pass in a direction opposite to the previous movement. This creates a cyclical movement across the interior surface to gradually electrochemically treat that surface.

[0063] In many embodiments, this movement can be actuated or driven using a suitable attraction device to drive the movement of the electrochemical treatment electrode across the interior surface of the metal article. In some embodiments, the method further comprises connecting the electrochemical treatment electrode to a winch or other linear actuator to control the speed of movement of the electrochemical treatment electrode across the interior surface. This allows a non-uniform surface treatment / surface finish to be achieved. Here, a controlled attraction method is used using a stepper motor or linear actuator to ensure that each section of the conduit is affected with the same amount of current for the same length of time.

[0064] The power supply or generator typically includes a suitable AC, DC, or pulsed power supply (controlled voltage or current) that is used to polarize both electrodes (i.e., the cathode / electrochemical processing electrode and the anode / metal article). In some embodiments, the power supply comprises a DC or pulsed voltage or current controlled power supply.

[0065] When the apparatus is used to electropolish a surface, the electrochemical treatment current is: At least one electrolytic polishing regime, each of which has at least 2 A / cm 2 and a voltage having a shaped waveform having a frequency of 2 Hz to 300 kHz, a minimum voltage of at least 0 V, and a maximum voltage of between 0.5 and 500 V. It may be applied in a current regime comprising:

[0066] Again, when the method of the present invention is used for electropolishing, the method works well with the applicant's electropolishing system taught in International Patent Publication WO2020 / 206492. When using this electropolishing / finishing method, accurate predictions of particle removal can be written into the electropolishing step / program, with reliable repeatability of the process.

[0067] As described for the second aspect of the invention, the electrochemical processing fluid can be any suitable fluid used in a particular electrochemical processing process. For example, for electropolishing, an electropolishing electrolyte can be used and can include any suitable conductive liquid. It should be understood that the composition, characteristics, and selection of the electrochemical processing fluid described in relation to the second aspect of the invention apply equally to the third aspect of the invention.

[0068] For electropolishing applications, the pH of the electropolishing electrolyte can be between 1 and 14 depending on its composition. In some embodiments, the pH of the electropolishing electrolyte during the electropolishing method of the present invention is preferably between 1.0 and 7.0, more preferably between 1.0 and 3.0. In one embodiment, the pH of the electropolishing electrolyte is about 1.5.

[0069] The temperature of the electropolishing electrolyte should be maintained at -25 to 350°C, preferably at 0 to 150°C, more preferably at 50 to 100°C, and even more preferably at 60 to 90°C. Again, the temperature of the electropolishing electrolyte depends on the composition of the electropolishing electrolyte. For example, when the phosphoric acid solution reaches 85%, the electropolishing electrolyte is viscous. Thus, the higher the temperature of the electropolishing electrolyte, the better the electrolyte works. The conduction is better at lower concentrations, but the resulting luster of the resulting metal article is not as good. It should also be understood that the current density is temperature dependent and will vary based on the concentration and composition of the electropolishing electrolyte, and therefore based on temperature.

[0070] A cooling method is usually required to maintain the processing temperature range. The metal article may be cooled through a variety of methods, including but not limited to cooling a heat sink, gas flow, or liquid flow. The electrochemical processing fluid, such as the electropolishing electrolyte, is typically maintained at a temperature preferably between 50-100°C, more preferably between 60-90°C, by flow of the electrolyte to or through a heat exchanger. In some embodiments, convection cooling means, such as a fan directed toward the electrochemical processing fluid, may be used. However, in a preferred embodiment, the heat exchanger may be immersed in the electrochemical processing fluid. For example, at small scale (laboratory or development scale), the heat exchanger may comprise a water / ice water bath in which a beaker containing the electrodes and electropolishing electrolyte is immersed. At larger scale (i.e., commercial / industrial processing), the heat exchanger may comprise recirculation of the electrochemical processing fluid and its cooling using a suitable cooling / heat exchange unit. Also, one or more filters may be used to collect metal / metal oxide debris from the electropolishing electrolyte.

[0071] In an embodiment, the electrochemical treatment fluid is pumped in an amount that wets the electrochemical treatment electrode. In this regard, the electrode and / or the interior surface of the metal article being treated are not fully immersed in the electrochemical treatment fluid, but are wetted to the extent that the electrochemical treatment fluid spreads over the interior surface of the metal article. Thus, the electrodes and related methods for electrochemically treating the interior surface of a metal article do not necessarily require the electrochemical treatment electrode and treatment surface to be fully immersed in the electrochemical treatment fluid to operate. A lesser amount of electrochemical treatment fluid may be pumped to the electrochemical treatment electrode that wets the electrode sufficiently to spread over the interior surface of the metal article and is sufficient for operation. In comparison, it is noted that most prior art configurations require submersion by electrochemical treatment fluid or filling of the complete conduit with electrochemical treatment fluid (electrolyte).

[0072] A chemical clean after the electrochemical treatment may be required to remove any loose material compounds on the surface of the metal and, if applicable, to allow the natural passivation layer to reform around the metal alloy.

[0073] The electrochemical treatment methods of the present invention may be carried out in a conventional electrochemical treatment compartment where the metal article is immersed in an electrochemical treatment fluid, or may be carried out with non-immersion techniques, such as brush applied electrochemical treatment techniques.

[0074] In some embodiments, the electrochemical processing fluid is contained in the electrochemical processing compartment. For electropolishing applications, the metal article is immersed in the electropolishing electrolyte and electropolishing is carried out within the electrolyte and in the container / vessel holding the electropolishing electrolyte. In this type of conventional electropolishing, the metal article is connected to the positive terminal of a power supply in a bath of electrolyte, thereby becoming the anode. The electropolishing electrode of the first aspect of the invention is the cathode, and is connected to the negative terminal of the power supply, thereby becoming the cathode for ion conduction. The electropolishing electrode is attracted through the internal cavity as described above.

[0075] In submerged electropolishing or surface finishing, the current density used in the method of the present invention can be selected based on the equipment and application.

[0076] In other embodiments, the electrochemical treatment fluid is applied as a fluid flow to / across the interior surface of the metal article. For electropolishing, this technique is known as non-submerged electropolishing and generally involves a flow of electropolishing electrolyte applied to the interior surface of the metal article in question, such as through a conduit with an outlet proximate to the electrode, and a conductive electropolishing electrode, immersed in the electropolishing electrolyte, moving across the surface to electropolish the surface surrounding the conductive electrode.

[0077] In this non-submerged method, the metal article is connected to the positive terminal of a power supply, thereby becoming the anode. A cathode comprising an electropolishing electrode of the first aspect of the invention is connected to the negative terminal of the power supply. The electropolishing electrode is configured as detailed above and is brought into engagement with a selected portion of the interior surface of the metal article.

[0078] In use, the electrolyte is pumped (typically from a reservoir) to a selected portion of the surface of the metal article to submerge a portion of the cathode and the surface of the metal article, thereby forming an electropolishing section on the surface of the metal article. A coolant may be provided to cool the electropolishing area. Examples of this electropolishing technique are taught in patent publications WO2009 / 105802, AU2013242795A1, and AU2017204328A1, the contents of which should be considered incorporated herein by this reference.

[0079] In non-submerged electropolishing or surface finishing, the current density used in the method of the present invention can be selected based on the equipment and application.

[0080] It should be understood that the dimensions (part dimensions) of metal articles and devices treated by the method of the present invention are scalable as the applied current regime is applied using a control system that can operate multiple inverter mobile batteries in parallel to achieve the desired output current / current density. Therefore, the method of the present invention can be similarly applied to electrochemically treat a portion of the dimensions of a golf ball and a portion of the dimensions of an automobile by scaling up the dimensions of the electrochemical treatment device and the inverters for applying the applied current regime.

[0081] A fourth aspect of the present invention provides an electrochemical treatment electrode configured to contact an interior surface of a metal article with an electrochemical treatment fluid, comprising: a flexible conductive body; a plurality of flexible elements connected to the flexible conductive body and extending generally outwardly of the flexible conductive body and configured to position an electrochemical treatment fluid about the flexible conductive body; Equipped with The flexible element comprises at least one flexible sheet or flexible body, or The electrode is preferably an electrochemical processing electrode further comprising at least one flexible sheet or flexible body connected to a flexible conductive body extending from or positioned adjacent to, between, and / or around the multiple flexible elements.

[0082] In an embodiment of this fourth aspect, the electrode comprises a flexible conductive body and a flexible element is connected to or extends through the flexible conductive body. The flexible element comprises at least one flexible sheet or body, or the electrode preferably further comprises at least one flexible sheet or body connected to the flexible conductive body, extending from or disposed adjacent, between and / or around a plurality of flexible elements. It should be understood that the above disclosure of the features of the invention in relation to the first aspect of the invention applies equally to this fourth aspect of the invention.

[0083] The flexible sheet or body is typically formed of, positioned adjacent to, disposed within, and / or surrounded by the flexible element, and acts as both an additional conductor and, in some instances, an absorbent for carrying any electrochemical processing fluids, such as electrolytes, used in the electrochemical processing procedure. Any suitable flexible sheet or body may be used, such as, for example, one or more foams, sponges, or fibrous materials. When the flexible sheet / body comprises a foam, any suitable foam may be used, such as natural foam or polymeric foam. In an embodiment, the foam comprises a high temperature foam, such as Intek® PFI-1120 high temperature foam. Similarly, any suitable fibrous material may be used, including woven and non-woven materials. In an embodiment, the fabric may be a fiberglass-based fabric, a carbon fiber-based fabric, or a 1.0 g / cm ZOPIN. 3 The flexible sheet comprises high temperature fibers such as . The flexible sheet is used to carry electrochemical processing fluids and may be preferably conductive to assist in the electrochemical processing of said interior surface of the metal article depending on the metal being processed. For example, the flexible sheet may be conductive for nickel alloys. In other embodiments, the flexible sheet may be non-conductive, for example for aluminum alloys. In one embodiment, the flexible sheet or body comprises a foam element configured to extend over and surround the electrode and the plurality of flexible elements. The foam element preferably comprises a sheath or other surrounding body that extends around the electrode and the plurality of flexible elements. The plurality of flexible elements preferably extend into the foam material, thereby providing conductive paths / elements within the foam material. However, it should be understood that the flexible sheet or body may be configured to extend over and surround the electrode using a variety of other means that may connect to or otherwise position the flexible sheet or body around the flexible conductive body.

[0084] A fifth aspect of the present invention provides an apparatus for electrochemically treating an internal surface of a metal article, comprising: At least one electrochemical treatment electrode according to the fourth aspect of the invention; an electrochemical treatment fluid source configured to provide an electrochemical treatment fluid onto the flexible element of the electrode and onto an interior surface of the metal article; Power supply and Equipped with An apparatus in which an electrochemical process electrode is connected to one terminal of a power supply and a metal article is connected to the other terminal of the power supply.

[0085] It is to be understood that the above disclosure of features of the invention relating to the second aspect of the invention applies equally to this fifth aspect of the invention.

[0086] A sixth aspect of the present invention provides a method of electrochemically treating an internal surface of a metal article, comprising the steps of: electrically connecting an electrochemical processing electrode according to the fourth aspect of the present invention to terminals of a power supply; electrically connecting the metal article to the other terminal of the power source; contacting at least an interior surface of the metal article with an electrochemical processing fluid, preferably an electrolyte; moving the electrochemical treatment electrode across the interior surface of the metal article while an electrochemical treatment current is applied between the terminals of the power source, wherein at least a portion of the plurality of conductive or non-conductive fibers contacts the interior surface of the metal article; thereby electrochemically treating the interior surface. The method includes:

[0087] It is to be understood that the above disclosure of features of the invention relating to the third aspect of the invention applies equally to this sixth aspect of the invention.

[0088] The present invention will now be described with reference to the accompanying drawing figures, which show specific preferred embodiments of the invention. [Brief description of the drawings]

[0089] [Figure 1] FIG. 2 is a front view of an electrochemical processing electrode according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a perspective view of the electrochemical processing electrode shown in FIG. 1. [Figure 3A] FIG. 2 is a front view of an electrochemical processing electrode according to one embodiment of the present invention, including a blend of flexible fibers. [Figure 3B] FIG. 3B is a first detailed view of circle A in FIG. 3A showing a mixed carbon fiber and Kevlar fiber embodiment of an electrochemical processing electrode. [Figure 3C] FIG. 2 is a front view of an electrochemical processing electrode according to another embodiment of the present invention, including a blend of flexible fibers. [Figure 3D] FIG. 3D is a second detail of circle A1 in FIG. 3C showing a mixed carbon fiber and Kevlar fiber embodiment of the electrochemical treatment electrode. [Figure 4A] FIG. 1 is a perspective view of an electrochemical processing electrode according to one embodiment of the present invention including a spring-based fiber connector. [Figure 4B] FIG. 2 is a front view of an electrochemical processing electrode according to one embodiment of the present invention including a spring-based fiber connector. [Figure 4C] FIG. 4C is a detailed view of circle B in FIG. 4B showing a mixed carbon fiber, Kevlar, and fiberglass embodiment of the electrochemical processing electrode. [Figure 5A] FIG. 1 is a perspective view of an electrochemical processing electrode according to one embodiment of the present invention, including a flexible sponge sheath. [Figure 5B] FIG. 5B is a detailed view of circle C in FIG. 5A. [Figure 6A] FIG. 1 is a perspective view of an electrochemical processing electrode according to one embodiment of the present invention comprising a flexible fiberglass sheet containing aluminum wires. [Figure 6B] FIG. 6B is a detailed view of the electrochemical treatment electrode along section DD of FIG. 6A. [Figure 7A] FIG. 2 is a diagram of an electrochemical processing electrode shaped into a sphere, according to an embodiment of the present invention. [Figure 7B] FIG. 2 is a diagram of an electrochemical processing electrode shaped into a sphere, according to an embodiment of the present invention. [Figure 8] FIG. 5 is a schematic diagram of an electrochemical processing device including the electrochemical processing electrode shown in one of FIGS. 1-4C. [Figure 9] FIG. 4B is a schematic diagram of an immersion electrochemical treatment device including an electrochemical treatment electrode as shown in one of FIGS. 1-4C. [Figure 10] FIG. 4B is a schematic diagram of a non-submerged electrochemical processing device including an electrochemical processing electrode as shown in one of FIGS. 1-4C. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0090] The present invention provides electrodes, associated electrochemical treatment systems, and methods that can be used to electrochemically treat the interior surfaces of cavities, hollows, channels, or openings in additively manufactured (3D printed) metal articles or products, such as heat exchangers or engine parts.

[0091] The electrochemical process of the present invention can be any electrochemical process in which a power supply (AC or DC) is used to treat a surface. Suitable electrochemical processes include electropolishing, electrocleaning, anodizing, parkerizing, and pickling. However, the following materials are exemplified in the context of an electropolishing application. It should be understood that the present invention is not limited to this application and can be applied to a variety of electrochemical processes.

[0092] 1 and 2 show an electrochemical processing electrode 100 according to one embodiment of the present invention. As shown, the electrochemical processing electrode 100 has two main sections: (1) a flexible conductive body 110 formed from two long strands of flexible conductive wire 111, 112, e.g., partially stripped magnet wire or the like; (2) a plurality of flexible elements 120 connected to the flexible conductive body 110 and extending generally radially outwardly of the flexible conductive body 110; In the illustrated embodiment, the flexible element 120 comprises carbon fiber bristles or strands that directly contact the conductive surfaces of the flexible conductive wires 111, 112 at the connection zone 122. However, as will be explained later, the flexible element can be any suitable flexible fiber and can comprise and / or be intermixed with non-conductive fibers.

[0093] Each carbon fiber is fixed in place in the connection zone 122 by being placed between two long strands of flexible conductive wires 111, 112, which are then twisted around the carbon fiber bristles to clamp or otherwise compressively engage the carbon fiber bristles between the flexible conductive wires 111, 112. Thus, in this conductive fiber embodiment, electrical current can flow through the flexible conductive body 110, through the connection zone 122, through the multiple flexible elements 120 to the application surface, and further through the metal article to be electrochemically treated to facilitate electrochemical treatment of the interior surface of the metal article (as shown below).

[0094] The flexible conductive body 110 also functions to position the electrochemical processing fluid around the flexible conductive body. In this embodiment, the use of a plurality of closely spaced bristles together provide adjacent elements and surface area to hold an electrochemical processing fluid, such as an electrolyte, around the conductive body 110 when in a hollow, channel, or opening in the metal article being electrochemically processed. Here, the plurality of bristles form a flexible brush on and within which the passing fluid of the electrochemical processing fluid, typically a viscous fluid, interacts with the bristles.

[0095] The dimensions of the flexible element 120 are typically configured to match the dimensions of the conduit or duct of the metal article undergoing electrochemical processing, and the length of the flexible element 120 is typically similar to or slightly larger than the radius of the conduit or duct. The flexible element 120 is designed to be flexible enough to elastically deform so that the electrode 100 can be inserted into and moved through a cavity, hollow, conduit, or opening in the metal article. The illustrated flexible element 120 comprises carbon fiber bristles having a length of 22 mm along the unidirectional plane and a strip of 200 mm length adjacent the unidirectional plane. However, it should be understood that any suitable conductive, preferably elastic, flexible strip, filament, whisker, fiber, or the like can be used. For example, the flexible element 120 can comprise a plurality of carbon fibers, metal fibers, or a mixture of different types of conductive and elastic fibers.

[0096] As shown in Figures 3A-3D, some embodiments further include a plurality of non-conductive fibers 121 intermingled with the conductive flexible element 120 (e.g., carbon fiber) and extending generally radially outward of the flexible conductive body 110. Examples of non-conductive fibers 121 include fiberglass as shown in Figures 3C and 3D, polyparaphenylene terephthalamide (Kevlar) as shown in Figure 3B, or a blend of polyparaphenylene terephthalamide (Kevlar) and fiberglass as shown in Figure 4C. However, it should be understood that any suitable high temperature non-conductive fiber can be used. The non-conductive fibers 121 are secured in place in the connection zone 122 using the same connection arrangement as the conductive fibers 120. For example, in Figures 3B and 3D, the non-conductive fibers 121 are held between the wire twists of two long strands of the flexible conductive wires 111, 112. In FIG. 4B, the non-conductive fiber 121 is held between the turns of the spring conductive body 125.

[0097] It should be noted that in Figures 3B and 3D, the carbon fiber strands 120 have a shorter length than the non-conductive fibers 121 (fiberglass in Figure 3D, Kevlar in Figure 3B). The longer non-conductive fibers ensure that the shorter conductive carbon fibers are properly spaced from the surface being electrochemically treated to reduce sparks or other high voltage discharge type events.

[0098] The flexible conductive body 110 shown in Figures 1 and 2 comprises two elongated flexible wires 111, 112 that define a longitudinal axis XX along its length. Thus, a plurality of flexible elements 120 are electrically connected to the flexible conductive body 110 and extend generally radially outward of the longitudinal axis XX of the flexible conductive body 110. Again, any suitable conductive wire may be used, such as a metal wire, such as stainless steel, gold, copper, aluminum, or any other metal or conductive material that exhibits good conductivity and corrosion resistance. In Figures 1 and 2, the elongated flexible wires 111, 112 comprise magnet wire, such as Beldsol double insulated magnet wire (available from Belden Cable), which combines the excellent dielectric properties of polyurethane with the robustness and solvent resistance of a nylon overcoat.

[0099] Each flexible wire 111, 112 includes an insulating coating or sleeve 115 over the non-electrically connected surface. The insulating coating or sleeve 115 may comprise a dielectric coating, for example, as a polymer coating, such as an enamel or urethane coating. Exemplary coatings include 4228 Red Insulating Varnish, CRC Urethane Seal Coat. It should be understood that if a flexible conductive body 110, such as a metal wire, is provided with an insulating coating or sleeve 115, the coating may be partially removed (e.g., exposed) at the connection zone 122 to expose the conductive material of the conductive body at the connection zone 122 to facilitate electrical contact and connection between the flexible conductive body 110 and the plurality of flexible elements 120.

[0100] The flexible conductive body 110 has a sufficient length so that an end can be connected to a suitable electrical terminal (cathode) of a power supply of an electropolishing apparatus (such as shown in Figures 8 and 9, described later) and also to extend through any necessary cavity, void, conduit, or opening in the metal article. As shown in Figures 3C and 3D, three or more flexible elements may be used to conduct electricity from a power source and to electrically connect and secure the flexible element 120 to the non-conductive fiber 121. Here, three sets of flexible wires 111, 112, and 112A are used.

[0101] Although the illustrated embodiment shows the flexible elements 120 connected to the flexible conductive body 110 through a compressive engagement by twisting the flexible conductive wires 111, 112, this conductive connection can be made by a variety of other suitable means. For example, the flexible elements 120 may be connected to the flexible conductive body through weaving, gluing, welding, inlaying, wedging, embedding, bonding, anchoring, or combinations thereof. In specific embodiments, the multiple flexible elements 120 are fastened, crimped, pressed, or tied into connection with the flexible conductive body 110. In still other embodiments, the multiple flexible elements 120 are pressed, crimped, soldered, welded, or glued to the flexible conductive body 110.

[0102] 4A, 4B, and 4C show an embodiment of the electrode 200 in which the flexible element 220 is spring-retained. Here, the connection zone 220 of the elongated flexible conductive body 210 comprises at least one tension spring 225. The tension spring 225 extends through the connection zone 220 and is electrically connected to the flexible wires 211, 212 that extend to a power source (not shown) as described for the embodiment shown in FIG. 1. The flexible element 220 is connected to the flexible conductive body through a compressive engagement between adjacent coils of the spring 225. In the illustrated embodiment, the flexible element 220 comprises carbon fiber intermixed with a blend of polyparaphenylene terephthalamide (Kevlar) and fiberglass, and is also connected to the flexible conductive body through a compressive engagement between adjacent coils of the spring 225.

[0103] 5A-7B show further and / or alternative embodiments of electrodes of the present invention.

[0104] 5A and 5B show an embodiment of the electrode 300 further comprising at least one flexible sheet or body in the form of a foam sheath 330 connected to the flexible conductive body 310 through a plurality of flexible elements 320. The foam sheath 330 forms a flexible body disposed around and surrounding the connection zone 322. As shown in FIG. 5B, the flexible elements are embedded in the foam sheath 330 so that electrical current can be transferred from the flexible conductive body 310 to the foam sheath 330. In most embodiments, the foam sheath 330 provides a sorbent for carrying any electrochemical processing fluid, such as the electropolishing electrolyte used in the electropolishing procedure. Again, the electrochemical processing fluid is typically a conductive fluid. Any suitable foam material may be used, such as natural or polymeric foams or sponges. In an embodiment, the foam comprises a high temperature foam, such as Intek® PFI-1120 high temperature foam (available from Trelleborg Applied Technologies). In the illustrated embodiment, the flexible element 320 comprises carbon fiber that is connected to the flexible conductive body 310 through a compressive engagement by twisting the flexible conductive wires 311, 312 as described above for other embodiments. Here, the flexible element holds the foam sheath 330 in place and, if conductive, including for example carbon fiber or metal elements, supports the flow of electrical current from the flexible conductive body 310 through the electrochemical treatment fluid filled / contained foam sheath 330 onto the surface to be electrochemically treated. However, it should be understood that this conductive connection can be made by a variety of other suitable means as described above. In other embodiments, the foam sheath 330 may be replaced by a fibrous material sheath. The fibrous sheath may be formed from any suitable fiber, including woven or non-woven fibrous materials. Similar to the foam sheath 330, the flexible sheath may be used to carry (e.g., wet) electrolyte and may be preferably conductive to support the electrochemical treatment of said interior surface of the metal article.

[0105] 6A and 6B show an embodiment of an electrode 400 further comprising a fiberglass flexible element 420 having fiberglass fiber lengths of different lengths at a connection zone 422 around the flexible conductive body 410. The flexible conductive body 410 has a similar configuration to the twisted wire embodiment described in connection with FIG. 1. Here, however, the radial length of the fiberglass flexible element 120 varies around the circumference of the conductive body 410. As shown, the first section 420A has a longer length than the second section 420B. The length can be configured to match the shape or configuration of a particular cavity or internal opening that the electrode is configured to electrochemically process.

[0106] 7A and 7B show an embodiment of an electrode 500 comprising a flexible sphere or ball 525 comprising multiple flexible elements 520 extending from a surface. In this embodiment, a flexible conductive body 510 comprises flexible wires 511 and 512 that connect to a power source (not shown) at one end and to the flexible ball 525 at the other end. The flexible ball 525 is formed from a foam core, typically high temperature foam, that may have some conductive properties. The foam is used to absorb and hold electrochemical treatment fluids that may be applied to the surface to be treated. The foam ball comprises and / or is attached to a series of concentric ribs, strips, or flanges that form the flexible element 520 that extends outwardly from the flexible ball 525. The flexible element 520 is formed from a carbon fiber mix formed as a molded shape. The flexible ball 525 may include one or more conductive elements therein, such as wires or fibers (not shown), to assist in conducting electrical current from the flexible wires 511 and 512 to the outer surface of the flexible ball. It should be noted that in other embodiments, the flexible ball 525 may include an internal cavity, or even be hollow, and may include within it a series of flexible elements, such as conductive elements, e.g., wires or springs, that are used to hold the electrochemical processing fluid around the conductive body and conduct electrical current from the conductive body to the exterior surface of the flexible ball 525. It should be understood that the foam shape has a shape memory such that it follows along the interior surface expanding and contracting as it is drawn through the diameter and shape of the changing interior passages.

[0107] Finally, although not shown, it should be understood that in some embodiments, a plurality of conductive particles are positioned adjacent and / or between a plurality of flexible elements. The conductive particles provide an additional conductor means that can be mixed into the electrolyte to shorten the gap of the electrolyte to the interior surfaces being electrochemically processed to minimize the resistance of the circuit within the cavity, or can form a low resistance electrolyte-fiber composite to accomplish this task.

[0108] Figure 8 provides a schematic diagram of a generic electrochemical processing device 600 that can incorporate the electrodes 100, 100A, 100B, 200, 300, 400, 500 shown in Figures 1-7C. The electrochemical processing device 600 shown includes an inverter power supply 630 capable of delivering a desired current waveform (direct current, pulsed direct current, or variable frequency alternating current) in short pulses. The inverter power supply 630 can include a computer controller (not shown).

[0109] The illustrated metal article 690 includes an internal conduit 692 that includes the interior surface that needs to be electrochemically treated. The metal article 690 is electrically connected to one terminal 680 of the power supply 630, and the other terminal 685 of the inverter power supply 630 is connected to the electrochemical treatment electrode 100. The electrochemical treatment electrode 100 is shown in FIG. 8 as the embodiment described and illustrated in connection with FIG. 1. However, it should be understood that each of the other embodiments of the electrodes 100, 100A, 100B, 200, 300, 400, 500 shown in FIGS. 1-7C can be used as well. An electrochemical treatment fluid, such as an electrolyte, can be applied to the electrode 100 and the metal article 690 to complete the electrical circuit.

[0110] Although not explicitly shown in FIG. 8, the apparatus 600 also includes an electrochemical processing fluid on and around the electrode 100 provided by an electrochemical processing fluid source (not shown in FIG. 8) configured to provide the electrochemical processing fluid onto the flexible element of the electrode 100 and onto the interior surface of the metal article 690. The electrochemical processing fluid source may be a pump system as shown and described below in connection with FIG. 10, or may be an immersion system as described below in connection with FIG. 9. As previously described, the electrochemical processing fluid is preferably a conductive fluid, such as an electrolyte, that assists in conducting electrical current from the electrode to the surface being treated to facilitate the desired electrochemical processing.

[0111] The electrochemical processing is carried out by using a power supply 630 to apply a current and voltage difference between the metal article 690 and the electrode 100, and moving the electrode 100 across the interior surface of the metal article while the current is applied. During this procedure, the interior surface of the metal article 690 is contacted with an electrochemical processing fluid, such as an electrolyte, to provide good electrical contact and conduction between the electrode 100 and the interior surface of the metal article 690.

[0112] FIG. 9 provides a schematic diagram of an exemplary electropolishing apparatus 700 that can incorporate the electrodes 100, 100A, 100B, 200, 300, 400, 500 shown in FIGS. 1-7C. The illustrated electropolishing apparatus 700 includes an electrolysis compartment 710 having an electrolyte reservoir 720 configured to position an electropolishing electrolyte 740. The electropolishing apparatus 700 includes an inverter power supply 730 capable of delivering a desired current waveform (direct current, pulsed direct current, or variable frequency alternating current) in short pulses. The inverter power supply 730 is controlled by a computer controller 735.

[0113] The metal article 790 shown includes an interior conduit 792 that includes the interior surface that needs to be electropolished. The metal article 790 is electrically connected to a positive terminal 785 of an inverter power supply 730, and the negative terminal 780 of the inverter power supply 730 is connected to an electropolishing electrode 100 (acting as the cathode) that also includes a container containing an electrolyte 740. The metal article 790 is suspended in a reservoir 720 of electrolyte 740 forming a complete electrical circuit with the electropolishing electrolyte 740.

[0114] Electrode 100 is shown in Figure 9 as the embodiment described and illustrated in connection with Figure 1. However, it should be understood that each of the other embodiments of electrodes 100, 100A, 100B, 200, 300, 400, 500 shown in Figures 1-7C can be used as well.

[0115] Although not shown, the electropolishing apparatus 710 may also include a mixing device, such as a mixing rotor, to agitate / mix the electropolishing electrolyte 740 and ensure uniform distribution of the electrolyte 740 around the metal article 790 and the electrode 100.

[0116] A computer controlled inverter power supply 730 is used to apply a current and voltage difference between the metal article 790 and the electrode 100. A computer 735 executes a program that steps the inverter 730 (power supply) through an applied current regime that includes a range of voltages / currents and frequencies that are predetermined to be optimal for the particular metal article 790 and the containing material being polished. For a given electropolishing electrolyte, the amount of metal removed from the metal article is proportional to the amount and time of current applied. Other factors such as the shape of the metal article affect the distribution of the current and, as a result, have a significant effect on the amount of metal removed in a localized area.

[0117] As previously mentioned, the electrodes 100, 100A, 100B, 200, 300, 400, 500 shown in Figures 1-7C and the electropolishing system 700 shown in Figure 9 work particularly well to use / embodiment the applicant's electropolishing system taught in International Patent Publication WO2020 / 206492. When used in the electropolishing system of WO2020 / 206492, the wire can be designed to carry the large currents required and the enamel (wire coating) melting point can be managed by duty cycle and wait / cooling times.

[0118] Electropolishing is performed in the electropolishing electrolyte 740 of the electropolishing apparatus 700 at a temperature ranging from -25°C to 200°C, preferably 0°C to 150°C. In an embodiment, the electropolishing electrolyte 740 is maintained at a temperature of about 50°C to 100°C, preferably 60°C to 90°C. The electropolishing apparatus 700 may also include a combined temperature probe / heating and cooling unit (not shown) that may be attached to the computer controller 735 or another controller (not shown) to monitor and control the temperature of the electropolishing electrolyte 740. A cooling method is typically required to maintain the processing temperature range. The metal article 790 may be cooled through a variety of methods, including but not limited to cooling a heat sink, a gas stream, or a liquid stream. The electropolishing electrolyte is typically maintained at a temperature between 50°C to 100°C, more preferably between 60°C to 90°C, by flow of electrolyte to or through a heat exchanger.

[0119] The electropolishing electrolyte 740 is typically an 85% concentration solution of phosphoric acid (H 3 PO 4 ) based solution. However, the electropolishing electrolyte 740 may include other components. For example, in some embodiments, the electropolishing electrolyte 740 includes a sulfuric acid (H 2 SO 4 ), hydrochloric acid (HCl), or phosphoric acid (H 3 PO 4 ), and one of water or a C1-C4 alcohol. Other electropolishing electrolyte compositions are possible. The pH of the electropolishing electrolyte 740 can be between 1 and 14 depending on its composition.

[0120] FIG. 10 shows a schematic diagram of a non-submerged electrochemical processing apparatus 800 including an electropolishing electrode 100, 100A, 100B, 200 as shown in one of FIGS. 1-4C. In these embodiments, the electropolishing electrolyte is applied as a fluid stream onto the surface of the metal article 890 using a pump 850 in which the electrolyte is pumped from a reservoir (not shown) through an inlet conduit 852 to the electropolishing electrode 100 and the metal article. Such electropolishing techniques are known as non-submerged electropolishing and generally involve a stream of electropolishing electrolyte being applied to the surface of the metal article 890, with the conductive electrode 100 being immersed in the electropolishing electrolyte and moved across the surface to electropolish the surface surrounding the conductive electrode 100.

[0121] Electrode 100 is shown in Figure 10 as the embodiment described and illustrated in connection with Figure 1. However, it should be understood that each of the other embodiments of electrodes 100, 100A, 100B, 200, 300, 400, 500 shown in Figures 1-7C can be used as well.

[0122] In this non-submerged method, the metal article 890 is connected to one terminal 880 of the power supply 830, thereby becoming the anode. The electropolishing electrode 100 shown in Figures 1 and 2 is connected to the other terminal 885 of the power supply 830 and acts as the cathode for the electropolishing system 800.

[0123] In use, electrolyte is pumped from a reservoir (electrolyte bottle 854) to selected portions of the surface of the metal article 890 to submerge portions of the electrode 100 and the surface of the metal article 890, thereby forming an electropolishing zone on the surface of the metal article 890. In some embodiments, a coolant may also be provided to cool the electropolishing area. Again, examples of this electropolishing technique are taught in patent publications WO2009 / 105802, AU2013242795A1, and AU2017204328A1.

[0124] In this non-submersion method, the electrolyte may be applied to the interior surface of the metal article of interest by any useful means. As shown, the electrolyte is pumped onto the interior surface through an electrolyte feed conduit 852 including a fluid outlet positioned in the electrode 100. Typically, the conduit is positioned along or parallel to the flexible wires 111, 112, with an outlet or nozzle (not shown) positioned in the flexible element 120. This can pump the electrolyte onto the interior surface of the interest and into the vicinity of the electrode 100. The apparatus 800 may also include a coolant conduit (not shown) including at least one fluid outlet positioned in the electrode 100, more specifically in the flexible element 120. Again, this can pump the coolant onto the interior surface of the interest and into the vicinity of the electrode. The coolant and electrolyte may be pumped using any suitable fluid transfer system, such as a pump, syringe, piston, or the like.

[0125] In each embodiment, the electropolishing electrode 100 can be attracted or otherwise moved through a cavity in a metal article to gradually polish the interior surface. This movement can be actuated or driven using a suitable attracting device, such as a linear actuator, winch, or the like.

[0126] In use, metal articles 790, 890 may be electropolished using the apparatus shown in Figures 9 and 10 using the following steps. 1. The terminal end 105 of the flexible conductive body 110 of the electrode 100 is connected to the negative terminal 780, 880 of the electropolishing power supply 730, 830, and the attracting end 106 of the flexible conductive body 110 may be attached (if applicable) to a suitable attracting device (not shown). 2. A metal article 790, 890 is connected to the positive terminal 785, 885 of the electropolishing power supply 730, 830. 3. An electrolyte is then applied to the inner surfaces of the channels 792, 892 of the metal articles 790, 890 and to the electrode 100, either by immersion (using the immersion arrangement shown in FIG. 8) or through the electrolyte inlet conduit 852 (if using the non-submerged arrangement shown in FIG. 9). 4. The electrode 100 is then moved across the interior surface of the metal article 790, 890 while an electropolishing current is applied between the positive terminal 785, 885 and the negative terminal 780, 880. The electrode 100 is now slowly pulled from the attracting end 106 of the flexible conductive body 110 through the conduit 592 to be polished. If another pass is required, the negative terminal 780, 880 of the electropolishing power supply 730, 830 can be connected to the attracting end 106 of the flexible conductive body 110 and the electrode 100 is pulled back through the conduit 592 in the opposite direction.

[0127] The electropolishing electrode 100 can be moved in one or more passes, preferably multiple passes, across the interior surface of the metal article 790, 890 to polish the interior surface to a desired surface roughness, where movement of the electropolishing electrode 100 across the interior surface through the conduit 592 can include being pulled back across the interior surface during each pass in a direction opposite to the previous movement. This creates a cyclical movement across the interior surface, gradually polishing that surface.

[0128] As explained above, the flexible element 120 is sized and configured to suit the shape and configuration of the interior cavity to be electropolished. For example, if the interior surface is part of a conduit or duct, the length of the flexible element 120 is selected to have a length that complements the radial dimension of the conduit or duct.

[0129] The electropolishing power supply or electropolishing generator 730, 830 typically includes a suitable AC, DC, or pulsed power supply (controlled voltage or current) that is used to polarize both electrodes (i.e., the cathode / electropolishing electrode and the anode / metal article). In some embodiments, the electropolishing power supply comprises a DC or pulsed voltage or current controlled power supply.

[0130] As previously mentioned, this electropolishing method works well with the applicant's electropolishing system taught in International Patent Publication WO2020 / 206492. Using this electropolishing / finishing method, accurate predictions of particle removal can be written into the electropolishing step / program, along with providing reliable repeatability of the process.

[0131] A chemical clean after electropolishing may be required to remove any loose material compounds on the surface of the alloy and, if applicable, to allow the natural passivation layer to reform around the metal alloy.

[0132] The electropolishing electrodes, apparatus, and methods of the present invention can be used to electropolish a variety of metals. Examples of suitable metals include iron and iron-containing alloys (such as tool steel H13, carbon steel (plain), stainless steel, etc.), aluminum and aluminum-containing alloys, titanium and titanium-containing alloys, chromium and chromium-containing alloys, copper alloys, brass alloys, and / or niobium. In particular, the present invention can be used to electropolish those metals and metal alloys that have a protective oxide coating. Examples of metals and metal alloys that can be used with the electropolishing method include stainless steel, chromium-based metal alloys such as nickel-chromium (nickel-chromium), nickel-chromium alloys, cobalt-chromium alloys, cobalt-chromium-molybdenum alloys, and titanium, titanium alloys, nickel alloys such as nitinol, aluminum, or aluminum alloys.

[0133] Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described, and it is understood that the invention includes all such variations and modifications that fall within the spirit and scope of the invention.

[0134] The terms "comprise", "comprises" or "comprising", when used in this specification (including the claims), are to be interpreted as specifying the presence of stated features, integers, steps or components but not excluding the presence of one or more other features, integers, steps. [Explanation of symbols]

[0135] 100, 100A, 100B Electrochemically treated electrodes, electrolytic polishing electrodes 105 Terminal end 106 Attracting End 110 Flexible conductive body 111, 112, 112A Flexible Conductive Wire, Long Flexible Wire 115 Insulating coating or sleeve 120 Conductive flexible elements, conductive fibers, carbon fiber strands 121 Non-conductive fibers 125 Spring Conductive Body 200 electrodes 211, 212 Flexible wire 220 Flexibility Element 225 Tension Spring 300 electrodes 310 Flexible conductive body 320 Flexibility Element 322 connection bandwidth 330 Foam sheath 400 electrodes 410 Flexible conductive body 420 Flexibility Element 422 connection bandwidth 500 electrodes 511, 512 Flexible wire 520 Flexibility Element 525 Flexible ball or ball 592 Conduit 600 Electrochemical Treatment Equipment 630 Inverter power supply unit 680, 685 terminals 690 Metal articles 692 Internal conduit 700 Electrolytic polishing equipment, electrolytic polishing system 710 Electrolytic compartment, electrolytic polishing device 720 Electrolyte Reservoir 730 Inverter power supply, electrolytic polishing power supply, electrolytic polishing generator 735 Computer Controlled Devices 740 Electropolishing electrolyte 780 Negative Terminal 785 positive terminal 790 Metal articles 792 Internal conduit 800 Electrochemical treatment equipment, electrolytic polishing system 830 Power supply unit, electrolytic polishing power supply, electrolytic polishing generator 850 Pump 852 Inlet Pipe 854 Electrolyte Bottle 880 Negative Terminal 885 positive terminal 890 Metal articles XX Longitudinal axis

Claims

1. An electrochemical process electrode configured to contact an interior surface of a metal article with an electrochemical process fluid, a flexible conductive body; a plurality of flexible elements connected to the flexible conductive body and extending generally outwardly of the flexible conductive body and configured to position an electrochemical treatment fluid about the flexible conductive body; Equipped with 1. An electrochemical processing electrode, wherein the plurality of flexible elements includes a plurality of conductive or non-conductive fibers extending generally outwardly of the flexible conductive body, the plurality of conductive or non-conductive fibers being configured to contact the interior surface of the metal article when the electrode is in use.

2. The electrochemical processing electrode of claim 1 , wherein the flexible elements include a plurality of wires, strips, cords, filaments, hairs, barbs, fibers, whiskers, or bristles.

3. 3. The electrochemical processing electrode of claim 1 or 2, wherein the flexible element comprises a conductive element, a non-conductive element, or a mixture thereof.

4. 4. The electrochemical processing electrode of claim 1, wherein the plurality of conductive or non-conductive fibers comprises conductive fibers comprising at least one of carbon fibers, metal wires, or a mixture thereof.

5. 5. The electrochemical processing electrode of claim 1, wherein the plurality of conductive or non-conductive fibers includes non-conductive fibers comprising at least one of fiberglass, polyparaphenylene terephthalamide (Kevlar®), or a mixture thereof.

6. 6. The electrochemical processing electrode of claim 1, wherein the plurality of flexible elements are connected to the flexible conductive body through compressive engagement, weaving, adhesion, welding, inlay, wedging, embedding, bonding, anchoring, or combinations thereof.

7. 7. The electrochemical processing electrode of claim 6, wherein the flexible element is fastened, crimped, pressed, or tied into connection with the flexible conductive body.

8. the flexible element comprises at least one flexible sheet or flexible body; or 8. The electrochemical processing electrode of claim 1 , further comprising at least one flexible sheet or body connected to the flexible conductive body, preferably extending from the plurality of flexible elements or positioned adjacent to, between and / or around the plurality of flexible elements.

9. 9. The electrochemical processing electrode of claim 8, wherein the flexible sheet or body comprises at least one of a foam, a sponge, or a fibrous material.

10. 10. The electrochemical processing electrode of claim 8 or 9, wherein the flexible sheet or body comprises a foam or sponge configured to extend across the electrode and the plurality of flexible elements and surrounding the electrode and the plurality of flexible elements.

11. 11. The electrochemical processing electrode of claim 1, further comprising a plurality of conductive particles positioned adjacent and / or between the plurality of flexible elements.

12. The conductive body is a metal wire, preferably a magnet wire, or Carbon fiber wire or long body 12. The electrochemical processing electrode according to claim 1 , comprising:

13. 13. The electrochemical processing electrode of claim 1, wherein the flexible conductive body comprises an elongate flexible conductive body defining a longitudinal axis along its length, and the plurality of flexible elements are connected to the flexible conductive body and extend generally radially outward from the longitudinal axis of the flexible conductive body.

14. 14. The electrochemical processing electrode of claim 13, wherein the elongated flexible conductive body comprises at least two elongated wires that are twisted or otherwise intertwined, and the plurality of flexible elements are connected to the flexible conductive body through a compressive engagement between the at least two elongated wires.

15. 14. The electrochemical processing electrode of claim 13, wherein the elongated flexible conductive body comprises at least one extension spring, the flexible element being connected to the flexible conductive body through compressive engagement between adjacent coils of the spring.

16. 16. The electrochemical processing electrode of claim 1, wherein the conductive body comprises a stainless steel, copper, aluminum, or any other conductive metal wire, or a carbon fiber wire or elongate body.

17. 17. The electrochemical processing electrode of claim 1, wherein the conductive body includes an insulating coating or sleeve over non-electrically connected surfaces.

18. 18. The electrochemical processing electrode of claim 17, wherein the insulating coating or sleeve comprises a dielectric coating, preferably a polymeric coating, more preferably an enamel or urethane coating.

19. 13. The electrochemical processing electrode of claim 1, wherein the conductive body comprises a flexible body including the flexible element extending outwardly from a surface of the flexible body, preferably comprising a sphere, ball, rod, or pipe.

20. 20. The electrochemical processing electrode of claim 19, wherein the flexible body includes an internal cavity, and is preferably hollow.

21. 1. An apparatus for electrochemically treating an interior surface of a metal article, comprising: At least one electrochemical treatment electrode according to any one of claims 1 to 20, an electrochemical treatment fluid source configured to provide an electrochemical treatment fluid onto the flexible element of the electrode and an interior surface of the metal article; Power supply and Equipped with The electrochemical process electrode is connected to a terminal of the power supply and the metal article is connected to the other terminal of the power supply.

22. 22. The apparatus of claim 21, wherein the electrochemical processing fluid source comprises a pump that pumps an electrochemical processing fluid over the electrode and over the interior surface of the metal article.

23. 23. The apparatus of claim 21 or 22, further comprising an electrochemical processing fluid inlet conduit including at least one fluid outlet positioned in the electrochemical processing electrode.

24. 24. The apparatus of any one of claims 21 to 23, further comprising a coolant conduit including at least one fluid outlet positioned in the electrochemical processing electrode.

25. 25. The apparatus of any one of claims 21 to 24, further comprising an attraction device for driving movement of an electrochemical treatment electrode across the interior surface of the metal article.

26. 1. A method for electrochemically treating an interior surface of a metal article, comprising: Electrically connecting the electrochemical processing electrode according to any one of claims 1 to 20 to a terminal of a power supply; electrically connecting the metal article to the other terminal of the power source; contacting at least an interior surface of the metal article with an electrochemical processing fluid, preferably an electrolyte; moving the electrochemical treatment electrode across the interior surface of the metal article while an electrochemical treatment current is applied between the terminals of the power source, wherein at least a portion of the plurality of conductive or non-conductive fibers contacts the interior surface of the metal article; thereby electrochemically treating said interior surface. The method includes:

27. 27. The method of claim 26, wherein the flexible conductive body of the electrochemical processing electrode is connected to a negative terminal.

28. 28. The method of claim 26 or 27, wherein the interior surface comprises at least one surface of a channel, hollow, cavity, opening, opening, conduit, tunnel, duct, tube, pipe, channel, slit, trench, chamber, rut, vessel, groove, valley, through hole, funnel, or trough.

29. 29. A method according to any one of claims 26 to 28, wherein the interior surface is part of a conduit or duct and the length of the flexible element is selected to have a length complementary to a radial dimension of the conduit or duct.

30. 30. The method of claim 29, wherein the internal surface is part of a conduit or duct having a diameter between 2mm and 5mm, preferably between 0.5mm and 5mm, preferably between 4mm and 10mm, more preferably between 4mm and 8mm.

31. 31. The method of any one of claims 26 to 30, wherein the electrochemical treatment electrode is moved across the interior surface through a tensile engagement of the flexible conductive body.

32. 32. The method of any one of claims 26 to 31, wherein the electrochemical treatment electrode is in contact with or in close proximity to the interior surface of the metal article as it moves across the interior surface.

33. 33. The method of any one of claims 26 to 32, further comprising connecting the electrochemical treatment electrode to a linear actuator to control a rate of movement of the electrochemical treatment electrode across the interior surface.

34. 34. The method of any one of claims 26 to 33, wherein the electrochemical treatment electrode is moved in at least two passes, and preferably multiple passes, over the interior surface of the metal article to electrochemically treat the interior surface to a desired finish.

35. 35. The method of any one of claims 26 to 34, wherein movement of the electrochemical treatment electrode across the interior surface includes being pulled back across the interior surface during each pass in a direction opposite to the previous movement.

36. 36. The method of any one of claims 26 to 35, wherein the power source comprises an AC, DC or pulsed voltage or current controlled power supply.

37. 37. The method of any one of claims 26 to 36, wherein the electrochemical processing fluid is delivered in an amount that wets the electrochemical processing electrode.

38. 38. The electrochemical processing electrode, apparatus, or method of any one of claims 1 to 37, wherein the electrochemical processing comprises at least one of electropolishing, electrocleaning, anodizing, parkerizing, or pickling.

39. An electrochemical process electrode configured to contact an interior surface of a metal article with an electrochemical process fluid, a flexible conductive body; a plurality of flexible elements connected to the flexible conductive body and extending generally outwardly of the flexible conductive body and configured to position an electrochemical treatment fluid about the flexible conductive body; Equipped with the flexible element comprises at least one flexible sheet or flexible body; or The electrode preferably further comprises at least one flexible sheet or body connected to the flexible conductive body extending from, or positioned adjacent to, between, and / or around, the plurality of flexible elements, an electrochemical processing electrode.

40. 40. The electrochemical processing electrode of claim 39, wherein the flexible sheet or body comprises at least one of a foam, a sponge, or a fibrous material.

41. 41. The electrochemical processing electrode of claim 39 or 40, wherein the flexible sheet or body comprises a foam or sponge configured to extend across the electrode and the plurality of flexible elements and surrounding the electrode and the plurality of flexible elements.

42. 1. A method for electrochemically treating an interior surface of a metal article, comprising: Electrically connecting the electrochemical processing electrode according to any one of claims 39 to 41 to a terminal of a power supply; electrically connecting the metal article to the other terminal of the power source; contacting at least an interior surface of the metal article with an electrochemical processing fluid, preferably an electrolyte; moving the electrochemical treatment electrode across the interior surface of the metal article while an electrochemical treatment current is applied between the terminals of the power source, wherein at least a portion of the plurality of conductive or non-conductive fibers contacts the interior surface of the metal article; thereby electrochemically treating said interior surface. The method includes:

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