Providing a copper alloy plate, in which center Mg concentration at a center part in a plate thickness direction 0.1 mass % or more and less than 0.3 mass %, center P concentration is 0.001 mass % or more and 0.2 mass % or less, and the balance is composed of Cu and inevitable impurities; in which surface Mg concentration at a surface is 70% or less of the center Mg concentration; in which a surface layer part defined by a prescribed thickness from the surface has a concentration gradient of Mg of 0.05 mass %/m or more and 5 mass %/m or less increasing from surface toward center part of the plate thickness direction; and in which restraint of color change of the surface and increase of electrical contact resistance, and adhesiveness of a plating film are excellent due to maximum Mg concentration in the surface layer part is 90% of the center Mg concentration.

An electrochemical method includes performing anodic halogenation of Cu foils, performing subsequent oxide-formation in a KHCO.sub.3 electrolyte, and performing an electroreduction in neutral KHCO.sub.3 to generate a copper catalyst.

An electrolyte for the electrochemical machining of a γ-γ″ nickel-based superalloy, includes NaNO3 in a content of between 10% and 30% by weight relative to the total weight of the electrolyte; a complexing agent selected from sulfosalicylic acid at a pH of between 3 and 10 and nitrilotriacetic acid at a pH of between 7 and 14, the complexing agent being present in a content of between 1% and 5% by weight relative to the total weight of the electrolyte; optionally, an anionic surfactant in a content of between 1% and 5% by weight relative to the total weight of the electrolyte; optionally, NaOH in order to obtain the desired pH; and an aqueous solvent.

An electrolyte for the electrochemical machining of a γ-γ″ nickel-based superalloy, includes NaNO3 in a content of between 10% and 30% by weight relative to the total weight of the electrolyte; a complexing agent selected from sulfosalicylic acid at a pH of between 3 and 10 and nitrilotriacetic acid at a pH of between 7 and 14, the complexing agent being present in a content of between 1% and 5% by weight relative to the total weight of the electrolyte; optionally, an anionic surfactant in a content of between 1% and 5% by weight relative to the total weight of the electrolyte; optionally, NaOH in order to obtain the desired pH; and an aqueous solvent.

An electrolyte for electrochemical machining of a γ-γ′ nickel-based superalloy includes NaNO.sub.3 at a content of between 10 and 50% by weight relative to the total weight of the electrolyte; an additive chosen from KBr, NaBr, KI, NaI and mixtures thereof, in an additive/NaNO.sub.3 molar ratio of between 1 and 15; optionally an ethylenediaminetetraacetic acid-based complexing agent at a content of between 1 and 5% by weight relative to the total weight of the electrolyte at a pH of between 6 and 12; optionally an anionic surfactant at a content of between 1 and 5% by weight relative to the total weight of the electrolyte; optionally NaOH to obtain the appropriate pH; and an aqueous solvent.

An electrolyte for electrochemical machining of a γ-γ′ nickel-based superalloy includes NaNO.sub.3 at a content of between 10 and 50% by weight relative to the total weight of the electrolyte; an additive chosen from KBr, NaBr, KI, NaI and mixtures thereof, in an additive/NaNO.sub.3 molar ratio of between 1 and 15; optionally an ethylenediaminetetraacetic acid-based complexing agent at a content of between 1 and 5% by weight relative to the total weight of the electrolyte at a pH of between 6 and 12; optionally an anionic surfactant at a content of between 1 and 5% by weight relative to the total weight of the electrolyte; optionally NaOH to obtain the appropriate pH; and an aqueous solvent.

An assembly for electropolishing metal surfaces by means of particles of solid electrolytes in a gaseous environment. According to one embodiment the assembly includes a container and a housing element configured to house at least two metal parts, so as to contain the parts avoiding that they can go out during the electropolish process and at the same time allowing that they can have a given movement within the housing element and at the same time endow them with electrical connectivity by means of a first electrode and a second electrode that are coupled to an electrical source 3. The assembly also includes means to produce a relative movement between the particles of solid electrolytes and the at least two metal parts.

A low-hazardous electropolishing process has been developed to remove oxide layer(s) from the surface of nitinol needles. Low concentrations of citric acid and sulfamic acid are mixed with medium concentrations of sulfuric acid to use as an electrolyte solution. The process can be easily fitted into current suture needle manufacturing processes as well as into processes require electropolishing of nitinol-containing medical devices.

A low-hazardous electropolishing process has been developed to remove oxide layer(s) from the surface of nitinol needles. Low concentrations of citric acid and sulfamic acid are mixed with medium concentrations of sulfuric acid to use as an electrolyte solution. The process can be easily fitted into current suture needle manufacturing processes as well as into processes require electropolishing of nitinol-containing medical devices.

In one implementation a cathode for electrochemical metal removal has a generally disc-shaped body and a plurality of channels in the generally disc-shaped body, where the channels are configured for passing electrolyte through the body of the cathode. The channels may be fitted with non-conductive (e.g., plastic) tubes that in some embodiments extend above the body of the cathode to a height of at least 1 cm. The cathode may also include a plurality of indentations at the edge to facilitate electrolyte flow at the edge of the cathode. In some embodiments the cathode includes a plurality of non-conductive fixation elements on a conductive surface of the cathode, where the fixation elements are attachable to one or more handles for removing the cathode from the electrochemical metal removal apparatus.