Abstract: A conductive electrode wire is passed through a molten salt bath maintained at a temperature above the melting point of the salts. A main electrical power supply passes an electric current between the electrode wire and an anode in the molten salt bath so that a metal coating layer is electrolytically deposited onto the core of the electrode wire. The high temperature of the molten salt bath ensures inter-diffusion of the metals of the core and the coating. This enables diverse coating structures to be obtained by choosing electrolysis and diffusion parameters.

Abstract: A conductor wire is passed through a bath of molten metal in a container. While it is passing through the bath of molten metal, the wire is heated by the Joule effect by an electric current produced by a current source. This improves the adhesion of the metallic surface layer deposited on the core of the wire, so that the wire can be drawn directly by dies downstream of the bath of molten metal. This provides a fast and low-cost method of manufacturing a spark erosion electrode wire.

Abstract: A metal or alloy spark erosion electrode wire in accordance with the invention has a surface conversion layer containing chemical compounds of said metal or alloy and at least one polyvalent transition element such as hexavalent chromium. This reduces the risk of the wire breaking in the spark erosion machine, and improves the surface state on the machined part.

Abstract: A filiform electrode with metal coating for spark erosion is disclosed, formed of a metal wire comprising a metal copper or copper-zinc alloy core (15) coated with a metal coating (16) comprising a copper alloy deposit. The core (15) has a substantially constant and homogeneous composition throughout its whole cross section, as far as its connecting interface (17) with the coating.