Process for electrodepositing metal and metal alloys on tungsten, molybdenum and other difficult to plate metals

摘要

This invention relates to an electrochemical treatment of metal substrates, including so-called "difficult to plate metals" such as tungsten and molybdenum, wherein deoxidation and plating are carried out in the same electrolyte bath by exploiting the electrochemical window in potential and pH of a reduction/deposition. This window may be illustrated using Pourbaix diagrams. In the first step of the treatment, a direct current at a reduction potential is applied to the substrate to reduce oxides present on the surface of the substrate without causing metal to be deposited from the electrolyte. In the second step, the reduction potential is changed to a more negative deposition potential, and a direct current at this deposition potential is applied for a time sufficient to deposit metal from the electrolyte.