GB1085005A - Improvements relating to methods of depositing metals on molybdenum - Google Patents

Abstract

A metal layer e.g. of Ni or Cu is electro-deposited on a Mo component by cathodically reducing the oxide layer initially covering the component in an electrolyte at a pH at which the reduction potential of Mo is reached until the oxide has been completely removed, and then electro-depositing the metal, the Mo component being enclosed in a reducing medium, preferably the electrolyte, when clean of oxide layer until coated with the metal. Preferably the whole operation is carried out in one bath, wherein after the oxide layer has been completely removed by cathodic reduction, e.g. in a concentrated HCl solution using a Pt anode, a concentrated solution of a salt of the metal to be electro-deposited e.g. of CuCl2 is added; alternatively, the anode may consist of the metal to be electro-deposited and the pH chosen so that the gradually dissolving metal only begins to be deposited after the oxide layer has been removed. Prior to electrolysis, the Mo component may be heated in H2 and pickled in an aqueous solution containing HNO3, H2SO4 and NaCl. The cathodically treated Mo component may be transferred to a separate plating bath, but without rinsing. The coated molybdenum is suitable for working, e.g. drawing of wire or rolling of foils, wherein it can be annealed between reduction stages without forming oxides or nitrides.