GB1094184A - Improvements in or relating to the electro-deposition of metals - Google Patents

Abstract

Electro-plating baths are prepared and/or maintained by adding to the fundamental plating solution, i.e. a solution consisting of the metallic ions which are to be plated out and the catalyst ions together with the pH buffer if used, an additive additional to the fundamental plating solution in the form of a pellet comprising the additive mixed with a substance which is not one of the constituents of the fundamental plating solution and which facilitates dissolution or dispersion of the additive in the bath and which is compatible with said solution and does not produce any undesirable side effects. As described the method is applied to nickel plating baths to which coumarin is supplied as an additive, the pellets used comprising coumarin mixed with one or more of the carbonates of sodium, potassium ammonium or nickel or nickel formate, or boric acid in the case of a fundamental plating solution not containing boric acid. The shape of the pellet may be chosen so as to encourage dissolution, e.g. by making it of toroidal form. Reference is made to Watts nickel baths and to pellets formed from coumarin and nickel carbonate.