REMOVAL OF ORTHOPHOSPHITE IONS FROM ELECTROLESS NICKEL PLATING BATHS

摘要

Orthophosphite ions produced by oxidation of hypophosphite in an electroless nickel plating bath can be removed by precipitation with an alkali metal or alkaline earth metal cation such as calcium. In order to avoid the precipitation of calcium sulfate and the generation of large amounts of particulates in the bath, nickel sulfate can be replaced by a nickel salt of an alkylsulfonic acid or hypophosphorous acid, whose anion forms a soluble salt with an alkali metal or alkaline earth metal cation.