Prodn. of moulds for mfr. of plastic mouldings - by electrodeposition of porous nickel@ surface using electrolyte contg. nickel sulphamate

摘要

A nickel coating is obtained on the surface of a mould using an electrolyte contg. 300-450 g/l Ni(NH2SO3)2.4H2O; 30-40 g/l H3PO3; 0-15 g/l NiCl2.6H2O at 40-60 deg.C, a pH of 3.5-5 and a cathode current density of 0.5-5 A/dm2. The surface contains 200-500 pores/sq.cm.. The non-conductive mould surface is initially metallised using a silver lacquer in a volatile solvent. USE/ADVANTAGE - Prodn. of moulds for making complicated plastic mouldings which have a specific surface texture. The coating has a porous nature, with pore dia. 20-50 microns, upto 150 microns.