The atmospheric corrosion resistance of electrodeposited tin-cadmium and tin-zinc coatings on steel

Abstract

A study has been made of the corrosion-resisting properties of tin-cadmium and tin-zinc coatings on steel in which both laminar and alloy coatings have been tested using atmospheric exposure and accelerated tests. It is concluded that electrodeposited coatings of zinc on a tin substrate or zinc alone possess a greater resistance to atmospheric corrosion in an industrial atmosphere than equivalent coatings of cadmium on tin or tin on cadmium, or tin-zinc alloy coatings. The corrosion resistance of tin-zinc laminar coatings depends primarily on the amount of zinc present. Alloy coatings of tin-zinc and tin-cadmium generally possess similar corrosion resistance to those of the tin and cadmium laminar coatings. Under simulated marine conditions (A.R.E. Salt Droplet test) the corrosion resistance of coatings containing cadmium is superior to that of corresponding coatings containing zinc.