Aluminium Sprayed Coatings: Their Use for the Protection of Aluminium Alloys and Steel

Abstract

SummaryA wide range of thin, aluminium sprayed coatings has been tested on aluminium alloy and mild steel substrates without any further protection for up to 16 years: limited tests continue. All coatings, which were 0·003 in (0·076 mm) thick, have given good protection. On the steel substrate, commercial zinc sprayed coatings have been included. Laboratory tests on aluminium alloy substrates (DTD687A-type core and HE15TF) have shown 99·5% aluminium (GIB) to be technically the optimum purity for pure aluminium coatings, and for the base purity of aluminium alloy coatings. Coatings from powder and wire pistols have given similar results; spraying in a range of non-oxidizing atmospheres has not given any marked advantage. Long term protection, of up to 15 years under marine conditions, has been provided to mild steel by these thin aluminium sprayed coatings. Early appearance of slight rust staining on aluminium sprayed coatings is not a reliable guide that further deterioration is imminent. Zinc coatings ha...