Periodic reverse current electrodeposited nickel pigmented anodised aluminium

Abstract

Aluminium anodically oxidised in sulphuric acid electrolyte was pigmented by an electrolytic colouring process with the use of alternating and periodic reverse current. The applied pigmentation electrolytes were based on nickel. The study reports on resistance against humidity of a selective Ni–Al₂O₃ layer. The samples before and after testing were analysed and compared. The quality of the coating, optical properties and influence of humidity on morphology and composition of the coatings were investigated. The influence of moisture on the quality of the selective Ni–Al₂O₃ layer is comparable to the commercial solar absorber type.