Zn–Ni–Al2O3 nano-composite coatings prepared by sol-enhanced electroplating

Abstract

Zn–Ni–Al2O3 nano-composite coatings were electroplated by our newly developed sol-enhanced electroplating method. In order to obtain the optimal chemical composition, corrosion resistance and mechanical properties, a systematic study of Zn–Ni–x–Al2O3 coatings with different sol concentrations (where x is the sol-doping concentration from 0 to 20ml/l) has been conducted. It was found that the Ni content, phase structure, surface morphology, mechanical properties and corrosion resistance of the nano-composite coatings were strongly affected by the sol concentration. The mechanical properties and corrosion resistance of sol-enhanced nano-composite coating were significantly improved compared to Zn–Ni alloy coatings. The microhardness of the sol-enhanced Zn–Ni–6ml/l Al2O3 coating was ∼312HV100 compared to ∼237HV100 of Zn–Ni coating. Meanwhile, the wear resistance has also been improved remarkably.