DEPENDENCE OF CORROSION BEHAVIOR OF Ni–MoS2/Al2O3 COATINGS IN RELATION TO THE Al2O3 RATIO IN MoS2/Al2O3 PARTICLES

The MoS2 particles were coated with Al2O3 ratio varying from 5 to 50 wt.% content. Ni–MoS2/Al2O3 composite coatings were prepared by means of pulse electrodeposition. The dependence of preferential orientation index and corrosion properties of these composite coatings was investigated in relation to the Al2O3 ratio in MoS2/Al2O3 particles. Polarization measurements have been used to evaluate corrosion resistance performance of coating. The Ni–MoS2/50 wt.% Al2O3 coatings showed the highest corrosion resistance compared with Ni–MoS2/5 wt.% Al2O3, Ni–MoS2/10 wt.% Al2O3, and Ni–MoS2/30 wt.% Al2O3 coatings. Thus, it is understood that the increase of ratio of Al2O3 in MoS2/Al2O3 composite particle improves the corrosion efficiency of coating. These Al2O3 act as inert physical barriers to the initiation and development of corrosion defect, hence improve the corrosion resistance of the coating.