Effect of MoS₂ Concentration on Microstructure and Tribological Behavior of Electrophoretic-Electrodeposited Ni-Co-Al₂O₃-MoS₂ Composites

Abstract

Ni-Co-Al₂O₃-MoS₂ composite coatings were prepared on the surface of LY12 aluminum alloys by electrophoresis-electrodeposition with different MoS₂ concentrations. The microstructure, morphologies and composition of Ni-Co-Al₂O₃-MoS₂ composites were characterized by X-ray diffractometer (XRD) and scanning electron microscopy (SEM) equipped with energy dispersive spectroscope (EDS). The micro-indentation hardness as well as friction and tribological properties of the coatings were tested by micro-hardness tester and friction and wear tester separately. Results revealed that the composite coating fabricated at 1.0 g⋅L^-1 MoS₂ achieved dense structure, and the average thickness of the coating was 39.820 µm. The micro-indentation hardness of the composite coating was decreased from 578 HV to 465 HV with the increase of MoS₂ concentration. Also, the composite coating synthesized at 1.0 g·L^-1 MoS₂ had the lowest friction coefficient and wear rate.

Keywords:
Ni-Co matrix; Molybdenum sulfide; Alumina; Microstructure; Anti-friction characteristics