Mechanical,tribological and oxidation resistance properties of Ni-based self-lubricating composite coatings at elevated temperature by APS

NiCrAlY-Mo-20Ag composite coating was fabricated by atmospheric plasma spraying. The influence of heat treatment on the mechanical properties, high temperature oxidation resistance properties and tribological properties of the coating were investigated. After 500 8C heat treatment, the microstructure of the coating becomes more homogeneous and the amount of precipitated Y2O3 phase clearly increases. The micohardness and adhesive strength of the composite coating are effectively improved after heat treatment. The coating heat-treated at 500 8C shows the highest micohardness and adhesive strength of 433.3 HV and 42.9 MPa as well as excellent lubricating properties over a wide range of temperature. Furthermore, the coating presents excellent oxidation resistance properties at 700 8C and 800 8C.