Research on Preparation and Optimization of Metal-based Nano-ceramic Composite Coatings

A 316L+ Al₂O₃ nano ceramic composite coating with 2%, 5% and 8% nano-Al₂O₃ ceramic particles were prepared by laser cladding on 316L substrate, and the microstructure and phase of the coating were analyzed by optical microscope（OM） and X-ray diffractometer（XRD）. Based on the microhardness and wear resistance, the mechanical properties and enhancement mechanism were analyzed. The results show that the coating with 5% Al₂O₃ has the best microstructure and performance than that of the coating with 2% and 8%, and the cladding layer has a dense structure without pores and cracks.The average grain size of the top equiaxed grain area is 5.95 μm with a maximum microhardness of 718.6 HV. The friction coefficient and wear loss mass are 0.69 and 4.26 mg, respectively.