Microstructure and Tribological Behavior of Laser Cladding NiCr/Cr_3C_2-Ag-BaF_2/CaF_2 Self-lubrication Wear-resistant Metal Matrix Composite Coating

The self-lubrication wear-resistant NiCr/Cr3C2-Ag-BaF2/CaF2 metal matrix composite coating was fabricated on 1Cr18Ni9Ti stainless steel substrate by means of laser cladding.The phase compositions and cross-sectional microstructures of the coating were analyed by means of scanning electron microscopy and X-ray diffraction.The friction and wear behavior of the composite coating sliding against Si3N4 ceramic ball from ambient to 500 ℃ was evaluated using a ball-on-disc friction and wear tester,and the worn surface morphologies of the composite coating were observed using a scanning electron microscopy.It was found that the laser cladding NiCr/Cr3C2-Ag-BaF2/CaF2 metal matrix composite coating on the stainless steel substrate had good friction-reducing and antiwear abilities at elevated temperatures up to 500 ℃.The laser cladding composite coating was dominated by mixed adhesion and abrasive wear as it slid against the Si3N4 ceramic ball below 200 ℃.With further increase in the test temperature up to 500 ℃,it was characterized by mild adhesive wear and plastic deformation.