Microstructure and properties of ZrB2-SiC continuous gradient coating prepared by high speed laser cladding

A continuous gradient coating was prepared using ZrB2-SiC composite ceramic powder by high speed laser cladding (HSLC) technology on 304 stainless steel. The coating is mainly composed of ZrB2, ZrC, SiC, (Fe, Cr) solid solution and Fe3Si. Microstructure and element exhibit clearly continuous gradient distribution from bottom to top in the coating. The continuous gradient structure gave the coating excellent interfacial bonding and outstanding surface mechanical properties (hardness and wear resistance). The hardness of the coating was as high as1810 HV0.5 at room temperature, and it remained above 1000 HV5 at 800 °C. The coefficient of friction decreased from 0.58 to 0.27 and the wear morphology gradually showed clear characteristics of abrasive, adhesive and oxidative wear with the increasing of temperature.