Research on Preparation and Properties of Cermet Coating on Surface of Rail Vehicle Wheels

To improve the wear resistance of Q235 surface of rail vehicle wheel material, Al₂O₃-Ni cermet composite coating was prepared by laser cladding on the wheel surface with YAG solid laser.The microstructure and wear resistance of matrix and coating were compared and analyzed by SEM, hardness tester, friction and wear tester. The results show that the thickness of the composite coating decreases with the increase of Al₂O₃ content.The composite coating is mainly composed of cellular crystals, oriented columnar crystals and equiaxed crystals. Excessive Al₂O₃ causes particle agglomeration. When the Al₂O₃ content is 20%, the overall hardness of the composite coating is highest, the wear resistance is best, the wear amount and friction coefficient are lowest, the wear surface is shallow furrow and a small amount of wear debris appear, and the wear mechanism is adhesive wear and abrasive wear.