Effect of Al₂O₃ Doping Content in Composite Plating Solution on Properties ofNi-P-Al₂O₃-PTFE Composite Plating

A Ni-P-Al₂O₃-PTFE (polytetrafluoroethylene) composite plating was prepared by electroless plating method with different content of Al₂O₃ in the composite plating solution. The effects of mass concentration (0-3.0 g·L^-1) of Al₂O₃ in the composite plating solution on the microstructure, hardness and wear resistance of the composite plating were studied. The results show that with increasing doping content of Al₂O₃ in the composite plating solution, the content of Al₂O₃ in the electroless plating Ni-P-Al₂O₃-PTFE composite plating increased first and then decreased, the crystallinity of the Ni-P matrix increased first and then decreased, the hardness increased first and then decreased, and the wear mass loss decreased first and then increased. When the mass concentration of Al₂O₃ was 2.0 g·L^-1, the crystallinity of the Ni-P matrix was good, the Ni-P-Al₂O₃-PTFE plating and Ni-P transition layer were bonded well, the content of Al₂O₃ in the composite plating was the highest, the PTFE and Al₂O₃ particles were uniformly dispersed in the Ni-P matrix, and the composite plating had the highest hardness of 7.6 GPa, and the smallest wear mass loss, indicating the composite plating had excellent wear resistance.