Microstructure and wear-resistant behaviors of Al2O3-TiO2 reinforced Ni-based composite coating plasma-sprayed on 6061 aluminum alloy

Aluminium alloy is a widely used lightweight alloy in automobile and rail vehicle components, especially in parts such as brake pads and wheels, which require high wear resistance. Herein, to improve the wear resistance of aluminium alloys, Al2O3–13%TiO2 (AT13) reinforced Ni-based composite coatings were prepared by plasma spraying on 6061 aluminium alloy. The impact of AT13 content and heat treatment on the microstructure and wear resistance of Ni-based alloy coatings was systematically investigated. From our analysis, it was demonstrated that, in comparison to the substrate, the average micro-hardness of the composite coating with 10 %AT13 increased by more than 11 times, with a high value of 1250.81 HV0.2. Moreover, the average friction coefficient and wear rate reduced by 66 % and four orders of magnitude, with low values of 0.17 and 8.99 × 10−7 mm3(N−1∙m−1), respectively, which indicated a significant enhancement in wear resistance. In addition, after heat treatment at 450 °C for 2 h, the micro-hardness of the composite coatings was improved, and the wear rate further decreased. This effect could be attributed to the encapsulation of the hard ceramic particles in the nickel-based alloy, which may suppress the dislocation motion in the composite coating. This study provides valuable insights into enhancing the wear resistance of metal-based alloy coatings with ceramic composite coatings.