Effect of adding soft Bi₂O₃ on structural modification and tribological regulation of Ni-5 wt% Al composite coating in wide temperatures range

An alternative process to fabricate Ni-5 wt% Al-Bi O composite coatings was developed through the atmospheric plasma spraying technique. The influence of soft Bi O additions on tailoring microstructure and tribological behavior of resulting Ni-5 wt% Al-Bi O composite coating was investigated over a broad range of temperatures. As the Bi O inclusion within the Ni-based matrix gradually increased, the obtained Ni-5 wt% Al-Bi O composite coatings featured as the increasingly compact laminated hierarchy. This was, however, compromised with no significant improvement in mechanical capabilities. All Ni-5 wt% Al-Bi O composite coatings demonstrated the temperature-mediated frictional characteristic. Nevertheless, wear aggravation occurred for as-received composite coatings at the medium temperatures. It was noteworthy that Ni-5 wt% Al-Bi O composite coatings entailed superior lubrication at 800 °C, which was intrinsically associated with the lubricious constituents primarily consisting of Bi O and NiO on the sliding surface. The influential factor of temperature and Bi O on varying friction and wear for Ni-5 wt%. Al-Bi O composite coating was discussed from the perspective of tribochemically oxidative interactions between the rubbing contacts. 2 3 2 3 2 3 2 3 2 3 2 3 2 3 2 3 2 3 2 3