Abstract
To solve the problem of high friction and wear of the plasma sprayed Al2O3 coating in a wide temperature range, two Al2O3-based composite coatings, namely Al2O3-(NiAl-Bi2O3) coating and Al2O3-(NiAl-Bi2O3)-H coating (heat treatment), were prepared by involving Ni-5 wt% Al and Bi2O3, and applying a simple heat treatment. Compared to the Al2O3 coating, two Al2O3-based composite coatings attained increased toughness and adhesive strength. In particular, heat treatment endowed Al2O3-(NiAl-Bi2O3)-H coating with improved compositional homogeneity and more NiBi intermetallic compound and & alpha;-Al2O3 phases. In terms of tribological behavior, when subjected to rubbing against the counterpart Al2O3 ball, Bi2O3 and NiBi were shown to have good lubricating properties, and they exerted friction-reducing and anti-wear effects in both Al2O3-based composite coatings at 25 and 400 degrees C, respectively. At 800 degrees C, under the action of thermo-mechanical coupling, a tribo-oxide layer composed of multiple oxides (Al2O3, Bi2O3, NiO and Bi2Al4O9) was generated on the worn surface of the two composite coatings, achieving the excellent lubrication and wear-resistance.

Keywords Plus：WEAR BEHAVIORTRIBOFILM FORMATIONALUMINACERAMICSFRICTION

Published in SURFACE & COATINGS TECHNOLOGY，Volume472，10.1016/j.surfcoat.2023.129935；NOV 15 2023