High temperature tribological behaviors and wear mechanisms of NiAl–NbC–Ag composites formed by in-situ decomposition of AgNbO3

NiAl–NbC–Ag composites were successfully prepared by vacuum-hot-pressing sintering with directly addition of AgNbO3 powders, where AgNbO3 were synthesized using a solid state reaction method. The tribological behaviors of composites were evaluated from 25 °C to 800 °C. The consequences reveal AgNbO3 are completely decomposed during sintering process and in-situ formed NiAl–NbC–Ag composites, which hold excellent high temperature tribologicial properties. At mid-low temperature, NAB20 (NiAl-20 wt%AgNbO3) has a relative lower friction coefficient compared to NiAl, which was attributed to the existence of Ag. While the lowered friction coefficients at 600 °C and 800 °C were attributed to the lubricating glaze layers formed by tribo-chemical reaction on the worn surfaces, which were consisted of typical layered structure Ag2Nb4O11, perovskite AgNbO3 with a highly flexible crystal structure and AgNb3O8. •AgNbO3 are completely decomposed during sintering and in-situ formed NiAl–NbC–Ag.•The micro-hardness of composites is significantly improved with hard NbC formed.•NAB20 registered the lowest COF (0.3) and the wear rate (3.5 × 10−5) at 800 °C.•At mid-low temperature, the improvement of COF was ascribed to soft metallic Ag.•The films formed were made up of Ag2Nb4O11, AgNbO3 and AgNb3O8 at 600 °C and 800 °C.