Tribological properties of NiCr–Al2O3 cermet-based composites with addition of multiple-lubricants at elevated temperatures

The tribological properties of NiCr-40 wt% Al2O3 (NC40A) cermet-based composites containing SrSO4 and other lubricant (graphite, MoS2 and Ag) against alumina ball were evaluated to identify their self-lubrication mechanisms from room temperature to 800 °C. The composites demonstrated distinct improvements in effectively reducing friction and wear, as compared to NC40A cermet. The best results were observed for NC40A–10SrSO4–10Ag composite, which exhibited satisfactory reproducibility of friction coefficient over a wide temperature range (200–800 °C) through high temperature cyclic friction tests due to the formation of synergistic lubricating films SrAl4O7, NiCr2O4 and Ag on the contact surface.