The influence of SrSO4 on the tribological properties of NiCr–Al2O3 cermet at elevated temperatures

The tribological properties of NiCr–40 wt%Al2O3 (NC40A) cermet-based self-lubricating composites containing 10 wt%–30 wt% SrSO4 against alumina ball were investigated at elevated temperatures. The results indicated that the friction coefficients and wear rates were significantly reduced by adding different amounts of SrSO4 above 200 °C. NC40A–10SrSO4 composite exhibited satisfactory tribological properties above 200 °C due to the formation of synergistic lubricating films SrAl4O7 and NiCr2O4 on the contact surface, while low friction coefficient and wear rate of NC40A–30SrSO4 composite at 400 °C were attributed to the synergistic lubricating effect of Sr4Al2O7, SrAl2O4 and NiCr2O4.