Influence of temperature on tribological properties of microarc oxidation coating on 7075 aluminium alloy at 25 °C –300 °C

Abstract The high-temperature tribological properties of bare 7075 Al – Zn – Mg – Cu alloy substrate and microarc oxidation (MAO) coating against ZrO 2 ceramic ball were evaluated at 25 °C −300 °C. Coefficients of friction were recorded, and wear rates were determined. Surface morphology and wear scars on the ZrO 2 ball were observed. Furthermore, wear mechanisms at three different temperatures were discussed. It was found that the MAO coating could maintain a low wear rate and a stable wear performance in an elevated temperature environment. At 300 °C, the wear rate of MAO coating was merely 1/11 of 7075 aluminium alloy substrate. MAO coating suffered mainly adhesive wear at ambient temperature, and both adhesive wear and abrasive wear at elevated temperatures.