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

Abstract

Abstract The high-temperature tribological properties of bare 7075 Al – Zn – Mg – Cu alloy substrate and microarc oxidation (MAO) coating against ZrO2 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 ZrO2 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.