Sliding wear behaviors of the AlNiTi amorphous coatings: effect of temperatures

Abstract

High-temperature wear behaviors are of prime importance for broadening the application guidelines of the Al-based amorphous coatings. For this objective, the effects of ambient temperatures on tribological behaviors of the AlNiTi amorphous coatings were investigated from room temperature (RT) to 450 °C. The results showed that the wear rate for the coating slid at 300 °C declines by two orders of magnitude in comparison to 2219-Al and 7075-Al alloys due to high hardness, strain tolerance, and elastic recovery capacity. With increasing temperatures, friction coefficients decrease steadily as a result of the oxide tribo-films formed on the wear track. However, there is an initial decrease in wear rate up to the temperature of 400 °C followed by a slight increase after the full devitrified temperature. The coating shows superior wear resistance at an elevated temperature of 400 °C because of the remained amorphous structure and intact protective oxide tribo-film. The wear mechanism of the coating transfers from brittle spalling coupled with oxidation wear to oxidative wear with increasing temperature up to 400 °C. After full devitrified temperature, the formation of deformed layers beneath oxide tribo-film aggravates marginally the wear of the coating. The synergistic effects of structure evolution, high-temperature hardness, and oxidization on tribological behaviors were discussed. These current findings provide insights into the real applications of the AlNiTi amorphous coating at evaluated temperatures.