Friction and wear characteristics of BaCr ₂O ₄ ceramics at elevated temperatures in sliding against sintered alumina ball

In this article, friction and wear characteristics of BaCr ₂O ₄ ceramics have been investigated using a high-temperature friction and wear tester from room temperature to 800 °C in dry sliding against sintered alumina ball. At room temperature, the friction coefficient and wear rate of BaCr ₂O ₄ ceramics are quite high. BaCr ₂O ₄ ceramics exhibit low friction coefficients and small wear rates with temperature increasing up to 400-600 °C. The oxidation reaction of BaCr ₂O ₄ during high-temperature wear tests is responsible for the tribological properties. The oxidized product of BaCr ₂O ₄ is BaCrO ₄, which forms a smooth self-lubricating film on the worn surface to effectively reduce friction and wear. However, at 800 °C, severe oxidation reduces the relative density of sintered BaCr ₂O ₄ ceramics, and further expedites the materials removal process.