ZrO2 ceramics present a good combination of fracture toughness and mechanical strength, which are related to the stress-induced phase transformation of tetragonal ZrO2 into monoclinic symmetry. In recent years, the potential of ZrO2 ceramics to be used as hot-section components in advanced engines, gas turbines and wear-resistant sliding components has attracted great attention. Consequently, it is necessary to find ways to effectively lubricate ZrO2 ceramics in extreme environments, as the friction coefficient of ZrO2 ceramics is very high and unacceptable especially at elevated temperatures.
Researchers at the State Key Laboratory of Solid Lubrication of the Lanzhou Institute of Chemical Physics have fabricatedZrO2 (Y2O3) with different contents of BaF2/CaF2 and Mo by hot pressed sintering and investigated the tribological behavior of the composites against SiC ceramic from room temperature to 1000℃.
It was found that the ZrO2 (Y2O3)–5BaF2/CaF2–10Mo composite possessed excellent self-lubricating and anti-wear properties. The low friction and wear were attributed to enhanced matrix and BaMoO4 formed on the worn surfaces.
The work has received support from the National Natural Science Foundation of China and National Program on Key Basic Research Project of China (973 Program).
The findings have been published in Tribology International (Tribology International 45 (2012) 43–49).
