High-temperature tribological properties of spark-plasma-sintered Al{sub}2O{sub}3 composites containing barite-type structure sulfates

摘要

Al{sub}2O{sub}3-50BaSO{sub}4-20Ag, Al{sub}2O{sub}3-50BaSO{sub}4-10SiO{sub}2, Al{sub}2O{sub}3-50(mass%)SrSO{sub}4, Al{sub}2O{sub}3-50PbSO{sub}4-5SiO{sub}2, Al{sub}2O{sub}3-50BaSO{sub}4 and Al{sub}2O{sub}3-50BaCrO{sub}4 composites (mass %) were prepared by spark plasma sintering and their microstructure and high-temperature tribological properties were evaluated. Al{sub}2O{sub}3-50BaSO{sub}4-20Ag composites (mass%) showed the lowest friction coefficients at the temperature ranging from 473 to 1073 K. Thin Ag film was observed on the wear tracks of the composites above 473 K. In addition, the friction coefficients of Al{sub}2O{sub}3 composites containing SrSO{sub}4 and PbSO{sub}4 were as low as those of Al{sub}2O{sub}3-BaSO{sub}4 and Al{sub}2O{sub}3-BaCrO{sub}4 composites at the temperatures up to 1073 K. The thin films formed on the wear; tracks of the Al{sub}2O{sub}3-SrSO{sub}4 composites were composed of Al{sub}2O{sub}3 and SrSO{sub}4 phases, while the films formed on the wear tracks of the Al{sub}2O{sub}3-PbSO{sub}4-SiO{sub}2 composites consisted of Al{sub}2O{sub}3, PbSO{sub}4 and SiO{sub}2 phases.