Tribological Properties of Spark-Plasma-Sintered ZrO2(Y2O3)–Al2O3–Ba x Sr1−x SO4 (x = 0.25, 0.5, 0.75) Composites at Elevated Temperature

Abstract

Self-lubricating ZrO2(Y2O3)–Al2O3–Ba x Sr1−x SO4 (x = 0.25, 0.5, 0.75) composites have been fabricated by spark plasma sintering (SPS) method. The tribological properties have been evaluated using a high-temperature friction and wear tester at room temperature and 760 °C in dry sliding against alumina ball. The composites exhibit distinct improvements in effectively reducing friction and wear, as compared to the unmodified ZrO2(Y2O3)–Al2O3 ceramics. The ZrO2(Y2O3)–Al2O3–Ba x Sr1−x SO4 (x = 0.25, 0.5, 0.75) composites have great low and stable friction coefficients of less than 0.15 and wear rates in the order of 10− 6mm3/Nm at 760 °C. Delamination is considered as the dominating wear mechanism of the composites at room temperature. At elevated temperature, the formation and effective spreading of Ba x Sr1−x SO4 (x = 0.25, 0.5, 0.75) lubricating films during sliding play an important role in the reduction of the friction and wear.