High-temperature friction and wear properties of X-BaSO ₄ (X: Al ₂O ₃, NiAl) composites prepared by spark plasma sintering

X-BaSO ₄ (X: Al ₂O ₃, Ni-Cr alloy and NiAl) composites were prepared by spark plasma sintering, and their friction and wear properties were investigated from at temperatures ranging from room temperature to 1073 K in air. The friction coefficients of the Al ₂O ₃-50mass% BaSO ₄ composites varied from 0.2 to 0.4 at the temperature range. The NiAl-50 mass% BaSO ₄ composites and Ni-Cr alloy-based composites containing 50 mass% BaSO ₄ showed low friction coefficients at temperatures over 873 K, although their friction coefficients were higher than 0.5 at 473 K and 673 K. The wear rates of the Al ₂O ₃-50 mass% BaSO ₄ composites were much higher than those of the NiAl-50 mass% BaSO ₄ composites and Ni-Cr alloy-based composites containing 50mass% BaSO ₄ at room temperature. In order to improve the wear resistance of the Al ₂O ₃-50mass% BaSO ₄ composites, it would be necessary to use fine Al ₂O ₅ and BaSO ₄ powders and to add some sintering additives to the composites.