Cavitation wear of structural oxide ceramics and selected composite materials

Abstract

The usage of ceramic materials in the applications endangered by intensive cavitation could limit erosion phenomena. In the presented work, cavitation erosion resistance of commonly used (in structural application), oxide phases (α-alumina, tetragonal zirconia) were investigated. Additionally, the behaviour under cavitation conditions of two composite materials, based on alumina and zirconia matrices, was tested. Significant difference in cavitation wear mechanisms for alumina and tetragonal zirconia materials was observed. Alumina was degraded by removing the whole grains from the large surface subjected to cavitation. Degradation of zirconia proceeded locally, along ribbon-like paths of removed grains. Cavitation wear of composites was strongly dependent on the residual stress state in the material. Alumina/zirconia composite with compressive stresses in the matrix showed a significant improvement of cavitation resistance. The zirconia/tungsten carbide composite with relatively high level of tensile stresses in the matrix was the worst of all investigated materials.