Sand erosion testing of novel compositions of hard ceramics

The sand erosion rates of novel compositions of hard ceramics such as tungsten carbide, silicon nitride, silicon carbide, and partially stabilized zirconia have been tested in air-sand erosion facilities. A new testing facility that ensured stable and reproducible erosion testing with sand velocities and concentrations up to 250 m/s and 5 wt% in air, respectively, was built at IMI. Special rig design features allowed accurate sand consumption monitoring during each test. High-speed photography was used to determine the sand velocity distribution at each test setting. Parallel testing of these materials in the benchmark facility at the University of Southampton elucidated the test parameters critical for reproducibility of the results in different test configurations. High-speed visualization of the sand impact on the material surface demonstrated fragmentation of almost every sand particle in the range of velocities of 60 m/s and higher. The evidence of extensive fragmentation contributed to understanding the origin of the erosion resistance of hard ceramics. The values of the velocity exponent (n) were typical of those reported in literature. However, unlike the expected erosion behavior of a brittle material, an ultrafine grained binderless tungsten carbide was more erosive at low impact angle.