The erosion performance of two commercial ceramics, alumina (Al_2O_3) and silicon carbide (SiC), has been studied in a laboratory fluidized-bed (FB) facility in the temperature range from 250 to 560 deg C. Tests were carried out in air using angular alumina particles with an average size of 100 mu m as erodent material at an impact velocity of 5 m/s. The SiC ceramic revealed a better erosion resistance than Al_2O_3, irrespective of temperature. It is assumed that, at testing temperatures, oxidation plays no transcendental role in the extent of damage. Instead, under present conditions, the high hardness value conferred into the ceramics through higher densifications might lead to a heifer erosion resistance. At temperatures above 250 deg C, SEM analysis on the surface of both ceramics disclosed ripple formation, i.e. a plastic deformation process occurring under particle impaction. This was less evident at the lowest testing temperature. Reasons to explain the behavior found are discussed.
展开▼
