Erosion characteristics of alumina ceramics at high temperatures

Abstract

The elevated temperature erosion behavior of alumina ceramics has been studied. There were five kinds of aluminas used in this study, with and without the silicate glassy phase and zirconia. The variables studied included temperature variation, material composition and microstructure, and impingement velocity and angle. The erosion mechanisms were also investigated for both the normal and oblique impacts. Erosion experiments were run in a sand-blast type of test rig using 120 grit silicon carbide particles. The variation in erosion as a function of temperature is explained in terms of the changes in material properties and microstructures. The examination of eroded surfaces revealed that the erosion characteristics of aluminas at elevated temperatures were significantly different from those at ambient temperature. There was plastic deformation occurring on the eroded surfaces at high temperatures and shallow impingement angles. The erosion of aluminas at elevated temperatures was thus not uniquely governed by the indentation fracture model and new modifications and factors needed to be considered.