MICROSTRUCTURAL INFLUENCE IN SLURRY EROSION OF CERAMICS

A simple slurry pot tester for evaluating the erosion behavior of mate rials is described. Measurements of the erosive wear of various cerami cs using this tester in an aqueous slurry of silicon carbide grits are presented. Effects of varying the erodent particle size distribution and the slurry loading are investigated. Scanning electron microscopic examination of the eroded ceramic surfaces provides insights into the erosion mechanisms. The material removal processes include chipping o ut of lateral cracks caused by impact of the erodent particles, grain boundary cracking and grain pull out, as well as plastic deformation c aused by the repeated sliding and impact of the particles. No simple c orrelation is evident between the erosive material loss and the hardne ss or conventional toughness of the materials. It is suggested instead that the ceramic microstructure has a controlling influence on the er osion mechanism.