THE EFFECT OF MICROSTRUCTURE ON WEAR MODES OF CERAMIC MATERIALS

The effect of the microstructure on the wear modes in structural ceramic materials was studied in two SiC and three Al2O3 materials. In each class of materials, it was observed that the predominant damage mode is determined by the microstructure of the material. The materials with weak grain boundaries were found to wear primarily by grain pluckout and so showed more wear than did (the one, alpha-SiC) materials with stronger grain boundaries. In addition, the presence of a softer second phase around the grain boundary, which in commercial materials is usually more ductile than the grain, changed the mode and amount of damage, resulting in improved wear resistance (only in repeated passes). Under repeat pass sliding, the amount of wear increased considerably in all the materials except the material with a softer second phase.