Temperature and energy partition for grinding of mixed oxide ceramics

Abstract

Mixed oxide ceramics show high potential for widespread utilization due to the transformation toughening effect of these ceramics. During grinding, the stress-induced transformation from the tetragonal to the monoclinic phase of ZrO2 particles ensures a high strength in combination with a high fracture toughness even after processing with unavoidable surface and subsurface damage due to micro-cracks. The thermal impact during grinding can be one of the main limitations of this transformation toughening effect in case of exceeding the temperature of retransformation back to the tetragonal phase. Thus, the technological basis for a reliable grinding process of mixed oxide ceramics requires a fundamental understanding of the grinding temperatures to maintain workpiece quality and strength requirements. This paper presents an analytical method to calculate the maximum grinding temperatures beneath a single abrasive grain and show their effect on the bending strength of ground mixed oxide ceramics as well as on the monoclinic phase content and on the residual stresses.