Pressure-less rapid rate sintering of pre-sintered alumina and zirconia ceramics

The aim of this work was to study rapid sintering of alumina and zirconia ceramics of relatively large size and to reveal a role of surface diffusion on their densification. Pressure-less rapid rate sintering in a specially designed furnace with the heating rates of 100 degrees C/min and 1500 degrees C/min was found as a possible way for preparing defect free and nearly dense (> 95%TD) alumina and zirconia ceramics which represents a crucial benefit for big scale sintering process in ceramic industry. Our results also showed that rapid transition over the intermediate temperature range in which surface diffusion dominates is not strictly required for achieving high density.