Enhancement of creep resistance of a sintered Si(sub 3)N(sub 4) ceramic by microwave annealing

摘要

Creep behavior was investigated for a sintered Si(sub 3)N(sub 4) ceramic following microwave annealing at 1400 and 1500C for 20 h. Results of creep tests at 1200C showed that microwave annealing can enhance the creep resistance in terms of lowering creep rate and, hence, extending creep rupture life, but the 1400C annealing was most effective. X-ray diffraction analyses showed that the crystalline second phase was transformed as a result of microwave annealing from single phase Y(sub 10)Al(sub 2)Si(sub 3)O(sub 18)N(sub 4) to several different phases. The situation was further complicated by evolution of additional phases during high temperature creep experiments.