Phase equilibrium and transition of ZrO2 ceramics

对于ZrO_2基陶瓷的c-t转变机理，目前存在两种完全不同的解释。一种是由Heuer教授提出的，认为这种转变是由第一阶类型引起的，另一种是由作者提出的，认为这种转变是第二阶类型。第一种解释自1992年作者应邀在澳大利亚召开的氧化锆国际会议上发表报告以来，一直流行于氧化锆陶瓷界。在这次会议上，作者澄清了许多实验结果不能从跃迁是第一类跃迁的观点来解释，并证实了当把跃迁看作是第二类跃迁时，并不存在矛盾。并阐明了各种实验结果是由于萤石晶格结构中的氧空位所致。当氧离子通过引入氧空位而从萤石结构中的理想位置移动时，存在将该转变的类型误认为第一类型的可能性。

There is two totally different interpretation about the mechanism of the c-t transition of ZrO2 based ceramics. One, which is proposed by Prof.Heuer, is that the transition is resulted from the first order type and the other, which is proposed by the author, is second type. The first interpretation has been popular in the field of ZrO2 ceramics since the author's invited presentation at the international conference of ZrO2 held in Australia on 1992. At this conference the author has cleared up that many experimental results can not be interpretated from the standing point that the transition is the first type and has confirmed that there is no contradictions when that transition is thought to be second order type. Moreover the author has made clear that various experimental results are resulted from the vacancies of oxygen in the fluorite lattice structure. When the oxygen ions move from the idea position in the fluorite structure by the introduction of the oxygen vacancies, there is the possibility that the type of this transition is mistaken for the first type.