成分和工艺对氧化锆陶瓷马氏体相变温度的影响

INFLUENCE OF COMPOSITION AND PROCESSING ON MsTEMPERATURE OF ZICONIA CERAMICS

采用热膨胀方法测定氧化锆陶瓷中四方相（ｔ）→单斜相（ｍ ）马氏体相变开始温度（ Ｍｓ ），研究了ＣｅＯ２－ ＺｒＯ２ 陶瓷中ＣｅＯ２ 含量和８ｍ ｏｌ％ ＣｅＯ２－ Ｙ２Ｏ３－ ＺｒＯ２ 陶瓷中Ｙ２Ｏ３ 含量以及烧结工艺和热处理条件对马氏体相变温度的影响。结果表明，提高ＣｅＯ２ 和Ｙ２Ｏ３ 含量均显著降低Ｍｓ 温度。当ＣｅＯ２ 为１２ｍ ｏｌ％ 或当ＣｅＯ２ 为８ｍ ｏｌ％ 、Ｙ２Ｏ３０７５ｍ ｏｌ％ 时， Ｍｓ 温度低于液氮温度（≈－ １９６℃）。成分一定时，延长烧结时间使Ｍｓ 温度下降；提高烧结温度使Ｍｓ点先下降后上升。分析认为烧结工艺对Ｍｓ 温度的影响是ｔ相晶粒尺寸和材料致密度综合作用的结果。随冷却速度增大， Ｍｓ 温度下降，热循环过程对Ｍｓ

Influence of CeO 2 and Y 2O 3 contents,sintering processes and heat treament on Ms temperature of ziconia ceramics were investigated by thermal dilatometry.It was shown that the increase in CeO 2 and Y 2O 3 contents leads to the decrease of Ms temperature.The Ms temperature is lower than the temperature of liquid nitrogen(≈-196℃) when the CeO 2 content is 12mo1% or CeO 2 is 8mo1% and Y 2O 3-0.75mol% .For each composition,the longer the sintering time,the lower is Ms,and the Ms temperature decreases initially and then increases with increasing sintering temperature.The variation of Ms with sintering processes is attributed to the competition between the grain size and density of the sintered specimen.It was also shown that Ms decreased with an increase of the cooling rate and was independent of heat cycle.