稀土氧化物CeO_2对ZTA陶瓷的结构及力学性能影响的研究

STUDY ON INFLUENCE OF RARE EARTH OXIDE CeO_2 ON STRUCTURES AND MECHANICAL PROPERTIES OF ZTA CERAMICS

稀土氧化物ＣｅＯ２具有熔点高、稳定性好等特异的物理化学性能．其中Ｃｅ原于具有较高的化学活性，Ｃｅ（４＋）与ＺｒＯ２中的Ｚｒ（４＋）具有相近的离子半径和相同的化合价，与ＺｒＯ２的固溶范围大，因而是一种理想的相交增韧稳定剂．本文研究了ＣｅＯ２作为稳定剂对ＺＴＡ陶瓷材料的显微组织和力学性能，以及对相变增韧剂的相成份和结构的影响．结果表明，增韧剂中ＣｅＯ２含量越高、ＺｒＯ２高温相稳定性越好，ＣｅＯ２的摩尔含量在１０～１２％时ＺＴＡ陶瓷材料综合力学性能最优，其抗弯强度σ（ｂｂ）为６２０ＭＰａ，断裂韧性Ｋ可达到８．ＯＭＰａｍ；ＣｅＯ２含量的增加有利于ＺＴＡ陶瓷的致密化，但晶粒却有粗化趋势，在特定工艺条件下，ＣｅＯ２摩尔含量低于１０％时可获得晶粒不大于４μｍ的致密的ＺＴＡ陶瓷材料．

Rare earth oxide CeO2 has specific physical chemical properties,such as higher melting point, better stability, etc. Ce has higher chemical activity,and Ce4+ has similar ionic radius and same quantivalence with Zr4+ of ZrO2. The dissolution range of CeO2 in ZrO2 is wide,and thus CcO2 is ideal phase transformation toughening component. In this paper, CeO2 is used as the stabilizer .and the infhlence of CeO2 on the microstructure and mechanical properties of ZTA ceramics and the phase and structure of phase transformation toughening component are studied.The experimental results show that:(1) The higher content of CeO2 in toughening component,the better stability of ZrO2 high temperature phase.(2)The comprehensive mechanical properties of ZTA ceramics with 10￣12% (mol) CeO2 are exCellent, which have a bend strength of 620 MPa and a fractUre toughness 8.0 MPam.(3) The increases of CeO2 content is to the benefit of ceramic material densification but result in growing grains of the ZTA ceramics. (4) As CeO2content is less than 16%mol, we can obtain densifical ZTA ceramiCS with less thsn 4 pm grain for in special process.