摘要
针对5Y-ZrO2/Al2O3复相陶瓷出现的晶粒异常长大和晶粒开裂问题展开研究。以ZrO2和Al2O3为主要原料,采用常压烧结工艺制备陶瓷样品,利用SEM观察显微组织。分析表明:MgO对抑制Al2O3晶粒异常长大有重要影响,MgO的加入量应随着Al2O3加入量的变化而改变;烧结温度的改变将导致异常长大的Al2O3晶粒细化。当烧结温度较低时,Al2O3晶粒将在短轴方向逐渐断开成段;当温度较高时,则沿着长轴方向逐渐开裂成条状。ZrO2晶粒的断裂主要与烧结温度有关:在1630℃以上烧结时,出现裂纹并贯穿晶粒;晶粒开裂的原因是:烧结温度较高时,陶瓷中形成了t-ZrO2,在降温过程中大颗粒的t相发生t→m相变,而小颗粒t相则无法变成m相,引起局部体积变化不均匀,从而产生相变应力导致晶粒穿晶断裂。
The study on both abnormal grain growth and grain cracking appearing in microstructure of 5Y-ZrO2/Al2O3 composite ceramic was done. Ceramic samples were prepared by pressureless sintering technology using ZrO2 and Al2O3 as the main raw materials. The microstructure was observed by scanning electron microscopy. The analysis shows that the MgO has an important effect on restraining abnormal Al2O3 grain growth, but the addition amount of MgO should be changed as the content of Al2O3 changing. The changing of sintering temperature will lead to refining of abnormal growth alumina grain. When sintering temperature is lower, the Al2O3 grain of abnormal growth will gradually disconnect into segments along a short axis direction. When sintering temperature is higher, then the Al2O3 grain of abnormal growth will gradually crack into strips along the long axis direc- tion. The fracture of ZrO2 grain is mainly connected with sintering temperature. When sintering tern perature is higher than 1630℃, the crack almost perforate throughout the grain. The reason of grain cracking is probably ceramic formed t-ZrO2 at higher sintering temperature, large size particles of t- phase will change into m-phase during cooling process, but small particles of t-phase cannot become m-phase, then causing the local volume change unevenness, and producing transformation stress lead to grain transgranular cracking.
出处
《现代技术陶瓷》
CAS
2012年第3期3-8,共6页
Advanced Ceramics
关键词
氧化铝
氧化锆
氧化镁
复相陶瓷
显微组织
异常长大
穿晶开裂
相变
aluminium
zirconia
magnesium oxide
composite ceramics
microstructure
abnormalgrowth
transgranular cracking
phase transition
