可切削氧化锆复合陶瓷的显微结构和断裂特征

Microstructure and fracture characteristic of machinable zircoina composites

为解决氧化锆陶瓷的难加工问题,掺入软相磷酸钙,制备出牙科CAD/CAM系统用氧化锆复合陶瓷材料,通过TEM和EADX方法研究烧结温度和磷酸钙含量对复合陶瓷显微结构和断裂方式的影响.结果表明,磷酸钙含量的增加导致瓷体致密度降低,升高烧结温度则有利于提高氧化锆复合陶瓷的致密度.高温下原料羟基磷酸钙分解生成磷酸三钙、氧化钙和水,导致磷酸钙晶粒中钙磷比例为8∶9,较初始状态降低.磷酸钙与氧化锆在陶瓷内部形成弱结合面,导致复合陶瓷断裂方式发生改变,随磷酸钙含量的增加,复合陶瓷由穿晶断裂逐渐过渡到沿晶断裂.

In order to solve the machinable problem of zirconia ceramic,zirconia doping calcium phosphate composites for dental CAD/CAM system were prepared.The effects of sintering temperature,calcium phosphate contents on microstructure and fracture mode of composites were studied by TEM and EADX.Results showed that the density of the ceramics composites decreases with the increasing of the content of the Calcium phosphate,but increases with the increasing of the sintering temperature.Calcium phosphate with hydroxide decomposed to calcium phosphate,calcium oxide and water at high temperature,so the ratio of Ca/P in crystal calcium phosphate decreased to 8∶9.Fracture type of ceramics composites changed due to the weak interface between calcium phosphate and zirconia,and the ceramics composites changed from transgranular crack to intergranular crack gradually.