牙科3Y-ZrO_2/LaPO_4可切削陶瓷材料的机械性能及断裂机制研究

Mechanical properties and fracture mechanism of a new dental machinable ceramic LaPO_4/3Y-ZrO_2

目的对牙科3Y-ZrO2/LaPO4切削陶瓷材料的机械性能进行测试,并对其断裂机制进行分析。方法按LaPO4含量的不同,分为15.5%,16%,16.5%,17%,17.5%,18%(体积百分比)6组测试其弯曲强度,韧性及硬度,并借助加载能谱仪(EDS)的扫描电子显微镜(SEM)对材料弯曲断口进行分析。结果随着LaPO4含量的增加,3Y-ZrO2/LaPO4切削陶瓷材料的机械性能呈现下降趋势,弯曲强度由685.93MPa下降到100.32Mpa,韧性由9.38MPam1/2下降到3.73MPam1/2,硬度由10.96Gpa下降为6.1Gpa。材料的弯曲断口显示,材料断裂以晶粒去除形式为主,LaPO4在两相体系中的断裂呈层片状形式。结论新型牙科3Y-ZrO2/LaPO4切削陶瓷材料机械性能已能满足一般嵌体和单冠,甚至后牙桥的需要并可降低牙科切削机的加工成本。

Objective To characterize the mechanical properties of a new dental machinable ceramic LaPO4/3Y- ZrO2 and investigate its fracture mechanism. Methods By adding different amount of LaPO4, samples of machinable ceramic LaPO4/3Y - ZrO2 were divided into six groups and their bending strength, fracture toughness and hardness were separately tested. The cross- sections were then analyzed with the aids of scanning electronic microscope （ SEM ） and energy dispersive spectroscopy （EDS）. Results With the increase of LaPO4, the mechanical properties of machinable ceramic LaPO4/3Y- ZrO2 were deteriorated. The bending strength was among the range of 96.81 -665.93MPa, the fracture toughness was among the range of 3.73 -9.38MPam^1/2, the hardness was among the range of 6.1 - 10.96Gpa. The cross - section showed that the grain elimination was the main form in the process of fracture. Multi - layered fracture occurred within LaPO4 granules in the cross - section of the two - phase composites. Conclusion The addition of LaPO4 into LaPO4/3Y- ZrO2 facilitates forming weak interface in this composite material and improves the machinable properties of 3Y- ZrO2 - based ceramics.