无压烧结Al_2O_3/ZrSiO_4复相陶瓷的研究

Research of Al_2O_3/ZrSiO_4 Ceramic Composites Obtained by Pressureless Sintering

以A1_2O_3颗粒为增强体,MgO-Y_2O_3为烧结助剂,采用无压烧结方法,在组分优化的基础上,制备的锆英石基复相陶瓷室温抗弯强度和断裂韧性分别可达371 MPa和3.4 MPa·m^(1/2);采用XRD、SEM分析样品的相组成和显微结构,结果显示:确定ZrSiO_4为主要晶相,另外还有少量Al_2O_3和ZrO_2的存在;确定复相陶瓷的强韧化是由Al_2O_3颗粒引发的裂纹偏转、微裂纹增韧和由ZrSiO_4分解而来的ZrO_2相变增韧共同作用而实现的,断裂方式主要为穿晶断裂。

Alumina-reinforced zircon ceramic composites with magnesia and yttria as sintering aids obtained by direct sintering were successfully fabricated. The flexural strength and fracture toughness of ceramic composites were 371 MPa and 3.4 MPa .m^1/2 respectively at room temperature. The results were explained by X-ray diffraction （XRD） analysis and Zirconium silicate was the main crystalline phase and scanning electron microscope （ SEM ） analysis. a small amount of alumina and zirconia could be observed. The mechanism of strengthening-toughening was the combination of crack deflection toughening, microcrack toughening caused by alumina particle and transformation toughening caused by zirconia which was derived from the thermal decomposition of zircon. The fracture mode was mainly transgranular fracture.