LaNbO4-MoSi2复合陶瓷的制备及力学性能

采用高温固相反应法合成了LaNbO4粉末,并通过热压法制备了LaNbO4-MoS i2复合陶瓷材料。通过扫描电镜、金相显微镜、X射线衍射仪进行试样显微组织结构和断裂特征分析,测试了其显微硬度、抗弯强度和断裂韧性等力学性能。实验结果表明:合成的LaNbO4粉末有少量未反应的La2O3剩余,固相反应前原料粉的高能球磨使得反应后LaNbO4结构由单斜相变成以四方相为主。LaNbO4-MoS i2复合试样与单相MoS i2相比,其晶粒明显细化,致密性提高,强度、硬度和断裂韧性均有较大提高。采用具有畴切换增韧特性的LaNbO4颗粒作为一种新的增强剂对MoS i2基陶瓷进行复合改性具有一定的研究价值。

Preparation and mechanical properties of LaNbO4 - MoSi2 ceramic composites

LaNbO_4 powder was synthesized by high-temperature solid phase reaction,and LaNbO_4-MoSi_2 ceramic composites were synthesized by hot pressing in this paper.The microstructures and fracture characteristics were analyzed by scanning electron microscope,metallographic microscope and X ray diffractometer.And the microhardness,bend strength and fracture toughness were tested at the same time.The experimental results showed that there were still some remaining La_2O_3 which had not been reacted in the synthesized LaNbO_4 powder,and the high energy ball-milling of raw powder before solid phase reaction made the structure of LaNbO_4 change from monoclinic to mainly tetragonal state.Compared with MoSi_2 sample,the crystal grain of LaNbO_4-MoSi_2 composite sample was obviously fine,and the compactness was increased.Microhardness,bend strength and fracture toughness were greatly improved as well.It is valuable to investigate MoSi_2 matrix ceramics reinforced with LaNbO_4 particles as a new composite phase,which has a characterization of domain structure transfer.