超重力下燃烧合成Al2O3-ZrO2（4Y）共晶陶瓷的自挤压工艺研究

Investigation of Self-pressing Processing for Al2O3-ZrO2（4Y） Eutectic Ceramics by Combustion Synthesis under High Gravity

引入自挤压工艺辅助超重力下燃烧合成制备Al2O3-ZrO2（4Y）共晶复合陶瓷,可有效地消除陶瓷制品的缩孔、缩松组织等缺陷,陶瓷致密性得到明显提高,同时又有效地抑制陶瓷裂纹萌生。XRD分析显示共晶陶瓷由α-Al2O3,t-ZrO2及少量的m-ZrO2三相组成,且随自挤压力增大,陶瓷中可相变的t-ZrO2的体积分数增加。SEM观察发现陶瓷的显微组织中的棒状共晶团随自挤压力的增大而细化,体积分数增加,且分布其上的t-ZrO2纤维直径变小,共晶团组织边缘处的ZrO2枝晶逐渐转变为细小的球晶,共晶团边界组织厚度逐渐减小,从而使陶瓷力学性能得以提升。

By introducing self-pressure processing into combustion synthesis under high gravity, Al2O3- ZrOE（4Y） eutectic composite ceramics without solidification shrinkage cavities and holes are achieved, and the self-pressure processing also effectively controls the macro-crack and promotes the ceramic densification significantly. XRD results show the eutectic ceramics are composed of or-Al2O3 ,t-ZrO2 and a few m-ZrO2 phases, and the volume fraction of the transformable t-ZrO2 increases with increasing self-pressure force. SEM images show that with increasing self-pressure force, the rod-shaped eutectic colonies are refined and the volume fraction of the colonies increases, whereas the average diameter of t-ZrO2 fibers in eutectic colonies decreases. Meanwhile, the irregular ZrO2 crystals around eutectic colonies transform into fine t-ZrO2 spherical crystals gradually, and thickness of eutectic colonies decreases with changes occurring in microstructures of the ceramics and the mechanical properties of the ceramics improved greatly.