ZrO_2(Y_2O_3)对燃烧合成Al_2O_3/YSZ自生复合陶瓷显微结构与力学性能的影响

Influence of ZrO_2(Y_2O_3) on the microstructures and mechanical properties of self-growth Al_2O_3/YSZ eutectic composite ceramics prepared by combustion synthesis

在铝热剂中引入不同量ZrO2(3Y)微米粉末,以燃烧合成技术,制备出Al2O3/10%、17%、21%、27%、33%ZrO2(3Y)系列成分自生复合陶瓷棒材。XRD分析与SEM观察显示:具有亚共晶成分的陶瓷熔体因以离异共晶方式生长,使得凝固后的陶瓷基体主要由α-Al2O3片晶、t-ZrO2枝晶或块晶组成;而随ZrO2(3Y)添加量的增多,陶瓷晶体生长方式又由离异共晶向共生共晶生长发生转化,共晶棒晶体积分数增多,使得Al2O3/33%ZrO2(3Y)的陶瓷基体以微米、亚微米t-ZrO2纤维镶嵌其上的Al2O3共晶棒晶和少量α-Al2O3片晶构成。经力学性能测试,系列陶瓷棒材的硬度与断裂韧度随ZrO2(3Y)添加量增多而逐渐升高,陶瓷棒材硬度最高值达15·7GPa,断裂韧度最高可达10MPa·m1/2。

By adding ZrO2 （3Y） micron powder in different guantity into the thermit and through combustion synthesis, a series of Al2O3/10 %, 17 %, 21%, 27 % and 33 96 ZrO2 （3Y） self- growing composite ceramic rods have been prepared. XRD and SEM analyses indicate that the composite ceramics with hypoeutectic component are composed of α-Al2O3 platelet grains and t- ZrO2 dendrites due to separated growth of Al2O3/ZrO2 from the melts. With the increase of ZrO2 （3Y） content, the volume fraction of rod - shaped eutectics increase because of growth manner transformation of Al2O3/ZrO2 phases from separated growth to coupled growth. Matrix of Al2O3/33 % ZrO2 （3Y） ceramic is composed of rod - shaped eutectics, in which micron/submicron t - ZrO2 fibers are embedded. The hardness and fracture toughness of Al2O3/ZrO2 （3Y） self- growth composite ceramics increase with increasing the ZrO2 （3Y） content, and the maximum values of vickers hardness and fracture toughness are 15.7GPa and 10 MPa·m^1/2 , respectively.