Al对ZrO_2增韧Si_3N_4烧结体的相变及性能的影响

Effect of Al on phase transformation and properties of ZrO_2(Y_2O_3) Si_3N_4 composite

在高温 (140 0℃ )、超高压 (4.2GPa)条件下制备了Al ZrO2 (Y2 O3 ) Si3 N4 烧结体。采用XRD分析及力学强度测试等方法 ,研究了Al对ZrO2 相变能力及ZrO2 增韧烧结体作用的影响。结果表明 :在烧结体中加入 2 %Al,利用Al与N反应生成AlN可阻止Zr O N化合物生成 ,避免ZrO2 在Si3 N4 基体中被N稳定生成不可相变t′ ZrO2 ,提高ZrO2 的t→m相变能力 ,使ZrO2 起到增韧氮化硅烧结体的作用 ;当Y2 O3 含量为 2 %～ 2 .5 % (摩尔分数 )时 ,烧结体抗压强度及断裂韧性均较高 ,ZrO2 相变增韧作用最大。

Al ZrO 2 Si 3N 4 composites were sintered at high temperature (1 400 ℃) and ultra high pressure(4.2 GPa). The effects of Al on the t→m ZrO 2 phase transformation and the toughness increment of sintered Si 3N 4 were investigated by XRD and mechanical tests. The results showed that 2%Al in the sintered material can prevent N from stabilizing ZrO 2 to form t′ ZrO 2 by producing AlN, both the potential of t→m phase transformation of ZrO 2 and toughness of sintered Si 3N 4 are increased. ZrO 2(Y 2O 3) Si 3N 4 has a combination property of high compressive strength and high impact toughness when Y 2O 3 content is 2.0%～2.5%(mole fraction). [