ZrO_(2)(Y_(2)O_(3))增韧的氮化硅烧结体的性能及相关系

STRUCTURE AND PROPERTIES OF SINTERED Si_(3)N_(4) TOUGHENED BY ZrO_(2)(Y_(2)O_(3))

在高温 (140 0℃ )超高压 (4 .2 GPa)下制备 Y2 O3部分稳定的 Zr O2 增韧的氮化硅烧结体 ,通过 XRD及机械性能测试等方法分析 Zr O2 的相结构 ,研究氮化硅烧结体的增韧机理。结果表明 ,烧结体中加入少量的铝粉 ,可提高t- Zr O2 的相变能力 ,达到利用部分稳定的 Zr O2 增韧氮化硅烧结体的目的。稳定剂 Y2 O3 在 Zr O2 中含量小于2 .5 mol%时 ,t→ m相变量及断裂韧性随 Y2 O3含量增加而逐渐提高 ,韧性提高来源于相变增韧和微裂纹增韧 ;Y2 O3含量大于 2 .5 m ol%时 ,t相接近 10 0 % ,韧性主要来源于相变增韧 ,增韧效果随 Y2 O3含量增加而逐渐减弱。 Y2 O3作为良好的烧结助剂 ,促进氮化硅烧结体在超高压下致密化 ,烧结体的硬度随 Y2 O3含量增加逐渐提高。

The sintered Si 3N 4 toughened by ZrO 2(Y 2O 3) was prepared at high temperature (1400℃) and ultra high pressure (4.2GPa). The phase structure and the mechanical properties were investigated by XRD and the measurements of compressive strength and micro hardness. The results show that the sintered Si 3N 4 was toughened by Y 2O 3 partially stabilized ZrO 2 with Al addition.The phase transformation and toughness were increased with Y 2O 3 content in less than 2.5mol% Y 2O 3.The toughness increasing came from t m transformation and micro cracks. Almost 100% t ZrO 2 were retained in more than 2.5mol% Y 2O 3 but the toughening effect was weakened by less transformation. The hardness was increased with Y 2O 3 content because Y 2O 3 can promote Si 3N 4 sintered as liquid at high temperature.