ZrO2 (Y2O3) 增韧的氮化硅烧结体的性能及相关系

在高温(1400℃) 超高压(4. 2GPa) 下制备Y₂O₃ 部分稳定的ZrO₂ 增韧的氮化硅烧结体, 通过XRD 及机械性能测试等方法分析ZrO₂ 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t2ZrO₂ 的相变能力, 达到利用部分稳定的ZrO₂ 增韧氮化硅烧结体的目的。稳定剂Y₂O₃ 在ZrO₂ 中含量小于2. 5mol% 时, t→m 相变量及断裂韧性随Y₂O₃ 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; Y₂O₃含量大于2. 5mol% 时, t 相接近100% , 韧性主要来源于相变增韧, 增韧效果随Y₂O₃ 含量增加而逐渐减弱。Y₂O₃ 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Y₂O₃ 含量增加逐渐提高。 

STRUCTURE AND PROPERTIES OF SINTERED Si3N4 TOUGHENED BY ZrO2(Y2O3)

The sintered Si3N4 toughened by ZrO2(Y2O3) 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 Si3N4 was toughened by Y2O3 partially stabilized ZrO2 with Al addition.The phase transformation and toughness were increased with Y2O3 content in less than 2.5mol% Y2O3.The toughness increasing came from t m transformation and micro cracks. Almost 100% t ZrO2 were retained in more than 2.5mol% Y2O3 but the toughening effect was weakened by less transformation. The hardness was increased with Y2O3 content because Y2O3 can promote Si3N4 sintered as liquid at high temperature.