Oxidation behaviour and strength degradation of a Yb2O3−SiO2−doped hot-pressed silicon nitride between 1200 and 1500°C
Oxidation behaviour and strength degradation of a Yb2O3−SiO2−doped hot-pressed silicon nitride between 1200 and 1500°C
复制标题
Yb2O3−SiO2−掺杂热压氮化硅在 1200 至 1500°C 之间的氧化行为和强度退化
DOI：
10.1080/01418610208239632
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
M. Mitomo
中科院分区：
文献类型：
--
作者：
Shuqi Guo;N. Hirosaki;T. Nishimura;Yoshinobu Yamamoto;M. Mitomo
摘要研究了Yb 2 O3 −SiO2−掺杂热压氮化硅陶瓷在1200 ~ 1500°C空气中长达100 h的氧化行为和强度退化。测量抛物线增重与氧化时间的关系。氧化产物由Yb_2Si_2O_7和SiO_2（α-方石英）组成。表观氧化活化能Q被确定为约285 kJ mol−1。观察到的高抗氧化性归因于晶界相的耐火度提高和烧结过程中广泛的失透使非晶相最小化。氧化后，发现材料的室温弯曲强度降低，并且这种降低发生在氧化的早期阶段。弯曲强度的降低与氧化物层和Si 3 N4块体之间的界面处和/或附近的缺陷的形成和粗化有关。
Abstract The oxidation behaviour and strength degradation of a Yb2O3−SiO2−doped hot-pressed silicon nitride ceramic were investigated in air for up to 100 h at temperatures between 1200 and 1500°C. The parabolic weight gain versus oxidation time was measured. The oxidation products consisted of Yb2Si2O7 and SiO2 (α-cristobalite). The apparent oxidation activation energy Q was determined to be approximately 285kJ mol−1. The high oxidation resistance observed was attributed to the raised refractoriness of the grain-boundary phase and the minimization of the amorphous phase by extensive devitrification during the sintering process. After oxidation, it was found that the room-temperature flexural strength of the material degraded and this degradation occurred during the early stage of oxidation. The decrease in the flexural strength was associated with the formation and coarsening of defects at and/or near the interface between the oxide layer and the Si3N4 bulk.