原位TiN/O′-Sialon复相材料的抗氧化性能研究

Study of Microstructure and Oxidation-resistance Property of in-situ TiN/O′-Sialon Composites

采用TG DTA、XRD和SEM技术研究了氧化温度、TiN含量和气氛氧分压对原位TiN O′ Sialon复相材料抗氧化性能的影响。结果表明 ,在 80 0～ 10 0 0°C的空气中 ,TiN氧化为TiO2 ,O′ Sialon不发生氧化 ,恒温时间足够长 ,材料转变为原位TiO2 O′ Sialon复相材料 ,氧化过程遵循对数规律 ,反应表观活化能为 5 6 .1kJ mol。在 12 0 0～ 132 0°C的空气中 ,TiN和O′ Sialon都发生氧化 ,材料表面有“保护膜”生成 ,氧化过程遵循抛物线规律 ,反应表观活化能为 4 8.8kJ mol;增加材料中TiN含量会导致材料氧化增重量增加 ,但也有助于材料表面“保护膜”的形成。提高气氛氧分压 ,材料的氧化程度加剧。

The influences of temperature, contents of TiN and oxygen partial pressure on oxidation-resistance properties of TiN/O′-Sialon were studied by TG-DTA、XRD and SEM techniques. The results show that only the oxidation of TiN to TiO 2 takes place whereas O′-Sialon is not oxidized in air at 800～1000 °C .If the reaction time is long enough, TiN/O′-Sialon will be oxidized to in-situ TiO 2/O′-Sialon. The oxidation behavior follows the logarithmic law. The apparent activation energy for oxidation is 56.1kJ/mol. Both TiN and O′-Sialon will be oxidized in air at 1200～1320 °C .A protective film is formed on the surface of the lower TiN content sample. The oxidation behavior follows the parabolic law with the apparent activation energy for oxidation 48.8 kJ/mol. The higher TiN content will make oxidation gain in weight increasing and be favorable of forming protective film at the same time. With oxygen partial pressure improved, oxidation reaction of TiN/O′-Sialon is enhanced.