摘要
采用等温氧化增重法,研究了1650℃热压烧结的TiB2-TiSi2复相陶瓷的高温氧化行为。通过XRD、SEM等分析手段,研究了高温氧化层的物相组成与显微结构,并结合热力学计算,探讨了TiB2-TiSi2复相陶瓷高温抗氧化机理。研究表明:TiB2-TiSi2复相陶瓷的氧化增重随时间变化符合抛物线变化规律;随着在空气中氧化时间延长,氧化增重初期增加较快,进而增加较为平缓,进入钝化氧化阶段;TiB2-TiSi2复相陶瓷的高温抗氧化机理为TiSi2先于TiB2与氧发生反应形成TiO2与SiO2保护层,阻碍了氧气与材料的进一步接触,使材料具有高温自愈合抗氧化性,提高了TiB2-TiSi2复相陶瓷的高温使用温度。
The oxidation behaviors of TiB2-TiSi2 multiphase ceramic that was hot-pressing sintered at 1650 ℃ were studied by a method of isothermal oxidation weight gaining at high temperature. The phase composition and microstructure were characterized by scanning electron microscopy （SEM） and X-ray diffraction （XRD）. In combination with thermodynamic analysis, the antioxidation mechanisms of TiB2- TiSi2 multiphase ceramic were probed. The results show that the change of oxidation weight gaining of TiB2-TiSi2 muhiphase ceramic with time accords with parabolic law. With oxidation time extending, the oxidation weight gaining increases quickly at first, and then gently adds, finally enters into passive oxidation stage. It is the antioxidation mechanism of TiB2-TiSi2 muhiphase ceramic that TiSi2 reacts with 02 preceding TiB2 and forms a protective layer including TiO2 and SiO2, which can hinder further contact between 02 and material and endow material self-healing antioxidation property at high temperature. This enhances the using temperature of TiB2-TiSi2 multiphase ceramic.
出处
《硅酸盐通报》
CAS
CSCD
北大核心
2015年第6期1670-1673,共4页
Bulletin of the Chinese Ceramic Society
基金
陕西省自然科学基金(2013JM6013)
