TiB2粉末的氧化行为研究

采用TG-DSC热分析仪,对TiB2粉末氧化进行了热重分析;采用等温氧化增重法,对TiB2粉末的氧化行为进行了研究,并对氧化产物进行了XRD分析和SEM分析.结果表明,TiB2粉末的氧化行为,在氧化温度低于1000℃时,其氧化增重与氧化时间之间符合抛物线规律,氧化机理为氧通过产物层的向内扩散为主要控制步骤;当氧化反应温度高于1000℃时,在氧化界面上的化学反应速度成为控制步骤.XRD和SEM分析表明,当氧化温度低于1200℃时,氧化产物相为TiO2(金红石)和B2O3(液相)当氧化温度高于1200℃时,由于B2O3液相转变为气相B2O3,氧化产物为TiO2(金红石).

The study on the oxidation behavior of TiB2 powder

By using TG - DSC thermal analysiser, the thermogravimetric analysis of TiB_2 powder in air was carried out. By using omnirange isothermal thermogrametiic method, the oxidation behavior of TiB_2 powder was studied. The XRD and SEM analysis about oxidation product were used as well. The result showed that when the oxidation temperature was below 1000℃, the oxidation behavior of TiB_2 powder obeyed paralic law between the oxidation gain in weight and oxidation time and the diffusion of oxygen through oxidation layer is the oxidation mechanism ; when the oxidation temperature was above 1000℃ , the main contrail procedure was the chemical reaction rate on the oxidation boundary. XRD and SEM analysis showed that the oxidation product was TiO_2 (rutile) and B_2O_3(liquid) when the the oxidation temperature was below 1200℃; when the oxidation temperature was above12001℃, the oxidation product was TiO_2(rutile) because of liquid B_2O_3 changeing into vapor B_2O_3.