还原气氛下铝热还原法合成TiN-Al_2O_3复合材料

Synthesis of TiN-Al2O3 composite material by aluminothermic reduction process in reductive atmosphere

以金属铝粉和钛白粉为原料,在匣钵中埋炭保护气氛下采用铝热还原氮化法制备了TiN-Al2O3复合材料。采用XRD、SEM和TEM等分析手段,研究了铝热还原氮化法制备TiN-Al2O3复合材料在不同热处理条件下(分别为1300℃3h、1400℃3h和1500℃3h)的物相组成、晶格常数、显微结构。研究结果表明:在埋炭气氛下采用铝热还原氮化法可以制备TiN-Al2O3复合材料;处理温度明显影响着铝热反应的程度及产物的形貌,随着处理温度的上升,处理后的产物中TiN含量逐渐增加,晶粒逐渐长大,晶格常数逐渐接近理论值。热力学计算发现,埋炭条件下,在较低的处理温度下,铝除参与铝热还原反应外,还与炭粉床中氧发生反应,导致参与铝热反应的金属铝不足,造成产物中有剩余的金红石存在。

TiN -Al2O3 composite material was prepared by aluminothermic reduction of TiO2 in coke bed from mixtures of TiO2 powder and metal AI powder. The phase composition, lattice parameter＇and the microstructure of the material after treatment at 1 300 ℃, l 400 ℃ and 1 500 ℃ for 3 h respectively were analyzed by XRD, SEM and TEM. The results show that TiN -Al2O3 composite material can be prepared in coke bed via aluminothermic reduction reaction. However,the treatment temperatures affect the evolution of aluminothermic reaction and morphology of the materials obviously. The content, grain size and lattice parameter of TiN in materials in coke bed increase with the increase of treatment temperature. Thermodynamic calculation confirms that metal AI reacts with oxygen in coke bed while it is involved in aluminothermic reduction reaction, then it causes the lack of Al which takes part in the aluminothermic reaction leading to a surplus rutile in the materials.