化学共沉淀法制备Mg_(0.3)Al_(1.4)Ti_(1.3)O_5复合粉体的反应过程

REACTION PROCESS IN PREPARING Mg_(0.3)Al_(1.4)Ti_(1.3)O_5 COMPOSITE POWDER BY CHEMICAL CO-PRECIPITATION

以TiCl4,MgCl2,AlCl3水溶液为原料,以氨水和碳酸氢铵为沉淀剂,利用化学共沉淀法,制备出了Mg0.3Al1.4Ti1.3O5复合粉体。对前驱体煅烧过程的热力学、动力学进行了研究,确定了合成Mg0.3Al1.4Ti1.3O5复合粉体的反应过程。结果表明:随着热处理温度的升高,前驱体中首先出现MgO和锐钛矿型TiO2反应得到的二钛酸镁(MgTi2O5),锐钛矿型TiO2,在650℃左右转化为金红石型TiO2。900℃左右MgTi2O5与αAl2O3反应生成镁铝尖晶石MgAl2O4。温度超过1100℃,MgAl2O4进一步与αAl2O3,金红石型TiO2反应,合成Mg0.3Al1.4·Ti1.3O5复合粉体。

Mg0.3Al1.4Ti1.3O5 composite powder was prepared by the method of chemical co-precipitation and heat treatment using TiCl4, MgCl2 and AlCl3 solution as raw materials, and ammonia and ammonium hydrocarbonate as precipitant. Thermo-dynamics and dynamics during the calcining of the precursor were explored in detail, and the process of synthesizing Mg0.3Al1.4Ti1.3O5 composite powder was validated. Results show that as the temperature increases MgO reacts with anatase to form MgTi2O5. At about 650°C, anatase transfers into rutile TiO2. Then MgTi2O5 reacts with Al2O3 to produce MgAl2O4 at 900°C. When the temperature is above 1100°C, the desired Mg0.3Al1.4Ti1.3O5 composite powder is synthesized by the reaction of MgAl2O4, Al2O3 and rutile TiO2.