Alteration of diaspore by thermal treatment^①

来源期刊：中南大学学报(英文版)2004年第2期

论文作者：杨华明 胡岳华 杨武国 敖伟琴 邱冠周

文章页码：173 - 175

Key words：diaspore; thermal treatment; X-ray diffraction; thermal analysis; activation energy

Abstract: Diaspore (α-AlOOH) was heated at various temperatures from 300 to 1 000℃for 2 h. The alteration of di-aspore by thermal treatment was investigated by differential thermal analysis, thermogravimetric analysis and X-ray diffraction. The mechanism of thermal decomposition of diaspore was discussed according to the Coats-Redfern equation.It is found that after thermal treatment at 500℃, diaspore is transformed entirely to corundum (α-Al₂O₃). Combined with the mass loss ratio obtained from the thermogravimetric analysis data, the activation energies for the thermal treat-ment of diaspore are calculated as E_a=10.4 kJ/mol below 400℃ and E_b=47.5 kJ/mol above 400℃, respectively,which is directly related to the structural alteration of diaspore during the thermal treatment. The results indicate that the thermal decomposition of diaspore is conducted primarily by means of an interfacial reaction.