热爆合成三铝化钛复杂反应动力学的差示扫描量热法

Differential Scanning Calorimetry Research on the Comprehensive Kinetics in Formation of TiAl_3 by Thermal Explosion Synthesis

用Ｆｒｉｅｄｍａｎ法研究了非等温ＤＳＣ条件下热爆合成反应Ｔｉ＋３Ａｌ→ＴｉＡｌ３的复杂反应动力学。根据表观激活能（Ｅａ）随转化率（ａ）的变化关系，识别出该反应至少包含３个Ｅ．值分别为１０９、１７５和８９ ｋＪ／ｍｏｌ的子过程。通过与Ｔｉ－Ａｌ二元系的反应和互扩散激活能的比较，提出了可能的复杂反应动力学机制。

Under the non-isothermal differential scanning calorimetric ( DSC) conditions, the comprehensive kinetics of the thermal explosion (TE) synthesis reaction Ti + 3Al --> TiAl3 was studied by Friedman method. According to the dependence of the apparent activation energy (E-a) on conversion degree (alpha) of this reaction, three processes of the reaction were determined with the values of E-a of 109, 175 and 89 kj/mol. By comparing the values of E-a, the rate-controlling steps of these three processes were interpreted as the direct chemical reaction at the interface between Ti(s) and Al(l) to form TiAl3, the interdiffusion between Ti and Al through TiAl3 -layer, and the interdiffusion between Ti and TiAl through TiAl3-layer, with the increasing of the extent of conversion.