低价钛卤盐热裂解过程动力学研究

Study on Kinetics of Thermal Pyrolysis Process of Low-valent Halogenated Titanium Salt

利用化学气相沉积(CVD)法制备高纯钛,对低价钛卤盐的热裂解作了动力学研究;重点分析该法制备高纯钛过程中,沉积基体温度和低价钛卤盐蒸气压对钛生长过程的影响。得出钛的生长速率与基体温度和低价钛卤盐蒸气压的关系式,并计算出低价钛卤盐蒸气压为86.1Pa时低价钛卤盐热裂解的表观活化能;讨论了整个反应历程,发现在生长区(沉积基体附近)内低价钛卤盐的迁移是该过程的速率控制步骤。

High purity titanium was prepared by CVD process, the kinetics of the thermal pyrolysis of low-valent halogenated titanium salt was researched. The influence of deposition substrate temperature and the vapor pressure of low-valent halogenated titanium salt on the titanium growth process was mainly analyzed during the preparation process of high purity titanium.The relation of titanium growth rate, deposition substrate temperature and the vapor pressure of low-valent halogenated titanium salt was achieved. An apparent activation energy of the thermal pyrolysis of low-valent halogenated titanium salt was calculated at vapor pressure of 86.1 Pa. The overall reaction process was discussed. It is found that the rate-limiting step of the process is the transfer of the low-valent halogenated titanium salt just in growth region （the neighborhood of the substrate）.