摘要
在CaH2-TiO2-Al体系中,采用还原扩散法制备TiAl合金,旨在探索一种新型、低成本、高效率的绿色冶金方法。在已知热力学可能的基础上,进行了动力学研究。在反应条件下,TiO2首先在CaH2的作用下被还原成金属Ti,Al以液态自身扩散或随液态及气态Ca迁移到Ti表面,被还原出来的高活性Ti与Al发生反应,生成TiAl合金。在反应过程中Al是主要扩散元素。可以采用一级液-固未反应核模型来分析还原扩散法制备TiAl合金,液-固界面化学反应为该反应的控制环节,界面化学反应受温度和时间影响较大,提高反应温度和增加反应时间有利于生成TiAl合金。反应的活化能为76.84kJ·mol-1,指前因子为1.54×10-2。
An attempt is made to explore a low cost, high efficiency and green metallurgical way to produce TiAl Alloy by a reduction-diffusion method in CaH2-TiO2-Al system. Kinetics has been studied based on the possibility of thermodynamics. Under the reaction conditions, Call2 decomposes into Ca and H2 firstly, then TiO2 is reduced to Ti by gaseous and liquid Ca, and Al transfers onto the Ti surface by diffusion itself in liquid state, or with gaseous or liquid Ca. The reduced high active Ti reacts with Al to form TiAl. In the reaction process, Al is the main diffuser. The forming process of TiAl can be analyzed by first class liquid-solid contracting core model. The rate-controlling step of the reaction is a liquid-solid interfaeial chemical reaction, which can be obviously effeeted by temperature and time. To increase the reaction temperature or to prolong the reaction time is beneficial to form the TiAl alloy. The reaction activation energy of the reduction-diffusion reaction is 76.84 kJ/mol with an exponential factor of 1.54×10^-2.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2008年第7期1153-1156,共4页
Rare Metal Materials and Engineering
基金
辽宁省博士启动基金(20021021)
