摘要
通过DSC/TG的热分析试验,研究氢化钛升温过程中分解的动力学规律,利用Coast-Redfern积分法计算了分解过程的动力学参数。结果表明,氢化钛热分解的开始温度为510℃,分解过程中总质量损耗率达3.15%,其中565～660℃温度范围内的质量损耗率占总质量损失的50%左右,分解过程中生成了比氢化钛热稳定性更高的TiHx(0.7<x<1.1)。氢化钛分解的动力学过程可分为4个阶段:阶段Ⅰ遵循随机成核和随后生长反应机制,其速率控制步骤为TiH2表面上TiHx的成核与生长;阶段Ⅱ与Ⅲ遵循化学反应机制,其速率控制步骤为TiHx/Ti和TiH2/TiHx界面上的结晶化学反应;阶段Ⅳ遵循三维扩散反应机制,其速率控制步骤为H穿过TiHx和Ti反应层的内扩散,与4个阶段对应的分解活化能分别为83.07、135.28、121.97和137.72 kJ/mol。
Kinetics of titanium hydride decomposition were investigated by DSC/TG tests during elevating temperature and kinetic parameters were calculated by Coast-Redfern integral method. The results show that the initial temperature of titanium hydride decomposition is 510℃, whose mass loss ratio reaches 3.15% totally during decomposition course. In the temperature range of 565-660 ℃, the mass loss ratio of titanium hydride decomposition makes up 50% of the total. TiHx formates during decomposition course that is stabler than titanium hydride at elavated temperature. Titanium hydride decomposition is divided into four stages. Stage I obyes nucleation and growth mechanism, whose rate- controlling step is the nucleation and growth of TiHx on the surface of titanium hydride; stages Ⅱ and Ⅲ obye the chemical reaction mechanism, whose rate-controlling step is the chemical reaction on interface of TiHx/Ti and TiH2/TiHx separately; stage Ⅳ obyes three-dimensional diffusion mechanism, whose rate-controlling step is the H diffusing in the conversion zone of TiHx and Ti. The activation energy of four decomposition stages is 83.07, 135.28, 121.97 and 137.72 kJ/mol respectively.
出处
《粉末冶金材料科学与工程》
EI
2011年第6期795-798,共4页
Materials Science and Engineering of Powder Metallurgy
基金
国家自然科学基金资助项目(50875294)
航空基金资助项目(20081125)
关键词
氢化钛
动态分解行为
累积叠轧
泡沫铝
titanium hydride
dynamic decomposition behavior
accumulative roll-bonding
aluminum foam
