Laves相
材料科学
合金
氢气储存
微观结构
差示扫描量热法
氢化物
热力学
脱氢
氢
解吸
热稳定性
冶金
金属间化合物
化学工程
化学
物理化学
催化作用
吸附
金属
有机化学
生物化学
工程类
物理
作者
Huaiying Zhou,F. Wang,J. Wang,Z.M. Wang,Qing Yao,Jianqiu Deng,Chengying Tang,Guanghui Rao
标识
DOI:10.1016/j.ijhydene.2014.07.054
摘要
The crystal structure, microstructure, hydrogen storage properties and thermal stability of the as-cast and annealed V35Ti20Cr45 alloys prepared by arc-melting were studied in this work. It was confirmed that the as-cast alloy is a body-centered cubic (bcc) single phase, while it consists of bcc main phase and C14-typed Laves secondary phase after annealed at 973 K for 72 h. As a result of the microstructure change, the activation performance and kinetic properties of the annealed alloy are improved greatly due to the catalysis of C14-typed Laves secondary phase in the annealed alloy. The kinetic mechanism of hydrogen absorption/desorption processes in the as-cast and annealed alloys was discussed using the Johnson-Mehl-Avrami (JMA) equation. Based on the plateau pressure data from pressure-composition-temperature (PCT) measurements with the Van't Hoff equation, the calculated formation enthalpies of the hydride formed in the as-cast and annealed alloys indicate that heat treatment results in lower thermal stability of the hydride in the as-cast alloy. Furthermore, using the Kissinger method with the peak temperatures from differential scanning calorimeter (DSC) measurements at different heating rates, the calculated activation energies of the dehydrogenation in the as-cast and annealed alloys suggest that heat treatment is very beneficial to improve hydrogen absorption/desorption capacities in the alloy.
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