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采用XRD和SEM分析了Ti0.7Zr0.3(Cr1-xVx)2(x=0.1,0.2,0.3,0.4)合金的相组成、晶体结构和元素成分;采用Sieverts装置、差热和热重分析仪(DTA-TG)测量了合金的活化性能、吸放氢P-C-T曲线、热力学参数及高温放氢特征.结果表明,合金为多相组织,存在C36(P63/mmc)和C15(Fd3m)2种Laves相和几种晶格常数近似的钒基bcc固溶体相.当V含量较低时,合金主要由C36型Laves相和少量bcc固溶体相组成.随着V含量增加,C36型转变为C15型Laves相,其中第3种(C层)堆垛存在几率增加,而且合金中bcc固溶体相含量增加.合金在2 MPa氢压和常温下能迅速活化;表面氧化后,x=0.1和0.2合金仍表现出优异的活化性能.随着V含量增加,合金的贮氢量增加、平台压力减小.合金氢化的相对偏摩尔焓变(ΔH)和熵变(ΔS)的变化范围为-7~-28 kJ/mol和-35~-95 J/(mol·K).DTA-TG分析表明,合金氢化物分解主要出现在500~600 K温度区间,并呈现对应不同类型氢化物的2个分解温度,加热到800 K时合金中稳定的氢化物完全分解.
The phase composition, crystal structure and elemental composition of Ti0.7Zr0.3 (Cr1-xVx) 2 (x = 0.1,0.2,0.3,0.4) alloy were analyzed by XRD and SEM. Sieverts apparatus, differential thermal and TGA (DTA-TG) was used to measure the activation properties, PCT curves of absorption and desorption of hydrogen, thermodynamic parameters and high-temperature hydrogen desorption characteristics. The results show that there are two kinds of Laves, C36 (P63 / mmc) and C15 (Fd3m) Phase and several vanadium-based bcc solid solution phases with similar lattice constants.When the content of V is low, the alloy mainly consists of C36-type Laves phase and a small amount of bcc solid solution phase.With the increase of V content, the C36 type is transformed into the C15 -type Laves phase , And the stacking probability of the third layer (C layer) increased, and the content of bcc solid solution phase in the alloy increased.The alloys were rapidly activated at 2 MPa hydrogen pressure and room temperature.After the surface oxidation, x = 0.1 and 0.2 alloy still showed With the increase of V content, the hydrogen storage capacity of the alloy increases and the plateau pressure decreases.The relative partial enthalpy change (ΔH) and entropy change (ΔS) of hydrogenation of the alloy range from -7 to -28 kJ / mol and -35 ~ -95 J / (mol · K) .DTA-TG analysis shows that the decomposition of the alloy hydride mainly occurs in the temperature range of 500-600 K and presents different types Completely decomposed when the decomposition temperature of the two was heated to 800 K in a stable hydride alloy.