Mg-Ni-Ti19Cr50V22Mn9的结构及氢化动力学研究

Study on the Structure and Hydrogenation Kinetics of the Composite Mg-Ni-Ti19CrsoV22Mn9

摘要:

采用机械合金化方法，将质量百分数为85Mg-5Ni-10Ti19Cr5oV22Mn9的复合材料在氢气保护气氛下球磨8h制备出复合储氢材料。用体积法测量了它在不同条件下的储氢性能，利用X射线衍射、显微镜技术和激光粒度分布仪考察了球磨时间对材料结构的影响，分析了氢化动力学与结构的相互关系。研究了材料在523K-573K的氢化反应动力学机理。结果表明，该复合材料在573K，20min内的吸放氢量分别为6．7％和6．6％。氢扩散为其限制性环节，吸放氢活化能分别为63kJ／mol和69kJ／mol。

Abstract:

The composite 85wt.%Mg-5wt.%Ni-10wt.%Ti19Cr50V22Mn9 was successfully prepared by mechanical alloying and its hydriding/dehydriding(H/D)properties were investigated by an isovolumetric method without any activation treatment.The effect of the milling time on the structure of the composite was measured by the X-ray diffraction,microscope and mastersizer technologies.The relationship between the technology and structure and properties was carefully analyzed.The composite can absorb and desorbe 6.70 wt.% and 6.6 wt.%,respectively,within 20 min at 573 K.Its H/D kinetic mechanism was studied and the results indicated that the rate-controlling step of the H/D processes is the diffusion of hydrogen,the very good agreement between the experimental results and calculated curves by a simple new kinetic model was presented.The activation energies were calculated to be 63 kJ?mol-1 for absorption and 69 kJ?mol-1 for desorption.