AB_5储氢合金微观结构X射线衍射正确表征

Characterization and research of cathode material AB_5 in Ni-MH battery by X-ray diffraction

在研究现代X射线衍射仪实验条件、参数和数据处理方法对衍射线峰位、强度和半高宽的影响之后,提出了测定和表征AB5储氢合金微观结构参数的X射线衍射(XRD)方法,并用这些方法表征初始AB5粉末的结构特征,研究了活化前后和循环前后AB5微结构的变化。这些研究包括:不同成分合金的相结构、点阵参数与权重原子半径的关系;成分相同、制备方法不同的合金的微结构,其微晶大小和残余应变状态与工艺条件的关系;MH-Ni电池负极中AB5合金粉充放电活化前后微结构的变化,发现活化后其晶粒明显细化,残余应变却增加了一个量级;由循环寿命实验前后对比研究可知,充放电循环使晶粒进一步细化,细化进程和微应变值与循环实验条件有关。

After investigating the influence of experimental conditions, parameters and data processing methods of modern X-ray diffractometer on peak positions, intensities and HWHM, XRD methods of correct measuring and characterization the microcosmic structural parameters of AB5-type hydrogen storage alloys were described and proposed. Original alloy materials were characterized and microstructure changes of the material in Ni-MH battery were researched by these methods, included the relationship between lattice parameters and weight atomic radius in the different composition alloys; the relationship among crystallite size ,micro-strain states and technological conditions for the microstructure of the alloys which were prepared by different methods with the same compositions; the micro-structural changes of Ni-MH battery before and after activating, it was found that after activation grains were fining obviously and residual strain increased an order of magnitude; grains were fining continuingly, fining process and micro-strains depend on circulation conditions.