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本文报告了贮氢材料LaNi_5的表面分凝及其影响因素。AES的深度剖面分析发现,气氛中的氧引起镧的表面分凝,在LaNi_5表层中,镧扩散到表面并且氧化。与此同时,镍以金属态析出,最表层为富镧贫镍层;次表层为富镍贫镧层。表面分凝层的厚度与分凝速度随温度增加而增加。在室温、超高真空中,清洁LaNi_5的表面分凝速度相当迅速,且与氧有关。表面分凝在贮氢材料研究中十分重要,它为改善材料活化、表面催化性质,为阐明贮氢表面机制提供实验数据。
This paper reports the surface segregation of LaNi_5 and its influencing factors. AES depth profile analysis found that oxygen in the atmosphere caused lanthanum surface segregation, in the LaNi_5 surface layer, lanthanum diffuses to the surface and oxidation. At the same time, nickel is precipitated in metallic state, the most surface is rich in lanthanum-depleted nickel layer and the sub-surface is nickel-rich depleted in lanthanum layer. The thickness of the surface sub-coagulation layer and the rate of coagulation increased with the increase of temperature. At room temperature, ultra-high vacuum, clean the surface of the LaNi_5 segregation rate is quite rapid, and with oxygen. Surface segregation is very important in the research of hydrogen storage materials. It provides experimental data for clarifying the surface hydrogen storage mechanism to improve the material activation and surface catalytic properties.