锂硼基吸气剂对不同气体的常温自激活吸气特性

Self-activated sorption of LiB based getters about different gases at room temperature

考察了锂硼基吸气剂在室温下对H_2、N_2、O_2、湿空气和干空气的长期吸气特性,采用XRD和SEM研究了锂硼基吸气剂在吸气后的物相及表面形貌的变化,分析了吸气机制。结果表明,室温下锂硼基吸气剂在H_2、O_2、N_2环境中吸气960h后,吸气量分别为QH=13._20Pa·m3/g、QO=4.35Pa·m^3/g、QN=_2.73Pa·m^3/g。锂硼基吸气剂关于纯气体的吸气模型主要分为3个阶段:Ⅰ阶段为表面锂反应控制阶段;Ⅱ阶段为Li和气体原子互扩散控制阶段;Ⅲ阶段为LiB中Li释出扩散或气体原子经产物层向内扩散控制阶段。锂硼基吸气剂在干空气和湿空气下的吸气过程不存在明显的3个阶段。封闭环境中一定量的水蒸气与吸气剂相互作用后,生成物有阻碍作用,使吸气量大大降低。

In this paper,the long-term sorption characteristics of LiB based getter for H2,N2,O2,wet air and dry air at room temperature were investigated.The changes of phase and micro-surface in the LiB based getter after sorption were investigated by XRD and SEM,and the sorption mechanism was analyzed.The results show that the sorption quantity of LiB based getter after 960 hat room temperature in the atmosphere of H2,O2 and N2 were QH =13.20 Pa·m3/g,QO=4.35 Pa·m3/g,and QN=2.73 Pa·m3/g,respectively.The sorption mechanism of LiB based getter material in pure gases can be divided into three stages：Ⅰfor the surface Li reaction control stage,Ⅱfor Li and gas atoms mutual diffusion control phase,Ⅲfor Li diffusion in LiB compound or gas atoms through the product layer diffusion control stage.There are no obvious three stages in the sorption process of LiB based getters under dry air and humid air.The product of the reaction between a certain amount of water vapor and LiB based getter in enclosed environment,hinder the absorption process and reduce the sorption quantity greatly.