吸气剂在低温容器中应用的研究进展

Applications of Non-Evaporable Getter Materials in Cryogenic Container:A Review Study

吸气剂是维持真空的重要工具之一。本文将低温容器真空夹层内使用的吸附剂归纳为三种:第一种是化学吸附,主要特征为吸气剂与吸附质发生化学反应,常见有氧化钯、氧化铜等;第二种是物理吸附,其特点为吸气剂与吸附质(一般为气体)由范德瓦尔力将吸附质吸收于吸气剂微孔内,比如分子筛、活性炭等;第三种吸附既具有化学反应又包含物理吸附,常见如银分子筛何银吸气剂。本文讨论了国内外学者对不同吸气剂在低温容器中的研究成果,分析了真空夹层中产生气体的原因,探究了吸气剂的选用、吸气性能、吸附过程以及吸附机理,提出了后续研究方向主要集中在低温环境下吸气剂对低温容器全真空寿命周期内维持真空的性能。

Herein,we tentatively reviewed the applications of non-evaporable getter(NEG)materials in fabrication of vacuum multi-layer insulation container(dewar).The conventional NEG materials can be classified into three types:I.chemical adsorbents(Pd-oxide,Cu-oxide…);II,physical adsorbents(molecular sieve,activated carbon,metal-organic-frame-works…)and III.physical-chemical hybrid adsorbents(Ag-molecular sieve,Ag-getter).In addition,the major basic and technological research subjects,including but not limited to the outgassing mechanisms of insulation layers,selection of appropriate getter material,adsorption mechanisms of getter materials,were also briefly discussed with specific examples.When it comes to significant increase of service-life of cryogenic containers,the technical problems/limitations,possible solutions and development trends in application of NEG materials were also discussed in a thought provoking way.