纳米复合W-La_2O_3材料的表面行为与热发射性能  

Surface behavior and emission properties of nano-composite W-La_2O_3 material

作　　者：席晓丽[1] 聂祚仁[1] 郝世明[1] 杨建参[1] 翟立力[1] 左铁镛[1] 

机构地区：[1]北京工业大学材料科学与工程学院,北京100022

出　　处：《中国有色金属学报》2005年第6期907-911,共5页The Chinese Journal of Nonferrous Metals

基　　金：教育部全国优秀博士学位论文作者专项基金资助项目(200030);国家高技术研究发展计划资助项目(2002AA322010);教育部高校青年教师奖励计划资助项目(第三届)

摘　　要：采用“液液掺杂—冷冻干燥—两段还原—SPS”法制备了纳米W La2O3发射材料,利用原位俄射电子能谱分析技术研究了高温过程中发射材料的表层元素含量以及纵向元素分布,并采用自行研制的微机控制全自动电子发射测量装置测试了材料发射性能。研究表明:纳米W La2O3发射材料的有效逸出功为2.92eV,1773K下零场发射电流密度为2.52A/cm2;加热过程中,材料体内以La2O3形式存在的镧、氧向表面扩散,在表层10nm的地方出现La、O富集区,并形成了超额La,对电子发射起积极作用。Nanocomposite W-La_2O_3 material was prepared by freeze-drying and its thermonic electron emission ability was measured. Surface behavior and depth profile of material from 298 to 1573K were in-situ investigated by Auger electron spectrometry. The results show that the nanocomposite W-La_2O_3 material shows good electron emission performance with the saturated current density of 2.52A/cm^2 at 1773K and work function of about 2.92eV. During heating La and O atoms in La_2O_3 diffuse to the surface to form a La and O rich layer at ion depth, which makes the material have good emission ability.

关 键 词：W-La2O3 材料 热电子发射 逸出功 

分 类 号：TG146[一般工业技术—材料科学与工程] TG422[金属学及工艺—金属材料]