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

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.