Sc_2O_3掺杂对Y_2O_3-Gd_2O_3-HfO_2难熔稀土氧化物直热式阴极热发射性能的影响  

Effect of Sc_2O_3-Doping on Thermal Emission Properties of Y_2O_3-Gd_2O_3-HfO_2 Thermal Cathode

作　　者：陈晓倩 王小霞[1] 张兆传[1] 李云[1] 赵庆兰[1] Chen Xiaoqian;Wang Xiaoxia;Zhang Zhaochuan;Li Yun;Zhao Qinglan(Key Laboratory of High Power Microwave Sources and Technology,Institute of Electronics,Chinese Academy of Sciences,Beijing 100190,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院电子学研究所高功率微波源与技术重点实验室,北京100190 [2]中国科学院大学,北京100049

出　　处：《真空科学与技术学报》2019年第2期131-135,共5页Chinese Journal of Vacuum Science and Technology

基　　金：国家自然科学基金项目(批准号:61771454)

摘　　要：Y_2O_3-Gd_2O_3-HfO_2难熔稀土氧化物直热式阴极具有制备工艺简单,热发射电流密度大,次级电子发射系数大,寿命长等优点,在大功率连续波磁控管中具有很好的应用潜力。为进一步提高Y_2O_3-Gd_2O_3-HfO_2阴极的热发射性能,本文对该阴极的发射物质进行了不同比例Sc_2O_3的掺杂,结果表明,Sc_2O_3的掺杂能有效提高Y_2O_3-Gd_2O_3-HfO_2阴极的热发射电流密度,其中,掺杂10%(质量比)Sc_2O_3的Y_2O_3-Gd_2O_3-HfO_2阴极热发射电流密度在1500℃下达到5.3 A/cm^2,比未掺杂时提升了35.5%。由于在阴极激活过程中Sc_2O_3与Y_2O_3形成了固溶体,合成氧化物中Sc得到电子并释放出游离Sc,增强了涂层的导电性,所以,Sc_2O_3掺杂Y_2O_3-Gd_2O_3-HfO_2难熔稀土氧化物直热式阴极热发射性能具有显著提高。The Sc2O3-doped Y2O3-Gd2O3-HfO2 coatings,an advanced direct-heating cathode material with excellent thermal emission properties,were synthesized via solid state reaction of refractory and rare-earth metal oxides.The influence of the Sc2O3-doping on the thermal emission properties of Y2O3-Gd2O3-HfO2 coatings was investigated with scanning electron microscopy and energy dispersive spectroscopy.The results show that the Sc2O3-doping effectively increased the emission current density of the cathode.To be specific,doping with 10%(wt) Sc2O3 increased the emission current density up to 5.3 A/cm2 at 1500℃,35.5% higher than that of the un-doped cathode.The free Sc atoms,possibly released in formation of Sc2O3 and Y2O3 solid solution and considerably increasing the conductivity of Y2O3-Gd2O3-HfO2 coatings,explained the mechanism responsible for the significant enhancement of thermal emission current density.

关 键 词：直热式阴极 Y2O3-Gd2O3-HfO2 Sc2O3掺杂 热发射电流密度 

分 类 号：O462[理学—电子物理学]