Y_(2)O_(3)含量对Y-Gd-Hf-O直热式压制阴极发射性能的影响  

Influence of Y_(2)O_(3) Contents on the Y-Gd-Hf-O Directly-Heated Pressed Cathode Thermionic Emission Properties

作　　者：王兴起 王小霞 罗积润 李云 Wang Xingqi;Wang Xiaoxia;Luo Jirun;Li Yun(Aerospace Information Research Institute,Chinese Academy of Sciences,Beijing 101407,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院空天信息创新研究院,北京101407 [2]中国科学院大学,北京100049

出　　处：《稀有金属材料与工程》2022年第12期4658-4665,共8页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(61771454)。

摘　　要：为了提高Y-Gd-Hf-O压制式高温阴极的热发射性能,制备了不同Y_(2)O_(3)/HfO_(2)摩尔比的Sc_(2)O_(3)掺杂Y-Gd-Hf-O直热式压制阴极。测试结果显示,当比值为5/2时,热发射能力最好,1500℃下发射电流密度为2.79 A/cm^(2)。阴极支取直流发射电流密度1.0 A/cm^(2),在1500℃的工作温度下,已经稳定工作了1320 h,并在该温度下经过696 h的10 W连续电子轰击后,发射电流仍保持为初始值的86%,表现出良好的耐电子轰击能力。XPS结合深度刻蚀表明,发射活性层主要集中在距表面50 nm深度范围内。表层SEM、EDS分析表明,阴极经过激活、老炼,活性物质粒径变大,Y/Hf原子比低于初始值,且随着Y_(2)O_(3)含量的提高,阴极表层n型半导体Y_(2)O_(3)-x的含量相应地增加,对改善阴极表面的导电性、降低逸出功和提高阴极的热发射性能有促进作用。To improve the Y-Gd-Hf-O pressed cathode thermionic emission ability, Sc_(2)O_(3)doped Y-Gd-Hf-O pressed cathodes with different molar ratios of Y_(2)O_(3)/HfO_(2)were prepared. The results show that the cathode with ratio of 5/2 demonstrates the best emission ability of 2.79 A/cm^(2) at 1500 ℃. The cathode works stably over 1320 h at 1500 ℃ with the load of 1 A/cm^(2) during the lifetime test, and the emission current decreases to 86% of the initial one after 10 W for 696 h continuous bombardment at the same temperature, reflecting a good anti-electron bombardment ability. XPS depth profile results show that the main active substances in work are concentrated in the depth range of 50 nm from the surface. After cathode being activated, the SEM and EDS results show that the active materials diameter increases to an extent, and the surface n-type semiconductor contents increase with the increase of Y_(2)O_(3)content, which is favorable for enhancing the conductivity, improving thermionic emission, and lowering the work function.

关 键 词：Y_(2)O_(3)掺杂 热发射 逸出功 耐电子轰击 寿命 

分 类 号：O462.2[理学—电子物理学]