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稀土镧钼热阴极材料表面镧元素的蒸发
引用本文:周文元,张久兴,刘燕琴,万小峰,周美玲,左铁镛. 稀土镧钼热阴极材料表面镧元素的蒸发[J]. 中国有色金属学报, 2004, 14(2): 189-193
作者姓名:周文元  张久兴  刘燕琴  万小峰  周美玲  左铁镛
作者单位:北京工业大学,新型功能材料教育部重点实验室,北京,100022
基金项目:国家重点基础研究发展计划(973计划)
摘    要:从理论上计算了碳化Mo-La2O3热阴极材料在不同温度下活性物质镧元素的蒸发速度,分析了镧元素蒸发对材料热电子发射及其稳定性的影响.计算结果表明:当温度为1623~1700K时,阴极中镧的扩散速度大于阴极表面镧的蒸发速度,Mo-La2O3阴极表面单质La的生成和蒸发保持平衡,阴极发射稳定; 当工作温度超过1700K,阴极表面镧的蒸发速度超过扩散速度,发射电流逐渐减少.测试了Mo-La2O3阴极FU-6051电子管在不同温度时的发射性能,热力学理论计算结果较好地解析了实验结果.

关 键 词:Mo-La2O3热阴极  热电子发射  稳定性  蒸发  扩散
文章编号:1004-0609(2004)02-0189-05
修稿时间:2003-07-02

Evaporation of element La on surface of Mo-La2O3 cathode
ZHOU Wen-yuan,ZHANG Jiu-xing,LIU Yan-qin,WAN Xiao-feng,ZHOU Mei-ling,ZUO Tie-yong Beijing University of Technology,Beijing ,China). Evaporation of element La on surface of Mo-La2O3 cathode[J]. The Chinese Journal of Nonferrous Metals, 2004, 14(2): 189-193
Authors:ZHOU Wen-yuan  ZHANG Jiu-xing  LIU Yan-qin  WAN Xiao-feng  ZHOU Mei-ling  ZUO Tie-yong Beijing University of Technology  Beijing   China)
Affiliation:ZHOU Wen-yuan,ZHANG Jiu-xing,LIU Yan-qin,WAN Xiao-feng,ZHOU Mei-ling,ZUO Tie-yong Beijing University of Technology,Beijing 100022,China)
Abstract:The evaporation rate of element La at different temperatures in carbonized Mo-La_2O_3 cathode were calculated according to thermodynamics theory. The results show that the diffusion rate is greater than the evaporation rate of La on cathode surface at the temperature range of 1 6231 700 K, so the formation and evaporation of La can remain balance and the emission current is stable, and that when the operating temperature is above 1 700 K, the evaporation rate of La exceeds its diffusion rate on the cathode surface so that the emission current decreases gradually. In addition, the emission properties of the FU-6051 tubes equipped with Mo-La_2O_3 cathodes were tested at different temperatures, and the experimental results confirme the thermodynamic calculation.
Keywords:Mo-La_2O_3 heated cathode  thermionic electron emission  emitting stability  evaporation  diffusion
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