Transactions of Nonferrous Metals Society of China The Chinese Journal of Nonferrous Metals

您目前所在的位置:首页 - 期刊简介 - 详细页面

中国有色金属学报

ZHONGGUO YOUSEJINSHU XUEBAO

第14卷    第6期    总第63期    2004年6月

[PDF全文下载]    [Flash在线阅读]

    

文章编号:1004-0609(2004)06-0985-05
稀土镧钼热阴极材料稳定发射机理
——碳化及发射寿命
周文元, 张久兴, 刘燕琴, 
万小峰, 周美玲, 左铁镛

( 北京工业大学 新型功能材料教育部重点实验室, 
北京 100022
)

摘 要: 探讨了碳化Mo-La2O3热阴极的寿命机理,分析了阴极工作温度和碳化度(碳化层厚度)对碳化Mo-La2O3阴极电子管寿命的影响。研究结果表明: 碳化Mo-La2O3热阴极的发射寿命是由碳化层中Mo2C的损耗决定的, 阴极表面Mo2C消耗殆尽, 阴极发射寿命即终结。阴极表面Mo2C一方面作为还原剂与La2O3作用被消耗,另一方面它在高温下会发生分解, 阴极中Mo2C的损耗包括上述两个方面。在相同温度时, 碳化Mo-La2O3阴极中与La2O3还原反应损耗的Mo2C和Mo2C在高温下分解损耗的相当。通过理论分析与计算建立了各因素影响寿命的数学模型, 并通过高温分解实验得到了Mo2C在不同温度下的分解速率。在1673K, Mo2C的分解速率为1.21×10-7 g/(cm2·s), 碳化度δ≥15%, Mo-La2O3热阴极可稳定发射1000h以上。

 

关键字: Mo-La2O3阴极;碳化; 发射寿命; 数学模型

Stable emission mechanism of Mo-La2O3 cathode
—Carbonization and emission lifetime
ZHOU Wen-yuan, ZHANG Jiu-xing, LIU Yan-qin, 
WAN Xiao-feng, ZHOU Mei-ling, ZUO Tie-yong 

Key Laboratory of Advanced Functional Materials, Ministry of Education, Beijing University of Technology, Beijing 100022, China

Abstract: The lifetime mechanism of Mo-La2O3 cathode was discussed, and the effect of the operating temperature of cathode and the carbonized ratio (thickness of carbonized layer) on lifetime of tubes equipped with carbonized Mo-La2O3 cathode was analyzed respectively. The emission can keep stable only when the operating temperature is in range of 1600K to 1700K and the carbonized layer must be composed of Mo2C. The results show that the lifetime of carbonized Mo-La2O3 cathode is decided by the consuming velocity of Mo2C of the carbonized layer of cathodes. The Mo2C is consumed as reducer for La2O3 and vaporized after decomposition during the working time. At 1673K, The consuming velocity is 1.21×10-7 g/(cm2·s). The stable emission lifetime of tubes equipped with carbonized Mo-La2O3 cathodes can exceed 1000h if the carbonized ratio is above 15%.

 

Key words: Mo-La2O3 thermoinic cathode; carbonization; emission lifetime; mathematical mode

ISSN 1004-0609
CN 43-1238/TG
CODEN: ZYJXFK

ISSN 1003-6326
CN 43-1239/TG
CODEN: TNMCEW

主管:中国科学技术协会 主办:中国有色金属学会 承办:中南大学
湘ICP备09001153号 版权所有:《中国有色金属学报》编辑部
------------------------------------------------------------------------------------------
地 址:湖南省长沙市岳麓山中南大学内 邮编:410083
电 话:0731-88876765,88877197,88830410   传真:0731-88877197   电子邮箱:f-ysxb@mail.csu.edu.cn