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新型钨铼混合基阴极的热电子发射性能
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北京工业大学,北京工业大学,北京工业大学,北京工业大学,北京工业大学,北京工业大学

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中图分类号:

TG 146.4

基金项目:

国家自然科学基金项目(面上项目,重点项目,重大项目)


Thermal electron emission properties of novel W-Re mixed matrix cathodes
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Beijing University of Technology,Beijing University of Technology,Beijing University of Technology,Beijing University of Technology,Beijing University of Technology,Beijing University of Technology

Fund Project:

Hubei Province Natural Science Foundation (2009CDA030, 2010CDB05807)

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    摘要:

    本文采用喷雾干燥结合两步氢还原法制备出W-Re混合粉末, 并在此基础上通过压制、烧结和浸渍工艺制备出W-Re混合基浸渍型阴极。采用SEM、XRD、AES对W-Re混合基阴极的微观形貌、物相、表面活性元素进行表征分析,并用电子发射测试系统测试阴极在950-1050℃的脉冲电子发射性能。结果表明,铼的含量决定了阴极基体的物相,铼含量为75at%的W-75Re阴极由Re3W单一物相组成,该阴极由于铼含量较高使得基体晶粒尺寸更细小,有利于活性自由钡的生成及其在阴极表面的扩散,从而W-75Re阴极具有相对较低的逸出功和较高的发射电流密度,其在1 000 ℃b时的零场脉冲发射电流密度为14.03 A?cm-2,有效逸出功为1.902 eV。

    Abstract:

    Tungsten-rhenium mixed powders were prepared by spray drying followed by two-step hydrogen reduction method. With these powders, W-Re mixed metal matrix cathodes were prepared by processes of die pressing, sintering and impregnation. Thermal electron emission properties of the cathodes were tested using the self-prepared pulsed power testing system. SEM, XRD and AES were adopted to analyze the surface morphology, phase structure and surface chemical elements of the cathodes respectively. It revealed that the phase of the cathodes depends on the content of rhenium in the matrixs. The W-75Re cathode (containing 75at% Re) is composed of Re3W singular phase. The emission testing results show that the W-75Re cathode impregnated with 411 salt has the lowest work function of 1.902 eV and the highest zero field emission current density of 14.03A cm-2 at 1000℃b among the prepared cathodes. It is possibly due to the high concentration of Re in the matrix, which results in fine grains in the matrix and is favourable to the formation of active Ba element and its diffusion on the cathode surface.

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引用本文

赖陈,王金淑,王茜,周帆,刘伟,杨帆.新型钨铼混合基阴极的热电子发射性能[J].稀有金属材料与工程,2016,45(7):1871~1875.[Lai Chen, Wang Jinshu, Wang Xi, Zhou Fan, Liu Wei, Yang Fan. Thermal electron emission properties of novel W-Re mixed matrix cathodes[J]. Rare Metal Materials and Engineering,2016,45(7):1871~1875.]
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  • 收稿日期:2014-05-29
  • 最后修改日期:2015-01-25
  • 录用日期:2015-02-06
  • 在线发布日期: 2016-10-09
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