共查询到19条相似文献,搜索用时 468 毫秒
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《中国无线电电子学文摘》2003,(2)
0462 2003020094新型压制钡钨阴极性能的研究/张红卫,白振纲,俞世吉,丁耀根(中国科学院电子学研究所)11真空电子技术.一2002,(3)一67一69研究了新型压制钡钨阴极的发射性能,并且分别用KYKY一2800扫描电子显微镜(5 EM)和美国BIR公司ACTIS工业CT微焦点系统来分析所研制的新型压制钡钨阴极的表面形貌和内部结构,并对比了传统的钡钨阴极,来说明简化覆膜浸渍钡钨阴极生产工艺的可行性.图5参1(冈,J)到了一组具有原子分辨率的F EM像.该像可能是从单壁碳纳米管束中突出的一根(16,0)锯齿型单壁碳纳米管开口端的发射形成的.理论计算了FEM图… 相似文献
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着重介绍类似于压制钡钨阴极的一种新型氧化物阴极的制作方法。该方法能使阴极工作温度在只有760℃条件下,却能支取直流发射3A/cm^2高电流密度的氧化物阴极。 相似文献
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一、引言氧化物阴极,钡钨浸渍阴极或压制阴极,以及它们的改进型铱膜钡钨浸渍阴极在各种电真空器件中得到了广泛的应用。在真空器件的性能改进和增长寿命问题上、管内残余气氛对阴极性能和寿命的影响,仍然是一个重要因素。不论是化学活泼气体如O_2、H_2O、CO_2等或是例 相似文献
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本文对渍制钡钨阴极多孔钨结构与发射和蒸发性能的有关数据进行了分析研究。结果表明,对于多孔钨结构,钨粉的颗粒度和孔隙的孔径大小决定了小孔内表面的总面积和钡在钨表面上的扩散路程,钡输送通道的大小和长短。这些因素对钡钨阴极的性能和工作机理有密切关系,但仅用多孔钨孔隙度来表征阴极性能那是不够严格的。最后我们提出了对于不同用途的阴极应采用的多孔钨结构。 相似文献
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本文全面系统地综述了钪酸盐钡钨阴极的发展趋向,并着重说明端层压制W Sc_2O_3的浸渍型阴极发射电流密度大,抗离子轰击能力强的特性。 相似文献
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通过分析影响钡钨阴极蒸发的各种因素,结合实际生产中的工艺要求,介绍了一种复合钨海绵体钡钨阴极制造工艺,能够有效降低钡钨阴极蒸发。 相似文献
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介绍了浸渍式钨酸盐钡钨阴极制造的工艺流程,并对钨海绵的压制、磨削夹具的设计、钨酸盐的制备、钨酸盐的浸渍等几个关键工艺进行了详细的探讨,指出只有严格按照相关工艺操作,才能制备出性能良好的阴极。 相似文献
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Wu Zhaohao 《电子科学学刊(英文版)》1987,4(4):273-281
Some data of emission and evaporation properties related to tungsten matrix structures of the impregnated cathodes are analyzed.
The results indicate that the particle size of tungsten powder and the pore size in the porous matrix determine the total
inside surface area of all pores, the diffusion length of barium atoms over tungsten grain surfaces, and the diameter and
length of the path through which barium atoms are transported. These factors all relate to the properties and operation mechanism
of an impregnated cathode; therefore, it would not be strictly correct to use only the matrix porosity for characterizing
the cathode properties. Finally, the preferred structures of porous tungsten matrix depending on different applications of
impregnated, cathodes are proposed. 相似文献
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通过分析传统环状钡钨阴极发射体制造工艺的优缺点,结合实际生产工艺需要,总结出一种新的钡钨阴极海绵钨环制造工艺,避免了传统浸铜工艺造成的铜残留,提高了阴极性能,延长了磁控管的寿命。 相似文献
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QING-BIN LU 《International Journal of Electronics》2013,100(4):645-655
Based on the analysis and synthesis of recent experimental results—in particular, on the role of oxygen in the surface of a tungsten substrate—previous suggestions are examined and disproved. Furthermore, a new model for the role of oxygen in the thermionic emitting surface of an impregnated tungsten cathode is proposed. The model assumes that, at oxygen concentrations of approximately 5 × 1014 atoms cm?2 or less, oxygen atoms are incorporated into the outermost layer of the tungsten substrate; this accompanies the surface roughening that lowers the work function, enhances the barium-substrate bond, and forms a compacted Ba-(W,O) atomic configuration that is most stable and has the lowest work function. At higher oxygen concentrations, the excess oxygen lies on a surface site between the barium adsorbate and the tungsten substrate, forming a less stable Ba-O-(W,O) configuration that increases the work function and poisons the emitting surface. This model can effectively explain all the observed experimental results. 相似文献
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Yin Shengyi 《电子科学学刊(英文版)》2014,31(2):159-167
With the most advanced Synchronous Radiation Photoelectron Spectrum (SRPS), the emission mechanism of M-type cathodes has been investigated from the perspective of chemical state. Based on the experimental results of SRPS analysis, a new model of the electron emission mechanism for M-type cathode is discussed. The main topics in this paper include the research status of electron emission mechanism of M-type cathodes; the advantages of SRPS technology; the distribution of oxygen chemical state on the cathode surface and the evolvement of oxygen chemical state during activation process; the relation between barium chemical state and osmium (Os)-coating; surplus barium and its formula; the characteristics of Os, and other noble metal coatings; the relation between film characteristics and emission performance of cathodes, the inhibition effects to the emission for Platinum (Pt)-coated cathode, etc. At the end of this paper, electron emission mechanism of M-type cathode is summarized and foreseen. 相似文献