- 必威体育下载

姓名
邮箱
手机号码
标题
留言内容
验证码

摘要

分别从基体和铝酸盐两方面优化了钡钨阴极. 在基体方面, 首先采用窄粒度钨粉结合放电等离子体烧结获得了孔径分布窄的基体; 再利用射频等离子体球化技术制备了球形钨粉, 采用球形钨粉制备了多孔基体, 获得了孔通道光滑、内孔连通性好、孔径分布更加窄的基体. 与窄粒度钨粉基体相比, 球形钨粉制备的阴极, 空间电荷限制区的斜率由1.25增加至1.37, 发射均匀性得到提高, 拐点电流密度由6.6 A·cm ^–2增至6.96 A·cm ^–2. 在此基础上, 采用液相法改善了铝酸盐物相组成, 发现空间电荷限制区的斜率增加至1.44, 拐点电流密度增加至21.2 A·cm ^–2. 通过理论计算对钡钨阴极发射的物理本质进行了研究, 发现钡钨阴极发射规律遵循偶极子理论.

关键词:

Abstract

The Ba-W cathode consists of the porous W matrix and the aluminate. During cathode operation, the Ba atoms are generated in the pores through the thermal reaction between the W and aluminate, and then diffuse along the pore channels to the W surface, lowering the work function. Therefore, the Ba yield and the Ba diffusion are significantly influenced by the micro pore structure of the matrix and the phase composition of the aluminate. Firstly, the matrix is fabricated with the narrow particle size distribution powder by the spark plasma sintering (SPS) technique, which shows the narrow pore size distribution (FWHM = 0.43 μm). Then the spherical powder with good fluidity and high tap density is prepared using the RF induction thermal plasma. The matrix prepared with spherical powder exhibits narrower pore size distribution (FWHM = 0.4 μm), smooth pore channels and good inter-pore connectivity. The two matrixes prepared with narrow particle powder and spherical powder are named N-matrix and S-matrix, respectively. The aluminates are prepared using the solid phase method and the liquid phase method, separately. The particles of solid phase aluminate precursor present all shapes and all sizes, while the particles of the liquid phase aluminate precursor are uniform in size and identical in shape. The phase of solid phase aluminate and the phase of liquid phase aluminate are analyzed by XRD, the results show that the former consists of the effective Ba ₃CaAl ₂O ₇phase and other impurity phases, while the latter is composed of two effective phases of Ba ₃CaAl ₂O ₇and Ba ₅CaAl ₄O ₁₂. The N+S and S+S cathodes are obtained by using the solid phase aluminate to impregnate the N-matrix and the S-matrix, and the U- jcharacteristics of the two cathodes are investigated. The double logarithmic curves of Uand jshow that the slope of 1.37 in the space charges limited (SCL) region for the S + S cathode is higher than that of 1.25 for the N+S cathode, so the S+S cathode exhibits better emission uniformity. The current density at the deviation point ( j _DEV) of the N+S cathode and that of the S+S cathode are 6.6 A·cm ^–2and 6.96 A·cm ^–2, respectively. So the improvement on the matrix obviously raises the emission uniformity of cathode, but the current density is increased less. Based on the excellent matrix of the S+S cathode, the S+L cathode is obtained by improving the aluminate of the S+S cathode with liquid phase aluminate. The U- jcharacteristics show the slope of the S+L cathode reaches to 1.44, and the j _DEVis 21.2 A·cm ^–2. So the improvement on the aluminate not only increases the uniformity, but also raises the current density. The present study shows that the U-jcurve calculated from the classical thermionic emission (TE) theory accords well with that of the S + L cathode at 1000 ℃, which indicates that the Ba-W cathode follows the classical TE theory rather than other emission theories, and the Ba-O dipole layer just changes the work function of the cathode.

Keywords:

作者及机构信息

通信作者:杨新宇,xyyinuang@hfut.edu.cn; 张久兴,zjiuxing@hfut.edu.cn

基金项目:国家自然科学基金(批准号: 51501051)和西北工业大学凝固技术国家重点实验室开放基金(批准号: SKLSP202119)资助的课题

Authors and contacts

Corresponding author:Yang Xin-Yu,xyyinuang@hfut.edu.cn; Zhang Jiu-Xing,zjiuxing@hfut.edu.cn

Funds:Project supported by the National Natural Science Foundation of China (Grant No. 51501051) and the Open Fund of the State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, China (Grant No. SKLSP202119).

文章全文: translate this paragraph

参考文献

[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10]
[11]
[12]
[13]
[14]
[15]
[16]
[17]
[18]
[19]
[20]
[21]
[22]

施引文献

下载: 全尺寸图片幻灯片

水平	(A) 探针位置	(B) 送粉率/ (g·min^–1)	(C) 载气流/ (L·min^–1)
1	顶端	2.5	2.5
2	中间	5	4
3	尾端	8	6

下载: 导出CSV

实验号	A	B	C	实验方案	球化率
1	顶端	2.5	2.5	A1B1C1	100%
2	顶端	5	4	A1B2C2	95%
3	顶端	8	6	A1B3C3	50%
4	中间	5	2.5	A2B2C1	75%
5	中间	8	4	A2B3C2	30%
6	中间	2.5	6	A2B1C3	90%
7	尾端	8	2.5	A3B3C1	1%
8	尾端	2.5	4	A3B1C2	3%
9	尾端	5	6	A3B2C3	1%
K₁	2.45	1.93	1.76	—	—
K₂	1.95	1.71	1.28	—	—
K₃	0.05	0.81	1.41	—	—
R	2.39	1.12	0.35	—	—

下载: 导出CSV

[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10]
[11]
[12]
[13]
[14]
[15]
[16]
[17]
[18]
[19]
[20]
[21]
[22]

[1]	漆亮文, 杜满强, 温晓东, 宋健, 闫慧杰.同轴枪放电等离子体动力学与杂质谱特性. 必威体育下载 , 2024, 73(18): 185203.doi:10.7498/aps.73.20240760
[2]	张雨涵, 赵欣茜, 梁英爽, 郭媛媛.感性耦合Ar/O₂等离子体放电特性的数值模拟. 必威体育下载 , 2024, 73(13): 135201.doi:10.7498/aps.73.20240436
[3]	祁超, 马玉田, 齐艳飞, 肖善曲, 王波.微观组织对叠片结构钨基面向等离子体材料的热疲劳效应的影响. 必威体育下载 , 2024, 73(11): 112801.doi:10.7498/aps.73.20240007
[4]	张雪雪, 贾鹏英, 冉俊霞, 李金懋, 孙换霞, 李雪辰.辅助放电下刷状空气等离子体羽的放电特性和参数诊断. 必威体育下载 , 2024, 73(8): 085201.doi:10.7498/aps.73.20231946
[5]	宋健, 李嘉雯, 白晓东, 张津硕, 闫慧杰, 肖青梅, 王德真.外电极长度对同轴枪放电等离子体特性的影响. 必威体育下载 , 2021, 70(10): 105201.doi:10.7498/aps.70.20201724
[6]	尚吉花, 杨新宇, 孙大鹏, 张久兴(Jiu-Xing Zhang).研究. 必威体育下载 , 2021, (): .doi:10.7498/aps.70.20211684
[7]	余鑫, 漆亮文, 赵崇霄, 任春生.同轴枪正、负脉冲放电等离子体特性的对比. 必威体育下载 , 2020, 69(3): 035202.doi:10.7498/aps.69.20191321
[8]	崔岁寒, 吴忠振, 肖舒, 陈磊, 李体军, 刘亮亮, 傅劲裕, 田修波, 朱剑豪, 谭文长.外扩型电磁场控制筒形阴极内等离子体放电输运特性的仿真研究. 必威体育下载 , 2019, 68(19): 195204.doi:10.7498/aps.68.20190583
[9]	陈坚, 刘志强, 郭恒, 李和平, 姜东君, 周明胜.基于气体放电等离子体射流源的模拟离子引出实验平台物理特性. 必威体育下载 , 2018, 67(18): 182801.doi:10.7498/aps.67.20180919
[10]	邹丹旦, 蔡智超, 吴鹏, 李春华, 曾晗, 张红丽, 崔春梅.脉冲放电产生螺旋流注的等离子体特性研究. 必威体育下载 , 2017, 66(15): 155202.doi:10.7498/aps.66.155202
[11]	王建龙, 丁芳, 朱晓东.高气压均匀直流辉光放电等离子体的光学特性. 必威体育下载 , 2015, 64(4): 045206.doi:10.7498/aps.64.045206
[12]	冯璟华, 蒙世坚, 甫跃成, 周林, 徐荣昆, 张建华, 李林波, 章法强.含氢电极真空弧放电等离子体时空分布特性研究. 必威体育下载 , 2014, 63(14): 145205.doi:10.7498/aps.63.145205
[13]	胡明, 万树德, 钟雷, 刘昊, 汪海.磁控直流辉光等离子体放电特性. 必威体育下载 , 2012, 61(4): 045201.doi:10.7498/aps.61.045201
[14]	汪宇, 李晓东, 余量, 严建华.滑动弧低温等离子体放电特性的数值模拟研究. 必威体育下载 , 2011, 60(3): 035203.doi:10.7498/aps.60.035203
[15]	李雪辰, 袁宁, 贾鹏英, 常媛媛, 嵇亚飞.大气压等离子体针产生空气均匀放电特性研究. 必威体育下载 , 2011, 60(12): 125204.doi:10.7498/aps.60.125204
[16]	胡佳, 徐轶君, 叶超.CHF3双频电容耦合放电等离子体特性研究. 必威体育下载 , 2010, 59(4): 2661-2665.doi:10.7498/aps.59.2661
[17]	丁振峰, 袁国玉, 高巍, 孙景超.柱面天线射频感性耦合等离子体放电模式特性的实验研究. 必威体育下载 , 2008, 57(7): 4304-4315.doi:10.7498/aps.57.4304
[18]	李汉明, 李钢, 李英骏, 李玉同, 张翼, 程涛, 聂超群, 张杰.绝缘阻挡放电等离子体发光光谱的特性. 必威体育下载 , 2008, 57(2): 969-974.doi:10.7498/aps.57.969
[19]	张忻, 李佳, 路清梅, 张久兴, 刘燕琴.(Bi1-x Agx)2(Te1-ySey)3粉体的机械合金化制备及其放电等离子烧结体的热电输运特性. 必威体育下载 , 2008, 57(7): 4466-4470.doi:10.7498/aps.57.4466
[20]	卢新培, 潘垣, 张寒虹.水中脉冲放电等离子体通道特性及气泡破裂过程. 必威体育下载 , 2002, 51(8): 1768-1772.doi:10.7498/aps.51.1768

计量

文章访问数:4980
PDF下载量:116
被引次数:0

搜索

留言板