- 必威体育下载

姓名
邮箱
手机号码
标题
留言内容
验证码

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:

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).

FullText HTML: translate this paragraph

References

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

Cited By

DownLoad: Full-Size Img PowerPoint

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

DownLoad: 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	—	—

DownLoad: CSV

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

[1]	Zhang Yu-Han, Zhao Xin-Qian, Liang Ying-Shuang, Guo Yuan-Yuan.Numerical simulation of inductively coupled Ar/O₂plasma. Acta Physica Sinica, 2024, 73(13): 135201.doi:10.7498/aps.73.20240436
[2]	Qi Chao, Ma Yu-Tian, Qi Yan-Fei, Xiao Shan-Qu, Wang Bo.Influence of microstructure on thermal fatigue effect of laminated tungsten based plasma-facing material. Acta Physica Sinica, 2024, 73(11): 112801.doi:10.7498/aps.73.20240007
[3]	Zhang Xue-Xue, Jia Peng-Ying, Ran Jun-Xia, Li Jin-Mao, Sun Huan-Xia, Li Xue-Chen.Discharge characteristics and parameter diagnosis of brush-shaped air plasma plumes under auxiliary discharge. Acta Physica Sinica, 2024, 73(8): 085201.doi:10.7498/aps.73.20231946
[4]	Song Jian, Li Jia-Wen, Bai Xiao-Dong, Zhang Jin-Shuo, Yan Hui-Jie, Xiao Qing-Mei, Wang De-Zhen.Effect of length of outer electrode on plasma characteristics in coaxial gun. Acta Physica Sinica, 2021, 70(10): 105201.doi:10.7498/aps.70.20201724
[5]	.. Acta Physica Sinica, 2021, (): .doi:10.7498/aps.70.20211684
[6]	Yu Xin, Qi Liang-Wen, Zhao Chong-Xiao, Ren Chun-Sheng.Comparative study of positive and negative pulsed discharge plasma characteristics of coaxial gun. Acta Physica Sinica, 2020, 69(3): 035202.doi:10.7498/aps.69.20191321
[7]	Qi Liang-Wen, Zhao Chong-Xiao, Yan Hui-Jie, Wang Ting-Ting, Ren Chun-Sheng.Motion characteristics of coaxial gun discharge plasma current sheet. Acta Physica Sinica, 2019, 68(3): 035203.doi:10.7498/aps.68.20181832
[8]	Cui Sui-Han, Wu Zhong-Zhen, Xiao Shu, Chen Lei, Li Ti-Jun, Liu Liang-Liang, Ricky K Y Fu, Tian Xiu-Bo, Paul K Chu, Tan Wen-Chang.Simulation study on plasma discharge and transport in cylindrical cathode controlled by expanding electromagnetic field. Acta Physica Sinica, 2019, 68(19): 195204.doi:10.7498/aps.68.20190583
[9]	Chen Jian, Liu Zhi-Qiang, Guo Heng, Li He-Ping, Jiang Dong-Jun, Zhou Ming-Sheng.Physical characteristics of ion extraction simulation system based on gas discharge plasma jet. Acta Physica Sinica, 2018, 67(18): 182801.doi:10.7498/aps.67.20180919
[10]	Zou Dan-Dan, Cai Zhi-Chao, Wu Peng, Li Chun-Hua, Zeng Han, Zhang Hong-Li, Cui Chun-Mei.Plasma characteristics of helical streamers induced by pulsed discharges. Acta Physica Sinica, 2017, 66(15): 155202.doi:10.7498/aps.66.155202
[11]	Wang Jian-Long, Ding Fang, Zhu Xiao-Dong.Optical properties of direct current glow discharge plasmas at high pressures. Acta Physica Sinica, 2015, 64(4): 045206.doi:10.7498/aps.64.045206
[12]	Feng Jing-Hua, Meng Shi-Jian, Fu Yue-Cheng, Zhou Lin, Xu Rong-Kun, Zhang Jian-Hua, Li Lin-Bo, Zhang Fa-Qiang.Spatiotemporal distribution of hydrogenous electrode vacuum arc discharge plasma. Acta Physica Sinica, 2014, 63(14): 145205.doi:10.7498/aps.63.145205
[13]	Hu Ming, Wan Shu-De, Zhong Lei, Liu Hao, Wang Hai.Magnetic control of the constant-current glow discharge plasma characteristics. Acta Physica Sinica, 2012, 61(4): 045201.doi:10.7498/aps.61.045201
[14]	Li Xue-Chen, Yuan Ning, Jia Peng-Ying, Chang Yuan-Yuan, Ji Ya-Fei.Characteristics of atmospheric pressure air uniform discharge generated by a plasma needle. Acta Physica Sinica, 2011, 60(12): 125204.doi:10.7498/aps.60.125204
[15]	Wang Yu, Li Xiao-Dong, Yu Liang, Yan Jian-Hua.Numerical simulation study on characteristics of gliding arc discharge. Acta Physica Sinica, 2011, 60(3): 035203.doi:10.7498/aps.60.035203
[16]	Hu Jia, Xu Yi-Jun, Ye Chao.CHF3 dual-frequency capacitively coupled plasma. Acta Physica Sinica, 2010, 59(4): 2661-2665.doi:10.7498/aps.59.2661
[17]	Ding Zhen-Feng, Yuan Guo-Yu, Gao Wei, Sun Jing-Chao.Experimental studies on the properties of the discharge modes in a cylindrical radio frequency inductively coupled plasma. Acta Physica Sinica, 2008, 57(7): 4304-4315.doi:10.7498/aps.57.4304
[18]	Li Han-Ming, Li Gang, Li Ying-Jun, Li Yu-Tong, Zhang Yi, Cheng Tao, Nie Chao-Qun, Zhang Jie.The characteristics of the spectrum emitted from dielectric barrier-discharge plasmas. Acta Physica Sinica, 2008, 57(2): 969-974.doi:10.7498/aps.57.969
[19]	Zhang Xin, Li Jia, Lu Qing-Mei, Zhang Jiu-Xing, Liu Yan-Qin.Mechanical alloying synthesis of (Bi1-xAgx)2(Te1-ySey)3 powder and thermoelectric properties of its bulk materials prepared by spark plasma sintering. Acta Physica Sinica, 2008, 57(7): 4466-4470.doi:10.7498/aps.57.4466
[20]	Lu Xin-Pei, Pan Yuan, Zhang Han-Hong.. Acta Physica Sinica, 2002, 51(8): 1768-1772.doi:10.7498/aps.51.1768

Catalog

Vol. 71, Issue 4 - 2022-02-20

Metrics

Abstract views:4709
PDF Downloads:113
Cited By:0

Search

Article