Fabrication of Aluminate for Scandia Doped Dispenser Cathode and Emission Property

doi:10.3724/SP.J.1077.2012.00480

Journal of Inorganic Materials ›› 2012, Vol. 27 ›› Issue (5): 480-484.DOI: 10.3724/SP.J.1077.2012.00480

• Orginal Article • Previous Articles Next Articles

Fabrication of Aluminate for Scandia Doped Dispenser Cathode and Emission Property

CUI Yun-Tao, WANG Jin-Shu, LIU Wei, WANG Xi, WANG Kai-Feng

(Key Laboratory of New Functional Materials, College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, China)

Received:2011-06-08 Revised:2011-08-30 Published:2012-05-10 Online:2012-03-31
About author:CUI Yun-Tao. E-mail: cuiyuntao@emails.bjut.edu.cn
Supported by:
National Natural Science Foundation of China (51071005);Natural Science Foundation of Beijing (2102007);Program for Excellent Talents in Beijing (PHR201006101);Doctoral Fund of Ministry of Education of China (20101103110018)

Abstract

Abstract:

Barium calcium aluminate (4BaO:CaO:Al₂O₃) was synthesized via liquid phase co-precipitation and solid phase mixing respectively and sintered in hydrogen atmosphere. Scandia doped tungsten powders were prepared in a new process of spray drying combined with two-step hydrogen reduction. During the preparation of scandia doped impregnated cathodes, a series of procedures, including pressing, sintering, impregnating, water cleaning and annealing were taken to obtain the impregnated cathodes. The results show that Ba₅CaAl₄O₁₂is formed after high temperature sintering. After impregnation, scandia doped impregnated cathodes with porous sub-micron structure are obtained. For full activation at 1150℃, the cathode surface is covered by a Ba-Sc-O active substance layer with a preferable atomic ratio, leading to its good emission property with space charge limited current density of 37.89 A/cm² at 850℃.

Key words: barium calcium aluminate, scandate cathode, liquid phase co-precipitation, spray drying

CLC Number:

TQ133

CUI Yun-Tao, WANG Jin-Shu, LIU Wei, WANG Xi, WANG Kai-Feng. Fabrication of Aluminate for Scandia Doped Dispenser Cathode and Emission Property[J]. Journal of Inorganic Materials, 2012, 27(5): 480-484.

Figures/Tables 6

Fig. 1 SEM images of aluminate precursors fabricated by different methods and corresponding EDS results

Fig. 2 XRD patterns of two aluminates calcined at different temperatures

Fig. 3 XRD pattern(a) and SEM image(b) of scandia doped tungsten powders

Fig. 4 SEM images of scandia doped imgrgnated cathode and corresponding EDS results (a) Surface; (b) Cross-section

Fig. 5 Electron emission property of the cathode impregnated with the aluminates prepared by different methods

Fig. 6 AES spectrum for surface of scandia doped impregnated cathode fully activated at 1150℃

References 16

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Fabrication of Aluminate for Scandia Doped Dispenser Cathode and Emission Property

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