悬浮区域熔炼法制备Ce1-xPrxB6单晶体及其热发射性能研究

doi:10.15541/jim20140027

无机材料学报 ›› 2014, Vol. 29 ›› Issue (10): 1073-1076.DOI: 10.15541/jim20140027

悬浮区域熔炼法制备Ce_1-_xPr_xB₆单晶体及其热发射性能研究

张繁星¹, 张忻¹, 张久兴¹, 梁超龙¹, 黄颖凯²

(1．北京工业大学材料科学与工程学院, 新型功能材料教育部重点实验室, 北京100124; 2．阿姆斯特丹大学范德瓦尔斯-塞曼研究所, 阿姆斯特丹1098XH)

收稿日期:2014-01-10 修回日期:2014-03-19 出版日期:2014-10-20 网络出版日期:2014-09-22
作者简介:张繁星(1988–), 男, 硕士研究生. E-mail: 18810371495@163.com
基金资助:
国家自然科学基金(50871002);北京市自然科学基金(2112007)

Synthesis and Properties of Single Crystal Ce_1-_xPr_xB₆ by Floating Zone Melting

ZHANG Fan-Xing¹, ZHANG Xin¹, ZHANG Jiu-Xing¹, LIANG Chao-Long¹, HUANG Ying-Kai²

(1. Key Laboratory of Advanced Functional Materials, Ministry of Education, College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, China; 2. Van der Waals-Zeeman Institute, University of Amsterdam, Amsterdam Science Park 904, 1098XH, Netherlands)

Received:2014-01-10 Revised:2014-03-19 Published:2014-10-20 Online:2014-09-22
About author:ZHANG Fan-Xing. E-mail: 18810371495@163.com
Supported by:
National Natural Science Foundation of China(50871002);Natural Science Foundation of Beijing(2112007)

摘要/Abstract

摘要：

以CeB₆和PrB₆粉末为原料, 采用放电等离子烧结结合悬浮区域熔炼法成功制备了晶体质量良好的多元稀土六硼化物Ce_1-_xPr_xB₆(x=0.1、0.2、0.4)单晶体, 并系统研究了该系列单晶体(100)晶面热电子发射性能。结果表明: Ce_0.8Pr_0.2B₆单晶(100)晶面具有最好的热发射性能, 在1873 K, 最大电流发射密度达到66.07 A/cm², 比CeB₆单晶的电流发射密度提高约20%。此外, Ce_0.9Pr_0.1B₆、Ce_0.6Pr_0.4B₆单晶(100)晶面的热发射电流密度分别为65.81 A/cm²和65.31 A/cm²。Ce_0.8Pr_0.2B₆单晶(100)晶面的逸出功最低, 为2.61 eV, 其它单晶(100)晶面的逸出功在2.64~2.753 eV范围内。因此, Ce_1-_xPr_xB₆多元稀土六硼化物单晶具有良好的发射性能和低的逸出功, 作为热阴极材料有很好的应用前景。

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关键词: Ce1-xPrxB6单晶体, 悬浮区域熔炼法, 热电子发射性能

Abstract:

High-quality single crystals Ce_1-_xPr_xB₆(x = 0.1, 0.2, 0.4) hexaborides were successfully prepared by the reactive spark plasma sintering (SPS) combining with the floating zone melting method using powder of CeB₆ and PrB₆ as raw materials. The thermionic emission properties of the (100) plane of single crystals were investigated. Results show that the (100) plane of Ce_0.8Pr_0.2B₆ single crystal has the maximum emission current density, 66.07 A/cm² at 1873 K, which is higher than the current reported CeB₆single crystal, increased by about 20%. In addition, the thermal emission current density of (100) plane of Ce_0.9Pr_0.1B₆, Ce_0.6Pr_0.4B₆ single crystals are 65.81 A/cm² and 65.31 A/cm², respectively. The (100) plane of Ce_0.8Pr_0.2B₆ single crystal has the lowest work function of 2.61 eV, while the work functions of other single crystals are in the range of 2.64-2.753 eV. Therefore, single crystals Ce_1-_xPr_xB₆ hexaborides have good thermionic emission and low work function, which promises good prospects in the application as a hot cathode material.

Key words: Ce1-xPrxB6 single crystal, floating zone melting, thermionic emission property

中图分类号:

TQ174

张繁星, 张忻, 张久兴, 梁超龙, 黄颖凯. 悬浮区域熔炼法制备Ce_1-_xPr_xB₆单晶体及其热发射性能研究[J]. 无机材料学报, 2014, 29(10): 1073-1076.

ZHANG Fan-Xing, ZHANG Xin, ZHANG Jiu-Xing, LIANG Chao-Long, HUANG Ying-Kai. Synthesis and Properties of Single Crystal Ce_1-_xPr_xB₆ by Floating Zone Melting[J]. Journal of Inorganic Materials, 2014, 29(10): 1073-1076.

图/表 6

图1 二次区熔Ce0.8Pr0.2B6晶体单晶衍射仪扫描图谱

Fig. 1 Diffraction photographs of second zone melting crystal Ce0.8Pr0.2B6 (a) 360° rapid scanning; (b) slow scanning alone the direction

图2 Ce0.8Pr0.2B6单晶断口SEM照片

Fig. 2 Fracture SEM image of the single crystal Ce0.8Pr0.2B6

图3 Ce0.8Pr0.2B6单晶(100)晶面定向后劳埃照片

Fig. 3 Laue picture of single crystal Ce0.8Pr0.2B6 (110) plane

图4 Ce0.8Pr0.2B6单晶(100)晶面摇摆曲线

Fig. 4 Rocking curve of Ce0.8Pr0.2B6 (110) plane

图5 Ce1-xPrxB6单晶(100)晶面在不同温度下的伏安特性曲线

Fig. 5 Voltage current characteristic of single crystal Ce1-xPrxB6 (100) plane

图6 Ce1-xPrxB6单晶(100)晶面零场电流密度

Fig. 6 Calculate J0 of single crystal Ce1-xPrxB6 (100) plane

参考文献 11

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悬浮区域熔炼法制备Ce_1-_xPr_xB₆单晶体及其热发射性能研究

Synthesis and Properties of Single Crystal Ce_1-_xPr_xB₆ by Floating Zone Melting

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