Microsoft Word - 11-152包黎红_英_doc.pdf

第 26 卷 第 10 期 无 机 材 料 学 报 Vol. 26 No. 10 2011 年 10 月 Journal of Inorganic Materials Oct., 2011 Article ID: 1000-324X(2011)10-1116-05 DOI: 10.3724/SP.J.1077.2011.11152 Effect of Ba-doping on the Structural, Grain Orientation and Thermionic Emis- sion Properties of Hexaboride GdB6 BAO Li-Hong, ZHANG Jiu-Xing, ZHOU Shen-Lin P (Key Laboratory of Advanced Functional Materials, Ministry of Education, College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124,China) Abstract: The polycrystalline rare-earth hexaborides (Ba Gd )B (x = 0, 0.2, 0.4, 0.8) were prepared by the reactive x 1-x 6 spark plasma sintering (SPS) method using mixed powder of BaH , GdH and B. The effects of Ba doping content on 2 2 the crystal structure, the grain orientation and the thermionic emission properties of the GdB6 were investigated by X-ray diffraction, electron backscattered diffraction and emission current measurements. It is found that all the sintered 2 samples exhibit high densification ( 97%) and high value of Vickers hardness (2070 kg/mm ). The maximum 2 thermionic emissi