Effect of Ba-doping on the Structural, Grain Orientation and Thermionic Emission Properties of Hexaboride GdB6

doi:10.3724/SP.J.1077.2011.11152

Abstract

Abstract: The polycrystalline rare-earth hexaborides (Ba_xGd_1-x)B₆(x = 0, 0.2, 0.4, 0.8) were prepared by the reactive spark plasma sintering (SPS) method using mixed powder of BaH₂, GdH₂ and B. The effects of Ba doping content on 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 samples exhibit high densification (> 97%) and high value of Vickers hardness (2070 kg/mm²). The maximum thermionic emission current density of GdB₆is 11 A/cm² at a cathode temperature of 1873 K, which is much higher than that of traditional method. With the increase of Ba content, the thermionic emission current density decreases from 11 A/cm²to 2.25 A/cm²at 1873 K.

Key words: rare-earth hexaborides, spark plasma sintering, emission property, doping

CLC Number:

TB34

BAO Li-Hong, ZHANG Jiu-Xing, ZHOU Shen-Lin. Effect of Ba-doping on the Structural, Grain Orientation and Thermionic Emission Properties of Hexaboride GdB₆[J]. Journal of Inorganic Materials, 2011, 26(10): 1116-1120.

References

[1] Nishitani R, Aono M, TanaKa T, et al. Surface states on the LaB6(100), (110) and (111) clean surfaces studied by angle-resolved UPS. Surf. Sci., 1980, 95(2/3): 341-358.

[2] Goebel D M, Watkins R M, Jameson K K. LaB6 hollow cathodes for ion and hall thrusters. J. Propul. Powder, 2007, 23(3): 552-558.

[3] Choi Y W, Cho C, Choi Y S, et al. Development of a 30 kW plasma gun system with a long lifetime. IEEE Trans. Plasma Sci., 2008, 36(5): 2765-2769.

[4] Swanson L W, McNeely D R. Work functions of the (001) face of the hexaborides of Ba, La, Ce and Sm. Surf. Sci., 1979, 83(1): 11-28.

[5] Zhou S L, Zhang J X, D. M. Liu, et al. Properties of CeB6 cathode fabricated by spark plasma reactive liquid phase sintering method. J. Inorg. Mater., 2009, 24(4): 793-797.

[6] Reiffers M, Sebek J, Santava E, et al. Thermal hysteresis of the phase-transition temperature of single-crystal GdB6. Phys. Stat. Sol. (b), 2006, 243(1): 313-316.

[7] Luca S E, Amara M, Galera R M, et al. Neutron differaction studies on GdB6 and TbB6 powders. Physica B, 2004, 350: e39-e42.

[8] Cheng H, Jiang J P. Cathode Electronics. Northwest Institute of Telecommunication Publishing House, 1986: 85-86.

[9] Zhang H, Zhang Q, Zhao G P, et al. Single-crystalline GdB6 nanowire field emiters. J. Am. Chem. Soc., 2005, 127(38): 13120-13121.

[10] Storms E K, Mueller B A. Thermionic emission and atom vaporization of the Gd-B system. J. Appl. Phys., 1981, 52(4): 2966-2969.

[11] Schmidt P H, Joy D C. Low work function electron emitter hexaborides. J. Vac. Sci. Technol., 1978,15(6): 1809-1810.

[12] Ma R G, Liu D M, Zhou S L, et al. Fabrication and emission property of polycrystalline La0.4Pr0.6B6 bulk prepared by spark plasma sintering. J. Inorg. Mater., 2010, 25(7): 1-5.

[13] Liu S P, Yang Q S, Chen W P, et al. Development of RE multiple boride (La0.55Ba0.45)B6 and (La0.4Eu0.6)B6 cathode materials. Rare Metals and Cemented Carbides., 2006, 34(3): 8-11.

[14] Zhou S L, Zhang J X, Liu D M, et al. Fabrication and charact erization of high—purity nanostructured bulk LaB6 polycrystal cathode material. J. Inorg. Mater., 2008, 23(6): 1199-1204.

[15] Zhou S L, Zhang J X, Liu D M, et al. Synthesis and properties of nanostructured dense LaB6 cathodes by arc plasma and reactive spark plasma sintering. Acta Mater., 2010, 58(15): 4978-4985.

[16] Uijttewaal M A, DeWijs G A, Groot R A. Ab initio and work function and surface energy anisotropy of LaB6. J. Phys. Chem. B, 2006, 110(37): 18459-18465.

[17] Gesley M, Swanson L W. A determination of the low work function planes of LaB6. Surface Science, 1984, 146(2/3): 583-599.

Effect of Ba-doping on the Structural, Grain Orientation and Thermionic Emission Properties of Hexaboride GdB₆

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