Open AccessSynthesis and properties of multiple boride Pr1-xCexB6 cathodes by reactive spark plasma sintering
Author(s) -
Xiaona Li,
Xin Zhang,
Jiuxing Zhang,
Lihong Bao,
Ning Zhang,
Fanxing Zhang
Publication year - 2012
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.61.228104
Subject(s) - spark plasma sintering , materials science , thermionic emission , boride , vickers hardness test , sintering , analytical chemistry (journal) , doping , plasma , crystallite , cathode , hot cathode , composite material , metallurgy , microstructure , optoelectronics , electron , physics , chemistry , chromatography , quantum mechanics
The polycrystalline Pr1-xCexB6 (x = 0.2, 0.4, 0.6, 0.8) hexaborides are prepared by the reactive spark plasma sintering (SPS) method using mixed powder of CeH2, PrH2 and B. The effects of Ce doping on the phase composition, the mechanical properties and the thermionic emission properties of the hexaboride are investigated. The single-phased hexaborides CexPr1-xB6 bulks are sintered at a temperature of 1450℃, pressure of 50MPa and holding time of 5 min, and the sintered samples show high value of Vickers hardness (24.34 GPa) and bend strength (226.02 MPa). The thermionic emission results show that with the increase of Ce content, the thermionic emission current density increases linearly and the maximum value of Pr0.4Ce0.6B6 reaches 47.3 A·cm-2 under an applied voltage of 950 V at 1973 K, which is much higher than that obtained by traditional method. Thus, the SPS technique represents a suitable method to synthesize the dense rare-earth hexaborides with excellent properties.