摘要
以LaH2,CeH2纳米粉和无定形B粉为原料,通过放电等离子烧结原位合成法制备了单相、高致密度的LaxCe1-xB6稀土六硼化物.系统研究了该系列化合物的晶体结构、表面织构、力学性能、电输运特性及热发射性能.结果表明,该方法制备出的样品致密度均高于96%,维氏硬度最高值达到2310 kg/mm2,说明具有良好的力学性能.热发射结果表明,当阴极温度为1873 K,外加电压为1 kV时,La0.6Ce0.4B6的最大发射电流密度达到40.7 A/cm2,该值高于单纯LaB6和CeB6电流密度值.因此,LaxCe1-xB6多元稀土六硼化物作为热阴极材料将有良好的应用前景.
Polycrystalline rare-earth hexaboride （Lax Ce1-x ）B6 were prepared by means of the reactive spark plasma sintering （SPS）, using mixed powders of GdH2, NdH2 and B. The crystal structure, surface texture, mechanical property, electrical resistivity, and thermionic emission properties of the sintered samples were investigated. It is found that all the samples sintered by SPS exhibit high densily （〉96%） and high value of Vickers hardness （2310 kg/mm^2）, which are much higher than those made by traditional method. Thermionic emission results indicate that the maximum emission current density of La0.6Ce0.4B6 is 40.7 A/cm^2 under the applied voltage of 1 kV at 1873 K, which is larger than that of LaB6 and CeB6. Thus, the mixed cystal of borides （LaxCe1-x）B6, as a cathode, promises good prospects in application.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2013年第19期382-387,共6页
Acta Physica Sinica
基金
国家自然科学基金(批准号:51161017)
内蒙古自治区重大基础研究开放课题(批准号:120294)
内蒙古自然科学基金(批准号:2010MS0104)资助的课题~~
关键词
稀土六硼化物
阴极材料
热电子发射
rare-earth hexaboride, cathode materials, thermionic emission
作者简介
通讯作者．E-mail：zjiuxing@bjut．edu．cn
