悬浮区域熔炼法制备Ce_(1-x)Pr_xB_6单晶体及其热发射性能研究  

Synthesis and Properties of Single Crystal Ce_(1-x)Pr_xB_6 by Floating Zone Melting

作　　者：张繁星[1] 张忻[1] 张久兴[1] 梁超龙 黄颖凯 

机构地区：[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

出　　处：《无机材料学报》2014年第10期1073-1076,共4页Journal of Inorganic Materials

基　　金：国家自然科学基金(50871002);北京市自然科学基金(2112007)~~

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Ce1-xPrxB6（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：Ce0.8Pr0.2B6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/cm^2,比CeB6单晶的电流发射密度提高约20%。此外,Ce0.9Pr0.1B6、Ce0.6Pr0.4B6单晶（100）晶面的热发射电流密度分别为65.81 A/cm^2和65.31 A/cm^2。Ce0.8Pr0.2B6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,Ce1-xPrxB6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。High-quality single crystals Ce1-xPrxB6（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 Ce0.8Pr0.2B6 single crystal has the maximum emission current density, 66.07 A/cm^2 at 1873 K, which is higher than the current reported CeB6 single crystal, increased by about 20%. In addition, the thermal emission current density of（100） plane of Ce0.9Pr0.1B6, Ce0.6Pr0.4B6 single crystals are 65.81 A/cm^2 and 65.31 A/cm^2, respectively. The（100） plane of Ce0.8Pr0.2B6 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 Ce1-xPrxB6 hexaborides have good thermionic emission and low work function, which promises good prospects in the application as a hot cathode material.

关 键 词：Ce1-xPrxB6单晶体 悬浮区域熔炼法 热电子发射性能 

分 类 号：TQ174[化学工程—陶瓷工业]