摘要
采用稀土CeO2与钨机械混合,制备了掺杂稀土氧化铈(CeO2)M型扩散阴极,利用扫描电镜、压汞仪等测试手段分析了阴极基体的微观结构。用水冷阳极二极管检测了阴极的发射性能。同时利用XPS对老练后阴极表面化学成分进行了分析。研究表明,掺杂稀土CeO2阴极基体孔径分布更均匀,平均孔径为2.08μm。在阴极正常工作温度1050℃下,掺杂稀土CeO2钡钨阴极的直流发射电流密度和脉冲发射电流密度分别为6.33 A.cm-2、17.48 A.cm-2,有效逸出功为1.86 eV,明显优于纯钨基M型扩散阴极。掺杂稀土CeO2有助于Ba的扩散,并吸附在阴极表面,使得M型阴极表面Ba3d峰明显增强。
The novel M-type cathode material has been successfully developed by mechanically adding CeO2 impurity into the tungsten matrix. Its microstructures and its emission properties were characterized with scanning electron microscopy （ SEM ）, X-ray photoelectron spectroscopy （XPS）, mercury intrusion poremeasurement （ MIP ） and water cooled anode diode. The results show that doping of rare-earth CeO2 significantly improves the characteristics of the cathode, and in normal working temperature of 1050 ℃, the CeO2 doped cathode outperforms its counterpart - - the conventional bariumtungsten cathode. For instance, the CeO2 doping results in a more uniform distribution of pores, with an average diameter of 2.08 μm. Its continuous and pulsed emission current densities are found to be 6.33 A·cm^-2 and 17.48 A·cm^-2, respectively;and its effective work function is 1. 86 eV. Besides, CeO2 doping promotes the diffusion and surface absorption of Ba, leading to higher Ba3 d peak.
出处
《真空科学与技术学报》
EI
CAS
CSCD
北大核心
2008年第4期295-298,共4页
Chinese Journal of Vacuum Science and Technology
关键词
稀土
CEO2
扩散阴极
发射电流密度
Rare earths, CeO2, Dispenser cathode, Emission current density
