Optimization of high-performance field emission rare earth tungsten alloy cathodes
Optimization of high-performance field emission rare earth tungsten alloy cathodes
Tao Wu 1Jinxing Zheng 2Haiyang Liu 2Yudong Lu 2Yifan Du 1Meiqi Wu 1Jiaming Shi 2Maolin Ke1
作者信息
- 1. Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences;University of Science and Technology of China
- 2. Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences
- 折叠
摘要
Cathodes are electron-emission sources in electronic vacuum devices and spacecraft potential-control systems; their performance affects not only the overall efficiency of the equipment, but also the long-term reliability and lifetime of the system. In space propulsion, cathode electron emission is governed mainly by thermionic and field-emission mechanisms. In this study, atomic models of W cathode surfaces doped with different rare-earth atoms were constructed using first-principles density functional theory calculations. Using a (2 ×2 ×1 ) W(001) surface model, 1 ML of O atoms was adsorbed at top sites of the surface, followed by doping rare-earth atoms (La, Ce, and Y) into the hollow sites of the W–O surface lattice. The work functions of the system with rare-earth atom coverages of 0.5 ML and 1 ML were calculated. Through liquid-phase synthesis, spark-plasma sintering, and heat treatment, nanoscale second-phase rare-earth oxide (La2O3, CeO2, Y2O3,etc.)-dispersed tungsten cathodes were produced. Different ignition experiments were designed to simulate various operating conditions. A cascade arc plasma source was used for mass-loss measurements and lifetime prediction. After testing, scanning electron microscopy and energy-dispersive spectroscopy of the cathode materials were conducted to analyze their composition, morphology, and elemental distributions. The results show that the W-La, W-Ce, and W-Y cathodes prepared with this method exhibit excellent ablation resistance and plasma-bombardment endurance at high temperature. The nanoscale dispersion of the doped phases endows thecathode with superior electron-emission properties, enhancing the overall efficiency of the system. At a plasma density of 1.0 × 1019 m−3 and operating temperature of 2000 K, the projected lifetime of rare-earth tungsten alloy cathodes exceeds 2000 h
Abstract
Cathodes are electron-emission sources in electronic vacuum devices and spacecraft potential-control systems; their performance affects not only the overall efficiency of the equipment, but also the long-term reliability and lifetime of the system. In space propulsion, cathode electron emission is governed mainly by thermionic and field-emission mechanisms. In this study, atomic models of W cathode surfaces doped with different rare-earth atoms were constructed using first-principles density functional theory calculations. Using a (2 2 1 ) W(001) surface model, 1 ML of O atoms was adsorbed at top sites of the surface, followed by doping rare-earth atoms (La, Ce, and Y) into the hollow sites of the WO surface lattice. The work functions of the system with rare-earth atom coverages of 0.5 ML and 1 ML were calculated. Through liquid-phase synthesis, spark-plasma sintering, and heat treatment, nanoscale second-phase rare-earth oxide (La2O3, CeO2, Y2O3,etc.)-dispersed tungsten cathodes were produced. Different ignition experiments were designed to simulate various operating conditions. A cascade arc plasma source was used for mass-loss measurements and lifetime prediction. After testing, scanning electron microscopy and energy-dispersive spectroscopy of the cathode materials were conducted to analyze their composition, morphology, and elemental distributions. The results show that the W-La, W-Ce, and W-Y cathodes prepared with this method exhibit excellent ablation resistance and plasma-bombardment endurance at high temperature. The nanoscale dispersion of the doped phases endows thecathode with superior electron-emission properties, enhancing the overall efficiency of the system. At a plasma density of 1.0 1019 m3 and operating temperature of 2000 K, the projected lifetime of rare-earth tungsten alloy cathodes exceeds 2000 h关键词
Field-emission cathode/ Rare-earth tungsten alloy/ First-principles calculations/ Work functionKey words
Field-emission cathode/ Rare-earth tungsten alloy/ First-principles calculations/ Work function引用本文复制引用
Tao Wu,Jinxing Zheng,Haiyang Liu,Yudong Lu,Yifan Du,Meiqi Wu,Jiaming Shi,Maolin Ke.Optimization of high-performance field emission rare earth tungsten alloy cathodes[EB/OL].(2026-09-18)[2026-09-24].https://chinaxiv.org/abs/202609.00168.学科分类
航空/航天
