Chemical States of Lanthanum in Carbonized La2O3-Mo Thermionic Cathode Materials
来源期刊：JOURNAL OF RARE EARTHS2003年第5期
论文作者：周美玲 张久兴 王金淑 左铁镛 聂祚仁 王亦曼
Key words：chemical state; lanthanum; La2O3-Mo; cathode; rare earths;
Abstract: The chemical reaction between lanthanum oxide and molybdenum carbide was studied by thermodynamic calculation, thermal analysis and in-situ X-ray Photoelectron Spectroscopy. The theoretical results show that at the environment allowing for the evaporation of lanthanum, such as in high vacuum, La2O3 in the La2O3-Mo materials can be reduced to metallic lanthanum by molybdenum carbide (Mo2C). To confirm the conclusion, many analysis methods such as XRD, SPS, and TG-DTA were taken. The experimental results show that the chemical state of lanthanum changes during heating. It was proved, for the first time, that reacted metallic lanthanum appears at the surface of this kind of material at high temperature.
周美玲1，张久兴1，王金淑1，左铁镛1，聂祚仁1，王亦曼1
(1.The Key Laboratory of Advanced Functional Materials, Ministry of Education China, School of Materials Science and Engineering, Beijing Polytechnic University, Beijing 100022, China)
Abstract:The chemical reaction between lanthanum oxide and molybdenum carbide was studied by thermodynamic calculation, thermal analysis and in-situ X-ray Photoelectron Spectroscopy. The theoretical results show that at the environment allowing for the evaporation of lanthanum, such as in high vacuum, La2O3 in the La2O3-Mo materials can be reduced to metallic lanthanum by molybdenum carbide (Mo2C). To confirm the conclusion, many analysis methods such as XRD, SPS, and TG-DTA were taken. The experimental results show that the chemical state of lanthanum changes during heating. It was proved, for the first time, that reacted metallic lanthanum appears at the surface of this kind of material at high temperature.
Key words:chemical state; lanthanum; La2O3-Mo; cathode; rare earths;
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