(北京工業(yè)大學(xué) 新型功能材料教育部重點(diǎn)實(shí)驗(yàn)室，北京 100022)
摘 要: 研究了碳化溫度、 碳化時(shí)間、 碳化時(shí)苯的壓強(qiáng)對(duì)Mo-La2O3陰極碳化度大小和碳化層組織的影響。結(jié)果表明：在1723K， 苯的壓強(qiáng)為1.5×10-2Pa， 碳化6min后Mo-La2O3陰極碳化度達(dá)到19.7%，碳化層為疏松多孔的Mo2C組織， 有利于陰極熱電子發(fā)射。 應(yīng)用掃描電鏡（SEM）、 Ｘ射線衍射儀（XRD）等手段對(duì)Mo-La2O3陰極碳化層的顯微組織和微觀結(jié)構(gòu)、 物相等進(jìn)行了觀察與分析。 并從熱力學(xué)與動(dòng)力學(xué)兩方面對(duì)Mo-La2O3陰極碳化機(jī)理進(jìn)行了探討。
關(guān)鍵字: Mo-La2O3陰極; 碳化度; 組織; 熱電子發(fā)射; 碳化機(jī)理
Mo-La2O3 cathode
DU Wei, ZUO Tie-yong
（The key Laboratory of Advanced Functional Materials, Ministry of Education, Beijing Polytechnic University,Beijing 100022, China）
Abstract:The carbonizing process of Mo-La2O3 cathode are investigated and the microstructures and phases of it’s carbonized layers are studied by TEM and XRD. The carbonizing temperature, carbonizing time and the pressure of benzene (C6H6) are the decisive factors. In the adequate benzene vapor (1.5×10-2Pa), Mo-La2O3 cathodes carbonized at 1723K and for 6min can obtain maximum carbonized ratio and coarse Mo2C particles carbonized layers, which is beneficial to the migration of activated rareearth element to the surface of the cathode during the operating. The carbonization mechanism of Mo-La2O3 cathode is also discussed.
Key words: Mo-La2O3 cathode; carbonized ratio; microstructure; thermionic electron emission; carbonization mechanism
