Mo-La_2O_3阴极碳化机理

Carbonization mechanism of Mo-La_2O_3 cathode

研究了碳化温度、碳化时间、碳化时苯的压强对Mo La2 O3 阴极碳化度大小和碳化层组织的影响。结果表明 :在 172 3K ,苯的压强为 1.5× 10 -2 Pa,碳化 6min后Mo La2 O3 阴极碳化度达到 19.7%,碳化层为疏松多孔的Mo2 C组织 ,有利于阴极热电子发射。应用扫描电镜 (SEM)、X射线衍射仪 (XRD)等手段对Mo La2 O3 阴极碳化层的显微组织和微观结构、物相等进行了观察与分析。并从热力学与动力学两方面对Mo La2 O3 阴极碳化机理进行了探讨。

The carbonizing process of Mo-La 2O 3 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 (C 6H 6) are the decisive factors. In the adequate benzene vapor (1.5×10 -2 Pa), Mo-La 2O 3 cathodes carbonized at 1 723 K and for 6 min can obtain maximum carbonized ratio and coarse Mo 2C 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-La 2O 3 cathode is also discussed.