Surface Carbonization of Mo-La2O3 Cathode
(School of Materials Science and Engineering, BeijingPolytechnic University,Beijing100022, P.R. China)
Abstract: The carbonized structures of Mo-La2O3 cathode specimens have been investigated by means of FESEM and XRD, respectively. The substructure of carbonized layer in the Mo-La2O3 cathode has been found for the first time. The results showed that the carbonized layer with uniform Mo2C was helpful to emission, while the demixing carbonized layer with a compact MoC outside layer was harmful to emission. The uniform Mo2C layer consists of coarse particles with lots of grain boundary crevices as well as holes arranging perpendicular to the wire axle and up to surface, which was beneficial to the migration of activated rare-earth in activation and operating.
Key words: microstructure; cathodes; Mo-La2O3; carbonization; emission