Scandia doped impregnated cathode prepared with hollow tungsten spheres

The scandia doped tungsten powders have been obtained by a new method of spray drying combined with two-step reduction in hydrogen atmosphere. Based on the powders, the cathode impregnated with 612 aluminates (SDI-612) has excellent emission capability of 72.2A/cm 2 at 900 o C b , moreover, the SDI-612 cathode has a lower evaporation rate of 8.45∗10 −9 g.cm −2 s −1 at 1150 o C b .