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
.