“…For example, in a 411-aluminate, the molar ratio of barium oxide, calcium oxide, and alumina is 4:1:1. Among these types, 612-aluminate can reach a balance between the emission capacity and the barium evaporation rate due to the moderate barium content 10 and becomes the preferred impregnant for Ba-W impregnated cathodes. For instance, the M-type cathode impregnated with 612-aluminate can provide a current density of 8 A/cm 2 at 1080 • C B (bright temperature) in dc mode and an average lifetime of 19,799 h. 11 Additionally, the emission current density at 1100 • C B can be enhanced by a factor of 2.0 ̶ 4.3 after doping the 612-aluminate with scandia.…”