A review on scandia doped tungsten matrix scandate cathode

As the cathode with the highest electron emission capability in the thermionic cathode, the scandate cathode has attracted more and more attention in recent years, especially the scandia doped tungsten matrix scandate cathode. Experimental studies show that scandia doped tungsten matrix scandate cathodes with submicron microstructures exhibit excellent emission capacity, and the pulse emission current density in the space-charge region can be over 35 A cm−2 at 850 °Cb. In the direct current (DC) condition with temperature compensation, the emission current density could reach 25 A cm−2 at 850 °Cb. The device lifetime is over 3700 h after operating at 950 °Cb with the DC loading of 40 A cm−2. The emission mechanism of the scandate cathode including the effect of the surface structure and composition on the work function of the cathode are systematically reviewed.