Effect of Sr-Doping on the Emission-Active Materials of Scandate Cathodes

In this article, co-precipitation was combined with a high-temperature solid-state reaction to realize strontium (Sr) doping of the emission-active materials (Ba–Sr–Sc–Ca–Al–O) of scandate dispenser cathodes. The precursor of the co-precipitation product was composed of alkaline Earth metal carbonates and hydroxides of Sc and Al. The final products included Ba2ScAlO5 and Ba3CaAl2O7 and Sr in the form of strontium aluminates (SrAl12O19 or SrAl4O7). At 1100°CB, the pulse current density of the Sr-doped cathode in a planar diode reached 215.5 A/cm2, exceeding that of conventional scandate cathodes without Sr. The developed emission-active materials and corresponding cathodes are more adaptable to vacuum electronic devices (VEDs) and have a wider range of potential applications than conventional cathodes.