Performance of an Oxide Cathode Prepared From Submicrometer Carbonates

We investigate the properties of oxide cathodes prepared from submicrometer filamentous triple carbonates, including the direct-current (dc) and pulsed-current (PC) emission, evaporation rate, and lifetime. Twenty cathodes were manufactured and tested. The testing results show that the dc emission current density is over 5.0 A/cm² beyond 800°Cbr and the PC emission current density is over 19.9 A/cm² for a 100-μs pulsewidth and 1% duty cycle at 850°Cbr. The evaporation rate is 2.09 ×10^-9 g·cm²·s^-1 at 850°Cbr as measured using a quartz crystal oscillating method. The demonstrated worst case lifetime (over five units) is 5000 h with 2.1 A/cm² at 800°C.