Lifetime of High-temperature Directly-heated Oxide Cathodes

In this paper we mainly describe the research progress in the lifetime testing for several kinds of high-temperature W base directly-heated oxide cathodes. The test results show that the lifetime of the 5% wt Sc
2
O
3
doped Y-Gd-Hf-O coating cathode is reached 6100h with a dc load of 1.0A/cm2 at 1500 °Cbr. The lifetime of the La2Hf207 coating cathode is beyond 11600h with a dc load of 0.65A/cm2 under 1400-1450°Cbr operating temperature. The lifetime of the Y2Zr207 coating cathode is also beyond 11600h with a dc load of 0.50 A/cm
²
under same temperature.