Thermionic Emission of a Novel Y 2 Hf 2 O 7 Ceramic Cathode Applied in High-Power Magnetron Tubes

In order to enhance output power and prolong lifetime of the high-power magnetron tubes, a novel Y 2 Hf 2 O 7 Ceramic cathode had been developed. The thermionic emission and lifetime characteristics of the Y 2 Hf 2 O 7 cathode had been measured. The results show that the cathode can provide 0.15A/cm2, 3.5A/cm2 current density for the space charge limitation at 1300 Cbr, 1600 °C br respectively under 300V anode voltage. The lifetime of the cathode is more than 4100 h with an initial load of 0.5A/cm2 at 1400Cbr.