High-Performance Scandate Cathode

Scandate cathodes have long attracted attention due to their higher emission current density, apparent low work function, and anticipated improved longevity compared to conventional cathodes. However, scandate cathodes have not been applied as extensively as their potential would imply. In this study, the compositional homogeneity of a scandia/tungsten composite powder was investigated by scanning electron microscopy, X-ray energy dispersive spectroscopy, and X-ray photoelectron spectroscopy. From these techniques, a sample providing the optimal coverage of tungsten by scandia particles was then chosen. A cathode fabricated from this sample displayed a greater than 200°C decrease (improvement) in knee temperature versus the standard M-type cathode.