Thermoemission properties of tungsten with additions of rare earth oxides

Thermoemission properties of tungsten with addition of rare earth oxides are studied in the superhigh vacuum set with oil-free pumping system. Electronic work function eφ is determined by the method of total saturation current. Temperature dependences are obtained of the work function for three types of cathodes: W+La2O3; W+φ2O3 and W+Dy2O3. It is stated, that the first two types eφ decreases approximately from 4.2 to 3.3 eV and from 4.5 to 3.8 eV, respectively, after activation at proper temperatures. These cathodes are the most effective ones at the temperature of 1700 (W+La2O3) and 1900-2100 K (W+ φ4O3). The work function of cathodes with addition of dysprosium oxide did not practically vary (4.55-4.3 eV) within the whole studied temperature interval (1500-2100 K)