The conductivity of oxide cathodes. Part 4: Electron transfer mechanisms

The present Part considers the mechanisms of electron transfer through the oxide-cathode matrix. In the temperature range 850¿1 100° K it is shown experimentally that, effectively, the whole of the electron stream passes through the vacuum interstices of the matrix. Progression is on a start-stop basis, with the electrons dissipating energy in the form of heat by successive non-elastic collisions with impeding oxide particles. The whole electron current is emitted thermionically at the cathodic core surface, where the theoretically predicted cooling effect is localized and observed. In the temperature range 290¿600° K, electron transfer is on a purely resistive basis and involves no act of thermionic emission, i.e. the electron never emerges from the solid oxide into vacuum. The results of the experimental work are in complete harmony with the hypothesis put forward in 1949 by Loosjes and Vink.