INVESTIGATIONS CONCERNING THE WORK FUNCTION OF DOPED GRAPHITE

In order to reduce the burning off of electrodes in electric arc furna ces, it is necessary to decrease the specific thermal load at the tip in the arc attachment area. This can be achieved by minimizing the wor k function of the electrode materials, whereby the peak temperature is reduced. The work function of doped graphite electrodes was investiga ted under conditions prevailing during standard industrial practice in order to achieve transferrable results. The measurement equipment dev eloped to meet this requirement is based on a design first proposed by Bade and Yos. By measuring the peak temperature of the electrode and its current density, the value of the work function of the material wa s calculated with a modified Richardson equation. Starting from materi als with well-known values of the work function, to verify the accurac y of the experimental method and the mathematical model, those of pure and doped graphites were determined. The additives, oxides as a rule, result in a significant reduction in electron work function in the ca se of magnesium, calcium and cerium oxides.