Investigations concerning the work function of doped graphite

Abstract

In order to reduce the burning off of electrodes in electric arc furnaces, it is necesary to decrease the specific thermal load at the tip in the arc attachment area. This can be achieved by minimizing the work function of the electrode materials, whereby the peak temperature is reduced. The work function of doped graphite electrodes was investigated under conditions prevailing during standard industrial practice in order to achieve transferrable results. The measurement equipment developed 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 was calculated with a modified Richardson equation. Starting from materials with well-known values of the work function, to verify, the accuracy of the experimental method and the mathematical model, those of pure and dopedgraphites were determined. The additives, oxides as a rule, result in a significant reduction in electron work function in the case of magnesium, calcium and cerium oxides.