Oxide coated nickel electrodes were investigated in concentrated alkaline solutions. Their electrochemical behaviour was studied in the potential regime between the double layer capacity region and the oxygen evolution, at 20, 50 and 80 degrees C. Cyclic voltammograms and quasi-steady-state current-potential curves change remarkably with temperature, correspondingly, the impedance of the system changes strongly with potential, but also with temperature. The experimental results do not support the Krasilshchikov mechanism suggested by many authors.