EVALUATION OF ELECTRODE MATERIALS FOR SLAG COATED MHD CHANNELS.

Static immersion and electrochemical corrosion tests were conducted on three candidate electrode materials in slag-seed mixtures at 1400 degree C. The flow of direct current was found to alter and accelerate the corrosion reactions that occur in simple immersion tests. In particular, electrolytic reactions at the slag/cathode interface result in corrosion rates an order of magnitude higher than found at the anode. These reactions, plus the reducing conditions found at the cathode, favor the use of metals or non-oxide ceramics as cathodes while the oxidizing conditions present at the anode favor the use of oxides as anodes. These tests indicate that the selection, testing, and use of electrode materials should always be carried out with serious attention to the electrochemical reactions occurring at the electrode/slag interfaces.