An electrochemical impedance study was made for a platinum working electrode in Na2SO4-10 mole percent (m/o) NaVO2 melts in a temperature range of 1150 to 1200 K. The principal electroactive oxidant is a solute of V2O5, which has a lower Warburg coefficient than that for the major oxidant S2O72- in pure Na,SO, melts in contact with 0.1 and 1%SO2-O-2 environments. The effects of temperature, basicity, oxygen potential, and polarization potential on the impedance of the system were investigated. The results are used to interpret hot corrosion induced by Na2SO4-NaVO3 deposits. In the vanadate-sulfate melt, the oxidant arrives at the electrode/electrolyte interface by the counterdiffusion of solutes with V4+(V2O4-derived) and V5+ (V2O5-derived) Electron hopping in this solution does not occur.