Abstract: The morphology of a coating of an oxyfluoride of cerium on a conductive substrate is improved by addition of tantalum, niobium and/or other pentavalent metals. Whereas a cerium oxufluoride coating shows cracks which may extend throughout the entire thickness of the coating, thus exposing finite portions of the substrate to corrosive attack, the pentavalent-doped coating has a substantially impervious structure. In addition to improvement of the coating morphology, the electrical conductivity is increased. The pentavalent-doped cerium oxyfluoride can be produced by electrodeposition or sintering. Coatings, substrates or bodies of this material may be employed as non-consumable anodes in molten aluminum electrowinning cells, as chemical sensors, or for corrosion protection and other applications.