Protective Coatings La–Mn–Cu–O for Stainless-Steel Interconnector 08Х17Т for SOFC, Obtained by the Electrocrystallization Method from Non-Aqueous Solutions

Abstract

A novel method for the formation of the protective layer on stainless steel interconnectors for solid oxide fuel cells was developed. The method was based on the electrocrystallization of metals from non-aqueous solutions on the stainless-steel interconnector with consecutive thermal treatments. Suggested method was applied for the stainless-steel 08X17T. Chemical composition of the electrolyte for the electrocrystallization was made in order to obtain the oxide protective layer of the stainless-steel interconnector of the following composition: LaMn0.9Cu0.1O3. As a result, a uniform oxide layer was formed on the stainless-steel interconnector surface, protected the stainless-steel from the high-temperature oxidation leading to degradation of the functional properties of the interconnector. Forming coatings were characterized by means of grazing incidence X-rays diffraction, X-rays photoelectron spectroscopy and scanning electron microscopy. Elemental analysis and phase composition have shown that the main components of the protective coatings are found to be compounds with perovskite and spinel structures. The protective coating in the contact with cathode material based on lanthanum-strontium manganite shows significant decrease of chromium propagation from the stainless steel as a result of the diffusive firing in comparison with the sample of the stainless steel without the protective coating. Electrical resistance of the interconnector with the protective coating does not show noticeable degradation during at least 500 h at the temperature 850°C in ambient air.