Cyclic oxidation of Ni–$$\hbox {Fe}_{{2}}\hbox {O}_{{3}}$$ composite coating electrodeposited on AISI 304 stainless steel

Abstract

Protective coatings can be applied to enhance the performance of interconnects in solid oxide fuel cells. In this study, AISI 304 steel was coated with a Ni–$$\hbox {Fe}_{{2}}\hbox {O}_{{3}}$$ composite to form a modified-Watt’s type electrolyte by the conventional electro co-deposition method. The characterization of the coatings before and after cyclic oxidation was performed by scanning electron microscopy and X-ray diffraction. In order to evaluate the oxidation behaviour, thermal cycling was carried out in a furnace at $$850{^\circ }\hbox {C}$$. The results indicated that the coated steel had better oxidation resistance in comparison with the uncoated steel. After 60 cycles of oxidation, the Ni–$$\hbox {Fe}_{{2}}\hbox {O}_{{3}}$$ composite coating was converted to $$\hbox {FeNi}_{{2}}\hbox {O}_{{4}}$$, $$\hbox {NiCrO}_{{4}}, \hbox {MnFe}_{{2}}\hbox {O}_{{4}}$$ and $$\hbox {Fe}_{{2}}\hbox {NiO}_{{4}}$$. The $$\hbox {Fe}_{{2}}\hbox {O}_{{3}}/\hbox {NiFe}_{{2}}\hbox {O}_{{4}}$$ composite coating reduced the outward migration of chromium and the growth rate of the $$\hbox {Cr}_{{2}}\hbox {O}_{{3}}$$ layer.