Oxidation behaviour of Mn-Co spinel coating on AISI 430 ferritic stainless steel with and without Cu in Ar-CO2-H2O atmosphere

AISI 430 ferritic stainless steel is a promising candidate for utilising as interconnects of solid oxide fuel cells due to its cost effectiveness and durability. Many methods for applying coating on steel substrates have been developed in order to decrease the degradation of steel due to oxidation rate and chromium volatile problems. Manganese-cobalt spinel exhibits high conductivity, thermal expansion compatible with ferritic stainless steels, and forms a barrier to inhibit chromium migration during oxidation. Copper can be added to manganese-cobalt spinel to improve electrical conductivity of the spinel coating. This work investigated oxide scale formation and oxidation rate of Mn-Co and Mn-Co-Cu coated samples in comparison with uncoated steel. The coated samples were prepared on the AISI 430 ferritic stainless steel using the electrodeposition technique. The oxidation rate was tested at 800℃ in Ar-20% CO2-5% H2O for 96 h. The results showed that both Mn-Co and Mn-Co-Cu coated samples could be formed continuous oxide layers. The SEM image showed a chromium oxide layer under the manganese-cobalt coating layer. The oxidation rate of the samples coated with Mn-Co spinel and Mn-Co-Cu spinel was lower than that of the uncoated steel.