The conductivity of MnCo2O4 spinel,the best route to form the MnCo2O4 protective coating applied by the sol-gel process,and its effect on the intermediate temperature oxidation behavior of SUS 430 alloy,a typical material for the interconnect of solid oxide fuel cell(SOFC),was investigated.The phase structure and surface morphology of the coating and surface oxides were characterized by XRD,SEM and EDS;the "4-probe" method was employed to determine the conductivity of MnCo2O4 spinel and the area specific resistance(ASR)of the surface oxides.The conductivity of MnCo2O4 spinel is excellent,which is 2 orders of magnitude better than that of MnCr2O4 spinel.Long-term thermally cyclic oxidation at 750°C in SOFC cathode atmosphere and ASR measurement have shown that calcined in reducing atmosphere followed by pre-oxidation in the air is the best technique for forming the MnCo2O4 protective coating,which enhances the oxidation resistance,and improves the electrical conductivity and adherence of coated SUS 430 alloy significantly.As a result,the MnCo2O4 spinel is the most potential candidate for SOFC metallic interconnect protective coating application.
