Co3O4 spinel protection coating for solid oxide fuel cell interconnect application

In the present study, electrophoretic deposition (EPD) method in different electric fields (30 – 300 V / cm) was used to apply Co3O4 spinel coating to SUS 430 as SOFC interconnect. The coated and uncoated specimens were pre-sintered in air at 800 and 900 °C for 3 h followed by cyclic oxidation at 700 and 800 °C for 500 h, respectively. X-ray diffraction analysis (XRD), Scanning Electron Microscope (SEM) and Energy Dispersive Spectroscopy (EDS) were used for characterization of the prepared samples. The results indicated that the electric field of 100 V was an effective voltage to obtain crack-free coating. A comparison between the oxidation resistance of coated and uncoated specimens indicated that the weight change of the coated specimen was larger than that of the uncoated one during the cyclic oxidation, so the Co3O4 coating is not effective for improving the oxidation resistance. According to the obtained results, the oxidation rate constant (Kp) for the coated specimens at 700 and 800 °C in air were 2.36×10-14 and 3.37×10-12gr2cm−4s−1, respectively.