Enhanced protection of SOFC interconnects with dual coating using combined electrophoretic and sputtering methods

Abstract

Chromium poisoning in 460FC stainless steel interconnects significantly impairs the performance of solid oxide fuel cells. A dual-layer coating was developed to address this issue, combining a Cu_1.25Mn_1.65Fe_0.1O₄ spinel layer, applied via electrophoretic deposition, and a Cu–Mn metal layer, deposited using sputtering. This approach demonstrated high effectiveness, producing coatings with uniform thickness and precise elemental composition. The oxidation rate was investigated by analyzing the coating's mass gain. The dual-layer coating underwent a thermal transformation, re-establishing the CuMn₂O₄ spinel structure through metal diffusion and forming a thick oxide scale. After 1000 h at 800 °C, the area-specific resistance of the SUS/EPD/SM dual-layer coated sample demonstrated excellent conductivity at 5.76 mΩ cm². Additionally, the SUS/EPD/SM dual-layer coating provides resistance to chromium poisoning, significantly reducing the chromium content diffusing from stainless steel to the surface compared to single-layer coatings produced by each method.