Co/LaCrO3 composite coatings for AISI 430 stainless steel solid oxide fuel cell interconnects

Rapidly decreasing electronic conductivity, chromium volatility and poisoning of the cathode material are the major problems associated with inevitable growth of chromia on ferritic stainless steel interconnects of solid oxide fuel cells (SOFC). This work evaluates the performance of a novel, electrodeposited composite Co/LaCrO3 coating for AISI 430 stainless steel. The oxidation behaviour of the Co/LaCrO3-coated AISI 430 substrates is studied in terms of scale microstructure and growth kinetics. Area-specific resistance (ASR) of the coated substrates has also been tested. The results showed that the Co/LaCrO3 coating forms a triple-layer scale consisting of a chromia-rich subscale, a Co–Fe spinel mid-layer and a Co3O4 spinel top layer at 800 °C in air. This scale is protective, acts as an effective barrier against chromium migration into the outer oxide layer and exhibits a low, stable ASR of ~0.02 Ω cm2 after 900 h at 800 °C in air.