Electrophoretic deposition of novel hybrid MnCo2O4: Mn1·7CuFe0·3O4 spinel protective coating on stainless-steel metallic interconnects for SOFCs application

An innovative hybrid spinel coating, composed of MnCo 2 O 4 and Mn 1 · 7 CuFe 0 · 3 O 4 spinel materials in varying ratios (1:0, 1:3, 1:1, 3:1, and 0:1 wt%), is applied on AISI 441 stainless-steel interconnects by electrophoretic deposition method, to improve electrical conductivity, and inhibit the migration and evaporation of chromium. Stainless steel have been coated with dense, uniform, and crack-free coatings using EPD method. The cross-sectional analysis reveals that the densification of hybrid coatings (1:1 wt%) sintered under reduction treatment (1000 °C for 2 h in H 2 ), followed by a subsequent oxidation treatment (900 °C for 2 h in air) is greater (29 %) than those sintered solely under oxidation treatment (900 °C for 4 h in air). What is more, Raman and XRD study suggests that the applied procedure provides a precise control over the phase composition of the hybrid coating materials. The electrical conductivity of the hybrid materials (1:1 wt%) is higher (45 %) than that of the MnCo 2 O 4 spinel material but lower (36 %) than that of the Mn 1 · 7 CuFe 0 · 3 O 4 spinel material at 600 °C. The novel hybrid spinel coating presents a promising candidate for protective coating on metallic interconnects, due to its higher electrical conductivity, and higher sinterability as compared to Mn–Co spinel coating. • A uniform, dense and crack-free hybrid coating applied onto stainless steel using the EPD method. • Hybrid coating is a promising candidate for protective coatings. • Hybrid coating densification in reduction + oxidation is higher than oxidation treatments. • Hybrid coating provides higher protection against Cr diffusion than Mn–Cu–Fe coating. • Electrical conductivity of hybrid coating is higher than Mn–Co and lower than Mn–Cu–Fe coatings.