Effect of the suspension composition for electrophoretic deposition on the selected properties of (Cu,Mn,Fe)-based protective coatings for solid oxide cells interconnects

The research evaluates suspensions for electrophoretic deposition of CuMn 1.9 Fe 0.1 O 4 (CMF-0.1) coatings on Crofer 22 APU substrates, targeting solid oxide cells (SOC) applications. A matrix of 22 solvent systems (ethanol, acetone, isopropanol, terpineol, and their mixtures) was studied under analogous processing conditions with respect to conductivity, current density, deposition yield (DY), coating thickness, and coating porosity (SEM-EDS). Although the relationships between suspension parameters and coating properties are complex, certain trends were identified. Among acetone/ethanol systems, deposition was most efficient, yielding porosity above 15 %; however, high ethanol content favored excessive thickness and defect formation. In contrast, terpineol/isopropanol systems showed the poorest performance. For 5 selected suspensions, static stability was assessed using backscattering/transmittance spectra and Turbiscan Stability Index (TSI) values, while zeta potential was determined via ELS. The coatings exhibited low surface resistivity and effective chromium barrier performance after 200 h at 700 °C. The results provide a solid foundation for the rational design of EPD suspensions. • Optimized solvent composition for EPD of CuMn 1.9 Fe 0.1 O 4 -based protective coatings • Investigated 22 solvent systems using acetone, ethanol, isopropanol, terpineol • Deposition yield <5 mg·cm −2 led to thin (<10 μm) and often discontinuous films. • 5 optimal coatings efficiently blocked CrO x during ASR test (200 h at 700 °C).