Inkjet Printing Towards Dense Spinel Protective Coatings for Solid Oxide Cell (SOC) Applications

This study aimed to develop a dense protective coating of Mn 1.7 Cu 1.3 O 4 spinel on SOC interconnects using inkjet printing. The work focused on formulating a well‐dispersed, stable, and agglomerate‐free ink to obtain a dense, uniform, and full surface coating layer. Achieving a dense layer, requires an ink with high powder content. However, highly loaded inks increase the risk of agglomeration and nozzle blocking. This makes the colloidal stability and dispersion properties critical. Mn 1.7 Cu 1.3 O 4 colloids were formulated in water using polyacrylic acid (PAA) as the dispersant. The PAA concentration was optimized through sedimentation tests and rheological analyses, both directly linked to colloidal stability. Isopropanol and propylene glycol were added to adjust ink properties for jettability. Interparticle interactions were modeled to understand the stability mechanism, focusing on the effects of particle size and pH for the aqueous PAA‐spinel system. The optimal PAA concentration for a specific solvent mixture was found as 0.4–0.6 vol% with the particle loading up to 20 vol%. Dense protective coatings were successfully obtained after sintering at using the optimized mixture. Corrosion ageing tests by monitoring the area specific resistance (ASR), with post‐test SEM/EDX analysis confirmed that the more optimized ink resulted in better corrosion protectiveness.