Stability of Aqueous Barium Titanate Suspensions for MLCC Inkjet Printing

BaTiO 3 ‐based materials are currently used for the fabrication of multilayer ceramic capacitors ( MLCC ) because of their high dielectric properties. The inkjet printing ( IJP ) process can be used to fabricate MLCC of complex configurations by integrating internal electrodes and dielectric layers in a single step using a multi printing‐head system. Stabilized aqueous suspensions of BaTiO 3 ‐based powders are required to obtain dielectric inks adapted to IJP . This study investigates the influence of BaTiO 3 powder hydrolysis in water on the surface chemistry and stability in relationship with the milling step used to adjust the powder grain size to IJP . Optimum parameters for a good stability of BaTiO 3 suspensions are identified. The selected dispersant is a polyacrylate ( PAA ) for which the content is adjusted to minimize the sedimentation rates as required by IJP . Moreover, the addition of ethylene glycol is shown to be necessary to avoid the formation of a gel structure which could result from the interaction of borates ions leached from the surface of BaTiO 3 with the PAA dispersant. A mechanism of gel formation is proposed.