The effect of electrostatic repulsive forces on the stability of BaTiO3 particles suspended in non-aqueous media

The effects of physicochemical properties of organic solvents and dispersants on the dispersion of barium titanate (BaTiO3) was investigated in a system where organic solvents, dispersants, binders, and plasticizers are used as processing additives in multilayer ceramic capacitor fabrication processes. In this study, phosphate esters and menhaden fish oil were used as dispersants. The dispersion properties of BaTiO3 suspensions were characterized by electrokinetic sonic amplitude, polymer adsorption and viscosity measurements. The steric and electrostatic stabilization mechanisms affecting the suspension properties of BaTiO3 were evaluated. The adsorption characteristics and electrokinetic behavior of BaTiO3 suspensions were correlated with the stability of BaTiO3 suspended in non-aqueous media. The stability of BaTiO3 achieved by steric stabilization was dependent on the fraction of surface coverage resulting from dispersant adsorption on the BaTiO3 particle. The electrostatic repulsive forces acting between BaTiO3 particles dispersed in organic media was found to be significantly greater than predicted and dependent mainly on the physicochemical properties of the organic solvent media. (C) 1998 Elsevier Science B.V.