Effect of surface hydroxyl groups on the dispersion of ceramic powders

Abstract

The effect of surface hydroxyl groups (OH) on the dispersity of ceramic powders was explored using the common ceramic powder barium titanate (BaTiO3) as the study model. To simulate the presence of OH on the powder, which is generally formed because of atmospheric storage, oxidative hydroxylation with hydrogen peroxide was used to produce and adjust the concentration of surface OH. Owing to the presence of a lot of surface OH, BaTiO3 particles aggregated because of hydrogen bonding and required a large amount of dispersant such as the ammonium salt of poly(acrylic acid) (PAA-NH4) for its dispersion stabilization. In addition, the commonly used binder poly(vinyl alcohol) (PVA) became more competitive with PAA-NH4 for adsorption onto the hydroxylated BaTiO3, thereby reducing the efficiency of the dispersant and impeding the dispersion of the powder.