Dispersion of nano-sized BaTiO3 powders in nonaqueous suspension with phosphate ester and their applications for MLCC

The stability of nano-sized BaTiO3 nonaqueous suspension with different phosphate ester surfactants was investigated. Among the three phosphate esters (mono-alkyl, di-alkyl and ethoxy types), the 2-ethoxy ethyl dihydrogen (1EO-) phosphate esters show not only better coverage over the nano-BaTiO3 powders, but also superior dispersion for the suspension. Contrary to the conventional 200 nm-BaTiO3 suspensions, which need longer carbon-chain phosphate esters surfactant for dispersing the BaTiO3 powders, the 50 nm-BaTiO3 suspensions require shorter carbon-chain phosphate esters surfactant for dispersing them. Multilayer ceramic capacitors (MLCC) made of 50 nm-BaTiO3 suspensions contain ultra-thin ceramic layer (2.6–2.8 μm), which shows the larger capacitance and superior breakdown voltage than those made of 200 nm-BaTiO3 powders.