Surface modification of Dy₂O₃-Nb₂O₅ dope mix for dielectric materials in aqueous dispersion

The electrokinetic mismatch between the basic dielectric compound (Ba,Ca)(Ti,Zr)O₃ (BCTZ) and Dy₂O₃-Nb₂O₅ dope mix in aqueous suspensions has been improved by a pre-firing and milling treatment of the dope mix. Pre-fired dope mix showed a much higher zeta potential which resulted in a drastic improvement of the particle dispersion in aqueous slurries. By use of surface-modified dope mix the homogeneity of the micro structure of multilayer ceramic capacitors is improved and the break-down voltage of thin (7 μm) dielectric layers increased. The results observed indicate the critical influence of the micro structural homogeneity on the breakdown voltage of MLCCs.