Synthesis of pure MgTiO3 by optimizing mixing/grinding condition of MgO+TiO2 powders

Through the dielectric materials used for the making of type I multilayer ceramic capacitors, the ilmenite magnesium titanate MgTiO3 is of particular importance. Yet, it seems difficult to get pure MgTiO3 with a controlled stoichiometry. In order to be able to synthesize it by solid-state reaction, we therefore studied the mixing/grinding behavior of the precursors MgO + TiO2. The evolution versus pH of the zeta potential values of both MgO and TiO2 (anatase) powders shows that it is impossible to get correct pH values allowing a good dispersion state and thus an easy control of the mixing of these two species when considering only electrostatic repulsion. So, we considered to add dispersing agent in order to get a steric dispersion behavior. Rheological characterization of the slurries showed that we were able to get a good dispersion state during the process of mixing/grinding. XRD and SEM/EDX analysis shows the ability of obtaining "pure" MgTiO3 with a controlled stoichiometry after calcination by controlling the rheological behavior of slurries during mixing/grinding. (C) 2007 Elsevier B.V. All rights reserved.