MgTiO3 for Cu base metal multilayer ceramic capacitors

The evolution of the cost of palladium justifies studies devoted to the use of cheap base metals as electrodes for multilayer ceramic capacitors. In a precedent [J. Eur. Ceram. Soc.10–11(2001) 1681] work we investigated on Mn acceptor together with W donor additions on the properties of MgTiO3 ceramics sintered at 1350 °C under a reducing atmosphere (wet N2-1%H2). As in acceptor/donor [Proceedings K1; 1206 CIMTEF, Florence (1998) 88] codoped BaTiO3 the insulating character of MgTiO3 was conserved. In order to employ these materials in the production of type-I multilayer ceramic capacitors with Copper inner electrodes we investigate now on the possibility of sintering magnesium titanate at low temperature. We have studied the densification behavior of different MgTiO3 compositions with lithium salts additions, considering particularly the effect of the non-stoechiometry expressed as the Mg/Ti ratio. Full densification appears below 1000 °C. The obtained ceramics, that have been co-sintered in a multilayer structure with Cu electrodes, are characterised by a resistivity higher than 1013 ohm cm together with a NPO dielectric constant ranging from 14 to 16 depending on the exact composition together with losses lower than 0.2%.