Low temperature sintering of MgTiO 3 with bismuth oxide based additions Florent BELNOU, Jérôme BERNARD, David HOUIVET, Jean-Marie HAUSSONNE LUSAC (EA2607), Université de Caen, BP 78, 50130 Cherbourg Octeville, FRANCE Abstract : MgTiO 3 is a classical material for type I MLCC. However its densification temperature is too high to allow co-sintering with copper electrodes. Investigations on low temperature sintering of MgTiO 3 show the complexity of this problem particularly when co- sintering with copper electrodes and thus a reducing atmosphere are involved in the process. Though feasibility of MgTiO 3 / copper MLCC has been demonstrated, studies have pointed out several remaining problems. Investigations on low temperature sintering of MgTiO 3 are thus still necessary to find a formulation which is not detrimental to dielectric behaviour. Sintering aid capabilities and/or good dielectric properties of bismuth oxide based additives make them good candidate materials to lower MgTiO 3 sintering temperature without altering its final properties. In this study bismuth titanate is either formed in-situ by reaction-sintering of Bi 2 O 3 -B 2 O 3 additives with MgTiO 3 or obtained by pre-calcination of Bi 2 O 3 and TiO 2 powders and then added to MgTiO 3 prior to sintering. Bismuth titanate appears as a good sintering aid that allows sintering of MgTiO 3 under 1000°C. It is yet highly sensitive to the nature of the sintering atmosphere, oxidizing or reducing. Dielectric properties of sintered specimens are compatible with type I capacitors applications. Keywords : Sintering, Dielectric Properties, Capacitors , Titanates, MLCC 1. Introduction MgTiO 3 is a classical material for type I MLCC. The highly variable and high cost of the noble metals, palladium and silver, classically used to form the inner electrodes is a recurrent economical problem. Using non noble metals for these electrodes (for instance copper) could be a solution but would require to sinter the capacitors under a reducing atmosphere. This kind of process has been widely investigated with type II multilayer ceramic capacitors but few reports have been published related to the case of type I capacitors. Another way of investigation could lie in trying to get rid of palladium, the main source of economical problems, leading to a partial solution, the use of silver electrodes. Both solutions have in common the same technological problem. Classical sintering temperatures of MgTiO 3 in air are around 1350°C. Sintering in a reducing atmosphere is also possible at 1350°C : this classically leads to reduction and thus conduction problems but it has been demonstrated that this drawback could be avoided when Ti 4+ in the B site of the ilmenite structure of MgTiO 3 was substituted with equal atomic amounts of W 6+ and Mn 2+ acting as a couple of donor/acceptor in the same way that previously stated for type II BaTiO 3 -based compositions 1,2 . The problem is that this temperature of 1350°C is totally inadequate for the use of copper or silver electrodes because the low melting points of these metals make the sintering temperature to be much lower than 1000°C. It is thus necessary to investigate on the possibility of lower the sintering temperature of MgTiO 3 .