Enhanced densification and microwave dielectric properties of Mg2TiO4 ceramics added with CeO2 nanoparticles

We report the study of the effects of processing parameters and additive concentration on the structure, microstructure and microwave dielectric properties of MTO–CeO2 (x wt.%) ceramics with x = 0, 0.5, 1.0 and 1.5 prepared by solid-state reaction method by adding CeO2 nanoparticles as a sintering aid. The pure Mg2TiO4 ceramics were not densifiable below 1450 °C. However, when CeO2 nanoparticles were added to MTO, the densification achieved at 1300 °C along with the increase in average grain size with the uniform microstructure and improved microwave dielectric properties. This is mainly driven by the large surface energy of CeO2 nanoparticles and their defect energy during the sintering process. While the addition of CeO2 nanoparticles in MTO ceramics does not change the dielectric constant (ɛr), the unloaded quality factor (Qu) was altered significantly. MTO–CeO2 (1.5 wt.%) ceramics sintered at 1300 °C exhibit superior microwave dielectric properties (ɛr ∼ 14.6, Q × f0 ∼ 167 THz), as compared to the pure Mg2TiO4 ceramics. The observed results are correlated to the enhancement in density and the development of uniform microstructure with the enhanced grain size.

► MTO ceramics are prepared at lower sintering temperature with fine CeO2 particles.
► CeO2 improves densification and form uniform microstructure with larger grains.
► MTO–CeO2 exhibit superior microwave dielectric properties, as compared to pure MTO.
► The mechanism to get higher densification and uniform microstructure are discussed.
► The properties are suitable for various microwave communication applications.