Effect of V2O5 on microwave dielectric properties of non-stoichiometric MgTiO3 ceramics

•Combined effects of MgO and V2O5 on MTO ceramics were studied for the first time.•MTO with 0.07mol excess MgO show a pure phase with excellent dielectric properties.•V2O5 forms a solid solution with MTO, densified at 1100°C due to liquid phase effect.•Microwave dielectric loss is heavily influenced by grain size and secondary phases.•Obtained MTO properties are suitable for LTCC and low-loss microwave applications. We report the effect of V2O5 addition on crystal structure, microstructure and microwave dielectric properties of non-stoichiometric MgTiO3 (Mg1+δTiO3+δ, where δ is excess MgO concentration) ceramics. The structural studies reveal that sample with δ=0.07 exhibits a single phase MgTiO3 and secondary phase of MgTi2O5 (Mg2TiO4) for below (above) the δ=0.07 composition. The optimum microwave dielectric properties of ɛr∼17.68, Q×f0∼161THz at 9.4GHz are obtained for δ=0.07, sintered at 1350°C for 3h. The improvement in loss is attributed to the improvement in uniform grain growth and suppression of secondary phases. V2O5 addition significantly lowered the sintering temperature of Mg1.07TiO3.07 to 1100°C, which is due to the formation of liquid phase. The XRD analysis reveals that V2O5 forms a solid solution with MTO. A good combination of ɛr∼15.8 and Q×f0 of 85.6THz at 9.3GHz are obtained for 0.5wt% V2O5 added Mg1.07TiO3.07.