Influence of LaAlO3 additive to MgTiO3-CaTiO3 ceramics on sintering behavior and microwave dielectric properties

• Effect of LaAlO3 addition on dielectric properties of 0.95MgTiO3–0.05CaTiO3 was studied.
• Effect of LaAlO3 addition on phase compositions and sintering behavior of 0.95MgTiO3–0.05CaTiO3was discussed.
• With 1.0 mol % LaAlO3 doped, the sintering temperature of 0.95MgTiO3–0.05CaTiO3 ceramics can be lowered to 1225 °C with excellent dielectric properties.
• Densification was used to analyze the dielectric properties.
• The relations between microstructure and microwave dielectric properties were investigated.

The microstructures and microwave dielectric properties of 0.95MgTiO3–0.05CaTiO3 ceramics with 1.0 mol % LaAlO3 addition, prepared by the conventional solid-state reaction route, were investigated. The sintering temperature of 1.0 mol % LaAlO3-doped 0.95MgTiO3–0.05CaTiO3 ceramics can be lowered to 1225 °C. Microwave dielectric properties were found to strongly correlate with the sintering temperature. The Q×f value increased with sintering temperature up to 1225 °C and decreased thereafter. The decrease in Q×f value was coincident with the observed abnormal grain growth. A maximum Q×f of 73300 GHz associated with an εr of 21.68 and a τf of -2.22×10−6/°C was achieved for the samples sintered at 1225 °C/4 h.