Calcium-doped MgTiO3–MgTi2O5 ceramics prepared using a reaction-sintering process

Calcium-doped MgTiO3–MgTi2O5 (MCT) ceramics prepared using a reaction-sintering process were investigated. Without any calcination involved, the mixture of MgO, CaCO3, and TiO2 was pressed and sintered directly. MCT ceramics were obtained after 2–6 h sintering at 1150–1250 °C. MCT containing high percentage of MgTi2O5 phase (45.6%) was observed at 1150 °C/2 h sintering and the percentage decreased to 37.2% at 1300 °C/2 h sintering. The maximum density 3.85 g/cm3 could be obtained at 1250 °C. Dielectric constant at 10 MHz reaches 23.7–25.9 in MCT ceramics sintered at 1150 and 1200 °C. ɛr = 22.4 and Q × f ∼ 40,400 GHz (at 9.8 GHz) and a τf value of −9.6 ppm/°C were obtained in MCT ceramic sintered at 1300 °C/2 h. The reaction-sintering process has been proven a simple and effective method to produce dense MCT ceramics with good dielectric properties even without the addition of sintering aid.