Effect of ZnO/WO3 additives on sintering behavior and microwave dielectric properties of (Sr,Ca)TiO3–(Sm,Nd)AlO3 ceramics

The effect of ZnO/WO3 additives on phase composition, microstructures, sintering behavior, and microwave dielectric properties of 0.7(Sr0.01Ca0.99)TiO3–0.3(Sm0.75Nd0.25)AlO3 (7SCT–3SNA) ceramics prepared via conventional solid-state route were systematically investigated. All the samples exhibited pure perovskite structures, and Ti4+ ions could be substituted by W6+ ions. While further increasing WO3 additives, the W6+ ions migrated into the lattice. The τf values of samples first became more positive, and then tended to move toward negative direction with increasing WO3 addition. Moderate ZnO/WO3 additives not only effectively reduced the sintering temperature from 1500 to 1330 °C but also improved the dielectric properties of 7SCT–3SNA ceramics. The 0.50 wt% ZnO doped 7SCT–3SNA sample with 1.00 wt% of WO3, sintered at 1330 °C for 4 h, was measured to show optimum microwave dielectric properties, with an εr of 45.12, a Q × f value of 51200 GHz (at 5.4 GHz), and τf value of + 2.68 ppm/°C.