Dielectric Ceramics with Tungsten-bronze Structure in the BaO–Nd2O3–TiO2–Nb2O5 System

Some tungsten-bronze compounds in the BaO–Nd2O3–TiO2–Nb2O5 system were prepared and characterized. Ba4Nd2Ti4Nb6O30 and Ba5NdTi3Nb7O30 had the filled tetragonal tungsten-bronze structure, and Ba3Nd3Ti5Nb5O30 consisted of the tetragonal tungsten-bronze major phase and a minor amount of secondary phase BaNd2Ti3O10. These compounds had significant relaxor behaviors, and the Curie temperatures (at 1 MHz) were 0 and 55 °C for Ba3Nd3Ti5Nb5O30 and Ba5NdTi3Nb7O30 ceramics, respectively. A high dielectric constant (213) combined with low dielectric loss (0.004 at 1 MHz) was obtained in Ba3Nd3Ti5Nb5O30 ceramics. In addition, the solid-solution range of BapNd6−pTi8−pNb2+pO30 was 3 < p ≤ 6.