Upper limit of x in Ba6−3xNd8+2xTi18O54 new tungsten bronze solid solution

In the present work, the upper limit of x in Ba6−3xNd8+2xTi18O54 ceramics was determined by investigating the phase constitution as the function of composition and process conditions. For the compositions of x ≤ 0.75, the new tungsten bronze structure is stable and the single phase structure is easy to be obtained. While, the new tungsten bronze structure becomes unstable for compositions of x = 0.8, 0.9 and 1.0, where the new tungsten bronze major phase is generally detected together with some secondary phases. The excellent microwave dielectric characteristics are not only obtained at x = 0.67 but also obtained at 0.8 and 0.9.