Abstract: A tantalate Ba3TiTa4O15 was synthesized by doping Ti4＋ in the binary system BaOTa2O5. The crystal structure was determined by Xray powder diffraction, and it belongs to paraelectric phase of tetragonal tungsten bronze structure at room temperature with unit cell parameters : a=1.256 27(6)nm, c=0.395 86(4)nm. Dielectric measurements showed that the phase transition of Ba3TiTa4O15 from ferroelectric to paraelectric occurred at －35 ℃, lower than that of Ba6Ti2Nb8O30. The dielectric constant of Ba3TiTa4O15 ceramic was stable at room temperature with the frequency increasing from 1 kHz to 1 MHz, while the dielectric loss was as low as 0.002. Ba3TiTa4O15 might be a suitable candidate for microwave dielectric ceramics.

Key words: Tantalate, Tungsten bronze structure, XRD, Dielectric property