Phase Formation and Crystal‐Structure Determination in the Bi₂O₃–TiO₂–TeO₂ System Prepared in an Oxygen Atmosphere

Abstract

Using X‐ray diffraction analysis and scanning electron microscopy it was revealed that in an atmosphere of flowing oxygen in the temperature range 700°–800°C, three new compounds are formed in the Bi2O3–TiO2–TeO2 pseudoternary system. These compounds are Bi2Ti3TeO12, Bi2TiTeO8, and Bi6Ti5TeO22, and all the compounds include Te6+. All three crystal structures were solved and refined using X‐ray powder diffraction data. Based on the results of the phase formation, a solid‐state compatibility diagram is proposed.

Sintering and Dielectric Characterization of Pseudoternary Compounds from the Bi2O3–TiO2–TeO2System

“…In a Bi 2 O 3 –TiO 2 –TeO 2 system fired in an oxygen flow between 700° and 800°C, the formation of pseudoternary compounds Bi 2 TiTeO 8 , Bi 2 Ti 3 TeO 12 , and Bi 6 Ti 5 TeO 22 can be detected, all of which include Te 6+ 9 . A sintering analysis of these powders in an oxygen flow atmosphere using a heating microscope was conducted, and according to these results (Fig.…”

“…We have already undertaken characterizations of the TiO 2 –TeO 2 7 and Bi 2 O 3 –TeO 2 8 systems fired in an oxygen flow, and ceramics with potential for use with LTCC technology were proposed. These systems represent subordinaries of a pseudoternary Bi 2 O 3 –TiO 2 –TeO 2 system within a diagram of solid‐state compatibility, and the crystal structures of the Bi 2 Ti 3 TeO 12 , Bi 2 TiTeO 8 , and Bi 6 Ti 5 TeO 22 compounds were recently reported 9 . As the sintering and dielectric properties were unknown, the aim of this study was therefore to prepare dense ceramic bodies and to determine their dielectric properties.…”

Investigation on the valence state of Te ions in the Bi6Ti5TeO22 thin film using X-ray photoelectron spectroscopy

“…[3][4][5] It was reported that Te 4+ ions in the Bi 2 O 3 -TiO 2 -TeO 2 compounds were easily oxidized and transformed to Te 6+ ions when exposed to an oxidizing atmosphere and that this transition induced a phase change. 1,2 The changes of the crystal structure and electrical properties were also observed for the BTT * Corresponding author. Tel.…”

“…1,2 Moreover, due to the low sintering temperatures of the BTT ceramics, the BTT films with a high ε r were easily grown at low temperatures (≤300 • C). [3][4][5] Therefore, their electrical properties have been studied for application to the embedded decoupling capacitors for printed circuit boards and the radio frequency (RF) metal-insulator-metal capacitors in semiconductor devices which require low processing temperatures.…”

Effect of SiO2 addition on the microstructure and microwave dielectric properties of ultra-low fire TiTe3O8 ceramics

“…TeO 2 with %20% porosity was shown to display a relative permittivity of 19.3, a Q Â f value of 30,000 GHz and a temperature coefficient of À119 ppm/8C. Recently, researchers have shown that TeO 2 -based ceramics possess very low sintering temperatures ranging from 650 to 800 8C and excellent microwave dielectric characteristics, including TiO 2 -TeO 2 , Bi 2 O 3 -TeO 2 , CaO-TeO 2 , BaO-TeO 2 , ZnO-TeO 2 , and Bi 2 O 3 -TiO 2 -TeO 2 systems [7,[10][11][12][13][14][15][16][17]. Single phase TiTe 3 O 8 sintered at 720 8C to %95% of theoretical density exhibits a relative permittivity of 50, a Q Â f value of 30,600 GHz and a temperature coefficient of +133 ppm/8C.…”