Sintering and Dielectric Characterization of Pseudoternary Compounds from the Bi 2 O 3 –TiO 2 –TeO 2 System
2007; Wiley; Volume: 90; Issue: 8 Linguagem: Inglês
10.1111/j.1551-2916.2007.01646.x
ISSN1551-2916
Autores Tópico(s)Nuclear materials and radiation effects
ResumoUsing X‐ray diffraction analysis, scanning electron microscopy, thermogravimetry, and measurements of the dielectric properties up to the MW frequency range, the characterization of Bi 2 Ti 3 TeO 12 , Bi 2 TiTeO 8 , and Bi 6 Ti 5 TeO 22 compounds, which all include Te 6+ , was performed. As the processes of Te 6+ reduction and the evaporation of TeO 2 ‐containing species contribute to the presence of secondary phases, the preparation of single‐phase ceramics is rather difficult. To minimize the amount of secondary phases during the firing process, the pellets were muffled in a corresponding compound and then fired in an autoclave furnace under 10 bars of oxygen pressure. By sintering the Bi 2 Ti 3 TeO 12 , Bi 2 TiTeO 8 , and Bi 6 Ti 5 TeO 22 between 840° and 1010°C, ceramics with ɛ r ranging from 36 to 350, Q × f values from 220 to 12 500 GHz, and τ f from +41 to +2600 ppm/K were obtained.
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