FETEIRA, Antonio and SINCLAIR, Derek C. (2008). Microwave dielectric properties of low firing temperature Bi2W2O9 ceramics. Journal of the American Ceramic Society, 91 (4), 1338-1341.Full text not available from this repository.
Phase stability, sinterability, and microwave dielectric properties of Bi2W2O9 ceramics and their cofireability with Ag, Cu, and Au electrodes have been investigated. Single-phase Bi2W2O9 powder was synthesized by solid-state reaction in air at 800°C for 3 days. X-ray powder diffraction data show Bi2W2O9 to have an orthorhombic crystal structure described by the noncentrosymmetric space group Pna21, with lattice parameters a=5.4401(8), b=5.4191(8), c=23.713(4) Å. Ceramics fired at temperatures up to 865°C remain single-phase but above this temperature ferroelectric Bi2WO6 appears as a secondary phase. The measured relative permittivity of Bi2W2O9 ceramics increases continuously from 28.6 to 40.7 for compacts fired between 860° and 885°C. The bulk relative permittivity of Bi2W2O9 corrected for porosity was calculated as 41.3. Bi2W2O9 ceramics fired up to 875°C exhibit moderate quality factors, Q×fr, ∼7500–7700 GHz and negative temperature coefficient of resonant frequency, ∼−54 to −63 ppm/°C. Chemical compatibility experiments show Bi2W2O9 ceramics to react with both Ag and Cu electrodes, but to form good contacts with Au electrodes.
|Research Institute, Centre or Group:||Materials and Engineering Research Institute > Structural Materials and Integrity Research Centre > Centre for Corrosion Technology|
|Depositing User:||Hilary Ridgway|
|Date Deposited:||06 Jun 2012 14:50|
|Last Modified:||06 Jun 2012 14:50|
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