Synthesis of Ultrafine Ba07.Srs3TiO3 by Mechanically Activating Process

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Date
2007
Authors
Mohd Noor, Prof. Dr. Ahmad Fauzi
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Abstract
The project 'Synthesis of Ultrafine Ba6.7Srp.3TiO3 by Mechanically Activating Process' was successfully completed early 2008. As reported in the technical report attached, the single phase BST was produced successfully at a relatively low temperature of 500oC, albeit the challenges encountered during the synthesis, one of which is the caking problem as well as melting of phase formed. The caking effect was due to the mechanical activation process, while the melting phase was a result of the low meting chemicals used. Calcination at 500oC wasthe lowest that we can achieved in this study. It was found that during sintering, the next stage of product formation, the pellets prepared from 400oC calcined mixturc crackcd ofter sintering. This is due to insufficient decomposition at 400oC. Further significant decompotion took place during sintering which caused the pellet to crack. The dielectric properties obtained in this studies were relatively low as compared to those derived from conventional solid state reaction route. The dielectric properties are most optimum in the grain size range of 2-5 pm, and subsequent declined if the grain size is smaller or bigger. Therefore ultrafine powder is expected to yield lower dielectric value, however it makes miniaturization possible which is crucial in electronic field. Furthermore, the decomposition of the remnant phase of BaCO: and SrCO: in the calcined powder contributed to the porous microstructure; hence degraded the dielectric properties.
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Materials and Mineral Resources Engineering
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