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Crystal structure and microwave dielectric properties of low temperature sintered MgO ceramic with LiF addition

Published online by Cambridge University Press:  06 February 2012

Akinori Kan ,
Hirotaka Ogawa  and
Tohru Moriyama
Akinori Kan*
Affiliation:
Department of Transportation Engineering, Meijo University, Nagoya 4688502, Japan
Hirotaka Ogawa
Affiliation:
Department of Transportation Engineering, Meijo University, Nagoya 4688502, Japan
Tohru Moriyama
Affiliation:
Department of Transportation Engineering, Meijo University, Nagoya 4688502, Japan
*
a)Address all correspondence to this author. e-mail: akan@meijo-u.ac.jp
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Abstract

The (1−x)MgO–xLiF ceramics (x = 0.02–0.08) were successfully sintered when the ceramics were sintered at 950 °C for 4 h in covered crucible. From the crystal structure analysis, it was found that a small amount of Li+ cation occupied Mg2+ site in MgO ceramic; the formation of oxygen vacancy induced by Li substitution for Mg was suggested by the evaluation of the bulk conductivity and the calculation of density of state (DOS) for the (Mg13O43)−60 and (Mg11Li2O42)−58 cluster models. As for the microwave dielectric properties of the (1−x)MgO–xLiF ceramics, the dielectric constant εr and the temperature coefficient of resonant frequency values of the ceramic were independent of the lithium fluoride (LiF) content, and these values were approximately 9.5 and −62 ppm/°C. On the other hand, the quality factor values strongly depended on the LiF content. As a result, the highest value of 282,230 GHz was obtained at x = 0.04. From these results, it is determined that the LiF addition is effective in reducing the sintering temperature of MgO without any detrimental effect on the microwave dielectric properties of MgO ceramics.

Keywords

dielectric propertiesceramicMg
Type
Articles
Information
Journal of Materials Research , Volume 27 , Issue 6 , 28 March 2012 , pp. 915 - 921
Copyright
Copyright © Materials Research Society 2012

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