Synthesis of low thermal expansion ceramics prepared from pyrophyllite and lithium source
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In this study, the low thermal expansion ceramic, petalite (Li2O • Al2O3 • 8SiO2), was synthesized by using pyrophyllite, and theircharacteristics were examined. Pyrophyllite is consisted of SiO2 and Al2O3, which are the main component of petalite. For thesynthesis of petalite, Li2CO3 or LiOH • H2O were used as a source of Li2O. In the mixing ratio of 6.7 : 1 wt% (pyrophyllite :Li2CO3), fully crystallized petalite was synthesized, and the powder compacts were densified at 1150 oC. Some Li compounds,which have low melting point, caused a formation of liquid phase in the densified samples. The petalite phase was transformedto β-spodumene during heating process, and the sintered petalite showed a negative thermal expansion coefficient of −0.43 × 10-6/oC. Finally, the experimental results showed that the pyrophyllite is an expected material for the synthesis of low thermalexpansion ceramics.
Abstract
In this study, the low thermal expansion ceramic, petalite (Li2O • Al2O3 • 8SiO2), was synthesized by using pyrophyllite, and theircharacteristics were examined. Pyrophyllite is consisted of SiO2 and Al2O3, which are the main component of petalite. For thesynthesis of petalite, Li2CO3 or LiOH • H2O were used as a source of Li2O. In the mixing ratio of 6.7 : 1 wt% (pyrophyllite :Li2CO3), fully crystallized petalite was synthesized, and the powder compacts were densified at 1150 oC. Some Li compounds,which have low melting point, caused a formation of liquid phase in the densified samples. The petalite phase was transformedto β-spodumene during heating process, and the sintered petalite showed a negative thermal expansion coefficient of −0.43 × 10-6/oC. Finally, the experimental results showed that the pyrophyllite is an expected material for the synthesis of low thermalexpansion ceramics.
참고문헌 (13)
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