原料としてカオリナイトを用いた2-八面体型フッ素雲母系マイカセラミックスの合成

概要

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Dioctahedral mica ceramics containing fluorine muscovite and amorphous phase were prepared by solid state reaction in air with using kaolinite and K_2SiF_6 as raw materials. The appropriate molar ratio for obtaining high contents of fluorine muscovite was 0.6K_2SiF_6 : 1.5 kaolinite. Fluorine muscovite crystallites were precipitated at 600-700℃ for shorter sintering times of 3-6h, developing house of cards microstructure with remaining relatively high porosity of 18-28% . The porosity depended on the heating rate. The lattice constant b of precipitated fluorine muscovite slightly increased with increasing temperature from 600℃ to 700℃ , coinciding with that of fluorine muscovite synthesized as a single phase in the closed system by using γ-Al_2O_3 as a raw material. This indicates that tetrahedral aluminium substitution slightly increases with increasing temperature and that fluorine muscovite having an ideal composition is formed at 700℃ . However, topaz crystallized as a stable high temperature phase at higher temperatures over 750℃ .
社団法人日本セラミックス協会の論文
1996-08-01