シリカと燐酸アルミニウムとの固溶について : クリストバライトとクジストバライト型燐酸アルミニウムとの固溶

概要

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As part of the investigation of the system SiO_2-Al_2O_3-P_2O_5, solid solution of SiO_2 and AlPO_4, both of cristobalite structure, was studied. At first it was confirmed that AlPO_4 can be formed from Al(OH)_3 and H_3PO_4 by mixing and drying at 110℃. Specimens of the SiO_2-AlPO_4 system were prepared from mixtures of various mole ratios of Al(OH)_3, SiO_2 gel and H_3PO_4, dried and stored overnight at 110℃. After formed into tablets, the mixtures were heated at 1450℃ for 2 hours. Crystals of tetragonal cristobalite structure were obtained which were determined to be of homogeneous phase by X-ray diffraction, D.T.A., microscopic observation and chemical analysis, and it was confirmed that A1PO4 and SiO_2 were solid-soluble in any proportions at a high temperature. When increasing the amount of the substitution, the crystal structure became so disturbed that only the diffraction from (101) plane was able to be observed and the others diminished. D.T.A. peaks of α-β inversion (tetragonal-cubic inversion) which appeared sharp at the end members, became also feeble and broad and shifted toward low temperature. Refractive indices by microscopic observation changed gradually with the composition of solid solutions, and at the same composition the value varied place to place in some small range, showing that the solid reaction did not proceed perfectly homogeneously.
社団法人日本セラミックス協会の論文
1964-05-01