ゾル-ゲル法によるCaO-SiO_2ゲルの作製と熱処理による変化

概要

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CaO-SiO_2 gel was prepared from Ca(NO_3)_2 and TEOS. The mixture of TEOS, Ca(NO_3)_2, H_2O and EtOH was immiscible at first, but became miscible by stirring for several hours. Wet gels containing 10-60 mol%CaO were formed and dry gels were amorphous at the composition of 10-40 mo1%CaO. It was found that a small amount of Ca(NO_3)_2 crystal precipitated in dry gels can react with SiO_2 gel by heat treatment and the heattreated gels were amorphous. The reaction of Ca(NO_3)_2 with SiO_2 gels was confirmed by disappearance of IR absorption peak attributed to NO^-_3 ion after heat treatment. The gels in the immiscibility region in this system(10, 20 mol%CaO)caused phase separation by heat treatment at 600-800°C. The tendency of phase separation was high for high CaO content gels. The crystallization behavior of gels in the immiscibility region was found similar to that of CaO-SiO_2 amorphous films prepared by sputtering method.
社団法人日本セラミックス協会の論文
1997-07-01