著者

中川 善兵衛 小坂 丈予 浦部 和順 山田 久夫

出版者

Japan Association of Mineralogical Sciences

雑誌

岩石鉱物鉱床学会誌 (ISSN:00214825)

巻号頁・発行日

vol.67, no.9, pp.283-290, 1972-09-05 (Released:2008-08-07)

参考文献数

12

被引用文献数

1 2

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The weathering process of quartz-diorite mass in Senmaya district, Iwate Prefecture, was studied from chemical and mineralogical angles. Especially the relationship between the compositional changes of the weathered rocks and their main constituent minerals was detailedly discussed. The non-altered quartz-diorite is chiefly composed of quartz, plagioclase, hornblende and biotite, together with few apatite and magnetite. As weathering proceeds, most of the primary minerals, plaigoclase, hornblende and biotite, are gradually eliminated and secondary minerals such as vermiculite, kaolin etc. appear in stead. The change in chemical composition of the weathered rocks is almost controlled by the solubility of each chemical component under netural conditions. Among the primary minerals, biotite is most sensitive for weathering, the sequence of the alteration being as follows:biotite-hydrobiotite-vermiculite-kaolin mineral In the earlier stage of the weathering, the alteration process of biotite was mostly affected by its original crystallographic structure, so that the change in chemical composition of that mineral differs markedly from that of the host rock. But it is also controlled by the solubility of each chemical component, thus the compositional change becomes to be similar to that of the host rock in the later stage.

著者

銭 端芬 大矢 豊 中川 善兵衛 浜野 健也

出版者

社団法人 日本セラミックス協会

雑誌

Journal of the Ceramic Society of Japan (日本セラミックス協会学術論文誌) (ISSN:09145400)

巻号頁・発行日

vol.103, no.1202, pp.1022-1026, 1995-10-01 (Released:2010-08-06)

参考文献数

20

被引用文献数

3 3

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Aluminum titanate ceramics were fabricated from compacts of aggregated mixture of alumina and titania. The mixture was prepared by precipitation of aluminum hydroxide from aqueous solution of aluminum nitrate, containing rutile powder. After calcination, the mixture was crushed and classified to fractions' 2-5, 5-10, 10-20, 20-47 and 47-77μm sizes. The SEM observation of compacts of the aggregates revealed that the aggregates were not broken by the compaction. The fired bodies of the compacts consisted of oriented aluminum titanate grains. The sizes of the oriented regions were about 4 times larger than the initial aggregate sizes. The reasons for the formation of the oriented grains were considered as follows: the formation of aluminum titanate has low change in free energy, increases elastic energy, and is endothermic. Because of these reasons, grain boundary energy becomes significant in nucleation of aluminum titanate and, therefore, the nucleation occurs epitaxially to result in the oriented texture. The semi-quantitative estimation of change in energies during formation of aluminum titanate agrees with the argument.