パイロフィライトおよびセリサイト圧粉体の脱水過程に伴う異常膨張

概要

論文の詳細を見る
The expansion characteristics of pyrophyllite and sericite during dehydroxylation were examined measuring linear expansion on pressed specimens with or without previous treatment of particle orientation, combining with X-ray diffraction data. The causes of the expansion were discussed comparing with the cases of talc and kaolinite that showed thermal shrinkage during dehydroxylation. The results are summarized as follows. 1) It was concluded that the expansion of pyrophyllite and sericite compacts resulted from the permanent lattice expansion along c-axis which reached 1.6〜2.0% and 0.5〜0.7%, respectively, and from the particle rearrangement induced by their lattice expansion. 2) Sericite compacts showed almost same degree of permanent linear expansion as that of pyrophyllite in spite of much less amount of lattice expansion of sericite, which would be attributed to the greater rearrangement of sericite particles owing to their feasible flexibility. 3) It is supposed that the lattice expansion of pyrophyllite or sericite is closely related to the mechanism of dehydroxylation (homogeneous) in which no cation movement takes place except for proton, while in the case of talc or kaolinite the reconstruction of lattice caused by the cation movement leaving pores behind (inhomogeneous), brings about the shrinkage of the bulk volume of the aggregates.
社団法人日本セラミックス協会の論文
1973-03-01