扇状塩基性硫酸マグネシウムの成長機構とその特性

概要

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Sector Iike crystals of magnesium hydroxide sulfate hydrate (trade name MOS・HIGE) were grown in a hydrothermal reaction at 180℃ using MgSO_4 and NaOH aqueous solutions. Their morphology and crystal structure were investigated by X ray diffraction, SEM and TEM. Typical morphology of the crystals was sector Iike bundles, each of them grows three dimensionally, not in a plane, in the opposite direction from its center. The element whiskers of the sector like crystal were always parallel to the b axis. In the initial stage of growih, a single crystallite composed of small whiskers growing along the b axis nucleates ill Mg (OH)_2 slurry. During the growih of long whiskers from the crystallite, their growth direction slightly inclines with one another because of the lattice mismatching between two whiskers caused by impurities such as Na, Ca, Si and so forth on the boundary of an element whisker. Sector-like crystals were examined by the X-ray diffraction method at various high temperatures. It is found that they deconrpose into MgSO_4 and MgO between 700℃ and 1000℃. The diameter dependence of the tensile strength of the crystals was measured mainly at room temperature.
社団法人日本セラミックス協会の論文
1994-05-01