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Relations Among Particle Size, Shape, and Surface Area of Mg(OH) 2 and Its Calcination Product
Author(s) -
PHILLIPS V. A.,
OPPERHAUSER H.,
KOLBE J. L.
Publication year - 1978
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1978.tb09235.x
Subject(s) - pseudomorph , crystallite , calcination , mineralogy , crystallography , materials science , particle size , coalescence (physics) , single crystal , grain size , surface layer , chemistry , analytical chemistry (journal) , layer (electronics) , metallurgy , nanotechnology , quartz , catalysis , chromatography , physics , biochemistry , astrobiology
Precipitated Mg(OH) 2 particles 0.05 to 1 μm in diam. and of various shapes were calcined in air for 1/2 h at 704°, 816°, 954°, 1093°, or 1232°C. At 704°C, BET surface areas, initially 11 to 32 m 2 /g, increased 1.4‐ to 7.6‐fold, and TEM observations showed pseudomorphs. Depending on the parent crystal size and shape, these particles contained either single layers or multilayers of MgO crystallites 40 to 260 Å in diam., roughly perpendicular to the original c axis. Pseudomorph stability varied greatly, even between particles of different shape in the same sample. Coalescence into single or linked angular particles occurred at 1093° and 1232°C, but one sample retained single‐layer pseudomorphs containing cubic crystallites. One observation indicated that sodium cation impurity decreased the surface area of oxide formed at 704°C.