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Relation of Composition of Hydrogarnet to Resistance to Sulfate Attack
Author(s) -
MARCHESE B.,
MASCOLO G.,
SERSALE R.
Publication year - 1972
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.1151-2916.1972.tb11239.x
Subject(s) - lattice constant , ion , sulfate , formula unit , crystallography , lattice (music) , materials science , crystal structure , hydrothermal circulation , chemistry , diffraction , chemical engineering , metallurgy , organic chemistry , physics , acoustics , optics , engineering
Crystallographic changes resulting from the entry of Si into the cubic lattice of tricalcium aluminate hexahydrate were examined in an effort to understand the sulfate resistance of hydrogarnets. Low‐SiO 2 hydrogarnets were prepared by hydrothermal treatment of specially prepared glasses. The lattice constants of the unit cell of C 3 AH 6 decreased when Si 4+ ions were introduced. In investigating the low‐Si members of the C 3 AH 6 ‐grossularite series, only those with well‐defined Si contents of 1, 3, and 6 Si 4+ ions/unit cell were found; the lattice constants were 12.52, 12.47, and 12.41 Å, respectively. Intermediate lattice constants represent mixtures of at least two members. A content of 0.125 SiO 2 /formula unit, corresponding to 1 Si 4+ ion in the unit cell of C 3 AH 6 , is not sufficient to produce resistance to sulfate attack; the lowest SiO 2 content which results in such resistance appears to be 0.375 SiO 2 /formula unit or 3 Si atoms/unit cell.