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Structure-property relations in lanthanide borate glassesGlass formation in the system Ln2O3-B2O3 (Ln = Nd, Sm) was studied. Glasses could be formed in the range from 0 to 28 mol pct rare-earth oxide (Ln2O3), but liquid immiscibility in these systems limits the range of homogeneous glasses to 0 to 1.5 and 25 to 28 mol pct Ln2O3. The infrared spectra indicate that the rare-earth-rich glasses are structurally similar to rare-earth metaborates (LnB3O6) which contain (B3O6)-infinity chains. The variation in density, transformation temperature, thermal expansion coefficient, and transformation-range viscosity of these glasses with the size of the rare-earth ion is discussed. Glasses near the metaborate composition have a transformation temperature of about 700 C, which is high for binary borate glasses. Glasses could not be formed in the systems Eu2O3-, Gd2O3-, Ho2O3-, and Er2O3-B2O3, even by quenching at 1300 C/s. The sudden lack of glass formation in the system Ln2O3-B2O3 with Ln(3+) ions smaller than Sm(3+) is explained on the basis of the size effect of the Ln(3+) ion on the stability of (B3O6)-infinity chains in these metaborates.
Document ID
19850060643
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Chakraborty, I. N.
(Missouri Univ. Rolla, MO, United States)
Day, D. E.
(Missouri-Rolla, University Rolla, United States)
Lapp, J. C.
(Missouri Univ. Rolla, MO, United States)
Shelby, J. E.
(Alfred University NY, United States)
Date Acquired
August 12, 2013
Publication Date
July 1, 1985
Publication Information
Publication: American Ceramic Society, Journal
Volume: 68
ISSN: 0002-7820
Subject Category
Nonmetallic Materials
Accession Number
85A42794
Funding Number(s)
CONTRACT_GRANT: NAS8-34758
Distribution Limits
Public
Copyright
Other

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