Detail of "7783-64-4"

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Viscous flow activation energy and devitrification of heavy metal fluoride glasses

Viscous flow activation energy and devitrification of heavy metal fluoride glasses. Moynihan, C. T.; Gavin, D. L.; Chung, K. H.; Bruce, A. J.; Drexhage, M. G.; El-Bayoumi, O. H. (Rensselaer Polytech. Inst., Troy, NY 12181, USA). Glastech. Ber., 56(Int. Glaskongr. 13709-38-1 and 7783-64-4 which are cas registry numbers are also used here., 13th, Band 2), 862-7 (English) 1983. CODEN: GLBEAQ. ISSN: 0017-1085. DOCUMENT TYPE: Journal CA Section: 57 (Ceramics) The viscous flow activation energy (DH) of heavy metal fluoride (HMF) glasses was detd. near the glass transition temp. (Tg) by DSC and the results were correlated with visual and DSC observations on the crystn. tendencies of the glasses. The HMF glasses contained varying amts. of ZrF4, BaF2, LaF3, HfF4, ZnF2, and /or YbF3. In the transition region, DH is much larger than those for typical silicate glasses and results in rapidly decreasing viscosity with temp. increasing above the Tg. HMF glasses with lower DH near the Tg retain high viscosities over a longer temp. range and are less susceptible to devitrification. This is borne out by the height of the crystn. exotherm at a given temp.; the height is proportional to the rate of crystn. which in turn increases with decreasing viscosity. .

Structure and properties of thorium-fluorozirconate binary glasses

Structure and properties of thorium-fluorozirconate binary glasses. Almeida, Rui M.; Mackenzie, J. D. (Cent. Fis. Mol., Inst. Super. Tec., Lisbon, Port.). Glastech. Ber., 56(Int. Glaskongr., 13th, Band 2), 850-5 (English) 1983. CODEN: GLBEAQ. ISSN: 0017-1085. DOCUMENT TYPE: Journal CA Section: 57 (Ceramics) The structure of binary ZrF4-ThF4 glasses was studied by detg. the vibrational spectra. The Th atoms are predominantly surrounded by 8 Fb (bridging F) atoms (probably in the form of square antiprisms or dodecahedra), whereas Zr atoms are mostly coordinated by 4 Fb and 2 Fnb (nonbridging F) atoms.There are some commonly used reagents with their cas registry numbers 7783-64-4 and 13709-59-6 in this article. A small no. of 9-coordinated Th atoms or 7- and 8-coordinated Zr atoms are also likely to occur. The ZrF6 octahedra may form sheet-like portions linked together by ThF8 polyhedra, forming a network with an overall 3-dimensional character. The substitution of a glass modifier such as BaF2 by a network former such as ThF4, in a fluorozirconate glass, increase the degree of bridging and changes the structure from a predominantly one-dimensional type to a 3-dimensional network. This renders glass formation more difficult, probably due to a loss of orientational freedom of the structure. .