Gadolinium and Hafnium Alumino-Borosilicate Glasses: Gd and Hf Solubilities
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Mat. Res. Soc. Symp. Proc. Vol. 608 © 2000 Materials Research Society
Table I. Gd- and Hf-bearing sodium alumino-borosilicate glass samples. Sample # AI15Gdl 8 B 15Gd42 B 15Gd48 NalOGd2O B15Hf30 B 15Hf31 Na30Hf3O Na30Hf34 Na30Hf35a Na30Hf35b PLO.35Hf8a
PLO.35Hf8b PLO.85Hf32
Description Clear Gd glass. No observable crystals Clear Gd glass. No observable crystals Clear Gd glass with crystalline phase. Elements in crystals: Si, Al, Na, 0 and Gd Clear Gd glass. No observable crystals Clear Hf glass. No observable crystals Clear Hf glass. No observable crystals Clear Hf glass. No observable crystals Clear Hf glass. No observable crystals Clear Hf glass with no crystals Different Hf glass from sample Na3OHf35a. Clear glass with euhedral HfI 2 crystals (up to tens of jtm in size). Elements confirmed in crystals: Hf and 0 Clear Hf glass with bladed crystals radiating outward from undissolved HfO2 particles. Heat-treated for one hour at 1560'C and one hour at 1450'C. Elements confirmed in crystals: Hf and 0 Hafnium glass with tiny crystals. Heat treated for 30 minutes at 1400'C after initially melted at 1560'C for one hour and one hour at 1450'C. Elements confirmed in crystals: Hf and 0 Clear Hf glass with well-developed, hexagonal crystals. Heat-treated for one hour at 1560"C and three hours at 1350'C. Elements confirmed in crystals: Hf and 0
were not formed under the same conditions as the samples used in the solubility study. For example, the Hf-bearing glasses, in particular, were melted for longer times in order to grow the large Hf0 2 crystals. The samples were prepared by mounting the glass grains in epoxy resin discs that were polished for determination of chemical composition and crystal morphology using BSE, EDS and EMPA. The size of the glass grains ranged from a few millimeters to up to one centimeter. Backscattered electron imaging and EDS spectra were used to examine the homogeneity of the glass matrix and precipitated crystals, and to characterize the morphology of precipitated crystals. A four-spectrometer Cameca CAMEBAX electron microprobe analyzer (wavelength dispersive system) was used to determine chemical compositions on the polished surfaces. The Cameca PAP correction routine was used in data reduction. The directly analyzed elements were Si, Al, Na, and Gd/Hf with 0 obtained by stoichiometry and B obtained by difference. Other elements were excluded because the glass and crystals were synthesized with known elemental contents. During each analytical session, spectrometers were verified for position, and each standard was recalibrated and analyzed prior to analyzing the glass samples. A focused beam in spot mode was not used because the glass samples may be damaged by the electron beam, due to the presence of the light elements, B and Na. Standards were Si0 2 for Si, andalusite (Al2SiOs) for Al, albite (NaAlSi 3O 8) or jadeite (NaAlSi 20 6) for Na, Gd phosphate (GdPO 4 ) for Gd, and metallic Hf for Hf. Glass standards were not used due to alkali loss. Different EMPA procedures were tested to search
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