Preparation of ZrF4-NaF-BaF2-LaF3-YbF2 glasses with YbF2 substitution for BaF2 (LaF3)

• Published in: Inorganic materials Vol. 49; no. 9; pp. 947 - 952
• Main Authors: Ivanenko, A. P., Kompanichenko, N. M., Omel’chuk, A. A., Savchuk, R. N., Zinchenko, V. F.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01-09-2013
• Subjects: Chemistry; Chemistry and Materials Science; Crystallization; Industrial Chemistry/Chemical Engineering; Inorganic Chemistry; Materials Science; Fluorozirconate; Lanthanum Fluoride; Rare Earth Fluoride; Ytterbium; Barium Fluoride
• ISSN: 0020-1685; 1608-3172
• DOI: 10.1134/S0020168513080062

We have prepared glasses and semicrystalline phases with a green color in the systems ZrF
4
(53.5)-NaF(20)-BaF
2
(20)-LaF
3
(6.5 −
x
)-YbF
2
(
x
) (0 ≤
x
≤ 6.5 mol %) (I) and ZrF
4
(53.5)-NaF(20)-BaF
2
(20 −
x
)-LaF
3
(6.5)-YbF
2
(
x
) (0 ≤
x
≤ 20 mol %) (II). Thermal analysis results demonstrate that, in both systems, the glass transition temperature of the samples containing ≤3 mol % YbF
2
lies in the range 200–250°C, their heating curves show two or three crystallization events (at 320–340, 380–460, and 415–490°C), and their melting points range from 460 to 490°C. Increasing the YbF
2
content of the glasses to 4 mol % and above (system I) has no effect on their glass transition temperature, reduces the temperature of the first crystallization event from 340 to 305°C, and produces extra peaks in the range 545–600°C, above the major melting peak, which can be accounted for by a nonequilibrium state of the glasses. Ytterbium difluoride substitution for barium difluoride (10 to 20 mol %) (system II) leads to the formation of semicrystalline phases and increases the glass-transition (305°C), crystallization (470–515°C), and melting (570–690°C) temperatures. The IR spectra of such samples show, in addition to a so-called “featureless continuum” (∼500 cm
−1
), absorption bands characteristic of the Yb-F bond. Electronic spectra also confirm that the glasses contain both divalent and trivalent ytterbium.