A study of the oxidation products of some LiRF4 phases

Safi, H.; Harris, I.R.; Cockayne, B.; Plant, J. G.

doi:10.1007/bf00540330

Cited by 10 publications

(5 citation statements)

References 5 publications

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“…Nevertheless in the growth of crystals by the Czochralski method, YLF was easily seeded only with the composition of 50.7 mol%LiF−49.3 mol%YF 3 . They concluded that the degree of congruence of this compound is closely related to contamination with oxygen compounds, mainly with moisture [5,6]. Then it was proposed a phase diagram of the system LiF−YF 3 composed by two eutectics, one with composition of 80 mol% LiF−20 mol% YF 3 at 979(2) K, and the other to the composition 49 mol% LiF−51 mol% YF 3 at temperature 1103(2) K, the same temperature was attributed to the melting of YLF.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic modeling of the LiF–YF3 phase diagram

Santos¹,

Klimm²,

Baldochi³

et al. 2012

Journal of Crystal Growth

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A thermodynamic optimization of the LiF−YF 3 binary phase diagram was performed by fitting the Gibbs energy functions to experimental data that were taken from the literature, as well as from own thermoanalytic measurements (DTA and DSC) on HF-treated samples. The Gibbs energy functions for the end member compounds were taken from the literature. Excess energy terms, which describe the effect of interaction between the two fluoride compounds in the liquid phase, were expressed by the Redlich-Kister polynomial function. The calculated phase diagram and thermodynamic properties for the unique formed compound, LiYF 4 , are in reasonable agreement with the experimental data.

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Section: Introductionmentioning

confidence: 99%

Thermodynamic modeling of the LiF–YF3 phase diagram

Santos¹,

Klimm²,

Baldochi³

et al. 2012

Journal of Crystal Growth

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“…Peritectic decomposition to a melt and the low-T (β-) phase of the REF 3 is observed for RE = Eu, Gd, Tb, and Dy, but the peritectic point shifts in this sequence closer to the solidus of the LiREF 4 phase. LiREF 4 for RE = Y, Ho to Lu melt congruently if the starting materials are very pure and the atmosphere is free of residual oxygen or moisture [3][4][5][6][7][8]. The main reason for the shifting of the stoichiometric composition, accepted by the referred authors, is that contamination with oxygen impurities results in the formation of oxyfluorides, oxidation to RE 2 O 3 , or hydrolysis that removes REF 3 from the melt.…”

Section: Introductionmentioning

confidence: 90%

“…For the smaller rare earth ions, starting from RE = Eu, the systems contain one intermediate phase LiREF 4 that crystallizes in the scheelite structure (space symmetry group I4 1 /a). Solid state synthesis and lattice parameters for all these compounds were reported by Keller and Schmutz [2].…”

Section: Introductionmentioning

confidence: 99%

Phase equilibria and prospects of crystal growth in the system LiF–GdF₃–LuF₃

Santos

Ranieri

Klimm

et al. 2008

Cryst. Res. Technol.

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Scheelite type LiGdF 4 , LiLuF 4 , and mixtures of both end members were prepared by a hydrofluorination route from the rare earth oxides and commercial LiF. The samples were purified by melting in HF/Ar mixtures, and were investigated by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX) techniques. Both end members show unlimited miscibility in the solid phase. Mixed crystals containing at least 65 mol-% LiLuF 4 melt under direct formation of the liquid phase. The gap between solidus and liquidus is narrow. LiGdF 4 and mixed crystals with less then 65 mol-% LiLuF 4 decompose peritectically under formation of (Gd,Lu)F 3 . Crystal growth is expected to be possible either from Lu-rich melts with the appropriate scheelite composition or from Gd-rich melts containing an excess of LiF. Dedicated to Prof. Ladislav Bohatý on the occasion of his 60th birthday

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“…The compositional interval between points 'a' and 'b', depends on the empiric aspects, as growth atmosphere and the reagents grades. The congruent or incongruent melting feature of the YLF compound is extensively discussed in the literature [10][11][12][13][14][15].…”

Section: Crystal Fibre Growthmentioning

confidence: 99%