Synthesis of zirconium (hafnium) fluoride compounds and their X-ray luminescence properties

Godneva, M. M.; Motov, D. L.; Boroznovskaya, N. N.; Klimkin, V. M.

doi:10.1134/s0036023607050026

Cited by 15 publications

(9 citation statements)

References 10 publications

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“…Note: The superscripts at the numbers refer to the following: (1) Cs 3 Zr 1.5 (PO 4 ) 3 (4, card 52 1181),(2) ZrO 2 (4, card 36 420), and(3) iso thermal calcination.…”

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“…Investigation of a number of the compounds showed that some of them are characterized by intense X ray luminescence. X ray luminophores promising for practical applications are hexafluorozirconates M 2 Zr(Hf)F 6 (M = K, Rb, Cs) and also Rb 3 Zr 2 F 9 SO 4 ⋅ 2H 2 O [2,3]. Two important results were obtained: on the one hand, the synthesized materials exhibit rela tively intense X ray luminescence over a wide wave length range, and on the other, it was found that the efficiency of the X ray luminescence efficiency can be enhanced and its spectrum and temporal characteris tics can be optimized by transforming some crystal lat tice defects to others, being X ray luminescence cen ters.…”

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Phase formation along the PO 4 3− /Zr = 1.5 section of the ZrO(NO3)2-H3PO4-CsF-H2O system

Godneva

Motov

Kuznetsov

et al. 2012

Russ. J. Inorg. Chem.

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492 † We previously studied the phase formation in sulfu ric acid solutions of titanium subgroup element com pounds in the presence of alkali metal fluorides [1]. Under "mild" synthesis conditions, we isolated about a hundred of alkali metal fluorometallates and fluoro sulfate metallates, most of which were obtained for the first time. Investigation of a number of the compounds showed that some of them are characterized by intense X ray luminescence. X ray luminophores promising for practical applications are hexafluorozirconates M 2 Zr(Hf)F 6 (M = K, Rb, Cs) and also Rb 3 Zr 2 F 9 SO 4 ⋅ 2H 2 O [2, 3]. Two important results were obtained: on the one hand, the synthesized materials exhibit rela tively intense X ray luminescence over a wide wave length range, and on the other, it was found that the efficiency of the X ray luminescence efficiency can be enhanced and its spectrum and temporal characteris tics can be optimized by transforming some crystal lat tice defects to others, being X ray luminescence cen ters. Phosphate zirconatesCsZr 2 (PO 4 ) 3 [4, card 34 0196], α Cs 2 Zr(PO 4 ) 2 [4, card 28 0356], and Cs 3 Zr 1.5 (PO 4 ) 3 [4, card 52 1181] are known. At low concentration of the phosphorus component, we isolated crystalline cesium fluorophosphate zirconate CsZrF 2 PO 4 ⋅ H 2 O and also amorphous oxofluorophosphate Cs 2 Zr 3 O 2 F 4 (PO 4 ) 2 ⋅ 3H 2 O and amorphous oxofluorophosphate nitrate CsZr 3 O 1.25 F 4 (PO 4 ) 2 (NO 3 ) 0.5 ⋅ 4.5H 2 O. The compound Cs 3 Zr 3 O 1.5 F 6 (PO 4 ) 2 ⋅ 3H 2 O was obtained, which forms in the crystalline or glassy state, depending on the con ditions. The formation of the compounds Cs 2 Zr 3 O 1.5 F 5 (PO 4 ) 2 ⋅ 2H 2 O, Cs 2 Zr 3 F 2 (PO 4 ) 4 ⋅ 4.5H 2 O, and Zr 3 O 4 (PO 4 ) 1.33 ⋅ 6H 2 O was established, which crys tallize only in mixtures with the known phases [5]. † Deceased.The system ZrO(NO 3 ) 2 -H 3 PO 4 -CsF-H 2 O was studied along the section at the molar ratio F/Zr = 2-5 at 2-5 wt % ZrO 2 . The initial substances were ZrO(NO 3 ) 2 ⋅ 2H 2 O and 85% H 3 PO 4 (both of analytical grade), and CsF (chemically pure). CsF was added while continuously stirring to ZrO(NO 3 ) 2 ⋅ 2H 2 O solu tions. After the mixtures became homogeneous, H 3 PO 4 was added to them. After keeping the obtained mixtures for 7-45 days, precipitates were filtered off, washed successively with water and alcohol, and dried in air. The ZrO 2 content in solution was calculated with the consideration of H 3 PO 4 before adding CsF. Phases in the precipitates were identified by X ray powder diffraction, crystal optical, thermal, elemen tal, and IR spectroscopic analyses. The X ray powder diffraction patterns were recorded with a DRF 2 instrument (graphite monochromator, CuK α radia tion). The crystal optical measurements were per formed using immersion liquids. The thermograms were recorded in air using a Pt-Pt/Rh thermocouple. The reference substance was calcined aluminum oxide. The weight loss was determined with a VT 1000 torsion balance at a heating rate of ~9 deg/min. The IR spectra in the frequen...

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“…Note: The superscripts at the numbers refer to the following: (1) Cs 3 Zr 1.5 (PO 4 ) 3 (4, card 52 1181),(2) ZrO 2 (4, card 36 420), and(3) iso thermal calcination.…”

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confidence: 99%

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confidence: 99%

Phase formation along the PO 4 3− /Zr = 1.5 section of the ZrO(NO3)2-H3PO4-CsF-H2O system

Godneva

Motov

Kuznetsov

et al. 2012

Russ. J. Inorg. Chem.

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“…KZrF5 crystallizes in the triclinic space group ( 1 P ) with coordination number Z = 6. In [15] it was confirmed that KZrF 5 is triclinic ( 1 P ) with a = 7.370 (1) 18 Unfortunately, we could not get access to this expensive database.…”

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“…The observed spectral trends with variation of composition were interpreted with a model where the structure of the rich in ZrF 4 melts is dominated by small size chains formed by "ZrF 6 " octahedral. 18 More specifically, the following schematic was proposed explaining the formation of different complex anions as a function of the ZrF 4 molar fraction in the melt 18 :…”

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Thermodynamic Assessment of Hot Corrosion Mechanisms of Superalloys Hastelloy N and Haynes 242 in Eutectic Mixture of Molten Salts KF and ZrF4

Glazoff¹

2012

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This computational work models the behavior of Haynes 242 and Hastelloy N in the binary molten salt eutectic mixture KF-ZrF 4 . Limiting the principal alloying elements to four-nickel, chromium, molybdenum, and iron-allows reasonable conclusions to be made about the nature of the hot corrosion resistance of these materials. It suggests that alloy composition optimization work could be conducted to further enhance alloy hot corrosion resistance.The onset of hot corrosion for both alloys is associated with chromium leaching and the formation of CrF 2 in relatively mild oxidizing conditions. However, the onset of hot corrosion for Alloy N requires harsher conditions than for Haynes 242. Thermodynamic data for these systems need to be generated in future research efforts in order to get a clearer picture of the mechanisms of hot corrosion onset. Firstprinciples atomistic simulations can illuminate those cases where experimental thermodynamic data is absent.Another important direction of research is coupling, in real time, the hydrodynamics of molten salt flow inside the reactor with a thermodynamic assessment of corrosion made under the assumption of local equilibrium on a sufficiently fine spatio-temporal grid. This would pave the way to understanding how corrosion develops in real space and time in heat exchanger loop components made of superalloys and steels. A possible application of this new technology would be the analysis of pyrolytic processes, when molten salts are used for catalytic purposes (e.g., biomass reactors, obtaining quality fuel out of heavy fractions of oil refining, etc.).Continuing this computational research effort will allow nuclear engineers to approach the problem of down selecting materials for NGNP AHTRs with greater confidence, less effort spent on expensive experimental work, and in shorter periods of time.

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Cation Influence on Zirconium/Hafnium Fluoride Coordination

Lötter

Purcell

Nel

et al. 2017

Emerging Trends in Chemical Sciences

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Synthesis of zirconium (hafnium) fluoride compounds and their X-ray luminescence properties

Cited by 15 publications

References 10 publications

Phase formation along the PO 4 3− /Zr = 1.5 section of the ZrO(NO3)2-H3PO4-CsF-H2O system

Phase formation along the PO 4 3− /Zr = 1.5 section of the ZrO(NO3)2-H3PO4-CsF-H2O system

Thermodynamic Assessment of Hot Corrosion Mechanisms of Superalloys Hastelloy N and Haynes 242 in Eutectic Mixture of Molten Salts KF and ZrF4

Cation Influence on Zirconium/Hafnium Fluoride Coordination

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