The luminescent properties of erbium(III)-doped fluorozirconate glass and fluorozirconate phosphate glass and glass ceramics containing NaPO3 were compared. The glasses were obtained by rapid melt quenching and were characterized using luminescence spectroscopy, differential thermal analysis, x-ray diffraction, and transmission electron microscopy. When NaPO3 was added, the relative luminescence intensity of Er(III) in the near infrared (NIR) region doubled at 1530 nm (4I13/2 → 4I15/2 transition). The luminescence intensity of other bands in the visible and NIR regions decreased. Luminescence quantum yields and lifetimes of the studied samples were measured. The reasons for the change in luminescence intensity after addition of NaPO3 and heat treatment of the samples were discussed.

For the first time, glass in the ZrF4–BaF2–NaPO3–Er(Nd)F3 system was obtained and investigated by differential thermal analysis (DTA), X-ray diffraction analysis (XRD), 19F and 31P MAS NMR, luminescence spectroscopy, and electron microscopy. It has been found that the addition of 2.5–20 mol

Fluorozirconate phosphate glasses of the ZrF 4 –BaF 2 –NaPO 3 composition doped with ErF 3 or NdF 3 have been investigated by of differential thermal analysis (DTA), X-ray diffraction (XRD) analysis, 19 F, 31 P MAS NMR and solid state NMR, luminescence spectroscopy, and electron microscopy (TEM and SEM). It has been found that the addition of 2.5-20 mol. % NaPO 3 increases the glass thermal stability factor (ΔT). The character of ionic mobility in a fluoride sublattice at varied temperature depending on the content of sodium metaphosphate in the glass composition has been investigated. The NMR data indicate a low degree of depolymerization of phosphate chains. NaPO 3 additives and heat treatment decrease the luminescence intensity of Er 3+ and Nd 3+ ions in the visible region. Isothermal heating in the temperature range of T g –T c1 causes crystallization of spherical particles of a composition of BaZrF6 . The particle sizes are 5–90 nm. The mechanism of the observed effects associated with an increase in the concentration quenching of luminescence during heat treatment is proposed. Fluorozirconate phosphate glasses doped with erbium or neodymium ions can be considered as potential precursors for the production of glass ceramics.

30BaZrF6–70NaPO3 glasses doped with 0.1–1.0 wt % EuF3 have been synthesized. The introduction of up to 1.0 wt % EuF3 has no noticeable effect on glass formation and thermal and crystallization stability of the glasses. Heat treatment of glasses can lead to the formation of glass ceramics. Crystallization during the heat treatment of glasses occurs in two stages with the appearance of Na3ZrF7, NaZr(PO4)3, and BaFPO3 crystalline phases in the glass phase. The presence of europium trifluoride in the glass is responsible for its luminescence, which increases without reaching saturation with increasing EuF3 content from 0.1 to 1.0 wt %.

Glasses and glass-ceramic samples in the BaZrF6-NaPO3 system doped with ErF3 have been synthesized. The component ratios, at which glasses and glass phases with crystals of different compositions are formed, have been determined. Two independent glass phases are formed in the system: phosphate and fluorozirconate. Dopant ions are localized mainly in the fluorozirconate matrix. The presence of erbium trifluoride in the system provides the luminescent properties of both produced glasses and glass-ceramics.

Thermal properties and ionic mobility of the phases formed in the Li3PO4-BiF3-LiF system in the temperature range 150-450 K were studied by DTA and Li-7, F-19 NMR methods. A narrow glass formation region was found in the 50BiF(3) cut. The types of ionic mobility in glasses and crystalline samples were examined in the temperature range 150-450 K. It was found that the diffusion of lithium ions is observed in glasses. Diffusion of the fluoride ions is characteristic for both crystalline and glass samples. The temperature ranges in which the diffusion of the corresponding ions and their dependence on the sample composition take place were determined.

The glasses in the system of ZrF4-BaF2 and NaPO3 obtained by melting glasses of ZrF4-BaF2 and NaPO3 were studied by methods of IR and Raman spectroscopy, X-ray diffraction, SAXS and differential scanning calorimetry. An analysis of the data showed that the glasses are built of two sub-networks, in one of which crystallization centers are formed. It was shown possibility of obtaining mixed optical nanoceramics in which fluorozirconate nanocrystallites are embedded in a phosphate glass matrix.

Синтезированы новые стеклокристаллические трехкомпонентные системы TeO2–BaZrF6–NaPO3. Методами ИК-, КР-спектроскопии и рентгенофазового анализа изучено влияние соотношения компонентов в системе на фазовый состав и строение полученных стеклокерамик. The new glass-crystalline three-component systems of TeO2–BaZrF6–NaPO3 have been synthesized. The influence of the ratio of the components in the system on the phase composition and structure of the glass-ceramics obtained has been studied by IR and Raman spectroscopy and X-ray phase analysis.

Physicochemical properties of materials obtained via the extrusion blending of oxyfluoride glass with the composition 3B2O3 · 97(40SnF2–30SnO–30P2O5) and F-4MB fluoroplastic are studied. The results from investigating their morphology, molecular composition, and thermal properties are presented.

Fluorozirconate-phosphate glasses of the ZrF4–BaF2–NaPO3(LiPO3) and ZrF4–BaF2–LaF3–AlF3–LiPO3 systems doped with EuF3, ErF3, and NdF3 were studied by the differential-thermal (DTA) and X-ray diffraction (XRD) analysis, luminescence spectroscopy, scanning and transmission electron microscopy (SEM and TEM) methods. Addition of the phosphate component up to 20 mol % decreases the glass transition temperature and increases the glass stability to crystallization. Heat treatment in the range >Tg–Tc1 of glass transition and first maxima of crystallization temperatures causes crystallization of nanosized β-BaZrF6 particles. At LiPO3 (NaPO3) concentrations of more than 80 mol %, glasses containing a crystalline phase are formed during the synthesis process.

The glasses doped with the Er3+, Nd3+ ions were synthesized in the oxyfluoride system TeO2–PbO·P2O5–PbF2:МF3 and studied by the IR and Raman spectroscopy (including low-frequency range of spectra), DSC, SAXS and luminescence methods. The role of REE ions in the structure forming, crystallization and luminescent properties of glasses is identified. It was found that the rare-earth element ions enter into the medium range order of glass structure and act as crystallite forming nuclei. The contribution of the Er3+ photoluminescence with emission levels at 524, 530, 545, and 554 nm into the inelastic scattering spectrum of glasses in the system of TeO2–Pb2O5·PbO–PbF2:xErF3 has been revealed.

Fluorozirconate–phosphate glasses of the composition ZrF4–BaF2–NaPO3 doped with EuF3 have been investigated by the methods of differential thermal (DTA) and X-ray diffraction (XRD) analysis, nuclear magnetic resonance (19F NMR, 19F and 31P MAS NMR), luminescence spectroscopy, and scanning electron microscopy (SEM). The thermal behavior of the fabricated glasses is similar to that of fluorozirconate glasses – NaPO3 dopants decrease the glass transition temperature (Tg) from 300 down to 250°C and increase the glass stability to crystallization (ΔТ). Resonance lines in 19F NMR spectra correspond to the glass fluorozirconate network, whereas the 19F and 31P MAS NMR data indicate to the presence of bridge and end fluorine atoms in the structure and to low degree of depolymerization of phosphate chains. Thermal treatment in the temperature range Tg–Тх1 induces crystallization of nanosized particles, whose composition corresponds to β-BaZrF6. The SEM data indicate to the globular structure of glasses and synthesized glass ceramics, while the particle sizes are within the range 20–160nm. The intensity of luminescence of glasses doped with europium(III) increases upon doping with 2.5–10mol% of NaPO3 and decreases in glass ceramics. In glass and glass ceramics, europium ions are predominantly present in the fluorozirconate matrix.

The microstructure and crystallization of the glasses with composition (100-x-y)TeO2-xPbO·P2O5-yPbF2:zMF3 (M= Er, Eu, Nd; x=42.5-30, y=5-30, z=0.5-3.0) were investigated by transmission electron microscopy (TEM) and luminescence methods. It was found that the doping with the rare-earth (III) fluorides promoted nucleation in the bulk glasses. The sizes of generated particles are about 2-5 nanometers and their shapes are close to spherical. The growth rate of crystallites depended on the lead fluoride content and glass forming rate. The heat treatment of the samples promotes the glass ceramic formation, where the crystalline phase is Pb2P2O7.

Glasses in the TeO2PbO·P2O5PbF2:0.5EuF3 system are obtained. The structure, crystallization and luminescent properties are discussed by data of Raman spectroscopy, mainly. It has been demonstrated that a glass network composed of mixed tellurite and phosphate polyhedra is formed in the glasses. Lead difluoride renders a modifying effect on the structure of the glass network at large, i.e., both tellurite and phosphate groups. It has been shown that at the initial stages of the crystallization of the 42.5TeO232.5PbO·P2O525PbF2:0.5EuF3 glass the phosphate phases (Pb3(PO4)2) enter into the crystallites. The destruction of the glass network is a partial. The tellurite groups are driven back into the residual glass. At the scattering excitation by a laser with the wavelength λ0=532nm the Eu3+ luminescence corresponding to the emission levels 578, 585, 590, and 612nm was revealed in glass of the composition 42.5TeO232.5PbO·P2O525PbF2:0.5EuF3. The glass crystallization affects the luminescence.

Recently, interest in ammonium hydrogen difluoride (NH4HF2) as a versatile fluorinating agent for the decomposition of natural materials resumed. It is considered to be a new and more efficient than hydrofluoric acid (HF) reagent in analytical chemistry. Thermodynamically possible fluorination reactions with NH4HF2 are exothermic and proceed even at room temperature with the entropy reserve. The fluorination products are of high symmetry phases (tetragonal or cubic) with partial substitution of fluoride ion for oxide (or hydroxide). The fluorination of refractory silicate zircon (ZrSiO4) is kinetically hindered, and its complete decomposition requires the use of a Teflon autoclave at 200 degrees C. The fluorination products are cubic (NH4)(3)Zr(OH)(x)F7-x (x = 0.3) and tetragonal double salt (NH4)(3)SiF7, which can be separated due to incongruent sublimation of (NH4)(2)SiF6. The mechanism of the latter process is proposed.

A phase diagram of the PbF 2 –SnF 2 system has been studied by differential thermal analysis and X-ray powder diffraction. The system forms Pb 1– х Sn х F 2 ( х ≤ 0.33) solid solution and three compounds. Pb 2 SnF 6 decomposes in solid state by a peritectoid reaction at 350°С; Pb 3 Sn 2 F 10 and PbSnF 4 melt by peritectic reactions at 565 and 380°С, respectively. The eutectic coordinates are 180°С, 90 mol % SnF 2 .

A rather simple and original method for processing of zirconium-containing raw material form Algoma deposit (Khabarovsk region, Russia) was suggested, which comprised fluorination of the initial sample with a diluted HF solution followed by the thermal treatment of fluorination products and pyrohydrolysis of zirconium tetrafluoride. Water vapors obtained by hydrogen and oxygen burning in a hydrogen torch as well as by simple evaporation were used for pyrohydrolysis. The feed rate of the water and its temperature were regulated. The temperature of water vapors reached 800-1200 degrees C. Zirconium dioxide with a purity of 99.97 % or more and a dispersity of 0.1 mu m or less was synthesized.