Glass Network Evolution with Bi3+/Ti4+Substitution in Phosphate Glasses Formulated with a Constant Oxygen/Phosphorus Ratio. EXAFS, XANES, and31P Double Quantum MAS NMR

2003 ◽  
Vol 15 (25) ◽  
pp. 4709-4716 ◽  
Author(s):  
Lionel Montagne ◽  
Sylvie Daviero ◽  
Gérard Palavit ◽  
Abdelillah Shaim ◽  
Mohamed Et-Tabirou
Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4326
Author(s):  
Pawel Goj ◽  
Aleksandra Wajda ◽  
Pawel Stoch

Iron-phosphate glasses, due to their properties, have many potential applications. One of the most promising seems to be nuclear waste immobilization. Radioactive 90Sr isotope is the main short-lived product of fission and, due to its high solubility, it can enter groundwater and pose a threat to the environment. On the other hand, Sr is an important element in hard tissue metabolic processes, and phosphate glasses containing Sr are considered bioactive. This study investigated the effect of SrO addition on a glass structure of nominal 30Fe2O3-70P2O5 chemical composition using classical molecular dynamics simulations. To describe the interaction between Sr-O ion pairs, new interatomic potential parameters of the Buckingham-type were developed and tested for crystalline compounds. The short-range structure of the simulated glasses is presented and is in agreement with previous experimental and theoretical studies. The simulations showed that an increase in SrO content in the glass led to phosphate network depolymerization. Analysis demonstrated that the non-network oxygen did not take part in the phosphate network depolymerization. Furthermore, strontium aggregation in the glass structure was observed to lead to the non-homogeneity of the glass network. It was demonstrated that Sr ions prefer to locate near to Fe(II), which may induce crystallization of strontium phosphates with divalent iron.


2020 ◽  
Vol 142 (1) ◽  
pp. 203-209 ◽  
Author(s):  
Paweł Goj ◽  
Małgorzata Ciecińska ◽  
Magdalena Szumera ◽  
Paweł Stoch

Abstract Iron phosphate glasses are materials that can have many applications like durable matrixes in waste immobilization techniques, biomaterials, optoelectronic devices, etc. Their possible usage is related to their glass network and thermal properties. The influence of Na2O content on thermal properties and crystallization ability of iron phosphate glass of base composition 30 Fe2O3–70 P2O5 mol% were studied. Increasing the content of Na2O causes a decrease in transformation temperature and increase in ΔCp. Characteristic temperatures, thermal stability and crystallizing phases were determined. Increasing content of sodium causes depolarization of iron phosphate glass network which causes a continuous change in ΔCp and glass transformation temperature. Discontinuous change in some glass properties suggests structure rebuilding about 30 mol% of Na2O.


Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 527
Author(s):  
Luukas Kuusela ◽  
Alexander Veber ◽  
Nadia G. Boetti ◽  
Laeticia Petit

The impact of the progressive addition of ZnO up to 5 mol% on the thermal, structural, and optical properties of Er3+-doped phosphate glasses within the system NaPO3-NaF-ZnO-Ag2O is discussed. The glass network was found to depolymerize upon the addition of ZnO. This promotes a slight increase in the intensity of the emission at 1.5 µm as well as enhances the silver ions clustering ability under the heat treating. The Ag-nanoparticles formed after moderate heat-treatment can further enhance the emission at 1.5 µm, whereas an excessive amount of the clusters leads to the opposite effect. The addition of ZnO helps to slightly increase the glass ability of the system. The crystallization behavior study revealed that surface crystallization is observed for all the glasses. It is found that even a small ZnO addition changes the crystalline phases formed after devitrification. Moreover, the addition of ZnO decreases the crystallization tendency of the glass.


2019 ◽  
Vol 290 ◽  
pp. 35-40 ◽  
Author(s):  
Syariffah Nurathirah S. Yaacob ◽  
M.R. Sahar ◽  
E.S. Sazali ◽  
S. Sulhadi

Tuning the concentration of nanoparticles (NPs) to accommodate wider application demanded a better understanding of the physicals and structural properties of the glass. A series of zinc phosphate glasses with the composition of (57-x) P2O5- 40ZnO-3Tb2O3 –xCuO, (0 ≤ x ≤ 2 mol %) has been prepared by melt quenching technique and their physical and optical characterization have been studied. The X-Ray Diffraction technique and UV-Vis Spectroscopy have been used to characterize the glass sample. The XRD confirms the amorphous nature of the prepared glasses. The physical properties of glasses with different CuO NPs such as density, molar volume, refractive index and electronic polarizability are determined. It is found that both density and molar volume decreases with increasing CuO NPs concentration. The optical band gap (4.54 eV-2.96 eV) and the Urbach energy (0.19 eV-0.54 eV) are showing a decreasing trend with the increasing amount of CuO NPs.This is due to the formation of non-bridging oxygen, (NBO) in the glass network. The glass exhibits high refractive index ~2.40 and polarizability ~1.12 ×10-23 cm3 and is useful for solid-state laser and optoelectronic devices.


2008 ◽  
Vol 39-40 ◽  
pp. 61-64 ◽  
Author(s):  
M. Elisa ◽  
Ileana Cristina Vasiliu ◽  
Cristiana Eugenia Ana Grigorescu ◽  
B. Grigoras ◽  
H. Niciu ◽  
...  

A wet non-conventional method for preparing aluminophosphate glasses is presented. Aluminophosphate glasses belonging to the oxide system Li2O-BaO-Al2O3-La2O3-P2O5, doped with rare-earth ions (Pr3+, Er3+, Gd3+, and Yb3+) were obtained. The influence of the doping ions on the optical properties of the phosphate glasses has been investigated in relation with micro-structural and local electronic phenomena The optical behavior of Li2O-BaO-Al2O3-La2O3-P2O5 glasses doped with 3% mol. rare-earth ions has been studied by ultra-violet-visible-near-infra-red (UV-VISNIR) spectroscopy. The transmission spectra revealed electronic transitions between 4f and 6s inner orbital of the rare-earth ions. Structural information via optical phonons was provided by infra-red (IR) absorption spectra in the range 400-4000 cm-1. IR optical phonons are characteristic for the vitreous phosphate network, showing out the glass network-forming role of P2O5. The absorption spectra present the main PO2 and P-O-P symmetrical stretch modes besides P-O-P bend mode, P-OH, P=O, PO3 2-, asymmetrical and symmetrical vibration modes. Fluorescence spectra of the rareearth- doped aluminophosphate glasses, in the visible range, were obtained by laser excitation at 514.5 nm. The fluorescence signals revealed specific electronic transitions, which provide visible and near-infra-red emission. Glasses containing rare-earth ions exhibit luminescence at the following wavelengths: Pr3+ ions at 820 nm and 880 nm, Er3+ ions at 520 nm, 550 nm and 560 nm, Gd3+ ions at 530 nm, 540 nm, 550 nm 820 and 880 nm, Yb3+ions at 530 nm, 540 nm, 550 nm and 980 nm.


Author(s):  
Rosli Hussin ◽  
Musdalilah Ahmad Salim ◽  
Nur Shahira Alias ◽  
Mutia Suhaibah Abdullah ◽  
Suhailah Abdullah ◽  
...  

Phosphate glasses in a system of magnesium calcium phosphate for host matrix luminescent materials wereinvestigated. The glass samples in a series of xMgO–(40- x)CaO–60P2O5 in molar ratio (0x40 mol%) were preparedusing melt-quenching technique. The effect of Mg and Ca content on the structure and glass stability againstcrystallization in the system of MgO–CaO–P2O5 ultraphosphate has been investigated using XRD, Infrared and Ramanspectroscopy. The compositions containing up to 40 mol% of CaO and /or MgO formed glasses and no crystallinephases were detected by XRD. The results of IR and Raman spectroscopy suggest that the phosphate network of theseglasses is composed of middle (Q2) and branching (Q3) phosphate tetrahedral and other calcium/magnesium anions.All the symmetric and asymmetric stretching vibrations of POP and PO2 observed in the spectra are characteristic ofQ3 and Q2 groups. The glass network, especially the Q2 units can be modified by the presence of Ca and Mg ions. Thismodification is primarily associated with the phosphate and the Q2 and Q3 phosphate units randomly distributed in thenetwork. Spectroscopic results shows that the modification of the phosphate network is higher for the Ca containingglasses with respect to the Mg ones, at the same alkali earth content, due to the well defined Ca properties as amodifying cation. Formation of P–O–H bond expresses the hygroscopic nature of the phosphate glasses. This studyshows that the vibrational spectroscopy (Infrared and Raman) are provide useful, complementary information aboutthe network structures of ultraphosphate glasses.


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