| 1. |
- Cedergren, Magnus, et al.
(author)
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Crystallization temperature of amorphous Fe80B20 under pressure
- 1978
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In: Journal of Non-Crystalline Solids. - : Elsevier. - 0022-3093 .- 1873-4812. ; 30:1, s. 69-76
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Journal article (peer-reviewed)abstract
- The resistance of rapidly quenched Fe80B20 was recorded versus T at a rate of 7 K/min and various pressures up to 2.5 GPa. The onset of crystallization, Tx, was defined by extrapolation at the sharp change in resistance associated with crystal growth. The resulting slope of Tx is 15 K/GPa. Separate measurements at atmospheric pressure yielded Tx versus rate of temperature increase, R = dT/dt. Crystallization times from the literature were recalculated to yield Tx, and the results are compared with our data. Nominally amorphous materials of the same composition show markedly different properties. It is also shown that the variation of Tx with R is mostly due to the change in viscosity.
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| 2. |
- Cedergren, Magnus, et al.
(author)
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Pressure and heating rate dependence of the crystallization temperature for amorphous (Fe65Ni35)75P16B6Al3 and Ti50Be40Zr10
- 1980
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In: Journal of Non-Crystalline Solids. - : Elsevier. - 0022-3093 .- 1873-4812. ; 37:2, s. 213-217
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Journal article (peer-reviewed)abstract
- The crystallization temperature, Tx, was determined at constant heating rate, R = dṪ/dt ≅ 7 K min−1, by monitoring the electrical resistance. Such experiments were carried out under pressures up to 2.5 GPa, and the resulting dTx/dP was 15.9 K GPa−1 for (Fe65Ni35)75P16B6Al3 and 8.7 K GPa−1, 8.1 K GPa−1 for the two crystallization processes in Ti50Be40Zr10. The activation energies of crystallization under atmospheric pressure were obtained from measurements of Tx at rates from 0.05 K min−1 −55 K min−1, analysed by plotting ln(Tx2R−1) versus Tx−1.
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| 3. |
- Forsman, Hans, et al.
(author)
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Dielectric relaxation and new phase of cyclooctanol at pressures to 1 GPa
- 1991
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In: Journal of Non-Crystalline Solids. - : Elsevier. - 0022-3093 .- 1873-4812. ; 131-133:Part 2, s. 1145-1148
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Journal article (peer-reviewed)abstract
- On the four previously known solid phases of cyclooctanol (I, II, IV and V in our notation), two (IV and V) are stable only at high pressure. In this work, new data on dynamic dielectric properties of cyclooctanol at high pressure are presented. The results are compared with corresponding thermal conductivity data. It is concluded that the dielectric properties of phase II are consistent with the thermal conductivity properties if it is assumed that a substantial fraction of the dipoles interact with each other. The molecular interaction favours reorientation around an axis of negligible dipole moment. The new solid phase, phase III, which was discovered through thermal conductivity measurements, is detected dielectrically in the present study.
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| 4. |
- Granqvist, Claes-Göran, et al.
(author)
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Towards the smart window : progress in electrochromics
- 1997
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In: Journal of Non-Crystalline Solids. - 0022-3093 .- 1873-4812. ; 218, s. 273-279
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Journal article (peer-reviewed)abstract
- Electrochromic devices have the ability to produce reversible and persistent changes of their optical properties. The phenomenon is associated with joint ion and electron transport into/out of an electrochromic thin film, in most cases being a transition metal oxide. This paper outlines the various applications of such devices in smart windows suitable for energy-conscious architecture, in variable-reflectance mirrors, and in display devices. Critical materials issues and design concepts are discussed. The paper also covers two specific research topics: computed electronic structure of crystalline WO3 incorporating ionic species, showing how reflectance modulation emerges from a first-principles calculation; and Li+ dynamics in heavily disordered Ti oxide, illustrating how diffusion constants derived from impedance spectroscopy can be reconciled with the Anderson—Stuart model.
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| 5. |
- Hofmeister, H., et al.
(author)
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Structure of nanometersized silicon particles prepared by various gas phase processes
- 1998
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In: Journal of Non-Crystalline Solids. - : Elsevier BV. - 0022-3093 .- 1873-4812. ; 232-234, s. 182-187
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Journal article (peer-reviewed)abstract
- We have explored various gas phase processes for the fabrication of nanometersized Si and SiOx particles and measured their structural properties (agglomeration, size, shape, crystallinity, surface roughness and internal structure) by conventional and high resolution electron microscopy. Agglomerated amorphous Si particles, 10-30 nm in size, were prepared by gas phase reactions including cluster growth processes in a low pressure silane plasma. Annealing at 900°C resulted in almost complete crystallisation of nearly spherical particles covered by an amorphous oxide shell. Inert gas arc evaporation of silicon yielded single crystalline, spherical Si particles, 4-16 nm in size, in which no defects were detected. These particles, agglomerated into chains and tangles, are covered entirely by a thin amorphous oxide layer. Thermal evaporation of solid SiO in an inert gas atmosphere produced agglomerated, nearly spherical amorphous SiOx particles, 8-24 nm in size, with considerable surface roughness. Upon annealing at 900°C, the formation of 3-6 nm sized Si crystallites in the interior of these particles was observed.
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| 6. |
- Jacobsson, Per, et al.
(author)
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Reorientational motion of the NO3− ion through the liquid-glass transition in Ca0.4K0.6(NO3)1.4 and Ca(NO3)2 + 8H2O
- 1994
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In: Journal of Non-Crystalline Solids. - : Elsevier. - 0022-3093 .- 1873-4812. ; 172-174:Part 1, s. 161-166
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Journal article (peer-reviewed)abstract
- The reorientational correlation function of the NO3- ion in Ca0.4K0.6(NO3)1.4 and in Ca(NO3)2 + 8H2O has been investigated by Raman spectroscopy from the low viscosity liquid at high temperatures through the liquid-glass transformation region and into the frozen glassy state. It was obtained from the reorientational contribution to the 1050 cm-1 symmetric stretch of the NO3- ion, determined from a comparison of the anisotropic and isotropic parts of the Raman band. It was found that the NO3- ion displays rapid reorientational motion over the entire temperature range studied, i.e., also well below the glass transition temperature, Tg. Two types of rotational motion were revealed from the time evolution of the reorientational correlation function which shows a change of behaviour around 0.2 ps. The fast process was attributed to a free-rotor-type motion and the slower process to reorientational diffusion. The relaxation time of the latter, τor, was observed to follow an Arrhenius temperature dependence over the range from above the melting temperature to well below Tg. It was found that τor decouples from the structural relaxation time at temperatures below ∼1.7Tg in the two systems studied.
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| 7. |
- Jacobsson, Per, et al.
(author)
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When is a polymer a polymer? A light scattering study of crossover from viscous fluidlike behaviour to chain constrained dynamics
- 1991
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In: Journal of Non-Crystalline Solids. - : Elsevier. - 0022-3093 .- 1873-4812. ; 131-133:Part 1, s. 104-108
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Journal article (peer-reviewed)abstract
- Light (Brillouin and Raman) scattering studies of a polymer (EO)n of increasing chain lenght give evidence of crossover at a length of about 25–30 backbone bonds from molecular weight Mw dependence to Mw independence in the dynamics related to the glass transition. The crossover gives an indication of the number of interacting particles and the size of the cooperatively rearranging regions in the polymer in the dynamic glass transition zone.
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| 8. |
- Konofaos, N., et al.
(author)
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Electrical characterisation of SrTiO3/Si interfaces
- 2002
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In: Journal of Non-Crystalline Solids. - 0022-3093 .- 1873-4812. ; 303:1, s. 185-189
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Journal article (peer-reviewed)abstract
- Deposition of SrTiO3 (STO) thin films by ultra-high vacuum rf magnetron sputtering was performed in order to produce high-quality STO/p-Si (1 0 0) interfaces and STO insulator layers with high dielectric constants. The deposition temperatures were in the range from room temperature to 550 °C. Capacitance-voltage (C-V) and conductance-frequency measurements showed that the dielectric constant of the films ranges from 55 to 120. C-V measurements on Al/STO/p-Si structures clearly revealed the creation of metal-insulator-semiconductor diodes. The interface state densities (Dit) at the STO/p-Si interfaces were obtained from admittance spectroscopy measurements. The samples deposited at lower temperatures revealed values of Dit between 2 × 1011 and 3.5 × 1012 eV-1 cm-2 while the higher temperature deposited samples had a higher Dit ranging between 1 × 1011 and 1 × 1013 eV-1 cm-2. The above results were also well correlated to X-ray diffraction measurements, Rutherford backscattering spectroscopy, and spectroscopic ellipsometry. © 2002 Elsevier Science Ltd. All rights reserved.
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| 9. |
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| 10. |
- Malmhäll, Roger, et al.
(author)
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Hall resistivity of a magnetic amorphous alloy : Effects of thermal cycling and annealing
- 1978
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In: Journal of Non-Crystalline Solids. - : Elsevier. - 0022-3093 .- 1873-4812. ; 28:2, s. 159-176
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Journal article (peer-reviewed)abstract
- We have studied the effects of thermal cycling and annealing on the Hall resistivity ρH and electrical resistivity ρ of an amorphous magnetic material, Metglas 2826A. Thermal cycling up to 600 K has no significant effect on ρ but changes ρH, especially at T > 300 K. Annealing at higher temperatures Ta affects ρH more strongly than it influences ρ. For Ta = 650 K the Curie temperature jumps by ∼ 300 K and this, combined with X-ray data, is regarded as being symptomatic of the onset of crystallization. It is demonstrated that, for a fixed T, the variation of the extraordinary Hall coefficient R1 is simple correlated with that of ρ for both the amorphous material and the annealed (crystallized) specimens. Furthermore, for a given Ta, the variations of R1 and ρ as functions of temperature exhibit the same formal relationship. The temperature dependence of ρ in the annealed specimens is rendered plausible in terms of recent theories of disordered materials. Room-temperature studies of electron spin resonance and the field dependence of the magnetization are also reported.
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| 11. |
- Adhikar, Subhra, et al.
(author)
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Thermodynamic analysis of gas phase chemistry in hot wire chemical vapor deposition of a-Si:H and μc-Si:H
- 2006
-
In: Journal of Non-Crystalline Solids. - : Elsevier BV. - 0022-3093 .- 1873-4812. ; 362:9-20 Spec Iss., s. 928-932
-
Journal article (peer-reviewed)abstract
- Gas phase reactions amongst filament-generated radicals play a crucial role in growth and properties of films deposited by hot wire chemical vapor deposition (HWCVD) technology. Gas phase species of interest are SiH4, H2, Si, H, SiH3, SiH2 and SiH. Partial pressures of these species for different sets of deposition conditions have been determined from the standard Gibbs free energy data. Equilibrium concentrations of the film forming precursors have been determined. The effect of the various process parameters on the equilibrium concentration of the precursors has been studied. H, Si and SiH are found to be the dominant species in gas phase above a filament temperature of 2300 K. However SiH3 and SiH2 concentration peaks are between 1900 and 2300 K, of the filament temperature
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| 12. |
- Ali, Sharafat, 1976-, et al.
(author)
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Preparation of oxynitride glasses from woody biofuel ashes.
- 2010
-
In: Journal of Non-Crystalline Solids. - : Elsevier BV. - 0022-3093 .- 1873-4812. ; 356:50-51, s. 2774-2777
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Journal article (peer-reviewed)abstract
- Oxynitride glasses have been prepared by melting woody biofuel ash from a power plant in south Sweden with addition of calcium metal as an extra modifier in a nitrogen atmosphere at 1350–1500 °C. The glasses were characterized by X-ray powder diffraction, differential thermal analysis and scanning electron microscopy. Cation and anion glass compositions were determined by energy dispersive X-ray analysis and combustion analysis, respectively. The glasses were found to be homogenous, translucent gray to black, and to contain up to 23 e/o of calcium and 5 e/o of nitrogen. The glass formation depends on the ratio of calcium metal introduction to the ash precursors. A strong exothermic reaction was observed at 650–850 °C, leading to the formation of amorphous and crystalline oxynitride phases that melt at high temperatures upon further heating. The glass densities vary between 2.76 g/cm3 and 2.92 g/cm3. The glass transition temperature was found to vary from 670 °C to 749 °C and increase linearly with the nitrogen content.
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| 13. |
- Alouhmy, M., et al.
(author)
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Random magnetic anisotropy approach in amorphous Fe88.4Zr11.6 films : Effects of hydrogen implantation
- 2021
-
In: Journal of Non-Crystalline Solids. - : Elsevier. - 0022-3093 .- 1873-4812. ; 566
-
Journal article (peer-reviewed)abstract
- The effects of hydrogen implantation on the magnetic properties in amorphous Fe88.4Zr11.6Hx films with different hydrogen contents (0≤ x≤16) were investigated. The Curie temperature increases with increasing hydrogen content while the coercivity presents an important decrease upon H implantation. Based on the analysis of the approach to saturation in magnetization, the local random anisotropy constant KL was extracted. The local random anisotropy constant decreases from 1.468 MJ/m3 to 0.667 MJ/m3 when the concentration of H increases from 0 to 16%. The ferromagnetic correlation length was found to significantly increase with increasing hydrogen content. The local anisotropy was also extracted from the coercivity based on the Alben and Becker theory, which fits reasonably with that obtained using random magnetic anisotropy approach.
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| 14. |
- Baroni, M. P. M. A., et al.
(author)
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Optical and morphological properties of porous diamond-like-carbon films deposited by magnetron sputtering
- 2006
-
In: Journal of Non-Crystalline Solids. - : Elsevier BV. - 0022-3093 .- 1873-4812. ; 352:32-35, s. 3734-3738
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Journal article (peer-reviewed)abstract
- Porous diamond-like-carbon (PDLC) thin films obtained on silicon substrate by DC low energy magnetron sputtering have been investigated by photoluminescence, transmission and reflection spectroscopy, photoacoustic and spectroscopic ellipsometry. The absorption features observed for these films show similarities with those of porous silicon (PS) as well as in the performed gradient structural pattern classification of the SFM porosity, by means of the computational GPA-flyby environment on PS and PDLC samples. The dielectric function is also calculated for the bulk diamond-like carbon using the full-potential linearized augmented plane wave method within the framework of local density approximation to density functional theory. From the measurement a low real dielectric constant of about 4.5 at 0.8 eV was found whereas the calculated e(1)(0) for the bulk diamond has a value of 5.5.
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| 15. |
- Bengtsson, F., et al.
(author)
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Alkali ion diffusion and structure of chemically strengthened TiO2 doped soda-lime silicate glass
- 2022
-
In: Journal of Non-Crystalline Solids. - : Elsevier BV. - 0022-3093 .- 1873-4812. ; 586, s. 121564-121564
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Journal article (peer-reviewed)abstract
- Diffusion kinetics and structural properties of chemically strengthened titania-doped soda-lime silicate glasses were studied by depth-resolved X-ray photoelectron spectroscopy, Raman spectroscopy and spectrophotometry. The glasses were ion exchanged, whereby Na+ in the glass was replaced by K+ in a molten salt bath, at four different treatment temperatures between 350 and 500 °C. The alkali diffusion coefficient, DK-Na, and corresponding activation energy were calculated to be between 3.26×10−12 and 4.47×10−11 cm2s−1 and between 101.1 kJmol−1 and 105.6 kJmol−1, respectively. DK-Na was observed to decrease as the TiO2 concentration was increased. Raman analysis showed Q3-silicate species with different bond lengths, which was attributed to surface compressive stresses, and increasing Si-O-Si bond angle with increasing ion exchange temperature. Ti3+ ions exist as a minor species in the glasses and its concentration depends on the TiO2 content. Deconvolution of the optical absorption spectra reveals Jahn-Teller compressive distortion of the Ti3+ octahedral coordination.
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| 16. |
- Boström, T, et al.
(author)
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Structure and morphology of nickel-alumina/silica solar thermal selective absorbers
- 2011
-
In: Journal of Non-Crystalline Solids. - : Elsevier BV. - 0022-3093 .- 1873-4812. ; 357:5, s. 1370-1375
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Journal article (peer-reviewed)abstract
- Nickel-alumina/silica thin film materials for the use in solar thermal absorbers have been investigated using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Elastic Recoil Detection Analysis (ERDA). The TEM images revealed that all layers have a very small thickness variation and that the layers are completely homogenous. High resolution images showed 5-10 nm (poly) crystalline nickel nano-particles. ERDA showed that both the silica and alumina compositions contain more oxygen than 2:1 and 3:2 respectively. SEM showed the surface morphology and characteristics of the top silica anti-reflection layer. Hybrid-silica has showed to generate a smoother surface with less cracking compared to pure silica. The final curing temperature revealed to be of importance for the formation of cracks and the surface morphology.
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| 17. |
- Brohede, Ulrika, et al.
(author)
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Percolation phenomena in controlled drug release matrices studied by dielectric spectroscopy and the alternating ionic current method
- 2007
-
In: Journal of Non-Crystalline Solids. - : Elsevier BV. - 0022-3093 .- 1873-4812. ; 353:47-51, s. 4506-4514
-
Journal article (peer-reviewed)abstract
- The combined radial and axial ionic drug release from – as well as the percolating ionic conductivity in – cylindrical tablets was investigated by the alternating ionic current (AIC) method and dielectric spectroscopy (DS), respectively. The binary tablets consisted of mixtures of insulating ethyl cellulose and the poor ionic conductor model drug NaCl at nine different concentrations. We found that the dc conductivity, extracted from DS in a well-defined range of frequencies by a power-law method, could be described by a NaCl volume fraction percolation threshold of 0.06 in a 3D conducting network. The low threshold was explained by water-layer-assisted ion conduction in μm-sized ethyl cellulose channels between NaCl grains as probed by Hg porosimetry and SEM. The drug release process, as probed by AIC, could be described by a matrix porosity percolation threshold of 0.22, equivalent to a NaCl volume fraction of 0.13. The higher percolation threshold found in the drug release experiments as compared to the DS recordings could be explained by the different probing mechanisms of the analysis methods. The present study should provide valuable knowledge for the analysis of a broad class of ion conducting systems for which the frequency response of the dc ion conductivity is superimposed on other dielectric processes in the dielectric spectrum. It also brings forward knowledge important for the development of controlled drug-delivery vehicles as the presented findings show that the drug release from matrix tablets with unsealed tablet walls substantially differs from earlier investigated release processes for which the drug has only been allowed to escape through one of the flat tablet surfaces.
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| 18. |
- Dastanpour, E., et al.
(author)
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On the glass forming ability (GFA), crystallization behavior and soft magnetic properties of nanomet-substituted alloys
- 2020
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In: Journal of Non-Crystalline Solids. - : ELSEVIER. - 0022-3093 .- 1873-4812. ; 529
-
Journal article (peer-reviewed)abstract
- This study was aimed to investigate the effect of substitution of Fe with Co, C, and Mo on the glass forming ability (GFA), crystallization behavior, and magnetic properties of Fe-B-Si-P-Cu (Nanomet) alloy. The thermodynamic parameters, P-HS and P-HSS, were used to guide towards increased GFA. The P-HSS enhanced from -2.04 kJ/mol for Nanomet to -4.83 kJ/mol for a Co4C1Mo1 (at.%) substituted alloy. As a result, the critical quench rate reduced significantly, manifested as a drop of the required rotational speed from 3000 rpm to 2000 rpm. The temperature interval between two crystallization peaks enlarged for the substituted alloy, allowing a broader annealing range for nanocrystallization. The saturation magnetization (M-S) and the coercivity (H-C) were nearly maintained. This work confirms the relevance of the parameters P-HS and P-HSS to improve the GFA of the Nanomet alloy, and it is suggested that the same strategy can be applied for other alloys.
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| 19. |
- Duenas, S., et al.
(author)
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Selection of post-growth treatment parameters for atomic layer deposition of structurally disordered TiO2 thin films
- 2008
-
In: Journal of Non-Crystalline Solids. - : Elsevier BV. - 0022-3093 .- 1873-4812. ; 354:2-9, s. 404-408
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Journal article (peer-reviewed)abstract
- Routes to atomic layer-deposited TiO2 films With decreased leakage have been studied by using electrical characterization techniques. The combination of post-deposition annealing parameters, time and temperature, which provides measurable aluminum-titanium oxide-silicon structures - i.e., having capacitance-voltage curves which show accumulation behavior - are 625 degrees C, 10 min for p-type substrates, and 550 degrees C, 10 min for n-type substrates. The best annealing conditions for p-type substrates are 625 degrees C with the length extended to 30 min, which produces an interfacial state density of about 5-6 x 10(11) cm(-2) eV(-1), and disordered-induced gap state density below our experimental limits. We have also proved that a post-deposition annealing must be applied to TiO2/HfO2 and HfO2/TiO2/HfO2 stacked structures to obtain adequate measurability conditions.
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| 20. |
- Edén, Mattias, et al.
(author)
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The split network analysis for exploring composition-structure correlations in multi-component glasses : II. Multinuclear NMR studies of alumino-borosilicates and glass-wool fibers
- 2011
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In: Journal of Non-Crystalline Solids. - : Elsevier BV. - 0022-3093 .- 1873-4812. ; 357:6, s. 1587-1594
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Journal article (peer-reviewed)abstract
- The preceding part [M. Edén, J. Non.-Cryst. Solids, 357, (2011) 1595-1602] introduced the "split network" strategy for estimating the network polymerization degree (r A) and mean number of bridging oxygen (BO) atoms (N̄BOA) for a network former A, given that these parameters are known for all other network builders in the multi-component oxide glass. However, as the detailed ordering of BO and non-bridging oxygen (NBO) species is often difficult to assess experimentally, we summarize some "rules of thumb" for predicting the coordination number and tendency to accept NBO ions for Al 3+, B 3+, Si 4+ and P 5+ cations: they are helpful in scenarios devoid of experimental data. Using the parameters r and N̄BO, we present expressions for the BO/NBO distributions among tetrahedrally coordinated cations, as predicted from the binary and random models. Multinuclear 11B, 27Al and 29Si solid-state NMR is exploited to derive the split network representations of a set of Na-Ca-(Al)-(B)-Si-O glasses. These results are subsequently used to gain structural insight into two commercial glass-wool fibers that constitute alumino-borosilicate networks modified by Na +, K +, Ca 2+ and Mg 2+ ions. © 2010 Elsevier B.V.
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| 21. |
- Edén, Mattias
(author)
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The split network analysis for exploring composition-structure correlations in multi-component glasses : I. Rationalizing bioactivity-composition trends of bioglasses
- 2011
-
In: Journal of Non-Crystalline Solids. - : Elsevier BV. - 0022-3093 .- 1873-4812. ; 357:6, s. 1595-1602
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Journal article (peer-reviewed)abstract
- We present a strategy, referred to as “split network” analysis, for assessing the average network polymerization (r(F)) and mean number of bridging oxygen (BO) atoms ( (N) over bar (F)(BO)) for each individual network former F in multi-component oxide-based glasses, primarily targeting those involving Al, B, P and Si. This requires a priori knowledge about the parameters (r(F), (N) over bar (F)(BO)) of all network builders, but one, whose values are deduced by the split network procedure. We illustrate split-network concepts for establishing composition/structure/bioactivity correlations in Na-Ca-Si-P-O glasses. The cooperating influences on the bioactivity from the average polymerization degree of the silicate network and the amounts of orthophosphate and sodium ions are discussed.
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| 22. |
- Ericsson, A., et al.
(author)
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Crystallization of a Zr-based metallic glass produced by laser powder bed fusion and suction casting
- 2021
-
In: Journal of Non-Crystalline Solids. - : Elsevier. - 0022-3093 .- 1873-4812. ; 571
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Journal article (peer-reviewed)abstract
- The crystallization behaviour during low temperature annealing of samples of the Zr59.3Cu28.8Al10.4Nb1.5 (at%) bulk metallic glass produced by suction casting and the laser powder bed fusion (LPBF) process were studied with small angle neutron scattering (SANS), X-ray diffraction and scanning electron microscopy. The in-situ SANS measurements during isothermal annealing reveals that the phase separation in the LPBF processed material proceeds at a smaller characteristic length-scale than the cast material. Quantitative analysis of the SANS data shows that, while the crystallization process in both materials proceed through rapid nucleation followed by diffusion limited growth, the LPBF processed material crystallizes with a smaller cluster size and at a higher rate. The smaller cluster size is attributed to the elevated oxygen content in the LPBF processed material which reduces the nucleation barrier and thus the thermal stability.
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| 23. |
- Es-Soufi, H., et al.
(author)
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Structure, thermal analysis and optical properties of lithium tungsten-titanophosphate glasses
- 2017
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In: Journal of Non-Crystalline Solids. - : Elsevier. - 0022-3093 .- 1873-4812. ; 463, s. 12-18
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Journal article (peer-reviewed)abstract
- A melt-quenching method is used to prepare homogeneous glasses inside the 20Li(2)O-(50-x)Li2WO4-xTiO(2)-30P(2)O(5) (x = 0, 5, 8,10 and 15 mol%) system. The amorphous and glassy states of the glasses are evidenced by the X-ray diffraction and differential scanning calorimetry (DSC) analysis, respectively. The glasses were found to be colorless. The determined parameters for the glasses such as density, molar volume and glass transition temperature (T-g) depend strongly on the chemical composition of the glasses. The density and T-g are found to decrease and increase with TiO2 content, respectively. Infrared (IR) spectroscopy is used to characterize their structural approach. This technique has allowed the identification of different phosphate structural units mainly pyrophosphate and metaphosphate in their structure. From the absorption edge studies, the values of the optical band gap, E-g, and Lirbach energy, Delta E, were evaluated. The optical band gap is found to depend on the glass composition and it decreases as the content of the TiO2 increases. (C) 2017 Elsevier B.V. All rights reserved.
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| 24. |
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| 25. |
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