Structure and Crystallization Study of Iron Phosphate Glasses

Moguš‐Milanković, Andrea; Day, Delbert E.; Furić, Krešimir

doi:10.4028/www.scientific.net/kem.132-136.2212

Cited by 51 publications

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“…Since the charge carrier concentrations are related to the iron ion content, the decrease in s dc is attributed to a decrease in the number of carriers with decreasing iron content. These results agree with previously reported ones [33][34][35] where s dc for alkaline earth-free iron phosphate glasses is attributed to the migration of polarons and charge transport can be visualized as carriers hopping a distance between the phosphate chains. The hopping conductivity depends upon the distance between iron ions and the conductivity is less than that in ionic conductive glass [32].…”

Section: Conductivity and Activation Energysupporting

confidence: 83%

“…10) no mixed alkali effect on s dc would be expected when the glasses do not contain any alkali (like Li, Na, K, Rb), unlike that observed in many mixed oxide glasses such as mixed alkali-containing silicate glasses [35]. We suggest that the absence of a mixed alkali effect is due to the Ca and Ba ions in these iron phosphate glasses being immobile.…”

Section: Conductivity and Activation Energymentioning

confidence: 68%

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Electrical Conductivity in Mixed Calcium and Barium Iron Phosphate Glasses

El‐Desoky

Kashif

2002

phys. stat. sol. (a)

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The electrical properties of xCaO–(20 — x)BaO–20Fe2O3–60P2O5 glasses with x = 0, 5, 10, 15 and 20 mol% have been studied in the frequency range 400 Hz–200 kHz and over a temperature range 323–593 K. The ac conductivity as a function of temperature was divided into two domains, one where the absolute magnitude of the ac conductivity was close to the dc conductivity and another where it was larger than the dc conductivity. At the same temperature, the dc conductivity varied only slightly in glasses with different CaO and BaO content. It is concluded that the conductivity in these mixed CaO and BaO iron phosphate glasses is electronic and depends upon the Fe2+/(Fe2+ + Fe3+) ratio. In the high‐temperature region above θD/2 (where θD is the Debye temperature) the Mott model of small polaron hopping (SPH) between nearest neighbours is consistent with the conductivity data, while at low temperature (below θD) the Greaves intermediate variable‐range hopping (VRH) model is found to be appropriate. The electrical conduction of the glasses is confirmed to be non‐adiabatic SPH. Mössbauer spectral analysis indicates the presence of both Fe2+ and Fe3+ ions.

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Section: Conductivity and Activation Energysupporting

confidence: 83%

Section: Conductivity and Activation Energymentioning

confidence: 68%

Electrical Conductivity in Mixed Calcium and Barium Iron Phosphate Glasses

El‐Desoky

Kashif

2002

phys. stat. sol. (a)

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“…[20] The Raman bands have been assigned using literature data for various glasses and crystalline materials. [6,24,25] Also, crystalline phases formed during heat treatment originate from the dominant phosphate structural units present in the starting glass. Therefore, the Raman bands for as-received glasses fall into similar ranges with the corresponding heat treated samples indicating some structural similarities between glassy and corresponding crystalline compounds.…”

Section: Raman Spectroscopymentioning

confidence: 99%

Iron Phosphate Glass-ceramics

Moguš‐Milanković¹,

Šantić²,

Pavić³

et al. 2015

Croat. Chem. Acta

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Abstract:The crystallization of 40Fe2O3-60P2O5, 10ZnO-30Fe2O3-60P2O5 and (43.3−x)PbO-(13.7+x)Fe2O3-43P2O5, (0 < x < 30), glasses and glassceramic have been investigated. The structural evolution of glasses during heat treatment at various temperatures and the tendency for crystallization for series of glasses with modified composition are characterized by a dendrite-like phase separation in the early stage of crystallization. Such a behavior leads to the formation of randomly dispersed agglomerates which contain the anhedrally shaped crystallites embedded in glass matrix. Therefore, regardless of the type of crystallization, controlled or spontaneous, the formation of crystalline phases in these phosphate glasses and glass-ceramics is attributed to the disordered interfaces between crystalline grains and glassy matrix.

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“…The dielectric constant and the tangent loss of the TeO 2 -P 2 O 5 system were investigated [2] in the frequency range of 0.1-10 kHz and different isotherms. Structural changes of meta-phosphates to pyro-and ortho-phosphates with increasing Fe 2 O 3 content in the P 2 O 5 glass were studied [3,4]. Also, the doping of Nd 3þ ion in phosphate glasses for fiber laser technologies [5] and the addition of some additives such as alumina, boric, lead, zinc, alkaline rare-earth and transition metal oxides into phosphate matrices improved their chemical durability to be suitable for sealing to medium and low expansion materials [6].…”

Section: Introductionmentioning

confidence: 99%

Infrared and Ultrasonic Investigations of Some [(MnO2)x-(P2O5)100?x] � 1 wt% Nd2O3 Glasses

Khafagy

2001

phys. stat. sol. (a)

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Infrared (IR) absorption spectroscopy and ultrasonic pulse-echo techniques are employed for studying optical and mechanical properties of some manganese-phosphate glasses doped with 1 wt% Nd 2 O 3 . IR spectra in the range 4000 to 200 cm À1 were recorded at room temperature and the effect of composition on the observed and assigned absorption bands is investigated. Variations of mid-band positions of those absorption bands with the MnO 2 content showed three composition regions, up to 20, 20-40 and 40-60 mol% MnO 2 . Ultrasonic measurements were carried out at 3 MHz frequency showing that the ultrasonic attenuation and the glass density are sensitive to the glass composition and behave conversely to each other. The results indicate that the longitudinal wave velocity and the longitudinal elastic modulus show the same trend with composition. However, the results of the ultrasonic measurements confirmed the occurrence of an anomalous behavior of the three composition regions observed in the IR investigations.

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Structure and Crystallization Study of Iron Phosphate Glasses

Cited by 51 publications

References 0 publications

Electrical Conductivity in Mixed Calcium and Barium Iron Phosphate Glasses

Electrical Conductivity in Mixed Calcium and Barium Iron Phosphate Glasses

Iron Phosphate Glass-ceramics

Infrared and Ultrasonic Investigations of Some [(MnO2)x-(P2O5)100?x] � 1 wt% Nd2O3 Glasses

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