Properties and structure of sodium-iron phosphate glasses

Yu, Xie; Day, Delbert E.; Long, Gary J.; Brow, Richard K.

doi:10.1016/s0022-3093(97)00022-7

Cited by 272 publications

(201 citation statements)

References 15 publications

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“…Fitted values of Center Shift (CS) and Quadrupole Splitting (QS), shown in Table 1 and Table 2, are similar to published values for other iron phosphate glasses [6], [7], [9], [10], [12], [13], [15], [17], [18], [20], [31] and [32] and are consistent with the conclusion that both Fe 2+ and Fe 3+ predominantly occupy a range of distorted octahedral sites in all of the modified iron phosphate glasses studied here. Sites with lower coordination numbers may also be present; however, the Mössbauer results indicate that their abundance is relatively low.…”

Section: Fe Mössbauer Spectroscopysupporting

confidence: 76%

“…Sites with lower coordination numbers may also be present; however, the Mössbauer results indicate that their abundance is relatively low. X-ray absorption spectroscopy, neutron diffraction and X-ray diffraction studies of a range of binary, ternary and modified iron phosphate glasses have provided average Fe-O coordination numbers from 4.8 to 5.5 [15], [16], [17], [18], [56], [57], [58], [59], [60] and [61] are consistent with those from other studies of iron phosphate glasses which have concluded that the near-neighbor local environment of iron is not greatly affected by the addition of modifier cations [16], [17], [18], [56], [57], [58], [59] and [60].…”

Section: Fe Mössbauer Spectroscopymentioning

confidence: 99%

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Effects of modifier additions on the thermal properties, chemical durability, oxidation state and structure of iron phosphate glasses

Bingham

Hand

Hannant

et al. 2009

Journal of Non-Crystalline Solids

169

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Modified iron phosphate glasses have been prepared with nominal molar compositions [(1−x)·(0.6P2O5-0.4Fe2O3)]·xRySO4, where x = 0-0.5 in increments of 0.1 and R = Li, Na, K, Mg, Ca, Ba, or Pb and y = 1 or 2. In most cases the vast majority or all of the sulfate volatalizes and quarternary P2O5-Fe2O3-FeO-RyOz glasses or partially crystalline materials are formed. Here we have characterized the structure, thermal properties, chemical durability and redox state of these materials. Raman spectroscopy indicates that increasing modifier oxide additions result in depolymerization of the phosphate network such that the average value of i, the number of bridging oxygens per -(PO4)-tetrahedron, and expressed as Q i , decreases. Differences have been observed between the structural effects of different modifier types but these are secondary to the amount of modifier added. Alkali additions have little effect on density; slightly increasing Tg and Td; increasing α and Tliq; and promoting bulk crystallization at temperatures of 600-700 °C.Additions of divalent cations increase density, α, Tg, Td, Tliq and promote bulk crystallization at temperatures of 700-800 °C. Overall the addition of divalent cations has a less deleterious effect on glass stability than alkali additions.57 FeMössbauer spectroscopy confirms that iron is present as Fe 2+ and Fe 3+ ions which primarily occupy distorted octahedral sites. This is consistent with accepted structural models for iron phosphate glasses. The iron redox ratio, Fe 2+/ΣFe, has a value of 0.13-0.29 for the glasses studied. The base glass exhibits a very low aqueous leach rate when measured by Product Consistency Test B, a standard durability test for nuclear waste glasses. The addition of high quantities of alkali oxide (30-40 mol% R2O) to the base glass increases leach rates, but only to levels comparable with those measured for a commercial soda-lime-silica glass and for a surrogate nuclear waste-loaded borosilicate glass. Divalent cation additions decrease aqueous leach rates and large additions (30-50 mol% RO) provide exceptionally low leach rates that are 2-3 orders of magnitude lower than have been measured for the surrogate waste-loaded borosilicate glass. The P2O5-Fe2O3-FeO-BaO glasses reported here show particular promise as they are ultra-durable, thermally stable, lowmelting glasses with a large glass-forming compositional range.

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Section: Fe Mössbauer Spectroscopysupporting

confidence: 76%

Section: Fe Mössbauer Spectroscopymentioning

confidence: 99%

Effects of modifier additions on the thermal properties, chemical durability, oxidation state and structure of iron phosphate glasses

Bingham

Hand

Hannant

et al. 2009

Journal of Non-Crystalline Solids

169

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“…Of more technological interest is the development of ternary systems such as the Na 2 O−CaO−P 2 O 5 system, which has been investigated extensively [12,38,39], and also the Na 2 O-Fe 2 O 3 -P 2 O 5 system [40], an extension of the developmental work on the binary Fe 2 O 3 -P 2 O 5 system [41] as a possible system for the encapsulation of nuclear waste.…”

Section: Phosphate-based Glass Structurementioning

confidence: 99%

Titanium-containing bioactive phosphate glasses

Kiani

Lakhkar

Salih

et al. 2012

Phil. Trans. R. Soc. A.

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The use of biomaterials has revolutionized the biomedical field and has received substantial attention in the last two decades. Among the various types of biomaterials, phosphate glasses have generated great interest on account of their remarkable bioactivity and favourable physical properties for various biomedical applications relating to both hard and soft tissue regeneration. This review paper focuses mainly on the development of titanium-containing phosphate-based glasses and presents an overview of the structural and physical properties. The effect of titanium incorporation on the glassy network is to introduce favourable properties. The biocompatibility of these glasses is described along with recent developments in processing methodologies, and the potential of Ti-containing phosphate-based glasses as a bone substitute material is explored.

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“…With the addition of Fe2O3 to a phosphate glass, the P−O−P bonds are replaced by more chemically durable P−O−Fe 2+ and/or P−O−Fe 3+ bonds. [5,9] In these glasses iron commonly exists in two valence states, as Fe 2+ and Fe 3+ and the Fe 2+  Fe 3+ equilibrium depends upon the melting atmosphere and the batch composition. [10,11] On the other hand, the preparation and properties of nanocrystallites embedded into glass matrix have received a considerable interest.…”

Section: Introductionmentioning

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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Properties and structure of sodium-iron phosphate glasses

Cited by 272 publications

References 15 publications

Effects of modifier additions on the thermal properties, chemical durability, oxidation state and structure of iron phosphate glasses

Effects of modifier additions on the thermal properties, chemical durability, oxidation state and structure of iron phosphate glasses

Titanium-containing bioactive phosphate glasses

Iron Phosphate Glass-ceramics

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