Structure of sodium phosphate glasses containing Al2O3 and/or Fe2O3. Part I

Moguš‐Milanković, Andrea; Gajović, Andreja; Šantić, Ana; Day, Delbert E.

doi:10.1016/s0022-3093(01)00701-3

Cited by 118 publications

(64 citation statements)

References 11 publications

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“…The Raman bands in the 1000−1300 cm −1 range are due to the symmetric and asymmetric stretching modes of P-non-bridging oxygen bonds, whereas bands in the 680−720 cm −1 range are due to the symmetric and asymmetric stretching modes of bridging oxygen atoms. 17,18 With increasing Fe 2 O 3 content the frequency of the most prominent stretching mode of non-bridging oxygen decreases consistently, from 1200 cm −1 (symmetric PO 2 stretch in Q 2 tetrahedra) to 1071 cm 5−7 Simultaneously, with the increase of Fe 2 O 3 content, the crystallization tendency of the glass increases. The competition of these unwanted properties, defines the optimal glass composition, namely 40Fe 2 O 3 -60P 2 O 5 (mol %), which exhibits excellent chemical durability and low crystallization tendency.…”

Section: Binary Iron Phosphate Glasses Structurementioning

confidence: 95%

Charge Carrier Dynamics in Materials with Disordered Structures: A Case Study of Iron Phosphate Glasses

Šantić¹,

Moguš‐Milanković²

2012

Croat. Chem. Acta

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Abstract. Materials with disordered structures have a crucial role in the rapid development of new technologies. Improvement of these materials for particular application, as well as preparation of novel composites is based on a thorough understanding of the basic mechanisms of charge carrier transport. Among various classes of structurally disordered materials, a family of iron phosphate glasses attracts special attention due to their unique combination of structural, electrical and mechanical properties. Generally, iron phosphate glasses are electronically conducting glasses with polaronic conduction mechanism where conduction takes place by electrons hopping from Fe 2+ to Fe 3+. Consequently, polaron transport directly depends on Fe 2+ /Fe tot ratio and overall Fe 2 O 3 content. However, by altering composition (addition of Cr 2 O 3 , MoO 3 , PbO, Na 2 O) and preparation conditions, the electrical conductivity of iron phosphate based glasses may vary over many orders of magnitude. This paper gives an overview of our recent studies of electronic and ionic transport in iron phosphate based glasses. (doi: 10.5562/cca1989)

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Section: Binary Iron Phosphate Glasses Structurementioning

confidence: 95%

Charge Carrier Dynamics in Materials with Disordered Structures: A Case Study of Iron Phosphate Glasses

Šantić¹,

Moguš‐Milanković²

2012

Croat. Chem. Acta

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“…Those authors state that the band is indicative of Q 2 species arising from disproportionation of Q 1 species to Q 0 and Q 2 species. Literature for a range of modifier-containing phosphate glasses shows a commonly-occurring band centered at ∼690 cm −1 with a broad tail stretching towards higher Raman Shifts [21], [47], [54] and [55]. This band has also been attributed to symmetric stretching of bridging oxygens (P-O-P)sym in Q 2 species.…”

Section: Raman 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

168

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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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“…Third, the dissolution behavior was studied in similar glass matrices. In particular, in phosphate [ 33 ] and zinc phosphate [ 34 ] matrices, the dissolution rate is on the order of 1 μ g cm − 2 min − 1 . These measurements show that the tolerance to humidity of these glass matrices is compatible with data storage applications.…”

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confidence: 99%

Silver Clusters Embedded in Glass as a Perennial High Capacity Optical Recording Medium

et al. 2010

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Structure of sodium phosphate glasses containing Al2O3 and/or Fe2O3. Part I

Cited by 118 publications

References 11 publications

Charge Carrier Dynamics in Materials with Disordered Structures: A Case Study of Iron Phosphate Glasses

Charge Carrier Dynamics in Materials with Disordered Structures: A Case Study of Iron Phosphate Glasses

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

Silver Clusters Embedded in Glass as a Perennial High Capacity Optical Recording Medium

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