Mixed ion–polaron transport in Na2O–PbO–Fe2O3–P2O5 glasses

Moguš‐Milanković, Andrea; Šantić, Ana; Reis, Signo Tadeu Dos; Furić, Krešimir; Day, Delbert E.

doi:10.1016/j.jnoncrysol.2004.07.012

Cited by 60 publications

(37 citation statements)

References 27 publications

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“…5 shows Kramers-Kronig corrected FTIR reflectance spectra which were composed of a number of overlapping absorption bands in the range 400-1400 cm −1 . These spectra were consistent with FTIR spectra for many other phosphate-based glasses [4,[6][7][8][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31].…”

Section: Fourier-transform Infra-red (Ftir) Reflectance Spectroscopysupporting

confidence: 81%

“…Broad absorption bands were found at ∼1020 cm −1 and 1050-1150 cm −1 with the weak, broad band at 1200-1300 cm −1 in spectra for samples B-3, B-4, P-3 and P-4. Assessment of a wide range of IR spectra indicated that as a general rule, the frequency of IR absorption bands in phosphate glasses of similar composition to ours, increases with increasing Q-value, albeit with a dependence upon the type of vibration [4,6,8,[13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31]. This could explain the change in the overall profile of spectra P-2 through P-4.…”

Section: Discussionmentioning

confidence: 59%

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Vitrified metal finishing wastes

Bingham

Hand

Forder

et al. 2005

Journal of Hazardous Materials

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Section: Fourier-transform Infra-red (Ftir) Reflectance Spectroscopysupporting

confidence: 81%

Section: Discussionmentioning

confidence: 59%

Vitrified metal finishing wastes

Bingham

Hand

Forder

et al. 2005

Journal of Hazardous Materials

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“…The new band at ∼470 cm −1 may arise from Q 0 (PO4) 3− units [52]. This suggestion is supported by interpretation of spectra for P2O5-Fe2O3-PbO-Na2O glasses by Moguš-Milanković et al [53] who claim that their band at ∼470 cm −1 arises from O-P-O bending modes of Q 0 units. It might be suggested that the 'disappearance' of the peak at ∼925 cm −1 is related to the conversion of Q 0 (PO4) 3− monomer units into more polymerized phosphate units.…”

Section: Raman Spectroscopymentioning

confidence: 55%

“…A Raman band at ∼630 cm −1 observed in spectra for P2O5-Fe2O3-FeO-Cs2O glasses [23] and for other iron phosphate glasses [28], [52] and [53], has previously been attributed to symmetric stretching of bridging oxygens (P-O-P)sym in Q 2 species. 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.…”

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

173

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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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“…Phosphate glasses doped with transitional metal (TM) ions are technologically important because of their semiconducting properties, optical absorption, electrical memory switching and photo-conducting properties. The properties that make phosphate glasses candidates for so many applications are related to their molecular-level structure [2][3][4]. A problem related to phosphate glasses containing TM oxides is related with their mixed dual role, as modifiers but also as network formers.…”

Section: Introductionmentioning

confidence: 99%

Optical, physical and structural studies of vanadium doped P2O5–BaO–Li2O glasses

Lakshmikantha

Ayachit

Anavekar

2014

Journal of Physics and Chemistry of Solids

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a b s t r a c tGlasses in the compositions (Li 2 O) 25 -(BaO) 25 -(P 2 O 5 ) 50 À x -(V 2 O 5 ) x (with x ¼0.5,1.0,1.5,2.0,2.5, and 3.0 mol %) have been prepared by the conventional melt quenching technique. X-ray powder diffractrogram show broad peaks which conforms glassy nature of the sample. Differential scanning calorimetry (DSC) thermograms show characteristic glass transition temperature (T g ) and it increases with increasing substitution of V 2 O 5 for P 2 O 5 . The measured physical parameters like density, refractive index, ionic concentration and electronic polarizability are found to vary linearly with increasing x. Infrared spectra exhibits few bands, which are attributed to (P ¼O) AS , (P¼ O) S , (V¼O), (P-O-P) AS ,P-O-V, (P-O-P) AS and O-P-O vibrations. The optical absorption spectra of VO 2 þ ions in these glasses show three bands and are assigned to the 2 B 2 -2 E, 2 B 2 -2 B 1 and 2 B 2 -2 A 1 transitions. Electron paramagnetic resonance spectra of all the glass samples exhibit resonance signals characteristic of VO 2 þ ions. The values of SpinHamiltonian parameters indicate that the VO 2 þ ions are present in octahedral sites with tetragonal compression and belong to C 4V symmetry.

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Mixed ion–polaron transport in Na2O–PbO–Fe2O3–P2O5 glasses

Cited by 60 publications

References 27 publications

Vitrified metal finishing wastes

Vitrified metal finishing wastes

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

Optical, physical and structural studies of vanadium doped P2O5–BaO–Li2O glasses

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