Title

Structural Properties of Cr₂O₃-Fe₂O₃-P₂O₅ Glasses I

Abstract

The structural properties of xCr2O3-(40 - x)Fe2O3-60P2O5, 0 ≤ x ≤ 10 (mol%) glasses have been investigated by Raman and Mössbauer spectroscopies, X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The Raman spectra show that the addition of up to 5.3 mol% Cr2O3 does not produce any changes in the glass structure, which consists predominantly of pyrophosphate, Q1, units. This is in accordance with O/P ≈ 3.5 for these glasses. The increase in glass density and Tg that occurs with increasing Cr2O3 suggests the strengthening of glass network. The Mössbauer spectra indicate that the Fe2+/Fetot ratio increases from 0.13 to 0.28 with increasing Cr2O3 content up to 5.3 mol%, which can be related to an increase in the melting temperature from 1423 to 1473 K. After annealing, the 10Cr2O3-30Fe2O3-60P2O5 (mol%) sample was partially crystallized and contained crystalline β-CrPO4 and Fe3(P2O7)2. The SEM and AFM micrographs of the partially crystallized sample revealed randomly distributed crystals embedded in a homogeneous glass matrix. EDS analysis indicated that the glass matrix was rich in Fe2O3 (39.6 mol%) and P2O5 (54.9 mol%), but contained only 5.5 mol% of Cr2O3. These results suggest that the maximum solubility of chromium in these iron phosphate melts is 5.5 mol% Cr2O3.

Department(s)

Mining and Nuclear Engineering

Second Department

Materials Science and Engineering

Keywords and Phrases

Mossbauer effect and spectroscopy; Phosphates; Raman scattering; Chromium compounds; Iron compounds; Structural properties; X ray diffraction analysis

International Standard Serial Number (ISSN)

223093

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2007 Elsevier, All rights reserved.


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