Glass Preparation and Characterization

1. BSE image Fe map Fe2O3+FePO4… P map Fe3PO7 Stability, Durability and Crystallization of Iron Phosphate GlassesMark E. Schlesinger, University of Missouri–Rolla, DMR 0502463 Glass Preparation and Characterization • Annealed thin–film glasses to produce glass compositions in Fe–P–O system (high-Fe, high-Fe2+/Fe3+) not previously achieved. • Demonstrated ability to change redox condition and crystallization behavior through post-melt heat treatments. • Demonstrated effects of “aging” and particle size on crystallization behavior of iron phosphate glasses. UV-Vis spectra showing change in redox condition with heat treatment. Phase Equilibria in Iron Phosphate Systems • Ten pure compounds synthesized successfully (ferric, ferrous and ferric–ferrous phosphates). Disproved existence of two compounds originally claimed in system. • Revision of Fe2O3–P2O5 phase diagram in progress (major changes from 1935 original). • Building block toward thermodynamic characteri-zation of Fe -P–O system, prediction of phases crystallizing from glasses. Decomposition of FePO7 quenched from 1200°C.

2. Stability, Durability and Crystallization of Iron Phosphate Glasses: A CIAM CollaborationMark E. Schlesinger, University of Missouri–Rolla, DMR 0502463 International collaborators: Dr. Edgar Zanotto (Univ. São Carlos, Brazil), studying crystallization kinetics of iron phosphate glasses prepared at UMR Dr. Miguel Prado (Bariloche, Argentina), studying corrosion of iron phosphate glasses prepared at UMR Liying Zhang (left) at MST meeting presenting poster on thermal behaviors of FePO4.Melodie Schmitt (right) at ICG meeting in France presenting research results. Both PhD candidates mentor undergraduate research assistants.