Crystallization of iron phosphate glasses containing up to 19 wt.% UO2.67
C.J.R. GONZÁLEXZ OLIVER; F.C. LOVEY; A. CANEIRO; D.O. RUSSO; D.S. RODRIGUEZ; J.E. FISCINA; J.MA RINCON
JOURNAL OF NON-CRYSTALLINE SOLIDS
ELSEVIER SCIENCE BV
Lugar: Amsterdam; Año: 2010 vol. 356 p. 2986 - 2986
Six new glasses having 4565wt.% P2O5, 1842% Fe2O3, 6.218.7%UO2.67 and about 6% (Na2O+Al2O3+MgO)were finally obtained aftermelting the batches in Al2O3/MgO crucibles. The higher TgTSOFT valueswere obtainedfor glasses AR6 (main components: 57.3%P2O5. 18.4%Fe2O3. 18.9%UO2.67) and AR7 (mc: 65%P2O5, 19%Fe2O3,9.5%UO2.67) and were the most stable glasses against crystallization. The lowest thermal expansion α wasmeasured for AR1 (mc: 54%P2O5, 27%Fe2O3, 13.5%UO2.67). AR7 was the least chemically durable composition,whereas the most durable glasses were those containing the highest percentages of UO2.67 (AR6, AR1 andAR5). The least stable glasses against crystallization were AR4 (mc: 45.8% P2O5, 42.2%Fe2O3, 6.4%UO2.67),AR5 (mc: 46.2%P2O5. 35.4%Fe2O3. 13.0%UO2.67) and AR2 (mc: 54.2% P2O5, 33.1%Fe2O3, 6.4%UO2.67); their DTAcrystallization (Tc) peaks were met at 560 °C (AR4), 600 °C (AR5) and 620 °C (AR2). For these glasses Tcincreased with UO2.67 increasing. The highest internal crystallizations were met for AR2 and AR5. Dendriticcrystal growth mode was detected for slowly heat treated (up to 650 °C) AR5 glass. The dendrite arms wereclearly seen by SEM and the EBSD (electron back scattered diffraction) patterns (fitted to phase FePO4)remained unaltered upon moving slightly the detection position throughout those arms.