Glass formation from iron-rich phosphate melts

Low temperature heat capacity Study of Fe(PO3)3 and Fe2P2O7

“…Recently, iron phosphate compounds have attracted considerable research interest in the field of material science due to their outstanding chemical, thermal, electrical and magnetic properties [1][2][3][4][5]. Crystalline and amorphous iron phosphate materials have been developed and applied widely in various technologically important fields such as catalysis [6][7], electrochemistry [8][9][10][11], optical and magnetic materials [12][13][14][15][16], biosensor fabrication [17], bio-absorbable glass fibers [18], industrial coatings [19], and tissue engineering [20].…”

“…Crystalline and amorphous iron phosphate materials have been developed and applied widely in various technologically important fields such as catalysis [6][7], electrochemistry [8][9][10][11], optical and magnetic materials [12][13][14][15][16], biosensor fabrication [17], bio-absorbable glass fibers [18], industrial coatings [19], and tissue engineering [20]. Moreover, the high chemical durability of iron phosphate glasses makes them suitable as alternative materials for safe immobilization and permanent disposal of a variety of high-level nuclear waste [3,[21][22][23][24][25][26][27].…”

“…We have also studied the thermal stability of glasses from the (Fe 4 (P 2 O 7 ) 3 + Fe(PO 3 ) 3 ) system [4], the properties of glass formation from iron-rich phosphate melts [3], and the behaviors of phase equilibria in iron phosphate systems [1,5]. To understand further these compounds and their chemical synthesis, the study of the thermodynamic properties, especially the heat capacity and entropy, is still relevant and necessary.…”

Probing the local structural changes across the amorphous to crystalline transition in iron phosphate glass: Positron annihilation and micro Raman studies

“…These have macroscopic consequences in terms of leaching, devitrification, structural and thermal stability of the matrices. Although several reports exist addressing the crystallization kinetics, structure property relationships, nature of bonding etc using techniques like DTA, Mossbauer, Infrared, Raman and XPS [12][13][14][15][16][17], there seems to be very little understanding on the nature and evolution of defects / microstructures in these systems that lead to the various phase transformations. It is well known that positrons are unique probes that serve to understand the nature and evolution of defects at the atomistic scale [18].…”

“…Barring a few earlier reports on the study of borosilicate glass matrices [19][20][21][22] and phosphate glasses [23,24] using positrons, there seems to be no work involving the study of iron phosphate glasses using positrons in the context of nuclear waste immobilization. It is well known that crystallization kinetics of nuclear waste glasses play a vital role in determining the suitability of these glasses as nuclear waste matrices [13,16] and hence it becomes interesting to understand the microstructural evolution of defects/voids accompanying the crystalline transition. In the present work, positron lifetime measurements were carried out for the first time on discs of iron phosphate glasses (40 mol% Fe 2 O 3 ; 60 mol% P 2 O 5 ; O/P=3.5, Fe/P=0.67 -henceforth referred to as IPG) annealed at various temperatures, spanning the glass transition and crystallization temperatures to look for definite signatures signaling these transitions.…”