engleski

Insight into Crystallization of Iron Phosphate Glasses

Crystallization of 40Fe2O3-60P2O5 glass and its effects on electrical conductivity have been studied by XRD, DTA, SEM and IS. The conductivity was measured for as-quenched glass and after thermal treatment up to 800 °C. XRD has shown barely detectable beginning of crystallization at 490 °C. With increasing annealing temperature, these glasses turned into nanomaterials consisting of crystallites FePO4 embended in glassy matrix. Formation of nanocrystallites leads to an enhancement of glass matrix conductivity as compared with the as-quenched glass. Heat treatment at 650 °C causes massive crystallization. Formation of Fe3(P2O7)2 microcrystallites causes a drop of electrical conductivity due to the blocking of the conduction pathwas at crystal/glass matrix interfaces. Further thermal treatment at 724 and 804 °C leads ti predominant growth of Fe3(P2O7)2 crystals. Increase of electrical conductivity of this glass-ceramics is explained by strengthening of the inetraction between Fe sites in crystalline phases.

Crystallization; Iron Phosphate Glasses; Electrical Conductivity

nije evidentirano