Title

Electrical Conductivity and Structural Properties of Cesium Iron Phosphate Glasses: A Potential Host for Vitrifying Nuclear Waste

Abstract

The thermally stimulated current (TSC) and dc conductivity for iron phosphate glasses containing up to 28 mol% Cs2O have been measured in a temperature range from 120 to 400 K. The dc conductivity and activation energy were constant and independent of Cs2O content. With increasing cesium concentration in cesium iron phosphate glasses the slowly moving cesium ions are more tightly bound to the non-bridging oxygen ions and make no measurable contribution to dc conductivity. The dc conduction in these glasses is totally electronic, controlled by electron hopping between iron ions. The ionic conduction is immeasurably small because of the low mobility of the cesium ions. This agreement is reinforced by the excellent chemical durability of the glasses, where the dissolution rate at 90°C changes little with increasing Cs2O content. Raman spectroscopy indicated that the structure of these glasses was composed of predominantly pyrophosphate (P2O7) groups, but the metaphosphate chains (PO3) also existed.

Meeting Name

Scientific Basis for Nuclear Waste Management XXIV (2000: Aug. 27-31, Sydney, Australia)

Department(s)

Materials Science and Engineering

Keywords and Phrases

Activation energy; Carrier mobility; Cesium; Electric conductivity; Electric currents; Ionic conduction; Radioactive wastes; Raman spectroscopy; Thermal effects; Phosphate glasses

International Standard Serial Number (ISSN)

2729172

Document Type

Article - Conference proceedings

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2001 Materials Research Society (MRS), All rights reserved.

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