Elaboration and Characterization of Glasses and Ceramic-Glasses within Theternary Diagram Lisub2/subO-Crsub2/subOsub3/sub-Psub2/subOsub5/sub

摘要

Use of the regular melting-quench method allowed the isolation of a small glass domain within the ternary system Li2O-P2O5-Cr2O3 at 1000°C. Electrical conductivity and dielectric permittivity measures on sample glasses and ceramic glasses of this domain were performed at a frequency of 10 kHz and at temperatures between 25°C and 300°C. The values of dielectric permittivity and electrical conductivity increase with increasing Li2O content. However, increases of Cr2O3 content, even at low concentrations, induce a change in electrical conductivity behaviour from that of a glass to that of a ceramic glass. The introduction of an increasing amount of Li2O content in vitreous phosphorus pentoxide changes its three-dimensional network;rupture of the P-O-P bond then occurs and there is formation of easily polarisable entities with quite high values of . The vibrational spectroscopy technique I.R has allowed an efficient investigation of the structural change versus composition within the above indicated ternary diagram. The maximal dielectric permittivity obtained at 300°C, both for the glasses and for the ceramic glasses varied in the order 104 to 3 × 105, while the maximum electrical conductivity obtained at 300°C for the ceramic glasses was in the order of 10-3 Ωcm-1.