A structural analysis of the physical properties of bismuth and lead based glasses

摘要

We report on a series of measurements of thedensity and glass transition temperature of a variety of glassfamilies containing bismuth (III) and lead (II) oxide. Comparisonsare drawn between the binary bismuth borate and lead boratesystems and the behaviour of density and calculated molarvolumes are related to changes in the formation of fourcoordinated borons, lead tetra hedra and bismuth octahedra. Theaddition of an alkali oxide is considered in a surbstitutional studyof the xLi_2O. cB_2O_3. (1-c-x) Bi_2O_3 ternary system andthe compositional behaviour of the density of this system ismodelled using a simple mixing scheme of separate bismuth andlithium borate subnetworks. A similar investigation wasperformed on the binary bismuth and lead silicate familiesindicating larger changes in the molar volume with the additionof the metal cation. Measurements of the density and transitiontemperatures of the bismuth borosilicate family were also carriedout. For the bismuth borosilicates the overall molar volume isincreased as the amount of bismuth in the glass is increased but inthe family Z=1 (where Z is the molar ratio of silica to bora) thereis a compaction at low bismuth concentrations. A mixing modelwhich utilises independent results from the binary bismuth borateand silicate glasses was successful at reproducing the densitytrend and it pointed to a proportional 'strong mixing' of theseparate silicate and borate subnetworks.