The effect of composition on the viscosity, crystallization and dissolution of simple borate glasses and compositional design of borate based bioactive glasses |
Posted on:2015-09-11 | Degree:Ph.D | Type:Dissertation |
University:Missouri University of Science and Technology | Candidate:Goetschius, Kathryn Lynn | Full Text:PDF |
GTID:1471390020452505 | Subject:Materials science |
Abstract/Summary: | |
Borate glasses have recently been developed for a variety of medical applications, but much less is known about their structures and properties than more common silicate glasses. Melt properties and crystallization tendency for compositions in the Na2O-CaO-B2O3 system were characterized using differential thermal analysis and viscosity measurements. Characteristic viscosity (isokom) temperatures varied with the ratio between the modifier content (Na2O+CaO) and B2O3, particularly at lower temperatures, consistent with the changes in the relative concentrations of tetrahedral borons in the glass structure.;Similar glasses were used to study dissolution processes in water. These alkali-alkaline earth glasses dissolve congruently and follow linear dissolution kinetics. The dissolution rates were dependent on the glass structure, with slower rates associated with greater fractions of four-coordinated boron. For glasses with a fixed alkaline earth identity, the dissolution rates increased in the order Li |
Keywords/Search Tags: | Dissolution, Glasses, Viscosity, Crystallization |
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