Non-linear dissolution mechanisms of sodium calcium phosphate glasses as a function of pH in various aqueous media
| Autor: | Serena M. Best, Xiang C. Zhang, Ruth E. Cameron, Kalliope Margaronis, Reece N. Oosterbeek |
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| Přispěvatelé: | Oosterbeek, Reece [0000-0002-2412-4505], Best, Serena [0000-0001-7866-8607], Cameron, Ruth [0000-0003-1573-4923], Apollo - University of Cambridge Repository |
| Rok vydání: | 2020 |
| Předmět: |
Dissolution rate
Materials science Sodium FOS: Physical sciences chemistry.chemical_element 02 engineering and technology Calcium 01 natural sciences chemistry.chemical_compound 0103 physical sciences Materials Chemistry Dissolution mechanism Dissolution Calcium-phosphate glass 010302 applied physics Condensed Matter - Materials Science Aqueous medium Materials Science (cond-mat.mtrl-sci) Transition time Dissolution behaviour 021001 nanoscience & nanotechnology Phosphate Phosphate glass Glass dissolution chemistry Chemical engineering Ceramics and Composites 0210 nano-technology Layer (electronics) |
| DOI: | 10.17863/cam.57806 |
| Popis: | Phosphate glasses for bioresorbable implants display dissolution rates that vary significantly with composition, however currently their mechanisms of dissolution are not well understood. Based on this systematic study we present new insights into these mechanisms. Two-stage dissolution was observed, with time dependence initially parabolic and later linear, and a two-stage model was developed to describe this behaviour. Dissolution was accelerated by lower Ca concentration in the glass, and lower pH in the dissolution medium. A new dissolution mechanism is proposed, involving an initial stage where diffusion-controlled formation of a conversion layer occurs. Once the conversion layer is stabilised, layer dissolution reactions become rate-limiting. Under this mechanism the transition time is sensitive to the nature of the conversion layer and solution conditions. These results reveal the dependence of P$_{2}$O$_{5}$-CaO-Na$_{2}$O glass dissolution on solution pH, and provide new insight into the dissolution mechanisms, particularly regarding the transition between the two dissolution stages. 21 pages, 17 figures |
| Databáze: | OpenAIRE |
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