Effects of magnesium for calcium substitution in P₂O₅-CaO-TiO₂ glasses

详细信息    查看全文

• 作者：Hiroshi Morikawa ; Sungho Lee ; Toshihiro Kasuga ; Delia S. Brauer
• 关键词：Biomaterials ; Glasses ; Metaphosphate glasses ; Phosphate invert glasses ; Dissolution
• 刊名：Journal of Non-Crystalline Solids
• 出版年：15 November, 2013
• 年：2013
• 卷：380
• 期：Complete
• 页码：53-59
• 全文大小：1009 K

文摘

Many phosphate glasses dissolve in aqueous solutions, and they are increasingly studied for use as degradable biomaterials. As magnesium has been suggested to improve glass formation in phosphate glasses, its effect on glass structure, thermal properties and dissolution were studied. Two phosphate glass series (one in the metaphosphate range with 50 mol.% P₂O₅ and one invert series with 30 mol.% P₂O₅) in the system P₂O₅-CaO-TiO₂, where calcium was partially (0 to 100% on a molar base) replaced by magnesium, were produced by a melt-quench route.

Substitution of magnesium for calcium reduced the glass density (owing to the lower atomic weight of magnesium compared to calcium), made the phosphate network more compact, and caused Raman bands to shift to higher frequencies. Magnesium substitution significantly improved the processing of the glasses in both series by widening the processing window. The solubility of both glass series was low as shown by negligible pH changes and low ionic concentrations, with less than 7.5% of ions being released over 1 week. There were no significant differences in the solubility of the two series, which is surprising as metaphosphate glasses are generally considered to be more soluble than invert glasses. Magnesium substitution had a marked influence on invert glass dissolution, increasing the solubility about three-fold compared to the calcium-containing glasses, while no such effect was observed for metaphosphate glasses. Results suggest that magnesium substitution affects metaphosphate glasses and invert glasses differently, but improves glass formation and processing in both.