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 P₂O₅–CaO–Na₂O glass dissolution on solution pH, and provide new insight into the dissolution mechanisms, particularly regarding the transition between the two dissolution stages.

用于生物可吸收植入物的磷酸盐玻璃的溶出速率随组成的变化而显着变化，但是目前尚不十分了解其溶出机理。基于这项系统的研究，我们提出了对这些机制的新见解。观察到两阶段的溶解，时间依赖性最初是抛物线的，后来是线性的，并且建立了一个两阶段的模型来描述这种行为。玻璃中较低的Ca浓度和较低的溶解介质pH可以促进溶解。提出了一种新的溶解机理，其涉及发生扩散控制的转化层形成的初始阶段。一旦转化层稳定，层溶解反应就成为速率限制。在这种机制下，过渡时间对转化层的性质和溶液条件很敏感。这些结果揭示了P的依赖性₂ O ₅ -CaO-Na ₂ O玻璃在溶液pH值上的溶解，并为溶解机理提供了新的见解，尤其是关于两个溶解阶段之间的过渡。