The influence of alkali and alkaline earths on the working range for bioactive glasses

✍ Scribed by Brink, Maria

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 175 KB
• Volume: 36
• Category: Article
• ISSN: 0021-9304
• DOI: 10.1002/(sici)1097-4636(199707)36:1<109::aid-jbm13>3.0.co;2-d

✦ Synopsis

Viscosity-temperature dependence has been investigated for glasses in a system where bioactive compositions are found. A glass is called bioactive when living bone can bond to it. In this work, high-temperature microscopy was used to determine viscosity-temperature behavior for 40 glasses in the system Na 2 O-K 2 O-MgO-CaO-B 2 O 3 -P 2 O 5 -SiO 2 . The silica content in the glasses was 39-70 wt %. All glasses containing <54 mol % SiO 2 devitrified during the viscosity measurements. Generally, glasses that devitrified contained more alkali but less alkaline earths than glasses with a large work-ing range. A working range is the temperature interval at which forming of a glass can take place. This temperature interval can, for bioactive glasses, be enlarged by decreasing the amount of alkali, especially Na 2 O, in the glass and by increasing the amount of alkaline earths, especially MgO. Optionally, B 2 O 3 and P 2 O 5 can be added to the glass. An enlarged working range is a prerequisite for an expanded medical use of bioactive glasses as, e.g., sintered and blown products, and fibers.