Effect of sodium content on the crystallization behavior of fluoramphibole glass-ceramics

✍ Scribed by Denry, I. L. ;Holloway, J. A.

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 229 KB
• Volume: 63
• Category: Article
• ISSN: 0021-9304
• DOI: 10.1002/jbm.10085

✦ Synopsis

Abstract

The purpose of this study was to evaluate the effect of sodium content on the crystallization behavior of glass–ceramics in the system SiO~2~‐MgO‐CaO‐Na~2~O‐K~2~O‐F. Five glass compositions were prepared with increasing sodium content. The compositions were melted at 1400 °C for 2 h and cast into 60 × 12‐mm ingots. Differential thermal analyses were performed on the glasses up to 1400 °C. Discs (1.5 × 12 mm) were cut from the ingots, nucleated in the temperature range 600–650 °C for 1–2 h, and crystallized in the temperature range 900–1000 °C for 0.5–4 h. The crystalline phases were analyzed by x‐ray diffraction. The microstructure was investigated by scanning electron microscopy. Differential thermal analyses showed that the crystallization exotherm occurred in the temperature range 600–750 °C. There was a linear relationship between the amount of sodium and the transformation temperatures. X‐ray diffraction revealed the presence of mica and diopside as major crystalline phases in the sodium‐free composition. Mica, diopside, and fluorrichterite were present in all other glass–ceramics. The microstructure of the sodium‐free glass–ceramic was characterized by the presence of hexagonal mica crystals and prismatic diopside crystals. All other compositions exhibited needle‐shaped fluorrichterite crystals (2–5 μm in length) in addition to mica and diopside crystals. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 48–52, 2002