Early Stages of Calcium Phosphate Formation on Bioactive Borosilicate Glass in Aqueous Phosphate Solution


The conversion of bioactive glass to a calcium phosphate material, typically hydroxyapatite (HA), by solution-precipitation reactions in aqueous phosphate solution, has been commonly reported. This paper describes the structural and compositional characteristics of the calcium phosphate material formed during the early-stage conversion (o5 h) of a borosilicate glass (designated H12) in aqueous phosphate solution. Disks of H12 glass were reacted with 0.25M K2HPO4 solution with a starting pH57.0 at 371C. The structure and composition of the product layer were characterized using thin film X-ray diffraction, scanning electron microscopy, and Fourier transform infrared reflectance spectroscopy. For reaction times o5 h, the results indicated the formation of brushite (CaHPO4 .2H2O) with coarse, plate-like crystals. In comparison, the formation of HA with small needle-like crystals was found at later times. This early-stage formation of brushite has not been reported in previous studies of converting bioactive silicate and borate glasses in aqueous phosphate solution.


Materials Science and Engineering

Keywords and Phrases

Aqueous Phoshate Solution; Bioacative Borosilicate Glass; Bioactive Glass; Borosilicate Glass; Calcium Phosphate

International Standard Serial Number (ISSN)

0002-7820; 1551-2916

Document Type

Article - Journal

Document Version


File Type





© 2008 John Wiley & Sons, All rights reserved.

Publication Date

01 May 2008