Comparison of hydroxyapatite ceramics and hydroxyapatite/borosilicate glass composites prepared by slip casting

Borosilicate glass powder with a softening point of 821degreesC was prepared by crushing Pyrex(R) borosilicate glass fragments. Hydroxyapatite (HA) ceramics and HA/borosilicate glass (50wt.%) composites were prepared by slip casting. The influence of borosilicate glass on the densification and phase change of hydroxyapatite was studied over sintering temperatures from 500 to 1200degreesC. It was found that the borosilicate glass inhibited the decomposition of HA phase and enhanced the densification of the composites. When the sintering temperature was higher than 1100degreesC, the glass liquid flowed away from the sample surface and was trapped inside the sample, leading to a structure of a relatively strong and dense HA/glass core and a bioactive and porous HA surface layer. (C) 2004 Elsevier Ltd and Techna Group S.r.l. All rights reserved.