Akademik Veri Yönetim Sistemi
BRITISH CERAMIC TRANSACTIONS, cilt.97, sa.5, ss.240-245, 1998 (SCI-Expanded)
The production of bioactive glass ceramics in the Na2O-CaO-MgO-Al2O3-SiO2-P2O5-CaF2 system yielding apatite and wollastonite as crystalline phases, by means of either the powder route or conventional casting has been investigated for four compositions. The kinetics and structural aspects of the crystallisation of the parent glasses of various compositions and sintering characteristics of the powders were examined. One glass composition, designated CP1, was found to be sinterable during a single heat treatment to yield a dense glass ceramic. The successful sintering of CP1 was found to be due to its wider working range prior to crystallisation in comparison with the other compositions. Furthermore, the slower crystallisation rate of CP1 and, consequently the presence of a higher quantity of residual glass facilitated the viscous flow necessary for sintering, resulting in a lower ultimate porosity. The production of the CP1 composition via cold pressing and firing or hot pressing yielded a fine microstructure with negligible porosity. These results are consistent with the superior mechanical properties of samples produced by the powder route in comparison with those obtained for materials made by conventional casting. The optimised sintered glass ceramic has great promise as a bioactive implant material, and could be used as matrix in a ceramic composite. BCT/227.