A Study on Crystallization and Properties of Calcium-Phosphate Bioglass

• Main Authors: Wu, Shih-Ching, 吳世經
• Other Authors: Hon, Min-Hsiung
• Format: Others
• Language: zh-TW
• Published: 1996
• Online Access: http://ndltd.ncl.edu.tw/handle/32404184150930047692

博士 === 國立成功大學 === 材料科學(工程)學系 === 84 === Experiments were carried out on a series of glass- ceramics in the system MgO-CaO-Al2O3-SiO2-P2O5. Crystal morphology, crystallization behavior, and mechanical strength were characterized and biocompatibility was also evaluated as expected the glass-ceramics to be an implant material. The crystallization of glass with chemical composition of MgO 3.0wt%, CaO 35wt%, Al2O3 7.8wt%, SiO2 41.4wt%, and P2O5 12wt%, led to the precipitation of apatite (Ca10(PO4)6O) in bulk specimen and then anorthite (CaAl2Si2O8) growing from the specimen surface as a surface layer. Optimum heat- treatment condition for nucleation were also studied and it was shown that 820℃, 1hour duration would result in the maximum numbers of nuclei. The microstructure and crystallization condition were investigated to determine the nucleation and crystallization processes. Samples with bending strength of 282.1 MPa could be prepared by suitable nucleation and growth heat-treatment. A surface compressive stress was found on the crystallized specimen and was thought to be responsible for the high strength of the crystallized glass-ceramics. The influences of composition on the nucleation and crystallization of glass were investigated by DTA. It was shown that the activation energy for crystallization of apatite decreased with decreasing Al/P ratio, but that for crystallization of anorthite, on the contrary, increased. Increasing the Ca/P ratio also decreased the activation energy for crystallization of apatite, whereas for anorthite crystallization, it was not affected significantly. Cell culture test, rat shoulder test and rabbit femur test of the glass-ceramicsas implants shown that these materials demonstrated good biocompatibility.