Investigation On The Bioactive Glass-ceramis Sintered At Low Temperature

Bioactive glass-ceramics is considered to be a good biomaterial in the field of bone repair. Researches is concentrated in Ceravital, A-W and Bioverit. But the high sintered temperature of these materials make it unfit for rapid prototyping technology. It is of great significance to research a glass system which could be sintered at low temperature.Bioactive glass-ceramics in the Na2O-B2O3-SiO2-CaO-P2O5-F system was prepared with the sintering method, which could be sintered and crystallized at low temperature. In this experiment, the match between the the sintering and crystallization was also discussed by controlling the formula. Results show that the crystal morphology is influenced by the raw material which provides P2O5. The sample perform small size crystal which is needle-like when the raw material is CaHPO4·2H2O. The studied different composite point in and beyond the phase separation section indicate that different morphology crystal of fluorapatite crystallized from the glass system. The flouorapatite is needle-like in the phase separation section and spherical or short rod-like beyond the phase separation section. Besides it is easier to crystallize in the phase separation section due to the lower crystallization energy. The system is easily to be phase separated to become net structure at nano-size whose morphology changes along the radial direction in the phase separation section. The crystallinity and mechanical properties are improved with the increasing content of CaO and P2O5, the apparent porosity and volume density are decreased to 3.15% and 2.54g/cm3, the bending strength is 65.26 MPa and the elasticity modulus(MOE) is 4.18 GPa when P2O5 is 24wt% heat treated at 800℃. With the increase of heat temperature, the crystallinity firstly increase and then decrease, which is 82.76% when temperature is 800℃. Besides the apparent porosity and volume density of all samples reach 5% and 2.13g/cm3, the hardness reaches 400 Hv. The bending strength and MOE of all samples are up to 55 MPa and 4GPa, respectively. The SBF immersed experiment shows that a certain phase rich in Ca, P is generated on the sample surface, which confirms this material is bioactive.