Preparation And Property Of Ions Doped Hydroxyapatite Bioceramics

Hydroxyapatite?HA?,an ideal dental restorative material,has been widely recognized by lots of scholars due to its similarity on crystal structure and composition with the mineral facies in human teeth,good biological activity and osteoinductivity.Recently,HA is only applied in the replacement and repair of non-load-bearing hard tissues of human because its mechanical properties are still not good enough.Therefore,it is of great significance to improve the mechanical properties of HA in implant materials for the applications in biomedical fields.In this study,nanometer HA and F-doped HA particles were prepared in simulated body fluid by chemical precipitation method.On the basis of F-doped HA,yttria stabilized zirconia?3Y-ZrO₂?and 58S bioactive glass were introduced in different ratio and then produced composite ceramics by calcinations.The specific contents were as follows:The nanometer HA containing trace Na and Mg elements was prepared by chemical precipitation method in simulated body fluid environment,of which the thermal behavior,phase,structure,morphology and composition were analyzed using TG-DTA,XRD,FT-IR,SEM,EDS methods.The results show that the spherical HA nanoparticles with high purity,good crystallinity,small size and uniform particle can be obtained when the Ca/P ratio of the initial feeding is 1.80and calcined at 800?for 2 h.With a certain amount of F element introduced,Na/Mg/F-HA nano-powders were prepared by chemical precipitation method in simulated body fluid environment under the optimum process conditions,and then the effects of F doping amount on crystal structure,microstructure,element composition and antibacterial properties of nano HA were analyzed and characterized by XRD,FT-IR,SEM and EDS.The research shows that F ion can inhibit the growth of HA particles,and the shape of HA particle gradually transforms from spherical into rodlike with the increasing of F doping amount.When F/P=0.25,the spherical HA nano powders with small size,uniform particle and best antibacterial properties can be prepared,which is suitable for the preparation of bioceramic.3Y-ZrO₂,58S and Na/Mg/F-HA were mixed according to different ratio,and the composite ceramics were prepared by calcined at high temperature.The phase and morphology of composite powder after calcinations were analyzed using XRD and SEM methods.The results show that ZrO₂ can inhibit the growth of HA particles,and 58S can contribute to the densification of the powders and inhibit the decomposition of HA.In addition,the sintering performance,in vitro solubility,bioactivity,mechanical properties of composite ceramics were tested and analyzed.The results show that the composite ceramic with the group allocation ratio of 87.80wt%Na/Mg/F-HA,9.76 wt%3Y-Zr O₂ and 2.44 wt%58S has the best comprehensive performance,so it is expected to become an ideal material for dental restoration.