Preparation And Characterization Of Nano Hydroxyapatite Powder And HA Bioceramics

Hydroxyapatite(HA) porous bioceramic with good biological properties has been more widely used in tissue replacement, repair of bone and bone disease treatment and tissue reconstruction, and has good prospects for the development. This paper describes the structure and properties of hydroxyapatite materials, and the progress in research and application status of the hydroxyapatite materials. In this subject, the hydroxyapatite ceremic materials were studied in two aspects, one is the preparation of HA nanopowder, another is the preparation of HA porous bioceramics.Hydroxyapatite powders were synthesized from Ca(NO3)2·4H2O and (NH4)2HPO4with precipitation method, and were characterized with XRD, SEM and other analysis tools. Investigating the impact of pH, concentration, reaction temperature, aging time and heat treatment in high temperature to the powder morphology, phase, particle size, purity and agglomeration. The result shows that the Ca/P ratio of the product increased with increasing pH, and the degree of crystallization of the products increase as the solution concentrion and reaction temperature, an appropriate extension of the aging time can improve the product purity. After700℃high temperature heat treatment, the particle showes spherical, and the particle size increase, dispersed more uniform. Comprehensive analysis to optimize the process parameters: pH10, theconcentration of0.5mol/L, reaction temperature of40℃, aging time of24h.The HA porous bioceramics were prepared by compression moding with the laboratory-made nano-HA powder as row materials, nano ZrO2particles as toughening agent, citric acid as pore-forming agent. Using SEM to analysis the microstructure and phase of the HA ceramics, using the Archimedes method and mercury porosimetry to test their porosity and pore size distribution, using the three point bending method to test the mechanical properties. Investigating the impact of the sinterring temperature, sintering time, the poreforming agent content and the amount of ZrO2to the porosity, pore size distribution, microstructure, the phase composition and mechanical properties of the HA ceramics. The results show that significant toughening effect of ZrO2on the HA ceramic. HA porous bioceramics were prepared with30wt%citric acid added as pore-forming agent,after the insulation3h in the sintering temperature of1200℃. When the corporation of nanoZrO2was20wt%in the eomPosite, the compressive strength reached61.3MPa.