Synthesis And Sintering Of Hydroxyapatite Powder

Hydroxyapatite has the characteristics of good biocompatibility,non-toxicity,no rejection reaction and degradability.It can also be used as a carrier for drug transportation.As the main inorganic component of human bone tissue and teeth,hydroxyapatite has a wide range of applications in the fields of bone replacement,reinforcement and repair materials,surgical orthopedics and dentistry.Hydroxyapatite(Ca10(PO4)6(OH)2)powders with different morphologies and sizes were synthesized by hydrothermal method,microwave hydrothermal method and precipitation method.The effects of reaction conditions on the synthesized products were investigated.The hydroxyapatite ceramic was prepared by sintering by using the powder synthesized by the precipitation method as a raw material.The effects of firing temperature and the amount of pore-forming agent sodium carboxymethylcellulose(CMC)on the structure of ceramic materials were discussed.The synthesis of HAP powder was studied by using calcium nitrate(Ca(NO3)2·4H2O)and diammonium hydrogen phosphate((NH4)2HPO4)as raw materials.The phase structure and microstructure of the product were characterized by XRD,SEM and TG-DSC.Research indicates:HAP whiskers with a length to diameter ratio of 6-20 were synthesized by hydrothermal method using urea as the pH adjuster and a reaction solution with a calcium ion concentration of 0.1mol/L at 180? for 24h;The plate-like HAP powder was synthesized by microwave hydrothermal method using urea as the pH adjuster and the reaction solution with the calcium ion concentration of 0.1mol/L was kept at 160? for 2h;Hydroxyapatite powder obtained by adding magnesium nitrate(Mg(No3)2·6H2O)by precipitation method was prepared with a magnesium doping amount of 5%,n(Ca2+)=0.5mol/L,reaction temperature of 30? and reaction time of 1h.The particle diameter of product is about 30nm-50nm.And the product has high uniformity and dispersibility,which can be used for the synthesis of HAP ceramics.In this paper,HAP powder in a certain size with different morphology can be applied to medicine,adsorption,and the preparation of ceramics and other fields.The nano-sized particle powder synthesized by the precipitation method was calcined at a certain temperature after compacting to obtain a hydroxyapatite ceramic having a certain density and porosity.From the combination of the microstructure and the calculation of the porosity,the porosity is large when the firing temperature is 1000?.Adding CMC is beneficial to the formation of pores in the sample.The study of HAP ceramics provides the synthesis and application of porous HAP ceramics with an effective way.