沉淀法制备碳酸羟基磷灰石的影响因素

通过沉淀法制各了高碳酸根(CO32-)含量的纳米碳酸羟基磷灰石(nanosized carbonated hydroxyapatite,CHA).研究了合成温度、初始原料碳酸氢钠(NaHCO3)和磷酸氢二铵[(NH4)2HPO4]的摩尔比[n(CO32-)/n(PO43-)]和pH值对CO32-替代的影响.用X射线衍射和透射电镜表征CHA粉体的物相组成和形貌.用碳硫元素分析仪和红外光谱研究了CO32-替代的含量和类型.结果表明:随着合成温度的升高或原料中CO32-浓度的减小,CHA晶粒尺寸和长径比增加;合成CHA中的晶相组成和CO32-含量主要由n(CO32-)/n(PO43-)决定;而CO32-的替代类型则主要取决于n(CO32-)/n(PO43-)和pH值.在高pH值或高n(CO32-)/n(PO43-)的合成条件下,能够获得以B型替代为主的CHA.

EFFECTIVE FACTORS OF PREPARATION FOR CARBONATED HYDROXYAPATITE BY THE AQUEOUS PRECIPITATION METHOD

Nanosized carbonated hydroxyapatite(CHA)with high carbonate content was synthesized by an aqueous precipitation method.The effects of the synthesis temperature,molar ratio of NaHCO3 to(NH4)2HPO4 in the initial reagents[n(CO3 2-)/n(PO4 3-)] and the pH value on carbonate substitution were investigated.The phase composition and morphology of the CHA powders were characterized by an X-ray diffraction and transmission electron microscope,respectively,and the content and type of the carbonate substitution were studied using carbon-sulfur elemental analysis and Fourier transform infrared spectroscopy,respectively.The results show that the size and aspect ratio of the CHA crystals increase as the precipitation temperature increases or carbonate content de-creases.The phase composition and the carbonate content of the CHA are mainly controlled by the n(CO3 2-)/n(PO4 3-);the substitution type of the CHA is determined by the n(CO3 2-)/n(PO4 3-)and pH value.With a high pH value or high n(CO3 2-)/n(PO4 3-),the CHA giving priority to B-type is obtained.