制备工艺参数对氟羟基磷灰石氟替代量和形貌的影响

THE EFFECT OF PREPARATION PARAMETERS ON FLUORIDE SUBSITUTION CONTENT AND MORPHOLOGY OF FLUORHYDROXYAPATITE

通过沉淀法制备了纳米氟羟基磷灰石(FHA)。研究了合成温度、初始氟离子浓度和pH值对氟替代量和形貌的影响。用透射电镜观察了FHA的形貌,用氟选择电极法测定了FHA中的氟含量。结果表明:随着合成温度或原料中氟浓度的升高,FHA晶粒尺寸和长径比增加;随着pH值的提高,长径比减小。合成FHA中氟含量随初始氟离子浓度和合成温度的增加而非线性增加,考虑到OH^-和F^-对羟基空位的竞争,高pH值不利于氟替代。

The nanosized fluorhydroxyapatite（FHA） had been synthesized by aqueous precipitation method. The effects of synthesis temperature,molar ratio of NH_4F to Ca（N03）2 ？ 4H_2O in the initial reagents[n（F^-）/n（Ca^（2＋））] and the pH value on the fluoride substitution and morphology were investigated.The morphology of FHA was observed by transmission electron microscope.The fluoride content in FHA was determined by F-selective electrode.The results show that the size and aspect ratio of FHA crystals increase as the precipitation temperature and n（F^-）/n（Ca^（2＋）） and decrease as the pH value.The fluoride content of FHA increases with n（F^-）/ n（Ca^（2＋）） and synthesis temperature nonlinearly.Considering the possibility of a competition between OH^-and F^- for occupation of the OH-site,high pH value isn＇t conductive to the fluoride substitution.