含锌羟基磷灰石的水热合成与结构表征

HYDROTHERMAL PREPARATION AND STRUCTURE CHARACTERIZATION OF ZINC-SUBSTITUTED HYDROXYAPATITE

自然骨中的无机组分并不是纯的羟基磷灰石[Ca10(PO4)6(OH)2,hydroxyapatite,HA],还含有锌(Zn)、镁(Mg)等离子。为满足临床要求,常常需要在HA中添加一些元素来改善其性能。含锌羟基磷灰石(Zn-HA)就是其中的一类改性材料。目前多采用溶胶-凝胶法制备Zn-HA,需高温烧结,粉体易团聚。以硝酸钙[Ca(NO3)2]、磷酸三铵[(NH4)3PO4]、硝酸锌[Zn(NO3)2]为原料,在200℃下水热处理8h制得Zn-HA。通过X射线荧光光谱、X射线衍射、红外光谱、透射电镜和热重-差热分析对Zn-HA的晶相、化学组成、形貌和热稳定性进行分析。结果表明:Zn取替代部分钙(Ca)进入HA的晶格中。随着Zn含量的提高,Zn-HA晶粒尺寸呈减小趋势,晶胞参数a,c和晶胞体积也呈减小趋势。Zn的掺入降低了HA的热稳定性。采用水热法可以制备纳米到微米尺寸的棒状、针状或片状Zn-HA粉体,且Zn-HA粉体具有高结晶度以及合适化学计量比和晶型。

Natural apatite is not pure hydroxyapatite（HA） because of the presence of minor constituents such as Zn2＋ and Mg2＋. To meet the requirements for clinical applications, some elements are substituted into the apatite to improve its function. Zinc-substituted hydroxyapatite （Zn-HA） is one of these modification materials. The main method of preparation of Zn-HA is the sol-gel process;however, sintering at high temperature usually leads to bigger crystal sizes. Zinc-substituted HA powders were prepared by the hydrothermal method at 200 ℃ for 8 h using Ca（NO3）2, （NH4）3PO4 and Zn（NO3）2 as reagents. The hydrothermal technique usually gives materials with a high degree of crystallinity and with a molar ratio n（Ca）/n（P） close to the stoichiometric value. The crystal size is in the range of nanometer to micrometer and the crystal shapes look like needles, sticks or blades. X-ray fluorescence spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscope, and thermogravimetric-differential thermal analysis were used to characterize the crystalline phase, chemical composition, morphology, and thermal stability of the Zn-HA. The results show that Zn is incorporated into the HA crystal structure. The crystal grain size of the Zn-HA, and the lattice parameter a, c and unit cell volume decreased when the Zn content was increased. The HA thermal stability decreased because of the Zn addition.