两步电化学法制备羟基磷灰石/氧化铝复合生物涂层的研究

研究旨在开发一种可应用于医用金属表面生物学改性的复合生物陶瓷涂层。通过先阳极氧化、再电沉积的两步电化学方法成功制备了羟基磷灰石(hydroxyapatite，HA)／Al2O3复合生物涂层。利用扫描电子显微镜(SEM)研究了阳极氧化Al2O3(anodic aluminum oxide，AAO)膜的表面形貌与HA／Al2O3复合涂层的表面及截面形貌结构；用X射线衍射仪(XRD)、Fourier变换红外光谱仪(FT-IR)与能谱仪(EDS)表征了复合涂层的物相组成；用等离子原子发射光谱仪(ICP-AES)和粘接拉伸试验分别测定涂层在模拟体液(SBF)中的体外行为和浸渍后涂层间的结合强度,结果表明：所制备的HA含有少量碳酸根，在SBF中呈现优良的稳定性并能诱导新的磷灰石层的形成；HA底部嵌入AAO膜的孔洞中形成互锁界面，经模拟体液处理后两者之间结合强度为3．2MPa。

STUDIES ON HYDROXYAPATITE/ALUMINA COMPOSITE BIOCOATING PREPARED BY ATWO-STEP ELECTROCHEMICAL METHOD

The purpose of this research was to develop a new compound bioceramic coating for the surface modification of biomedical metals. Hydroxyapatite (HA)/Al_2O_3 composite biocoating was successfully prepared by a two-step electrochemical method including anodization and subsequent electrodeposition. The surface morphologies of porous anodic aluminum oxide (AAO) and HA/Al_2O_3 composite coating and the cross section microstructure of the HA/Al_2O_3 coating were investigated with SEM. The compositions of HA/Al_2O_3 coating were determined by XRD, FT-IR, and EDS techniques. In vitro behavior in a simulated body fluid (SBF) and adhesive performance of the as-prepared composite coating were investigated by ICP-AES and tensile test, respectively. The results show that the electrodeposited HA layer, containing a small amount of CO_3~(2-), has good stability in SBF and can induce the deposition of apatite from SBF. It is also found that an interlocking-like interface in HA/(Al_2O_3) composite coating is formed due to the embedding of HA layer into the pores of AAO. The adhesive strength between HA and AAO is of 3.2 MPa after soaking in SBF for 7 d.