Fabrication of Sandwich-Like Hydroxyapatite-Al<sub>2</sub>O<sub>3</sub>-Si(<i>100</i>) Biocomposite

Abstract

A novel composite biocoating of hydroxyapatite(HA)/Al2O3 has been successfully prepared on Si(100) substrate by a hybrid technique of physical vapor deposition (PVD), anodization, and electrodeposition. The fabricated composite biocoating was also annealed under temperatures ranging from 573 to 973 K. Scanning electron microscope (SEM), energy dispersive spectrometry (EDS), and X-ray diffraction (XRD) were employed to investigate morphologies and compositions of the HA/Al2O3 composite biocoating. It is found that Ca-deficient hydroxyapatite (CDHA) coating holding a Ca/P atomic ratio of 1.61 has been directly electrodeposited onto porous anodic Al2O3 with 1.5~3 μm pore diameter formed by anodization of PVD-deposited aluminum layer on Si(100) and subsequent pore-widening. The embedding of HA outer coating into porous anodic Al2O3 results in a sandwich-like structure in the finally obtained HA/Al2O3 composite biocoating on Si(100). XRD results indicate the decomposition of HA into β-TCP at an annealing temperature above 873 K.