A novel biocomposite coating of hydroxyapatite/Al2O3 was fabricated on titanium using a multi-step technique including physical vapor deposition(PVD), anodization, electrodeposition and hydrothermal treatment. Anodic ...A novel biocomposite coating of hydroxyapatite/Al2O3 was fabricated on titanium using a multi-step technique including physical vapor deposition(PVD), anodization, electrodeposition and hydrothermal treatment. Anodic Al2O3 layer with micrometric pore diameter was formed by anodization of the PVD-deposited aluminum film on titanium and subsequent removal of part barrier Al2O3 layer. Hydroxyapatite coating was then electrodeposited onto the as-synthesized anodic Al2O3 on titanium. A hydrothermal process was finally applied to the fabricated biocomposite coating on titanium in alkaline medium. Scanning electron microscopy(SEM), energy dispersive spectrometry(EDS) and X-ray diffractometry(XRD) were employed to investigate the morphologies and compositions of the pre-and post-hydrothermally treated hydroxyapatite/Al2O3 biocomposite coatings. The results show that micrometric plate-like Ca-deficient hydroxyapatite (CDHA) coatings are directly electrodeposited onto anodic Al2O3 at constant current densities ranging from 1.2 to 2.0 mA/cm2 using NaH2PO4 as the phosphorous source. After hydrothermal treatment, the micrometric plate-like CDHA coating electrodeposited at 2.0 mA/cm2 is converted into nano-network Ca-rich hydroxyapatite (CRHA) one and the adhesion strength is improved from 9.5 MPa to 21.3 MPa. A mechanism of dissolution-recrystallization was also proposed for the formation of CRHA.展开更多
Hydroxyapatite coatings were prepared on titanium substrate by electrochemical deposition technology, in which the electrolyte was 0.042 mol/L Ca(NO3)2 and 0.025 mol/L (NH4)2HPO4 with pH 4.4 adjusted by dilute HNO3 an...Hydroxyapatite coatings were prepared on titanium substrate by electrochemical deposition technology, in which the electrolyte was 0.042 mol/L Ca(NO3)2 and 0.025 mol/L (NH4)2HPO4 with pH 4.4 adjusted by dilute HNO3 and NH4OH. The morphology and phase composition of the coatings were investigated by scanning electron microscopy(SEM) and X-ray diffractometry(XRD). The effect of the deposition voltage and electrolyte concentration on the morphology and the structure of the coating was also discussed. The results show that coating thickness increases and the morphology changes from porous form to actionomprphic-assembled form with increasing deposition voltage(from 1 V to 3 V). In addition, it is found that the anodic oxidation of the titanium is effective in improving the tear strength between the HA coatings and the Ti substrate.展开更多
基金Project(50472031) supported by the National Natural Science Foundation of China
文摘A novel biocomposite coating of hydroxyapatite/Al2O3 was fabricated on titanium using a multi-step technique including physical vapor deposition(PVD), anodization, electrodeposition and hydrothermal treatment. Anodic Al2O3 layer with micrometric pore diameter was formed by anodization of the PVD-deposited aluminum film on titanium and subsequent removal of part barrier Al2O3 layer. Hydroxyapatite coating was then electrodeposited onto the as-synthesized anodic Al2O3 on titanium. A hydrothermal process was finally applied to the fabricated biocomposite coating on titanium in alkaline medium. Scanning electron microscopy(SEM), energy dispersive spectrometry(EDS) and X-ray diffractometry(XRD) were employed to investigate the morphologies and compositions of the pre-and post-hydrothermally treated hydroxyapatite/Al2O3 biocomposite coatings. The results show that micrometric plate-like Ca-deficient hydroxyapatite (CDHA) coatings are directly electrodeposited onto anodic Al2O3 at constant current densities ranging from 1.2 to 2.0 mA/cm2 using NaH2PO4 as the phosphorous source. After hydrothermal treatment, the micrometric plate-like CDHA coating electrodeposited at 2.0 mA/cm2 is converted into nano-network Ca-rich hydroxyapatite (CRHA) one and the adhesion strength is improved from 9.5 MPa to 21.3 MPa. A mechanism of dissolution-recrystallization was also proposed for the formation of CRHA.
文摘Hydroxyapatite coatings were prepared on titanium substrate by electrochemical deposition technology, in which the electrolyte was 0.042 mol/L Ca(NO3)2 and 0.025 mol/L (NH4)2HPO4 with pH 4.4 adjusted by dilute HNO3 and NH4OH. The morphology and phase composition of the coatings were investigated by scanning electron microscopy(SEM) and X-ray diffractometry(XRD). The effect of the deposition voltage and electrolyte concentration on the morphology and the structure of the coating was also discussed. The results show that coating thickness increases and the morphology changes from porous form to actionomprphic-assembled form with increasing deposition voltage(from 1 V to 3 V). In addition, it is found that the anodic oxidation of the titanium is effective in improving the tear strength between the HA coatings and the Ti substrate.
