Characterization of calcium phosphate deposited on valve metal by anodic oxidation with polarity inversion.
Electrochemical deposition of calcium phosphate (CAP) on valve metals such as Ta, Nb, and Zr, was performed by anodic oxidation with alternate polarity inversion at an applied 20 VDC. A saturated hydroxyapatite(HAP)-phosphoric acid solution (pH 3) was used as the electrolyte. FTIR, XRD, and XPS were employed to investigate the detailed characteristics of the deposition. HAP was precipitated on Ta; HAP including brushite and monetite on Nb; and HAP and monetite on Zr. The Ca/P atomic ratios were 1.3-1.5 by XPS, and HPO(4)(2- )bands were detected on Ta by FTIR. Therefore, the HAP precipitated on Ta was a Ca-deficient HAP. In addition, the XPS spectra of the specimens showed that phosphate ions were incorporated into the anodic oxide film. Deposits with nano-grain size were observed by AFM. The results confirmed that CAP with nano-grain size was deposited on valve metals by the anodic oxidation with polarity inversion.
Okawa
Seigo
S
Division of Biomaterial Science, Department of Oral Health Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan. sokawa@dent.niigata-u.ac.jp
Homma
Kikuo
K
Kanatani
Mitsugu
M
Watanabe
Kouichi
K
D002130:Calcium Phosphates / Q000737:chemistry*; D020099:Coated Materials, Biocompatible; D017886:Durapatite; D055664:Electrochemical Techniques; D008670:Metals / Q000737:chemistry*; D053758:Nanoparticles; D009556:Niobium / Q000737:chemistry; D010084:Oxidation-Reduction; D010756:Phosphoric Acids; D056951:Photoelectron Spectroscopy; D012996:Solutions / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013635:Tantalum / Q000737:chemistry; D014961:X-Ray Diffraction; D015040:Zirconium / Q000737:chemistry
D002130:Calcium Phosphates; D020099:Coated Materials, Biocompatible; D008670:Metals; D010756:Phosphoric Acids; D012996:Solutions; D009556:Niobium; D013635:Tantalum; D017886:Durapatite; C020243:calcium phosphate; D015040:Zirconium; C030242:phosphoric acid