title: Characterization of calcium phosphate deposited on valve metal by anodic oxidation with polarity inversion.
abstract: 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.
authors.affiliation: 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
authors.forename: Seigo
authors.initials: S
authors.lastname: Okawa
authors.forename: Kikuo
authors.initials: K
authors.lastname: Homma
authors.forename: Mitsugu
authors.initials: M
authors.lastname: Kanatani
authors.forename: Kouichi
authors.initials: K
authors.lastname: Watanabe
mesh_terms: 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
chemical_list: 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