title: Synthesis and properties of hydroxyapatite-containing porous titania coating on ultrafine-grained titanium by micro-arc oxidation.
abstract: Equal channel angular pressing results in ultrafine-grained (approximately 200-500 nm) Ti with superior mechanical properties without harmful alloying elements, which benefits medical implants. To further improve the bioactivity of Ti surfaces, Ca/P-containing porous titania coatings were prepared on ultrafine-grained and coarse-grained Ti by micro-arc oxidation (MAO). The phase identification, composition, morphology and microstructure of the coatings and the thermal stability of ultrafine-grained Ti during MAO were investigated subsequently. The amounts of Ca, P and the Ca/P ratio of the coatings formed on ultrafine-grained Ti were greater than those on coarse-grained Ti. Nanocrystalline hydroxyapatite and alpha-Ca(3)(PO(4))(2) phases appeared in the MAO coating formed on ultrafine-grained Ti for 20 min (E20). Incubated in a simulated body fluid, bone-like apatite was completely formed on the surface of E20 after 2 days, thus evidencing preferable bioactivity. Compared with initial ultrafine-grained Ti, the microhardness of the E20 substrate was reduced by 8% to 2.9 GPa, which is considerably more than that of coarse-grained Ti (approximately 1.5 GPa).
authors.affiliation: School of Materials Science and Engineering, Dalian University of Technology, Dalian, People's Republic of China. yaozaiqi@gmail.com
authors.forename: Z Q
authors.initials: ZQ
authors.lastname: Yao
authors.forename: Yu
authors.initials: Y
authors.lastname: Ivanisenko
authors.forename: T
authors.initials: T
authors.lastname: Diemant
authors.forename: A
authors.initials: A
authors.lastname: Caron
authors.forename: A
authors.initials: A
authors.lastname: Chuvilin
authors.forename: J Z
authors.initials: JZ
authors.lastname: Jiang
authors.forename: R Z
authors.initials: RZ
authors.lastname: Valiev
authors.forename: M
authors.initials: M
authors.lastname: Qi
authors.forename: H-J
authors.initials: HJ
authors.lastname: Fecht
mesh_terms: D003460:Crystallization; D017886:Durapatite / Q000138:chemical synthesis* / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D015394:Molecular Structure; D010084:Oxidation-Reduction; D013057:Spectrum Analysis / Q000379:methods; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*; D014961:X-Ray Diffraction; D014965:X-Rays
chemical_list: D017886:Durapatite; D014025:Titanium