title: Characterization of hydroxyapatite films obtained by pulsed-laser deposition on Ti and Ti-6AL-4v substrates.
abstract: OBJECTIVE
  Pulsed-laser deposition (PLD) is a development process to obtain hydroxyapatite (HA) thin film. It is an alternative to hydroxyapatite deposition techniques usually employed to cover orthopaedic or dental titanium implant surfaces. The aim of this study is to find out the characteristic ratio for Ca/P (1.66) deposit on titanium implant with the PLD process.
  
  
  METHODS
  In a preliminary study, the coating parameters of pure and highly crystalline HA on Ti or Ti-6Al-4V substrates were verified by analysing the deposit by Rutherford backscattering spectroscopy (RBS). Ablation parameters to reach a stoichiometric hydroxyapatite composition (ideal Ca/P atomic ratio) and to control the growth of crystalline phases were: 575 degrees C for the substrate temperature, 0.4 mbar H2O vapour pressure in the ablation chamber, the target substrate distance was 40 mm and the deposition time was 120 min. In a second part, the film properties were analysed by means of XRD, SEM, AFM. The coating adhesion of the HA to the substrate was determined with a micro scratch tester.
  
  
  RESULTS
  The analysed HA thin films showed a perfect crystallized and textured deposit. Sample observation and surface quality analysis demonstrated a surface roughness and adhesion of the films to the substrates compatible with biological applications.
  
  
  CONCLUSIONS
  These results suggest that pulsed-laser deposition is a suitable technique to obtain crystalline and adherent hydroxyapatite films on Ti or Ti-6Al-4V substrates. The quality of the HA deposit with the PLD process could be an interesting option for coating dental implant.
authors.affiliation: Faculté de Chirurgie Dentaire, Université Denis Diderot, Paris 7, France. oblind@noos.fr
authors.forename: Olivier
authors.initials: O
authors.lastname: Blind
authors.forename: Lorena H
authors.initials: LH
authors.lastname: Klein
authors.forename: Bruno
authors.initials: B
authors.lastname: Dailey
authors.forename: Laurence
authors.initials: L
authors.lastname: Jordan
mesh_terms: D000497:Alloys; D002130:Calcium Phosphates; D020099:Coated Materials, Biocompatible; D003460:Crystallization; D018360:Crystallography, X-Ray; D003722:Dental Alloys; D017886:Durapatite / Q000032:analysis; D007834:Lasers; D008422:Materials Testing; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D012542:Scattering, Radiation; D013057:Spectrum Analysis / Q000379:methods; D013499:Surface Properties; D014025:Titanium
chemical_list: D000497:Alloys; D002130:Calcium Phosphates; D020099:Coated Materials, Biocompatible; D003722:Dental Alloys; C031462:titanium alloy (TiAl6V4); D017886:Durapatite; D014025:Titanium