Journal of Materials Science, Vol.39, No.11, 3605-3611, 2004
Determination of mechanical properties of pulsed laser-deposited hydroxyapatite thin film implanted at high energy with N+ and Ar+ ions, using nanoindentation
Hydroxyapatite ( HA) is extensively studied for various applications in bone implantology. We report here a comparison between the effects of ion beam implantation treatment using nitrogen and argon ions, on the mechanical characteristics of HA films grown by pulsed laser deposition. We used for deposition a KrF* excimer laser. Crystalline and stoichiometric HA films were grown on Ti-5Al-2.5Fe alloy substrate, previously coated with a TiN buffer layer. After deposition, the film were implanted with ions of N+ and Ar+ of high energy (1-1.5 MeV range) and dose set at 10(16) at cm(-2). The hardness and elastic modulus were determined by nanoindentation tests using a spherical tipped nanoindenter with a 5 mum-tip radius. From the load-displacement curves, we put into evidence an enhancement of the mechanical characteristics of the HA films after implantation, especially for those implanted with N+ ions. This improvement of the mechanical characteristics is related to the changes of surface morphology and the densification of the HA layer after ion treatment. (C) 2004 Kluwer Academic Publishers.