Mechanical properties of pulsed laser-deposited hydroxyapatite thin film implanted at high energy with N + and Ar + ions. Part I: nanoindentation with spherical tipped indenter

Abstract

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, using 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. From the load–displacement curves determined by nanoindentation tests using a spherical tipped nanoindenter ( R=5 μm), we put into evidence an enhancement of the mechanical characteristics (hardness and elastic modulus) of the HA films after implantation, especially for those implanted with N + ions. Moreover, using various applied normal loads (ranging from 1 to 100 mN) in different implanted areas, a good reproducibility of nitrogen implantation effect are observed.