FABRICATION AND CHARACTERIZATION OF HYDROXYAPATITE-MAGNESIUM COMPOSITE THIN FILMS ON MAGNESIUM PLATES FOR IMPLANT APPLICATIONS

摘要

Hydroxyapatite (HA)-magnesium (Mg) composite thin films were grown on magnesium substrates using a multitarget pulsed laser deposition technique. The microstructural and corrosion properties of HA-Mg composite thin films were investigated using methods such as x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray (EDX) analysis, and potentiodynamic polarization. While the XRD studies have indicated the amorphous nature of the HA-Mg composite coating, SEM and EDX studies have shown that the composite films are stoichiometric. The potentiodynamic polarization study indicates that the corrosion of magnesium decreases with increase in the hydroxyapatite content in the composite film. The corrosion potential (E_(corr)) and corrosion current density (I_(corr)) for the uncoated magnesium, 30HA-70Mg, and 50HA-50Mg coated magnesium are -1.59, -1.57, -1.54 V and 1.21×10~(-5), 1.38×10~(-6), 2.52×10~(-7) A/cm~2,respectively. Preliminary cytotoxicity test conducted on the samples shows no adverse effect on human bone marrow stromal cells. The advantage of the composite coatings is the realization of adjustable corrosion and biological properties by a simple maneuvering of composition which in turn is realized by changing the number of laser pulses on a respective target.