Mechanical and Corrosion Properties of Magnesium–Hydroxyapatite (Mg–HA) Composite Thin Films

Magnesium (Mg)–hydroxyapatite (Ca10(PO4)6(OH)2, abbreviated as HA) composite films have been grown on Mg plates using a pulsed laser deposition technique. Mechanical property measurements and analysis have indicated that hardness and Young's modulus of nMg–(100–n)HA composite coatings increase with Mg content in the coatings and reach a maximum at a 70Mg–30HA composition. n and 100–n in the nMg–(100–n)HA represent the relative number of laser pulses impinging on Mg and HA targets, respectively. Direct current potentiodynamic polarization studies have shown that the corrosion of Mg plate (control) decreases with an increase in the HA ratio in the composite films. For example, the corrosion current density of Mg plate reduces by ∼350 times after coating the Mg plate with 10Mg–90HA composite film. The reduction in corrosion current density of Mg plates was also accompanied by a positive shift in the corrosion potential (∼6%) due to this coating. The mechanism behind the reduction in corrosion behavior of Mg plates due to nMg–(100–n)HA composite coatings has been understood by electrochemical impedance spectroscopy.