In this work, we studied the effects of hot isostatic pressing and surface anodizing on the behavior of an in-situ surface modified magnesium matrix nano-composite with different wt.% of hydroxyapatite by stir-centrifugal casting. The hot isostatic pressing and anodizing were conducted to reduce the defects and to replace the sur- face of Mg/HA with a ceramic matrix nano-composite layer of MgO/HA, respectively. The composition of the conversion layer of anodizing was evaluated using energy dispersive spectroscopy and X-ray diffraction. The electrochemical tests were conducted in the simulated body fluid. The results show that the dominant deposition is vertical Mg(OH)2 nano-rods on the hot isostatic pressed-anodized surface during immersion in the simulated body fluid. According to the electrochemical results, a homogeneous distribution of 1.8 wt% nano- hydroxyapatite in the magnesium oxide matrix with a well-arranged nanostructure on the surface, after hot isostatic pressing and anodizing, reduces the H2 release and corrosion rate. Also, the mentioned specimen demonstrates the lowest thermodynamic tendency for corrosion (−1.345 V) and the corrosion rate of 3.8388 mm × year−1 with the highest protection efficiency of 42.26% compared to the as-cast pure magnesium. Therefore, it can be considered as a promising material in designing biomedical bone implants.
