Preparation and evaluation of HA–PP coating on AZ31B magnesium alloy for implant applications

To make Mg alloy implants have better corrosion resistance and reduced degradation rate in the human body, hydroxyapatite (HA), polypropylene (PP), and HA+PP coatings were added to the surface of AZ31B through dip coating. Coated samples were tested for weight differences, corrosion rate, surface roughness, and microscopic view. Scanning electron microscopy and energy dispersive spectroscopy analysis confirm coating on the substrate surfaces. The potentiodynamic polarisation test result shows that the corrosion rate in the uncoated substrate (10.138 mm/y) was higher compared to HA-coated = 0.5084 mm/y, PP-coated = 0.442 mm/y, and HA/PP-coated = 0.3275 mm/y. After 14 days, weight loss (5.5%) was highest in the uncoated and lowest in the HA-PP-coated (0.9%). Deposition of the bone mineral was higher on the HA-coated sample, showing superior bone integration properties. Hybrid coating improved electrochemical properties compared to HA coating on Mg alloy.