Calcium Phosphate/Titania Sol-Gel Coatings on AZ31 Magnesium Alloy for Biomedical Applications

Calcium phosphate layer was coated onto AZ31 magnesium substrate with an insertion of a titania buffer layer by sol-gel method. The calcium phosphate layer was employed to enhance the bioactivity of the magnesium alloy, and the titania buffer layer was inserted to improve the bonding strength between the calcium phosphate layer and magnesium substrate, as well as to prevent the corrosion of the magnesium substrate. The structure and composition of the sol-gel coatings were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The bonding strength, corrosion behaviors and the hydrogen evolution rate of the samples were also studied. The results showed that the sol-gel coatings improved the corrosion resistance and reduced the hydrogen evolution rate of the magnesium alloy in simulated body fluid (SBF) solution. The titania buffer layer could significantly improve the bonding strength and the corrosion resistance.