Preparation and characterization of mesoporous 45S5 bioactive glass-ceramic coatings on magnesium alloy for corrosion protection

To improve the bioactivity and corrosion resistance, mesoporous 45S5 bioactive glass-ceramic (45S5 MBGC) coatings were prepared on AZ31 magnesium alloy by the sol-gel dip-coating method and the evaporation-induced self-assembly (EISA) process. Non-mesoporous 45S5 bioactive glass-ceramic (45S5 BGC) coatings were also prepared for comparative investigation. The results showed that 45S5 MBGC coatings were prone to crack-free and uniform with larger special surface area, pore volume and better surface wettability in contrast to 45S5 BGC coatings. A possible mechanism of mesopore formation was proposed to better understand the role of Pluronic F127 (F127) in the preparation process. Furthermore, 45S5 MBGC coatings had desired adhesion strength to AZ31 substrate owing to chemical bonding interface. Electrochemical tests in simulated body fluid (SBF) revealed that 45S5 MBGC coatings could obviously improve the pitting corrosion potential and polarization resistance of AZ31 substrate, meanwhile, corrosion current density was significantly decreased, suggesting effective anti-corrosion property. Therefore, 45S5 MBGC coated magnesium alloys had potentials for use as biodegradable biomedical implant material.