Tuning of the Mg Alloy AZ31 Anodizing Process for Biodegradable Implants

Area of Science:

• Materials Science
• Biomaterials Engineering
• Corrosion Science

Background:

• AZ31 magnesium alloy is a promising biomaterial due to its biodegradability.
• Mg alloys suffer from poor corrosion resistance, limiting their biomedical applications.
• Developing protective coatings is crucial for enhancing Mg alloy performance in vivo.

Purpose of the Study:

• To develop and optimize hard anodizing coatings on AZ31 Mg alloy.
• To evaluate the corrosion resistance and biocompatibility of the developed coatings.
• To investigate the effect of post-anodizing annealing on coating properties.

Main Methods:

• Hard anodizing of AZ31 Mg alloy in a glycerol phosphate electrolyte.
• Optimization of anodizing parameters for enhanced corrosion resistance.
• Electrochemical impedance spectroscopy in Hank's solution at 37 °C.
• Post-anodizing annealing at 350 °C for 24 hours.
• Material characterization using energy-dispersive X-ray spectroscopy and Raman spectroscopy.
• Gravimetric measurements for hydrogen evolution rate.
• In vitro biocompatibility testing with preosteoblast cell lines.

Main Results:

• Optimized anodizing conditions significantly improved corrosion resistance.
• Post-anodizing annealing further enhanced the corrosion resistance of magnesium phosphate coatings.
• Hydrogen evolution rates were within acceptable limits for biomedical applications.
• In vitro tests confirmed the biocompatibility of the coatings with preosteoblast cells.

Conclusions:

• Hard anodizing combined with annealing is an effective method to improve the corrosion resistance of AZ31 Mg alloy.
• The developed coatings exhibit excellent biocompatibility, making them suitable for biomedical devices.
• This approach offers a promising strategy for utilizing AZ31 Mg alloy in orthopedic and other biomedical applications.