Effect of Anodizing Parameters on Corrosion Resistance of Coated Purified Magnesium

TL;DR

This study investigates how anodizing parameters affect the corrosion resistance of stearic acid-coated purified magnesium, aiming to improve its suitability as a biodegradable biomaterial.

Contribution

It introduces a specific anodizing process to significantly enhance magnesium's corrosion resistance for biomedical applications.

Findings

Optimal anodizing at +4V for 4 min at 70°C in borate benzoate improves corrosion resistance by 1000x.

Electrochemical tests confirm the effectiveness of the anodizing parameters.

Hydrophobic coating reduces magnesium corrosion in biological environments.

Abstract

Magnesium and its alloys are being considered for biodegradable biomaterials. However, high and uncontrollable corrosion rates have limited the use of magnesium and its alloys in biological environments. In this research, high purified magnesium (HP-Mg) was coated with stearic acid in order to improve the corrosion resistance of magnesium. Anodization and immersion in stearic acid were used to form a hydrophobic layer on magnesium substrate. Different DC voltages, times, electrolytes, and temperatures were tested. Electrochemical impedance spectroscopy and potentiodynamic polarization were used to measure the corrosion rates of the coated HP-Mg. The results showed that optimum corrosion resistance occurred for specimens anodized at +4 volts for 4 minutes at 70{\deg}C in borate benzoate. The corrosion resistance was temporarily enhanced by 1000x.