Super-Hydrophobic Stearic Acid Layer Formed on Anodized High Purified Magnesium for Improving Corrosion Resistance of Biodegradable Implants

TL;DR

This study demonstrates that a super-hydrophobic stearic acid layer on anodized high purified magnesium significantly reduces corrosion rates, enhancing its potential for biodegradable implant applications.

Contribution

It introduces a novel coating process combining anodization and stearic acid application to drastically slow magnesium corrosion in simulated body fluid.

Findings

Hydrophobic coating reduces corrosion rate by 1000x

Electrochemical tests confirm improved corrosion resistance

Coating process is effective at 37°C in simulated body fluid

Abstract

Magnesium and its alloys are ideal candidates for biodegradable implants. However, they can dissolve too rapidly in the human body for most applications. In this research, high purified magnesium (HP-Mg) was coated with stearic acid in order to slow the corrosion rate of magnesium in simulated body fluid at 37{\deg}C. HP-Mg was anodized to form an oxide/hydroxide layer, then it was immersed in a stearic acid solution. Electrochemical impedance spectroscopy and potentiodynamic polarization were used to estimate the corrosion rate of HP-Mg specimens. The results confirm that the hydrophobic coating can temporarily decrease the corrosion rate of HP-Mg by 1000x.