Surface characterization and corrosion protection of silane coated AZ31 magnesium orthopedic implants

The present study was done to investigate the corrosion behavior of AZ31 magnesium alloy coated with silane coatings consisted of methyltriethoxysilane (MTES), 3glycidoxypropyltriethoxysilane (GPTMS) and tetraethylorthosilicate (TEOS) in alcohol and acid base sols. The corrosion behavior was assessed by electrochemical impedance spectroscopy (EIS) during immersion in a simulated body fluid. Scanning electron microscopy (SEM) and water contact angle were used to perform a surface analysis. The electrochemical results proved an improvement in anticorrosion properties of AZ31 substrates. The coating achieved by the alcohol base sol evinced a more corrosion resistant barrier compared with the sample coated in an alcohol-base sol. The less resistant coating attained by acid sol was found to be replete with local delaminated areas which facilitate electrolyte penetration. High rates of corrosion on magnesium implants has hampered their usage in practice. The relatively resistant coating achieved by the alcohol-base sol is highly likely to be promote cell viability on magnesium implants.

Keywords:

Magnesium AZ31 , Silane coating , Electrochemical impedance spectroscopy , Polarization spectroscopy