Improving corrosion protection of Mg alloys (AZ31B) using graphene-based hybrid coatings

In the present work, a study was carried out to compare the morphology and electrochemical properties of pure and graphene-modified hybrid silica sol-gel coatings deposited on anodized AZ31B magnesium alloys. The precursor solution was prepared using tetraethoxysilane (TEOS) and 3-glycidoxypropyl-trimethoxysilane (GPTMS), with the addition of chemically modified graphene nanosheets (GN-chem). Homogeneous and adherent coatings were obtained using GPTMS-TEOS (GT) and GPTMS-TEOS-GN-chem (GT/GN-chem) solutions with uniform thickness around 4 mu m. Raman, SEM images and EDS analyses confirmed the presence of graphene nanosheets in the coatings. Potentiodynamic polarization results using 0.05 M NaCl electrolyte solution showed that graphene containing silica coatings significantly improve the corrosion resistance of AZ31B alloys. In addition, a significant passive region was observed for GT/GN-chem coatings.

Automated summary

A study compared the morphology and electrochemical properties of pure and graphene-modified hybrid silica sol-gel coatings on anodized magnesium alloys. The presence of graphene in the coatings improved the corrosion resistance of the alloys significantly, with a significant passive region observed in the graphene-containing coatings.