Multi-walled carbon nanotubes – zinc in commercial acrylic sealant as a coating for anticorrosive protection system in metallic building structures

Abstract

Corrosion protection is a matter of primary importance. In this regard, different methods have been explored to improve the protection of vulnerable areas of metallic structures with the aim of maintaining the homogeneous distribution of the protective layer and reducing cracks that allow the entry of corrosive agents. In this study, coatings with Multi-Walled Carbon Nanotubes and Zinc (MWCNTs-Zn), synthesized by the chemical vapour deposition method, in a commercial acrylic sealant were tested to protect welds. The coatings were produced with three different MWCNTs-Zn ratios (80:20; 50:50; 20:80) and applied to welded joints. The tested samples, characterized by SEM and XRD, showed a good dispersion of the MWCNTs tubular structure surrounding the Zn lamellar structure. In addition, the coatings exhibited a particle size range from 29 to 352 nm, which acted as a barrier against the corrosive medium, improving the anticorrosive performance. Electrochemical techniques and accelerated tests at different ages showed that these coatings offer an effective protective barrier. The samples were subjected to an accelerated corrosion test during 336 h, the 50:50 MWNTCs-Zn ratio presented better results than the 80:20 ratio (i_corr and R_corr, ∼50% lower in the cyclic corrosion test and 27% lower in the salt spray test).

Keywords:

• Structural steel
• multi-walled carbon nanotubes (MWCNTs)
• corrosion protection
• electrochemical tests
• accelerated tests

Acknowledgements

Authors would like to thank the Mexican Council of Science and Technology (CONACYT) for its financial support through the Chairs-CONACYT-Project Number 746 and the National Laboratories 2022-321116 for their technical support. In addition, authors would like to thank Juan Francisco Perez Robles from CINVESTAV, Querétaro, México.

Data availability statement

Data available on request from the authors. The data that support the findings of this study are available from the corresponding author, [M.P. Gurrola], upon reasonable request. Basic, Share upon Request.

Disclosure statement

No potential conflict of interest was reported by the authors.