Corrosion performance and mechanism of clay-lignin biocomposite: Effective bio based coating with strong adhesion character for extended carbon steel protection

• Published in: Materials today communications Vol. 41; p. 110493
• Main Authors: Akachar, Soukaina, Zarki, Youssef, Ben Seddik, Nordin, Azaryouh, Leila, El Achaby, Mounir, Draoui, Khalid, Ait Aghzzaf, Ahmed
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2024
• Subjects: Alkyd coating system; Clay-lignin biocomposite; Corrosion protection; EIS measurements; Strong adhesion; Strong adhesion; Clay-lignin biocomposite; EIS measurements; Alkyd coating system; Corrosion protection
• ISSN: 2352-4928; 2352-4928
• DOI: 10.1016/j.mtcomm.2024.110493

The development of sustainable and eco-friendly anticorrosion coating for metal substrates is a pivotal advancement in various engineering fields. Hence, the novel sepiolite-lignin (SP-L) and bentonite-lignin (BN-L) biocomposites were successfully introduced in an alkyd resin 5.0 wt% and applied on carbon steel (CS), to prepare the alkyd SP-L (A/SP-L) and BN-L (A/BN-L) coatings. Particle size and zeta potential measurements were conducted to determine the average particle size and assess the stability of the reinforcing pigments. The corrosion performance of A/SP-L and A/BN-L coatings revealed higher protection with an impedance modulus of about 5.18 × 105 Ω.cm² and 7.86 × 105 Ω.cm², respectively, after 6weeks of immersion in 3 % NaCl solution, measured by electrochemical impedance spectroscopy (EIS), which were extremely higher than the reference alkyd (RA) 1.13 × 103 Ω.cm². The adhesion of the three coated samples before and after immersion was assessed using pull-off test, while their hydrophobicity and impermeability were evaluated using saline corrosion and water absorption tests. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were utilized to examine the corrosion mechanism. The results demonstrated an excellent coating quality and interfacial adhesion against corrosion. [Display omitted] •A/SP-L and A/BN-L coatings improved exceptional long lasting protection of CS in 3 % NaCl solution•The well-distributed and uniformly dispersed inhibitors enhanced the compactness of the alkyd coating.•The impermeability and hydrophobic properties of A/SP-L and A/BN-L coated samples greatly improve the CS protection.•Incorporated SP-L and BN-L biocomposites into the coating system block and/or prolonge the diffusion pathways of corrosion media.