Development of anti-corrosion and hydrophobicity of a nanostructured Ce-La film via the PDA post-treatment modification

• Published in: Journal of alloys and compounds 2023-12, Vol.968, p.172139, Article 172139
• Main Authors: Flehan, Abdullah, Jinna, Liu, Tabish, Mohammad, Kumar, Anuj, Mohammed, Yusof A.Y.A., Mubeen, Muhammad, Makhlouf, Mohamed M., Yasin, Ghulam
• Format: Article
• Language: English
• Subjects: Cerium conversion coating; Cerium-lanthanum conversion coating; Corrosion resistance; Polydopamine post-treatment modification; Surface modification
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2023.172139

The Ce-La film has been created to improve the adhesion of the organic coatings with the metal surface. However, the development of cracks coincides with the formation of the Ce-La conversion coating. In addition, the high hydrophilicity of the Ce-La conversion coating adversely affects its adherence properties. In this study, poly-dopamine (PDA) in two forms namely PDA-A and PDA-B were employed as post-treatment layers to enhance the adhesion and corrosion resistance of the Ce-La film on Q235 carbon steel. The microstructure, wettability, and corrosion resistance were investigated. The results revealed that the PDA healed the cracks and increased the surface roughness and thickness of the Ce-La conversion coating. Moreover, the Ce-La film becomes more hydrophobic, and the contact angle increased from 6.509° to 61.745° and 85.009° after applying the PDA-A and PDA-B layers, respectively. The application of the PDA-B post-treatment layer significantly improved the overall corrosion resistance (Rt) of Ce-La conversion coating, increasing the Rt from 1180.6 to 1299.6 Ω.cm2 and decreasing the corrosion current density (icorr) from 2.466 to 1.652 µA/cm2. These findings demonstrate that applying PDA can improve both the adhesion and corrosion resistance of the Ce-La conversion coating. •Polydopamine was successfully applied as a post-treatment layer on the Ce-La conversion coating.•The morphological, thickness, and compositional properties of the Ce-La conversion coating were enhanced by the application of the polydopamine post-treatment layer.•The contact angle measurements showed that polydopamine post-treatment greatly enhanced adhesion in the Ce-La conversion coating.•Polydopamine post-treatment modification enhanced the anti-corrosion of the Ce-La conversion coating.