In this work, ordinary epoxy coatings were modified by hydrophobic nanoSiO 2 and hydroxyl PDMS to construct ultrahydrophobic epoxy coatings for corrosion protection and self-cleaning of phosphatized Q235 carbon steel. Ordinary epoxy polymer coating was fabricated via polyaddition reaction between E44 (bisphenol A epoxy resin oligomer) and DDM (4,4-diaminodiphenyl methane). The microscopic morphologies of coatings showed that many SiO 2 nanoparticles were presented on the surface of ultrahydrophobic epoxy coating. Through static water contact angle measurement, the modified epoxy coating displayed ultrahydrophobicity with a water contact angle of approximately 150°. However, adding too much nanoSiO 2 caused cracks on the modified epoxy coating, which deteriorated the corrosion resistance of the coating. According to the corrosion test results, the modified coating added with 6.7 wt% hydrophobic nanoSiO 2 and chemically modified with hydroxyl PDMS showed the best corrosion protection performance, which was reflected by the high impedance of approximately 10 9 Ω·cm 2 after 50 d immersion in 3.5 wt% NaCl (aq.). Besides, the coating also presented good self-cleaning performance. The coating extracted from the slurry still remained clean without any contamination.
The current research focus is to design a robust micro/nano-structured superhydrophobic epoxy coating to improve the wetting and anti-corrosion behavior of Q355 mild steel in harsh environment and obtain desired properties of self-healing and self-cleaning. Modified attapulgite (APT) and cerium nitrate based high-performance corrosion inhibitor ODA/PDA/APT-Ce 3+ (OPA Ce 3+ ) coatings were synthesized by the addition of dopamine (DA) and octadecylamine (ODA) which resulted in excellent corrosion inhibition by enhancing the corrosion protection performance of metal alloy and improving the water contact angle of the synthesized epoxy based OPA Ce 3+ coating to more than 160°. While wettability and corrosion protection were strongly associated with cerium nitrate and DA content, the surface microstructure of coated steel samples were relevant to attapulgite quantity. Moreover, the OPA Ce 3+ surface coating demonstrated good self-healing properties to counter chemical deterioration in harsh environment after being exposed for several hours to 3.5 wt% sodium chloride, acidic and alkaline solution. It was able to regain its superhydrophobic properties following hot air flow over the coating surface. The OPA Ce 3+ epoxy coatings displayed long-lasting and outstanding self-healing performance in terms of its wettability and electrochemical stability.
危险品化学品经营许可证（带存储）