Smart ZnS@C filler for super-anticorrosive self-healing zinc-rich epoxy coating

• Published in: Nano research 2022-05, Vol.15 (5), p.4756-4764
• Main Authors: Yang, Kai, Duan, Yixue, Liu, Guicheng, Ma, Guoyan, Fu, Hao, Chen, Xuyong, Wang, Manxiang, Zhu, Gangqiang, Yang, Woochul, Shen, Yiding
• Format: Article
• Language: English
• Subjects: Atomic/Molecular Structure and Spectra; Barrier layers; Biomedicine; Biotechnology; Carbon; Cathodic coating (process); Cathodic protection; Chemistry and Materials Science; Coatings; Condensed Matter Physics; Corrosion; Corrosion prevention; Epoxy coatings; Fillers; Maleic anhydride; Materials Science; Nanotechnology; Protective coatings; Research Article; Self healing materials; Shielding; Structural steels; Substrates; Water vapor; Zinc; Zinc coatings; Zinc sulfide
• ISSN: 1998-0124; 1998-0000
• DOI: 10.1007/s12274-022-4161-5

The zinc-rich epoxy cathodic protection coating is the most widely used anticorrosion material for marine steel. However, traditional conductive fillers lack the intelligent self-healing effect, which limits the long-term anticorrosion performance. Herein, with uniform carbon-coated ZnS (ZnS@C) nanoballs as the smart active release filler, we propose an anticorrosive and self-healing zinc-rich maleic anhydride epoxy coating. Due to the high pore filling efficiency of the nanoballs, the water vapor transmission rate of the coating with an initial corrosion efficiency of 99.92% and a low-frequency impedance of ∣ Z ∣ f =10mHz = 3.88 × 10 10 Ω·cm 2 , was reduced by 52%. The carbon-shell of the nanoball increases electron transmission paths in the coating and improves conductivity by nearly two orders of magnitude, which effectively activates more Zn-sites and extends the cathodic protection time. Moreover, once the steel-substrate undergoes regional corrosion, the SO 4 2− hydrolyzes from the ZnS-core of the nanoball and reacts with iron ions on the corroded area accurately and intelligently to fill the gap and self-heals into a new dense barrier layer (Fe 2 (SO 4 ) 3 , etc.), which significantly improves the shielding protection ability during the long-term usage of the coating. The effective anticorrosion time of the proposed coating could be up to 3,400 h.