ZrO2-Embedded CNT Networks for Synergistically Toughened Superhydrophobic Anticorrosion Coatings of Pipeline Steel

Superhydrophobic coatings show promising potential for applications in petroleum pipeline anticorrosion due to their exceptional water repellency. A core bottleneck in the development of superhydrophobic coatings is their limited mechanical and corrosion durability, which is closely linked to microstructural fragility. Inspired by the protective mechanism of leaf mineralization, a superhydrophobic coating is developed via a simple low-temperature spraying method to reduce wear and corrosion in pipelines. A micro–nano structure is obtained by the synergistic effect of polydopamine (PDA)-linked ZrO2 nanoparticles and carbon nanotubes (CNTs) (ZrO2/CNTs@PDA). The CNTs imitate cellulose nanofibers to create a three-dimensional (3D) porous network. The ZrO2 nanoparticles simulate plant-based mineralized materials in both the internal holes of the network and the surfaces of the carbon nanotubes, thereby enhancing the mechanical strength and corrosion resistance of the ZrO2/CNTs@PDA coating. The ZrO2/CNTs@PDA coating exhibits a high water contact angle (WCA) of 165.6°, a small sliding angle (SA) of 6°, and an oil contact angle of 138.8°, demonstrating excellent superhydrophobicity and oleophobicity. The ZrO2/CNTs@PDA hydrophobic coating shifts the corrosion potential of X80 steel from −0.643 to +0.305 V and has a 7 orders of magnitude decrease in corrosion current density. The coating’s corrosion resistance showed no significant change after being immersed in 3.5 wt % NaCl solution for 21 days, confirming its excellent durability. Even after 1500 cm of abrasion, the coating retained a WCA above 150°, demonstrating its remarkable wear resistance. The coating exhibits excellent self-cleaning and antifouling performance, effectively repelling the accumulation of various substances such as sand, methylene blue, oil, and milk. It is worth emphasizing that the ZrO2/CNTs@PDA hydrophobic coating can be produced efficiently on a large scale while also demonstrating effective corrosion resistance, self-cleaning, and antifouling properties even under harsh operating conditions.