Research on the Construction of Durable Superhydrophobic Surface Based on the Two-Step Method of X80 Steel and Its Anti-hydrate Adhesion Performance

Hydrate formation and accumulation in oil and gas pipelines pose a critical risk to flow assurance. Pipeline coating technology presents a promising strategy to mitigate this problem. However, most existing studies focus on applying functional coatings onto the pipe substrate to prevent hydrate deposition. Such approaches often involve complex processes and carry the risk of coating delamination. To overcome these limitations, this study directly constructed a superhydrophobic surface on X80 pipeline steel. An innovative two-step method based on chemical etching and surface modification was proposed. A composite solution of hydrogen peroxide and hydrochloric acid was employed to etch the X80 steel, creating a micro-nano structured surface, which was subsequently modified with perfluorooctyl triethoxy silane to impart low surface energy. This process successfully fabricated an etched-modified surface@X80 with anti-hydrate deposition properties. The designed surface significantly increased the water contact angle from the original 97.3° to 151.4°, achieving superhydrophobicity. Experimental results demonstrated that the etched-modified surface@X80 exhibited excellent resistance to methane hydrate deposition. In contrast to the bare substrate, which was completely covered by methane hydrates, no hydrate adhesion was observed on the etched-modified surface@X80. Furthermore, the surface showed remarkable mechanical durability. After 120 load-friction cycles, the water contact angle remained at 142.5°. The adhesion force between the surface and hydrates was quantified using a micro-mechanical force method, revealing an average value of only 0.001 mN/m for the etched-modified surface@X80. This represents a reduction of approximately 99.19% compared to the bare substrate. These findings indicate that the shear force generated by fluid flow within the pipeline is sufficient to resist hydrate deposition on the etched-modified surface@X80. In summary, this study successfully constructed a superhydrophobic surface on X80 pipeline steel via a simple and efficient two-step method. The resulting surface possesses excellent mechanical stability and anti-hydrate adhesion performance, offering a novel and reliable solution for ensuring flow safety in deepwater oil and gas transportation and hydrate development pipelines.