Preparation and performance analysis of Zn-Ni/SiC composite coatings for oil pipeline applications

To enhance the corrosion resistance and drag reduction performance of X80 pipeline steel used in oil transportation, Zn-Ni/SiC coatings were prepared via direct current electrodeposition. Unlike previous studies that focused on Zn-Ni coatings, this work systematically investigates the role of SiC content on phase evolution, microstructure, and surface functional properties. A particular novelty of this study lies in the promotion of the γ-Ni₅Zn₂₁ phase and suppression of the η-Zn phase through SiC incorporation. The coating with 4 g/L SiC exhibited the best performance, achieving a 167.6 % increase in microhardness, 49.4 % and 48.1 % reductions in wear rate and friction coefficient, a 49.9 % increase in contact angle, and a 73.3 % improvement in polarization resistance. These enhancements were attributed to grain refinement, dispersion strengthening, and improved surface uniformity. This study offers new insights into the design of multifunctional Zn-Ni-based composite coatings and provides theoretical support for protecting pipeline steels in corrosive service environments.