Preparation and Corrosion Resistance of Thermally Cured EP-PVC Composite Powder Coatings

Marine metal structures such as ships and submarines are exposed to highly corrosive environments, requiring coatings that provide durable protection while maintaining environmental safety. This study investigates thermally cured EP-PVC composite powder coatings prepared via electrostatic spraying, comparing layer-by-layer and co-curing processes. The EP-PVC primer layer and PVC topcoat were analyzed using FT-IR, Raman spectroscopy, and TEM to understand microstructural evolution. Mechanical tests, including hardness, gloss, adhesion, and impact resistance, along with salt spray and potentiodynamic polarization tests, demonstrated that layer-by-layer cured coatings exhibit superior adhesion, hardness, and corrosion resistance, with corrosion rates as low as 0.0018 mm/a and overall protection reaching 67%. The enhanced barrier properties and interfacial bonding of the composite coatings effectively inhibit corrosive media penetration. These coatings are particularly suitable for electromagnetic engineering applications, such as protective surfaces for antenna arrays, RF transmission structures, and high-frequency marine electronics, where durable corrosion resistance is critical for long-term signal integrity and system reliability.