Corrosion protection of mild steel via cerium nitrate loaded acrylic-vinyl polysilazane based hybrid coatings

Abstract

This study presents an efficient anticorrosive coating based on an organic-inorganic hybrid polymer composed of methyl methacrylate, styrene, tert-butyl acrylate, and vinyl polysilazane. The synthesized resin exhibits excellent thermal resistance and stability, as confirmed by thermogravimetric analysis (TGA). Additionally, leveraging the resin's highly alkaline nature, cerium oxide (CeO₂) nanoparticles were doped in situ within the polymer matrix. The hybrid resins were subsequently applied to mild steel panels using a dip-coating technique. The resulting coatings are transparent, flexible, thin, pore-free, and possess low surface roughness (<2.62 nm), along with good thermal stability (>350 °C). Their remarkable anticorrosive performance and durability are attributed to forming a highly crosslinked acrylic-polysilazane network, combined with a cerium oxide protective barrier layer that adheres to the substrate. Furthermore, the cerium ions suppress both cathodic and anodic corrosion reactions, enhancing the corrosion resistance. Notably, the coating system containing 2 wt% cerium achieved a high impedance value of 10⁶ Ω cm², corresponding to a corrosion rate of 0.112 × 10⁻⁵ mm/year. This study demonstrates that these acrylic-vinyl polysilazane coatings, incorporating ceria as a corrosion inhibitor, offer a promising alternative to conventional protection systems.