Green Carbon and Hexagonal Boron Nitride Heterostructure Reinforced Epoxy Composite With Improved Thermomechanical Properties and Anticorrosive Performance

ABSTRACT Protective epoxy (EP) coatings are widely used to prolong the service life of engineering materials in harsh conditions; however, their performance is often restricted by low thermal conductivity, inadequate mechanical strength, and poor long‐term corrosion resistance. To address these constraints, this study investigates integrating green carbon (GC) and hexagonal boron nitride (h‐BN) heterostructures into the EP matrix to develop multifunctional coatings. Mechanical characterization revealed significant improvements over EP, including ~98% higher ultimate tensile strength (UTS), ~65% more fracture strain, and ~60% higher reduced modulus ( E _r ). Thermal transport analysis using infrared thermography revealed lower temperature gradients along the specimen height, indicating improved heat conduction within the heterostructure composite. Electrochemical studies further demonstrated that the optimized heterostructure composite coating on carbon steel (CS) resulted in a ~9‐fold increase in impedance modulus and a ~92% reduction in corrosion rate (CR) compared to EP‐coated CS. These benefits are attributed to uniform filler dispersion, increased interfacial interactions that enable effective stress transfer and cross‐linking within the EP matrix, the formation of thermally conductive pathways, and improved barrier protection against corrosive ions. These findings emphasize GC and h‐BN heterostructures as effective reinforcements for EP coatings, improving mechanical, thermal, and anticorrosion properties.