Enhancement of Interfacial Strength and Corrosion Resistance of Adhesives via Synergistic Effect of Metallic Surface Treatment and α‐ ZrP Nanosheets

ABSTRACT Polyurethane (PU) nanocomposites with enhanced mechanical performance and adhesive bonding are crucial for aerospace and automotive applications. This study investigates the reinforcing effect of α‐zirconium phosphate (α‐ZrP) nanosheets into PU; it also studies synergy between α‐ZrP's reinforcing effect and aluminium (Al) surface anodization on the mechanical strength and corrosion properties of PU‐based adhesive systems. The incorporation of α‐ZrP nanosheets into PU significantly improved the composite's mechanical properties: tensile strength and Young's modulus increased by 52% and 26%, respectively at 0.5 wt%. The adhesion bonding was evaluated using Al/PU single lap joints where synergy of nano‐reinforcement with anodizing Al‐surface treatment was studied. At 0.5 wt% of α‐ZrP loading, the lap shear strength and fracture energy increased 1.37 and 1.54‐fold, respectively, compared to neat PU adhesive. When combined with anodized Al surface, these enhancements reached 2.89‐fold for lap shear strength and 6.06‐fold for fracture energy due to efficient stress transfer and enhanced energy dissipation via mechanical interlocking at the adhesive‐adherend interface. Additionally, Tafel tests showed superior corrosion resistance of anodized Al/α‐ZrP‐PU coating in acidic, alkaline and saline environments. This work provides a facile strategy for designing high‐performance metal‐polymer systems for adhesive/coating applications through the integration of nanoscale reinforcement and surface engineering.