The surface modified titanium nitride (TiN) nanoparticles with mercaptopropylmethyldimethoxysilane (MPMDMS) were incorporated into polyurethane (PU). The electrochemical impedance spectroscopic (EIS) studies revealed excellent protection behaviour for the PU-MPMDMS/TiN coated AA7055 in 3.5% NaCl solution. The coating resistance of the PU-MPMDMS/TiN nanocomposite was found to be 6917.19 k ohm.cm(2). It was also found that the coating resistance of PU-MPMDMS/TiN nanocomposite was over 44.58% higher than that of the PU coating. The measured current by scanning electrochemical microscopy (SECM) over the PU-MPMDMS/TiN nanocomposite coating was very low (1.5 nA) compared to pure PU coated AA7055 (14.9 nA). The surface morphological studies of the coated AA7055 by SEM/EDX analysis and X-ray diffraction (XRD) analysis revealed that the TiN nanoparticles were enriched at the corrosion products which prevented corrosion initiation processes. The enhanced mechanical properties were noticed for the PU-MPMDMS/TiN nanocomposite. The results showed that the newly developed PU-MPMDMS/TiN nanocomposite coating possessed enhanced hydrophobic behaviors (WCA: 157o). Therefore, it was concluded that the newly synthesized PU-MPMDMS/TiN nanocomposite provided excellent barrier, hydrophobic, and mechanical properties due to the addition of MPMDMS/TiN nanoparticles to the polyurethane resin which prevented the degradation of materials and helped to prolong the life of the coated AA7055 aluminium alloy.
