A novel hybrid composite coating of poly-3-amino-5-mercapto-1,2,4-triazole/TiO2 on copper for corrosion protection

Poly-3-amino-5-mercapto-1,2,4-triazole/TiO₂ (p-AMTA/TiO₂) composite was effectively synthesized over the copper surface by cyclic voltammetric technique and used as a protective coating against corrosion. The resulting polymeric composite was characterized using Fourier transform infrared spectroscopy. The presence of TiO₂ particles in the polymer matrix was substantiated from X-ray diffraction pattern and energy-dispersive X-ray spectrum. The uniform dispersion of TiO₂ particles in the polymeric matrix was confirmed by the scanning electron microscope images. The protective effect of composite coating was evaluated by electrochemical impedance spectroscopy and potentiodynamic polarization methods in 3.5 % NaCl medium. Impedance measurements showed that charge transfer resistance (R _ct) values increased for polymeric composites which suggested the enhanced corrosion protection of copper. Further, the decrease in corrosion current density (i _corr) values and shifting of corrosion potential (E_corr) toward the cathodic direction confirmed the anticorrosive behavior of the polymeric composite. The reason for the higher protection of polymeric composite may be due to the well-dispersed TiO₂ particles in the polymer matrix exhibiting the enhanced barrier properties to protect copper surface from corrosion. The defects in the coatings can be reduced by embedded TiO₂ particles in the pores of the polymeric films to enhance the corrosion protection, consequently.