Preparation and characterization of Ni-Cr nanocomposite coatings containing TiO2 nanoparticles for corrosion protection

Purpose - The purpose of this paper is to investigate the effect of TiO2 nanoparticle content on the corrosion behavior of Ni-Cr/TiO2 nanocomposite coatings applied by pulse-reverse electroplating. Design/methodology/approach - Ni-Cr/TiO2 nanocomposite coatings with various contents of TiO2 nanoparticles were electrodeposited by pulse-reverse method from a bath containing TiO2 nanoparticles to be codeposited and citric acid as the complexing agent. The surface morphology and the composition of coatings were studied by scanning electron microscopy (SEM) equipped by energy dispersive X-ray system (EDS). The corrosion performance of coatings in the 0.5 M NaCl as a corrosive solution was investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods. Findings - It was found that the surface of Ni-Cr/TiO2 nanocomposite coatings showed a finer structure that was more uniform and compact in appearance than was that of Ni-Cr coatings. The incorporation of TiO2 nanoparticles in the alloy coating matrix improved the corrosion performance of the coatings and the higher content of nanoparticles gave better corrosion resistance. Originality/value - Applying the Ni-Cr coatings by the pulse-reverse plating method eliminated cracks that were a problem in the Ni-Cr alloy coating structure. Furthermore, the corrosion resistance was improved by the addition of TiO2 nanoparticles to the alloy matrix. This paper reports the optimum plating conditions that gave the better corrosion performance.