Development of Ni–Al2SiO5/Ni–SiO2 Coating Doped with Benzotriazole: Corrosion, Structural Evolution and Thermal Degradation Study

Abstract

Several engineering mild steel components have catastrophically failed, due to structural defects, corrosion and wear deformation. These drawbacks have prompted a continuous mild steel modification, for its higher durability and efficiency. In an attempt to improve the metal performance, Ni–SiO 2 (silicon dioxide), Ni–SiO 2 –C 6 H 5 N 3 (1H-benzotriazole), Ni–Al 2 SiO 5 (niquel + aluminum silicate) and Ni–Al 2 SiO 5 –10C 6 H 5 N 3 composite films were developed on mild steel samples, at a constant temperature of 45 ºC, and deposition time of 20 min. The coating performances were investigated by potentiodynamic polarization technique, CERT UMT-2 multi-functional tribological testing, high resolution optical microscopy and high diamond pyramid indentation. The samples were further subjected to heat-treatment, and its effects on hardness were examined. Potentiodynamic polarization study carried out in 0.5 M HCl revealed an improved anti-corrosion resistance. The hardness and wear tests showed better mild steel mechanical properties. Ni– Al 2 SiO 5 –10C 6 H 5 N 3 coated sample had better hardness and wear resistance features that those from the other samples. High resolution optical microscopy unveiled the particles homogeneous distribution throughout mild steel, with a new surface evolution. Mild steel surface morphology and other properties was optimized by Ni–SiO 2 , Ni–SiO 2 – C 6 H 5 N 3 , Ni–Al 2 SiO 5 and Ni–Al 2 SiO 5 –10C 6 H 5 N 3 coatings. Comparatively, NiAl 2 SiO 5 – C 6 H 5 N 3 coated mild steel exhibited the overall best performance characteristics, and it is thus recommended for advanced applications in petrochemical and marine industries.