화학공학소재연구정보센터
Process Safety and Environmental Protection, Vol.141, 366-379, 2020
Corrosion behaviour of Zn-Ni alloy and Zn-Ni-nano-TiO2 composite coatings electrodeposited from ammonium citrate baths
Electrochemical and corrosion behaviour analysis of Zn-Ni alloy and Zn-Ni-nanoTiO(2) composite coatings electrodeposited on steel from ammonium citrate containing bath was performed. The complexation of zinc and nickel ions in citrate stabilized the electroplating bath. The electrochemical behaviour of samples showed that Zn-Ni alloy with the incorporation of 0.003 mol/l of titania (TiO2) nanoparticles exhibited noble corrosion potential (E-corr) and decreasing corrosion current (I-corr). This leads to increase impedance modulus with a more compact and durable uniform coating of 25.84 nm grain size. The surface characterization and crystalline phase texture of the coatings were investigated by scanning electron microscopy (SEM) integrated with energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The topographical structure of the coating was analyzed by atomic force microscopy (AFM). The chemical composition result showed that the Zn-Ni+0.003TiO(2) coating electrodeposited from a citrate bath in various immersion tests reduced dezincification in the coating. The presence of higher intensity of the gamma-phases (gamma-NiZn3)(815) and gamma-Ni2Zn11 (330) (631) plane orientation and p-Ti phase provide better corrosion resistance performance of the coating. The most significant corrosion products for Zn-Ni alloy electroplating are simonkolleite, hydrozincite, zincite, and wulfingite. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.