The Effect of Bath pH and Temperature on the Corrosion Behavior of Co-Electrodeposited Ni-Cu/Cr 2 O 3 Nanocomposite Coat
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JMEPEG https://doi.org/10.1007/s11665-020-05301-y
The Effect of Bath pH and Temperature on the Corrosion Behavior of Co-Electrodeposited Ni-Cu/Cr2O3 Nanocomposite Coatings Ali Taherimanesh, Ali Mohammad Rashidi
, and Shahab Zangeneh
Submitted: 16 June 2020 / Revised: 7 October 2020 / Accepted: 22 October 2020 The aim of this work was to assess the influence of pH and temperature of bath plating on the performance of Ni-Cu/Cr2O3 nanocomposite coatings in a corrosive environment. For this purpose, Ni-Cu/Cr2O3 nanocomposite coatings were successfully carried out on the carbon steel by co-electrodeposition method from an aqueous composing of H2O, NiSO4, NiCl, CuSO4, Na3C6H5O7, and H3BO3 with and without 6 g/L Cr2O3 nanoparticles. The microstructure of samples was studied by x-ray diffraction and scanning electron microscopy, and corrosion behavior of the coatings was assessed by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in the 3.5% NaCl solution. It was observed that by increasing the bath pH from 3 to 7 the corrosion current density (icorr) determined by Tafel extrapolation method was changed from 7.4 to 12.5 lA/cm2 and that polarization resistance (RP) obtained from EIS measurements was decreased from 850 to 452 XÆcm2. The values of icorr and RP were changed from 11.2 lA/ cm2 and 514 XÆcm2 to 6.1 lA/cm2 and 1265 XÆcm2, respectively, as the bath temperature was varied from 25 to 45 °C. Compared to the Ni-Cu nanocrystalline coating, the value of Rp showed more than 324% improvement when co-electrodeposition of Ni, Cu, and Cr2O3 was carried out at a temperature of 45 °C and pH value of 4.5. Keywords
coating, composite, corrosion, nanomaterials
1. Introduction It has been increasingly clear that the majority of destructions in the industry due to corrosion can be managed by coating of materials with more durable substance and/or by surface modification by different methods such as laser surface alloying, ion implantation, and other techniques (Ref 1). A wide variety of organic, metallic, glasses, and ceramics coatings were employed to increase corrosion resistance. Among them, nickel and its alloys such as Ni-Cu coatings due to combination of good corrosion resistance, mechanical, electrical, anti-biofouling, and catalytic properties are widely used to protect steel components in various acidic, alkaline, and chloride (seawater) environments (Ref 2, 3). Electrochemically co-deposition of hard particles suspended in the electrolytic bath by means of electroplating or electroless plating methods is a commercially viable approach to apply nanocomposite coatings. These nanocomposite coatings show superior properties as related to theirs (Ref 4, 5). For example, Thurber et al. (Ref 6) revealed an increase of 380%, 300%, and 25% in adhesion shear strength, polarization resistance, and Vickers microhardness, respectively, for the Cu-Ni coatings incorporated with MMT (a type of layered silicate) as compared to the pure Cu-Ni coating. Ali Taherimanesh, Ali Mohammad Rashidi, and Shahab Zangene
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