Effect of Cobalt Content on Wear and Corrosion Behaviors of Electrodeposited Ni–Co/WC Nano-Composite Coatings

Abstract

Metal-ceramic composite coatings are widely used in automotive and aerospace industries as well as micro-electronic systems. Electrodeposition is an economic method for application of these coatings. In this research, nickel-cobalt coatings reinforced by nano WC particles were applied on carbon steel substrate by pulse electrodeposition from modified Watts bath containing different amounts of cobalt sulphate as an additive. Saccharin and sodium dodecyl sulphate (SDS) were also added to electroplating bath as grain refiner and surfactant, respectively. The effect of cobalt content on wear and corrosion behavior of the coatings was investigated. Wear and corrosion properties were assessed by pin-on-disk and potentiodynamic polarization methods, respectively. Phase analysis was performed by X-ray diffraction (XRD) using CuK(alpha) radiation and the worn surfaces were studied by means of Scanning Electron Microscopy (SEM). The results showed that the addition of cobalt improved the wear resistance of the coatings. In the presence of 18 g/L cobalt in electrodeposition bath, the wear rate of the coating decreased to 0.002 mg/m and the coefficient of friction reduced to 0.695 while they were 0.004 mg/m and 0.77 in the absence of cobalt, respectively. This improvement in wear properties can be attributed to the formation of hcp phase in metallic matrix. Meanwhile, the corrosion resistance of the coatings slightly reduced because cobalt is more active metal with respect to nickel.

Comparative study on the corrosion behaviour of Lord Razor Blade Steel (LRBS) in aqueous environments

“…This means also that MS is more corroded in the tested solutions than LRBS specimens. It is widely recognized that the presence of other elements such as Cr and Co in LRBS specimens reinforced the corrosion resistance of LRBS in comparison with MS [3,4].…”

Robust Ni/WC superhydrophobic surfaces by electrodeposition

“…33 The WC nanoparticles (NPs) contribute to nickel grain size reduction during codeposition while hardness and wear resistance of the composite coating are enhanced. [34][35][36] Although the coatings have excellent wear resistance, they are intrinsically hydrophilic as the embedded WC particles in the coatings have strong covalent bonds and high surface energy. 37 Therefore, developing a simple, inexpensive approach for a robust superhydrophobic surface is high required.…”

Microstructure and properties of Ni–Co–TiO2 composite coatings fabricated by electroplating

“…Various solid particles, such as SiC, 10 CeO 2 , 11 Al 2 O 3 (Ref. 12) and WC, 13 have been incorporated into the NiCo coating matrix through electrochemical methods. However, limited research has been so far reported on the preparation and property of electrodeposited Ni-CoTiO 2 composite coatings, 14,15 and the existing research focused on the corrosion property of composite coatings.…”