Effect of Carbon Nanotubes on Corrosion and Tribological Properties of Pulse-Electrodeposited Co-W Composite Coatings

Abstract

Cobalt-Tungsten (Co-W) alloy coatings possessing high hardness and wear/corrosion resistance, due to their ecofriendly processing, have been of interest to the researchers owing to its various industrial applications in automobile, aerospace, and machine parts. This technical paper reports Co-W alloy coatings dispersed with multiwalled carbon nanotubes (MWCNTs) produced by pulse electrodeposition from aqueous bath involving cobalt sulfate, sodium tungstate, and citric acid on stainless steel substrate (SS316). Studies on surface morphology through SEM, microhardness by Vickers method, microwear by pin-on-disk method, and corrosion behavior through potentiodynamic polarization method for the Co-W-CNT coatings were reported. Characterization studies were done by SEM and EDX analysis. The results showed that the corrosion and tribological properties of the pulse-electrodeposited Co-W-CNT alloy coatings were greatly influenced by its morphology, microhardness, %W, and MWCNT content in the coatings.

Preparation and characterization of pulsed electrodeposited cobalt–graphene nanocomposite coatings

“…3 Nanocomposite coatings based on cobalt (Co), tungsten (W), carbon nanotubes (CNTs), nickel (Ni), molybdenum (Mo), and zirconium (Zr) have been developed by pulsed electrodeposition techniques. 4–7…”

“…1 further states that the functionalization of nanotubes has considerably improved the co-deposition of cobalt ions. Addition of tungsten (W) into Co-MWCNT coatings has shown to have more improvement in the corrosion and tribological properties, 4 which was aided by the enhancement in overall microhardness provided by tungsten.…”

Mechanical and microstructural properties of carbon nanotubes reinforced chromium oxide coated boiler steel

“…Silva et al (2011) and Hvizdoš et al (2011) observed that the high strength and improvements in the synthesis of CNT recently has made it possible to use CNT in composite materials. It has been observed that addition of CNT in traditional coatings has increased the corrosion resistance at room temperature (Chen et al, 2005;Edward Anand and Natarajan, 2015;Praveen et al, 2007). The thermal sprayed coating is a porous material; therefore, a thermal sprayed coating has many local microcracks or through pores, and it is coated on a rough surface (Fukanuma, 1994;Pawlowski, 2008).…”

“…CNT are nanoparticles; therefore, these can easily enter and fill these pores and can decrease the porosity and also can increase the microhardness of these coatings. A few researchers have developed some CNT-Al 2 O 3 mix coatings and studied their wear behaviour (Balani et al, 2008a;Edward Anand and Natarajan, 2015;Guo and Tam, 2014;Gutierrez-Gonzalez et al, 2015;. But no researcher has sprayed CNT-Cr 2 O 3 composite coatings on boiler tube steel, and no studies are available in the literature to this effect.…”

Cyclic high temperature corrosion studies of carbon nanotubes-Cr2O3 composite coatings on boiler steel at 900°C in molten salt environment

“…Due to their nano size, CNT can easily enter these pores and can reduce the porosity of coatings. The addition of CNT in traditional coatings has increased the corrosion and wear resistance at room temperature (Keshri et al , 2010; Balani et al , 2008; Gutierrez-Gonzalez et al , 2015; Guo and Tam, 2014; Edward Anand and Natarajan, 2015).…”