A study on electrodeposition of Ni-noncovalnetly treated carbon nanotubes nanocomposite coatings with desirable mechanical and anti-corrosion properties

• Successful incorporation of non-covalently functionalized CNTs in electrodeposition bath
• Optimum electrodeposition condition obtained for Ni-MWCNT coatings with desirable properties
• Remarkable effect of CNTs on the texture, crystallite size, and internal microstrain of the coatings
• Nano-indentation and microhardness test confirm increased hardness and elastic modulus of the coatings.
• Corrosion rate decreases with increase in CNT content.

In this study, we report on the successful incorporation of non-covalently functionalized multi-wall carbon nanotubes (MWCNTs) in electrodeposition bath using a multi-step dissolution to enhance dispersing and untangling. We observed that a saturation concentration exists for CNT dispersion in the electrodeposition solution and consequently an optimum condition for electrodeposition of Ni-MWCNT was obtained at a current density of 4 A/dm2, and CNT concentration of 2 g/l. X-ray diffraction spectrum revealed a remarkable effect of CNTs on the texture, crystallite size, and internal micro-strain of the coatings. On the basis of nanoindentation and micro-hardness tests, increased hardness and elastic modulus of the coatings were observed which directly depend upon CNT content of the composite coating. Corrosion study results in 3.5% sodium chloride solution showed that corrosion rate decreases with increase in CNT content, though the corrosion rate is directly influenced by nickel crystallite size.