The effects of electrodeposition current density on properties of Ni–CNTs composite coatings

The effects of electrodeposition current density on the properties of Ni–carbon nanotubes (CNTs) composite coating were studied with methods of scanning electron microscopy (SEM), tensile testing, hardness testing and electrochemical testing. The results show that the composite coating becomes coarser when the depositing current increases. As the depositing current density increases, carbon content in the composite coating first increases then decreases, with the highest carbon content at 8 A/dm2. The adherence, cracking resistance, micro-hardness and electrochemical resistance of the composite coatings all reach their peak values at 8 A/dm2. The results indicate that the existence of CNTs in the composite coatings improves toughness, strength and corrosion resistance of the coatings.