Effect of stirring rate on the microstructure and microhardness of Ni–CeO2 nanocomposite coating and investigation of the corrosion property

The nickel–ceria nanocomposite coatings have been pulse electrodeposited from a Watts-type electrolyte containing nano-sized ceria particles have been synthesized by high energy ball milling technique. The influence of the stirring rate of the plating bath on the microstructure and hardness of nickel–ceria nanocomposite coating has been investigated and the corrosion property of the nanocomposite coatings has also been studied. Experimental results show that both the co-deposition of ceria particles in the Ni matrix and microhardness of the composite coating increase up to the stirring rate of 450rpm. Beyond this stirring rate the co-deposition of ceria particles decreases in the Ni matrix resulting in a decrease in the hardness of the composite coating. Another reason of decreasing hardness of the composite coating is the agglomerations of ceria particles that take place after the stirring rate of 450rpm. Higher corrosion resistance has been found for the nickel–ceria nanocomposite coating electrodeposited from electrolyte with the stirring rate of 450rpm. ► The nano-sized ceria, produced by high energy ball milling technique, co-electrodeposited successfully in the nanocrystalline nickel matrix for producing Ni-CeO2 nanocomposite. ► SEM micrographs reveal that the approximately uniform distribution of the ceria in the nickel matrix upto the stirring rate of 450 rpm, beyond that agglomeration of ceria take place in the coating with pits. ► The hardness of the nanocomposite coating increases with the increase of the stirring rate upto 450 rpm. Beyond this amount, the hardness decreases due to agglomeration of the ceria particles in the nickel matrix. ► For Ni–CeO2 nanocomposite coatings the polarization resistance increases and corrosion rate decreases upto the stirring rate of 450 rpm.