Electrodeposition of nickel–graphene nanoplatelets (GNPs) composite coatings and evaluation of their morphological, electrochemical, and thermo-mechanical properties

Nickel matrix was electrodeposited on a conducting substrate from nickel Watts’s bath having priorly dispersed graphene nanoplatelets (GNPs) to produce GNPs-Ni composite coatings. It was found, by atomic force microscopy, that addition of GNPs improved the hardness as well as the roughness of the coatings in proportion to the GNPs addition. While observing the torn surfaces under scanning electron microscope, pure nickel coatings showed a pure ductile behavior but as the volume of GNPs is increased, the torn surfaces showed nearly brittle behavior as for the 0.4 wt.% GNPs composites. The electrochemical and thermo-mechanical analysis showed 0.2 wt.% GNPs’ addition as optimum concentration with highest corrosion resistance and strain recovery in comparison to other compositions. The corrosion rate of nickel matrix was best inhibited by 0.2 wt.% GNPs addition due to the uniform dispersion and dense structure overall. The thermomechanical analysis at 473 K temperature showed highest strain recovery rate for the 0.2 wt.% GNPs composites due to homogeneous dispersion.