Enhanced hardness of nickel coating reinforced functionalized carbon nanomaterials via an electrodeposition technique

Abstract

In this paper, the nickel (Ni) coatings reinforced carbon nanomaterials including graphene nanoplatelets (GNPs), multi-walled carbon nanotubes (MWCNTs) and MWCNTs/GNPs hybrid material prepared by the electrodeposition technique were investigated. GNPs and MWCNTs were functionalized with carboxylic (–COOH) function groups (GNPs–COOH, MWCNTs–COOH) then uniformly dispersed into Watts solution for the electrodeposition process. The obtained results revealed that the microhardness of the Ni coating reinforced COOH functionalized carbon nanomaterials is much improved compared to the bare Ni coating and Ni coating containing carbon nanomaterials without functional groups. The Ni coating containing MWCNTs–COOH/GNPs–COOH hybrid material showed the highest hardness value of 270 HV that is higher 44.7% compared to the bare Ni coating. The enhancement was attributed to the uniform dispersion of functionalized carbon nanomaterials in Ni matrix, the synergistic strengthening effect of the MWCNTs and GNPs, the grain refinement of Ni matrix and the enhanced load transfer effect from Ni matrix to MWCNTs and GNPs via atomic bonding during the electrodeposition process.