Electrodeposition of Nickel/Graphene Oxide Particle Composite Coatings: Effect of Surfactants on Graphene Oxide Dispersion and Coating Performance

Abstract

The dispersibility of graphene oxide particles (GOs) in nickel electrolytes is critical for its uniform incorporation in the nickel matrix during the electrodeposition process. In this study, we study the fundamental interaction of surfactants and nickel ionic strength for uniform and stable incorporation of GOs in nickel electrolytes and their effect on coating performance. The results indicate that the non-ionic surfactant Polyethylene glycol (PEG) has the optimal dispersibility of GOs in nickel electrolyte, followed by the cationic surfactant Cetyltrimethylammonium bromide (CTAB) and the anionic surfactant Sodium dodecyl sulfate (SDS). It is also noted that the increasing nickel ionic strength would deteriorate the stability of GOs, attributing to the generation of cross-linking of high strength divalent nickel ions with dispersed graphene oxide. The electrodeposited coatings show that more incorporation of graphene oxide in the coating is achieved when the PEG surfactant is used, which leads to an increased hardness by 146% and a decreased friction coefficient by 72.7% under low nickel sulfamate concentration (200 g l−1), compared to pure nickel coating. Eventually, the study shows that higher nickel ionic strength would deteriorate the performance of the coatings, while the selection of proper surfactant can compensate for it.