Electrodeposition of CNTs/copper composite coatings with enhanced tribological performance from a low concentration CNTs colloidal solution

A novel colloidal solution containing low concentration carbon nanotubes (CNTs) is proposed as the plating solution of electrodeposition to prepare CNTs/copper (CNTs/Cu) composite coatings. The CNTs/Cu composite coatings are characterized by X-ray diffraction and scanning electron microscope. Their tribological behaviors are evaluated in dry conditions over a range of applied loads and CNTs content in plating solution. Negatively charged CNTs stably coexist with [Cu II EDTA] 2− complexes due to the electrostatic repulsion between them, which facilitates the homogenous electrodeposition of individual CNTs in the Cu matrix and reduction of CNTs content required in the plating solution. The CNTs concentration in plating solution significantly affects the surface morphology and compactness of the deposits. CNTs/copper composite coatings obtained from the plating solution with moderate CNTs concentration, e.g. 0.12   g   L −1 , show obviously lower and steadier friction coefficient and higher wear resistance than pure copper coatings.