Optimisation of the electrodeposition process of Ni-W/ZrO2 nanocomposites

Abstract

Ni-W/ZrO2 nanocomposite coatings were synthesised by electrochemical deposition from an aqueous sulphate-citrate electroplating solution containing zirconia nanoparticles in suspension. The electrodeposition process was carried out under a galvanostatic regime and controlled hydrodynamic conditions (in a rotating disc electrode system). The main aim of the study was to optimise the process parameters for the electrodeposition of Ni–W coatings modified by ZrO2 particles. Based on the results of previously conducted research, the set of experiments (eight series) was designed. The relationship between chemical composition, microstructure, and mechanical, wear and corrosion properties of Ni-W/ZrO2 nanocomposites, along with the electrodeposition parameters such as content of ZrO2 powder suspended in the galvanic bath, cathodic current density, hydrodynamic conditions and, ultrasonic field frequency were studied. Within the range of the experiments, the preferred combination of process parameters was determined to be zirconia nanoparticle content in the plating bath of about 5 g/L, ultrasonic (35 kHz) DC electrodeposition with current density of 11 A/dm2, applied cathode rotating rate of 600 rpm, yielding hardness, wear and corrosion rates of about 8 GPa and 1.4·10−6 mm3/Nm and 6 μA/cm2, respectively.