Electrodeposition of nanocrystalline Ni–W coatings strengthened by ultrafine alumina particles

In the present study, the electrodeposition conditions for Ni–W/Al2O3 nano-composite coatings from aqueous electrolyte solutions have been developed with the view of preparing hard protective coatings. The influence of processing parameters (type of alumina powder, current density, ultrasonic field frequency) on the metal matrix characteristics and the electrochemical behaviour of the electrode was discussed. The effect of the structure of the nano-dispersive phase on the content and distribution of embedded Al2O3 particles has also been reported. Based on mechanical and microstructural properties of the coatings, the optimum conditions for obtaining the crack-free homogeneous Ni–W/Al2O3 composite coatings have been determined.