Nickel composite plating with fly ash as inert particle
(Institute of Materials Science, 18 Hoang Quoc Viet, 10 000, Hanoi, Vietnam)
Abstract: The Ni/FA composite plating was realized by electrodeposition with fly ash (FA) as inert particles. The main compositions of FA are 72% SiO2 and 25% Al2O3 in the size of 3-7 μm. Electrodeposition was performed in Watts bath containing FA with concentrations of 5, 20, 50 g/L, current densities of 2 and 4 A/dm2, temperature of 50 °C and magnetic stirring of 250 r/min. Scanning electron microscope (SEM+EDX), electrochemical and mechanical technique were used to study morphology, composition and properties of coating. FA content in deposit is dependent on the FA concentration in solution, as well as the plating parameters. Since FA particles were incorporated in the coating, the mechanical and electrochemical properties of the coating were increased. The microhardness of Ni/FA composite plating reaches HV 430 in comparison with HV 198 of pure Ni coating. It was confirmed by electrochemical measurement that the corrosion resistance of Ni/FA composite coating was higher than that of pure Ni.
Key words: composite plating; fly ash; microhardness; corrosion resistance; inert particles