Effect of Current Density and Fly Ash Composition on Nickel Grain Size and Hardness of Nickel-Fly Ash Composite Coating Deposited on Aluminum Alloy 6061
Keywords:current density, fly ash composition, grain size, Ni-FA composite coating
The nickel- fly ash (Ni-FA) composite coatings were deposited on zincated aluminium alloy 6061 (AA6061) substrate by using electrodeposition technique. The electrodeposition process was carried out for 1 hour at 40º C. The current density used was extended from 1, 5 to 9 A/dm2. Fly ash particles was added to nickel citrate bath at 0, 10, 50 and 90 g/l for electrodeposition of Ni-FA composite coating. The produced composite coatings were characterized using X-ray Fluorescence (XRF) and X-ray Diffraction (XRD). Microhardness of Ni-FA composite coatings were also investigated in this study. As the current density increased from 5 to 9 A/dm2. The nickel grain size in the Ni-FA composite coating were decreased. The decreasing in nickel grain size resulted in increasing of hardness value. Besides, the hardness results show a clear increasing trend with an increase of fly ash composition from 10 to 90 g/l, due to the presence of hard oxide in the fly ash particles.