Improving performance of an open cell aluminium foam through electro-deposition of nickel

The aim of this work is to investigate the mechanical performances and corrosion resistance of open-cell aluminium foams with an electroplated nickel coating. The influence of two different electrolytic solutions on mechanical properties and corrosion resistance was studied: The Watts solution (nickel sulphate-based solution) and a nickel sulphamate solution (widely adopted). Scanning electron microscopy and stereoscopic analysis allowed for the estimation of the coating uniformity and adhesion to the substrate. In order to assess the improvement of performances, compression and corrosion tests were performed on coated and uncoated foams. In addition, annealing was investigated in relation to different operational parameters, related both to electro-deposition (electrolyte, deposition current and time) and to annealing (treatment temperature). From the results, the yield stress and the corrosion resistance improved. Moreover, the annealing at increasing temperature was found to reduce the yield stress, but Ni-coated foams showed higher values of stress for all the considered treatment temperatures.