EFFECT OF SURFACTANT AND SACCHARIN ADDITION ON THE MORPHOLOGY AND WEAR BEHAVIOR OF Ni-Al₂O₃ NANO-COMPOSITE COATINGS

Nano-composite Ni-Al₂O₃ coatings due to their good wear and corrosion resistance have been widely used in different industries. The agglomeration of nano-particle ceramics in the electrolyte is a serious problem in electrodeposition process that leads to the presence of agglomerated particles in the coating and influences its properties. Using a suitable surfactant can be helpful to control the agglomeration of ceramic particles. In this research nano-composite Ni-Al₂O₃ coating has been deposited from an alumina containing Watts bath using a square pulse current and Sodium Dodecyl-Sulphate (SDS) as surfactant. It was observed that SDS addition has an important effect on the reduction of particles agglomeration and increases the incorporation of finer particles into the coating. Addition of saccharin to the electrolyte, decreases the grain size and the alumina content in the coating, and also, leads to lower agglomeration and better distribution of ceramic particles. Moreover, the synergistic addition of SDS and saccharin, decreases the grain size, increases the hardness and wear resistance, but has no effect on the crystallographic texture of the coating.