Nanocrystalline alumina dispersed in nanocrystalline nickel: enhanced mechanical properties

Nickel–alumina nano-composites have been electrochemically deposited by pulse plating from a suspension of nano-Al2O3 in a Watts-type electrolyte. The influence of duty cycle and amount of suspended Al2O3 on the content of Al2O3 in the deposit was studied. With an optimized set of plating parameters, the influences of additives on wear resistance, hardness and the deformation behaviour (quasistatic and dynamic compression tests) of these nickel–alumina nano-composites in comparison to pure nano-nickel were investigated. The addition of Al2O3 tripled the yield stress and improved the hardness up to twice the value of pure nickel. Due to its high hardness and stiffness, the nickel–alumina composites deposited with the additive naphthalene-1,3,6-trisulfonic acid trisodium salt in the electrolyte are appropriate to wear resistant coating. Nickel–alumina nano-composites deposited without any additives are hard and at the same time ductile and so considered as ideal structural materials.