Nano-sized Y2O3 particles were codeposited with nickel by electrolytic plating from a nickel sulfate bath. The effects of the incorporated Y2O3 on the structure, morphology and mechanical properties (including microhardness, friction coefficient and wear resistant) of Ni-Y2O3 composite coatings were studied. It is observed that the addition of nano-sized Y2O3 particles shows apparent influence on the reduction potential and pH of the electrolyte. The incorporated Y2O3 increases from 1.56 wt.% to 4.4 wt.% by increasing the Y2O3 concentration in the plating bath from 20 to 80 g/l. XRD results reveal that the incorporated Y2O3 particles favour the crystal faces (2 0 0) and (2 2 0). SEM and AFM images demonstrate that the addition of Y2O3 particles causes a smooth and compact surface. The present study also shows that the codeposited Y2O3 particles in deposits decrease the friction coefficient and simultaneously reduce the wear weight loss. Ni-Y2O3 composite coatings reach their best microhardness and tribological properties at Y2O3 content 4.4 wt.% under the experiment conditions. (C) 2011 Elsevier B. V. All rights reserved.