LAUSR

Abstract The objective of this work is to study the synthesis of Cu-ZrO 2 nanocomposites using the thermochemical process followed by powder metallurgy method, and investigate their mechanical properties. Cu-ZrO 2 nanocomposite has been formed in-situ by adding ammonia to ZrOCl 2 solution, then adding Cu(NO 3 ) 2 solution to the deposition, precipitate heating them at 600 °C for 1 h and reduction by hydrogen atmosphere. The analysis of powders structure were examined by X-ray diffraction (XRD) which indicated the presence of CuO and ZrO 2 after oxidizing whereas copper oxide is transformed into elementary copper and ZrO 2 particles remain in its form after reduction. Cu-ZrO 2 powder mixtures were compacted under a compressive force of 700 MPa and sintered at 950 °C for 2 h in hydrogen atmosphere. The results of FE-SEM and EDS studies showed Cu-ZrO 2 composites have a uniform microstructure in which zirconia nanoparticles (45 nm) are distributed uniformly in the Cu matrix. The relative densities of the nanocomposites decreased gradually from 96.1% to 90.2% with increasing zirconia content up to 9 wt. %. The results indicated that microhardness, compressive strength and wear resistance increased with increasing ZrO 2 content. The wear rate of the nanocomposites increased with increasing applied loads or sliding velocity.