Mechanical and tribological behavior of nanostructured copper-alumina cermets obtained by Pulsed Electric Current Sintering

Nanostructured Cu-Al2O3 powders obtained by the reduction of CuO with Al in a high energy ball mill were successfully consolidated by Pulsed Electric Current Sintering (PECS). The effect of the composition and microstructure of these PECS Cu-Al2O3 cermets on their strength was investigated. The friction and wear behavior of these cermets were studied under reciprocating sliding against corundum at 23 degrees C and 50% RH, and compared to the behavior of coarse grained PECS sintered pure copper. The effect of grain size on the coefficient of friction was masked by the formation of a surface tribolayer. The wear depth recorded on Cu-Al2O3 is lesser than half the one on coarse grained copper. Surface and subsurface deformation studied through FIB cross-sections showed that delamination and oxidative wear were active on Cu and Cu-Al2O3 cermets respectively under the current sliding test conditions. PECS Cu-Al2O3 cermets showed a good thermal stability even at 600 degrees C. (C) 2012 Elsevier B.V. All rights reserved.