Some properties of Cu-MgO composites produced by powder metallurgy

Pure Cu matrix composite reinforced with MgO were successfully produced by powder metallurgy method. Nano sized MgO particles with 0.5, 1, 2 and 3 wt.% were mixed with copper powder in size of 40 ?m mechanically and compacted by applying 220 MPa pressure and sintered at 700°C for 2 hours in an open atmospheric furnace followed by hot pressing with the pressure of 590 MPa. SEM studies revealed that MgO particles were dispersed homogenously in copper matrix and any oxides of copper matrix were not detected which confirmed by EDS and XRD analyses. With the addition of 3wt.% MgO particles, hardness of composites increased from 89 HVN to 122 HVN while, relative density decreased from 94.2% to 84.1% and electrical conductivity from 90.15 to 43.5 IACS (International Annealed Copper Standard). As a result, optimum electrical conductivity and hardness balance for promising contact material was obtained with the addition of max. 2wt.% of MgO.