Cu-Al BASED METALLIC-CERAMIC COMPOSITE POWDERS REINFORCED WITH Al2O3 FABRICATED BY REACTIVE MILLING

The aim of this work was to fabricate by reactive milling Cu-Al/Al2O3 composite powders and determination of their phase composition. Copper oxide CuO and copper salt Cu-2(OH)(2)CO3 (hydroxycarbonate) were used as reagents for mechanochemical processes. Various high energy ball milling processes were performed in order to obtain composite powders consisting of Al2O3 and CuAl2 or Cu9Al4 intermetallic compounds. It was shown that independently on the milling energy and reagents used (salt, oxide), the formation of Cu9Al4 is not observed, but instead of it Cu(Al) solid solution and Al2O3 are formed. Cu9Al4 phase as a metallic matrix of the composite powder was synthesized in the case of milling of CuO with excess amount of Al only. On the other hand, in the case of CuAl2 compound, its formation was observed in both milling processes, i.e. salt-Al and oxide-Al. Simultaneously, other compounds from the Cu-Al system were observed in the final product of mechanosynthesis. This fact can be attributed to low values of enthalpy of formation for CuAl2 and Cu9Al4 intermetallic compounds, -4 and -8 kJmol(-1), respectively, and their low thermodynamic stability. However, the presented results of reactive milling of different powder mixtures containing copper oxide or copper salt with Al confirm the possibility of metallic-cera-mic composite powders fabrication.