A Study on CuO-Al₂O₃ Infiltration by Aluminium

This paper reports preliminary studies regarding a new fabrication process for aluminium alloy matrix particulate reinforced composites, which uses ceramic preforms with alumina and tailored amounts of reactive copper oxide, CuO. An Al2O3-CuO mixture with 75 mol% CuO was selected, aiming at a 10-40vol% reinforcement phase fraction in the final composite, after aluminium infiltration. Molten aluminium infiltration progress was studied as a function of ceramic’s composition, doping, and infiltration time. The resulting microstructures were investigated by OM, SEM, FESEM and EDS in order to establish the liquid aluminium infiltration profile at the metal/ceramic interface. Infiltration experiments showed that the 3CuO (s) + 2Al (l) → 3Cu (l) + Al2O3 (s) redox reaction is triggered at the experimental conditions used, but the infiltration process is slow and does not go to completion. The use of NaOH as a doping agent promotes effective infiltration of molten aluminium upon the ceramic green mixture.