Cold compaction of metal–ceramic powders in the preparation of copper base hybrid materials

The compressibility behavior of Cu–Al2O3 powders in the preparation of composite compacts was studied. The effect of ceramic content on densification during compaction and resulting microstructure was evaluated through two methods, a conventional admixture powder metallurgy technique, and a modified chemical deposition and powder metallurgy route. Experiments were performed using plain and electroless copper coated alumina particles with a medium particle size of 58.3 μm; two sizes of copper powders, 17.6 and 60 μm, were used to adjust the ceramic content to 30, 40, 50 and 60 vol.%. The pressure–density response showed a decrease of porosity with increasing metal content but no effect with copper particle size. Densification was slightly higher when using coated fillers; the surface treatment also eliminated interparticle contacts and reduced the amount of voids providing clean interfaces.