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.