Preparation and sintering of Al2O3-Cu composite powders

This work has been initiated in order to find new routes for the preparation of 3D interconnected ceramic-metal composites, usually obtained by direct metal oxidation or liquid infiltration of a ceramic preform. The system under investigation is the alumina-copper system. The key point of this new route was the preparation of very fine composite powders which allowed the material to be densified by natural sintering. The first part of the presentation deals with the preparation of the composite powders which was achieved using an electroless process. Influence of experimental parameters controlling the deposition of a copper layer on a submicronic alumina powder was investigated. The second part deals with the processing of the composite. A statistical design methodology was applied to determine the main parameters controlling the shrinkage. For some conditions, a new in-situ Cu-CuAlO2 Composite is formed, which presents an interesting microstructure with CuAlO2 acicular grains.