ELABORATION AND TEM STRUCTURAL STUDY OF INTERFACES IN COMPOSITES PRODUCED BY PRECIPITATION

Model ceramic matrix composites have been manufactured in a wide range of materials using the precipitation of a metal (Cu, Ni, Cr) in a cer amic matrix (nitride AIN or oxides MgO, Al2O3) providing, in each case low energy configurations at the heterophase interfaces. In connectio n to microelectronic applications, copper metallic particles precipita te in AIN after implantation by copper ions and anneal of the ceramic matrix. Faceted particles are imaged by HRTEM and are associated to a low energy structural and chemical configuration. Internal reduction e xperiments have been carried out on (Mg,Ni)O, (Mg,Cu)O and (Al,Cr)2O3 mixed oxides; the morphology, chemical composition and orientation rel ationship of the different precipitates are obtained through TEM obser vations and discussed in terms of interfacial energy and precipitate g rowth mechanism and kinetics. Conventional and high resolution TEM in conjonction to structural models have allowed a comprehensive descript ion of the interface.