Experimental models for activtation mechanism of pressureless infiltration in the non-wetting steel-alumina MMC system

Common activation mechanisms, which are responsible for infiltration in other non-wetting systems, play only a secondary role in the Ti activated Al 2 O 3 /X3CrNiMo13-4 system for pressureless alloy infiltration into porous ceramic preforms. Experiments with a model pore consisting of two juxtaposed parallel alumina plates with lithographically imprinted arrays of Ti-dots show that transport through the vapour phase and subsequent condensation of the steel components onto the activator are the key steps of the activation mechanism. The mechanism was additionally confirmed by infiltration experiments with porous alumina preforms consisting of alternating layers with and without Ti parallel to the infiltration direction. Only layers with activator particles were infiltrated.