Towards optimization of SiC/CoSi2 composite material manufacture via reactive infiltration: Wetting study of Si–Co alloys on carbon materials

Abstract

Among manufacture techniques for SiC ceramics, reactive infiltration has proven to be the most efficient. However, materials manufactured with this technique present minimum 10% of unreacted silicon. Si hinders the performance of the material. The replacement of Si with a MexSiy can improve the performance of the composite. Since Me–Si alloys wet carbon materials, they are suitable candidates to be used as infiltrants in SiC/MexSiy composite production via reactive infiltration. To optimize the process, it is necessary to identify the mechanisms involved in infiltration and the parameters governing them. A basic wetting study can provide a clear understanding of the operative mechanisms and allow obtaining accurate parameters. In this work, the wetting behavior of silicon-cobalt alloys on carbon materials was studied using the sessile drop technique. The influence of temperature, composition and carbon crystallinity was evaluated, observing a strong dependence of process kinetics and reactivity with temperature and carbon crystallinity.