THEORETICAL STUDY OF REACTIVE MELT INFILTRATION TO FABRICATE THE Co-Si/C COMPOSITES

Cobalt-Silicon based carbon composites (Co-Si/C) have established a noteworthy consideration in recent years as a replacement for conventional materials in the automotive and aerospace industries. To achieve the composite, a reactive melt infiltration process (RMI) is used; in which a melt impregnates a porous preform by capillary force. This method promises a high-volume fraction of reinforcement and can be steered in such a way to get the good "near-net" shaped components. A mathematical model is developed using reaction-formed Co-Si alloy/C composite as a prototype system for this process. The wetting behavior and contact angle are discussed; surface tension and viscosity are calculated by Wang's and Egry's equations respectively. Pore radii of 5μm and 10μm are set as a reference on highly oriented pyrolytic graphite. The graphs are plotted using the model, to study some aspects of the infiltration dynamics. This highlights the possible connections among the various processes. In this attempt, the Co-Si (62.5 at. % silicon) alloy's maximum infiltration at 5μm and 10μm radii were found as 0.05668m at 125sec and 0.22674m at 250sec respectively.