Development of high thermal conductive SiC fiber reinforced SiC matrix composites for fusion reactors (Thesis)

Taguchi, Tomitsugu

A 3 dimensional model (after cubic model) was developed to quantitively predict the thermal conductivity of SiC fiber-reinforced SiC matrix (SiC/SiC) composites. The cubic model showed that thermal conductivity of the composites increased by decreasing the porosity and ensphering the shape of pore. The SiC/SiC composites were fabricated by chemical vapor infiltration (CVI) and reaction bonding (RB) processes. The thermal conductivity of the composites by RB process was higher than that by CVI process. The reason is that the porosity of the composites by RB process was lower than that by CVI process and the shape of pore in the composites by RB process was almost sphere. The thermal conductivity of the SiC/SiC composite by RB process was consistent with the estimated value by the cubic model. The cubic model also showed that the thermal conductivity of the composites increased by introducing a high thermal conductive new phase parallel to the direction of heat flow. To verify the prediction, a SiC/SiC composite with carbon nano-fiber (CNF) were fabricated by RB process. The thermal conductivity of the SiC/SiC composite with CNF was approximately 90 W/mK at room temperature. The thermal conductivity of the SiC/SiC composite was coincided with the estimated value by the cubic model. They concluded that the cubic model was useful for predicting the thermal conductivity of fiber-reinforced composites.