Influence of Constituents on Transverse Thermal Conductivity of Melt Infiltrated SiC/SiC Composites.

Transverse thermal conductivity of the BN/SiC coated Sylramic SiC preforms, and melt infiltrated SiC/silicon and SiC/SiC composites were measured at room temperature and at 1300d̀C in argon. The preforms contained two different vol % of CVI SiC coatings. Influence of BN interface, vol% CVI SiC content, and matrix porosity on thermal conductivity was determined and compared with those predicted by a composite mechanics based model. The model was also used to determine the possibility of improving transverse thermal conductivity of SiC/SiC composites by replacing SiC in the MI matrix with A1N or TiB2 particles. Preliminary results correlating constituents and thermal conductivity are discussed.