Damage evaluation of W-coated SiC by thermal conductivity measurement

To evaluate the damage of W-coated SiC/SiC composites by thermal conductivity, evaluation of thermal conductivity measurement was performed for W-coated Sic, which was damaged by electron beam-induced thermal impact. After thermal impact of about 6 MW/m(2), melted phases around W/SiC interphase and reduction of thermal conductivity were observed. It was suggested that the temperature of the W/SiC interphase was raised to the melting point of a reaction phase, by the thermal impact of about 6 MW/m(2), and therefore a melted phase flowed out from the W/SiC interphase and cracks, reducing the thermal conductivity. Numerical calculations showed that the temperature of the W/SiC interphase could be controlled by the thickness of the W coating. The relation between melted phases and reduction of thermal conductivity will be investigated. (C) 2004 Elsevier B.V. All rights reserved.