THERMAL-CONDUCTIVITY AND RETENTION CHARACTERISTICS OF COMPOSITES MADEOF BORON-CARBIDE AND CARBON-FIBERS WITH EXTREMELY HIGH THERMAL-CONDUCTIVITY FOR FIRST WALL ARMOR

The thermal conductivity of the composite hot-pressed at 2100 degrees C including B4C and carbon fibers with a thermal conductivity of 1100 W/m . K was nearly the same as that of the composite including carbon fibers with a thermal conductivity of 600 W/m . K. This resulted from the higher amount of B diffused into the carbon fibers through the lar ger interface. The B4C content in the composite can be reduced from 35 to 20 vol% which resulted from the more uniform distribution of B4C b y stacking the flat cloth woven of carbon fibers (carbon fiber plain f abrics) than in the composite with 35 vol% B4C including curled carbon fiber plain fabrics. The decrease in the B4C content does not result in the degradation of D (deuterium)-retention characteristics or D-rec ycling property, but will bring about the decreased amount of the surf ace layer to be melted under the bombardment of high energy hydrogen i ons such as disruptions because of higher thermal conduction of the co mposite.