Evaluation of silicon carbide composite and refractory coatings for launchers and fusion technology applications

Summary form only given. Refractory-coated copper (Ta/Cu and LC Cr/Cu) and silicon carbide (SiC) composite material surfaces have been exposed to high heat fluxes from 2 to 70 GW/m/sup 2/ over 0.1 ms duration using the electrothermal launcher SIRENS, which produces high heat fluxes from blackbody spectrum photons. The thickness of the plasma boundary layer "vapor shield" increases and its temperature decreases, which results in less heat transported to the surface. Electroplated LC Cr has the lowest erosion among refractory-coated copper samples (0.11 /spl mu/m/kJ), about an order of magnitude less than that of sputtered LC Cr (1.62 /spl mu/m/kJ). Sputtered Ta has an erosion rate of 2.8 /spl mu/m/kJ, about a factor of 2 higher than that of sputtered LC Cr. Repetitive exposure showed that the erosion rate decreases with the increase in the number of exposures and energy input. Preliminary results on SiC showed that surface erosion is insignificant (0.06 /spl mu/m/kJ).