Behaviour of carbon and boron-carbon materials at high temperatures in TEXTOR

Test limiters made from graphite and boron-doped graphite have been exposed in TEXTOR to high heat loads up to about 30 MW/m 2 . Maximum surface temperatures up to 3000°C have been reached. Boron sublimes thermally from the boron-doped graphite exceeding the boron sputter-fluxes at about 2000°C. At the same temperature the carbon release increases sharply. The carbon release from the pure graphite shows no measurable increase up to surface temperatures of about 2200°C and increases then steeply. The results are compared with the expected carbon and boron release by physical sputtering, radiation enhanced sublimation and normal thermal sublimation.