Investigation Of W Components Exposed To High Thermal And High H/He Fluxes

Powder metallurgy tungsten and plasma-sprayed tungsten samples were exposed to high heat and particle fluxes in order to study changes in the surface morphology. Actively water-cooled and adiabatically loaded samples were irradiated with H, He, and mixed 90% H/10% He neutral beams at power densities of 2 MW m(-2) and 10 MW m(-2) with fluences up to 3 x 10(25) m(-2). For He irradiation of adiabatically loaded samples a peak surface temperature of 2100 degrees C was reached. Under this condition the growth of a coral-like surface structure modification due to bubble formation was the dominant process observed. In all other cases physical sputtering was the surface modification process. For hydrogen irradiation of actively cooled samples with much lower surface temperatures no formation of blisters was observed. Instead, we found small nano-sized pores. (C) 2011 Elsevier B.V. All rights reserved.