Erosion and deposition effects on the vessel wall of TEXTOR-94

Two different sets of long term samples (LTS) were exposed in TEXTOR-94 at the liner with boronized and siliconized wall conditions. Measured erosion/ deposition rates of the coating constituents were compared with sputtering rates calculated for pure elements. D-0-fluxes at the LTS locations were de termined by the B2-EIRENE code. Over the whole liner, erosion of initial co atings by D-0 is observed. Boron erodes at a rate of 8.4 x 10(13) B cm(-2) s(-1),while silicon erodes at a rate of 5.6 x 10(13) Si cm(-2) s(-1), a fac tor of 1.5 lower than that of boron. With boronized walls, carbon atoms ini tially present in the a-C/B:D layers are eroded at a rate of 7.6 x 10(12) C cm(-2) s(-1), at the same time 1.7 x 10(12) (Fe + Cr + Ni) cm(-2) s(-1) ar e deposited. Compared to boronized conditions where carbon erodes, depositi on of carbon (1.7 x 10(13) cm(-2) s(-1)) and of metals (3.8 x 10(12) cm(-2) s(-1) occurred during the Si campaign. Due to long time exposure at high w all temperature (350 degreesC), hydrogenic isotopes desorb; (D + H)/(B + C) and (D + H)/(Si + C) ratios degrade from originally similar to0.4 to simil ar to0.2. (C) 2001 Elsevier Science B.V. All rights reserved.