Temperature and angular dependences of sputtering yield of B4C-carbon fiber composite irradiated with low energy deuterium ions

The sputtering conditions at the divertor in next fusion experimental react ors such as ITER were simulated by using a super low energy ion source (SLE IS). B4C-carbon fiber composite was sputtered with low energy and high flux deuterium ions from SLEIS. The flux was as high as 1-2 x 10(20) D+/m(2)/s with D-3(+) of 200 eV. The target temperatures were 200-700 degrees C, name ly, in the chemical sputtering region, the incident angles were 0-60 degree s and two kinds of surface finish of samples were used. The results were co mpared with those of SIC doped CFC and 2D (two directional)-CFC. The chemic al sputtering yields of 38% B4C-carbon fiber composite at temperatures of 2 00-700 degrees C were smaller than those of 2D-CFC, showing a temperature d ependence similar to those of 10% SiC doped ID-CFC. The chemical sputtering yields at 500 degrees C of 38% B4C-carbon fiber com posite and 10% SiC doped 1D-CFC decreased with the incident angle. The sput tering yields of 38% B4C-carbon fiber composite were lower than those of 10 % SiC doped ID-CFC and 2D-CFC (CX-2002U). The surface structures of the sam ples after sputtering examined with SEM have greatly differed from those be fore sputtering, showing a pattern of needle-like leaves. (C) 1999 Elsevier Science B.V. All rights reserved.