Micron-scale analysis of SiC/SiCf composites using the new Lisbon nuclear microprobe

A new nuclear microprobe has now been commissioned at ITN, Lisbon. This pap er first describes the layout and modes of operation of the new microprobe, which is located on a 3.1 MV single-ended Van de Graaff accelerator. Withi n two days of first commissioning the microprobe, a spatial resolution of s imilar to 1.5 mu m was achieved for backscattering analysis, and a resoluti on of similar to 1.0 Fun for transmission work. The steps taken to produce this resolution, and the remaining factors, which further limit it are disc ussed. The first results from this microprobe for the spatially resolved an alysis of SiC/SiCf ceramic composites are presented here. These materials h ave applications in fusion technology and structural changes were investiga ted after exposure to lithium orthosilicate and lithium titanate breeder ma terials in fusion relevant conditions. Ti and Cr rich precipitates could be found in the samples that were exposed to lithium titanate. (C) 2000 Elsev ier Science B.V. All rights reserved.