Study of solid-state reactions of SiC/SiC f composites using microbeams L.C. Alves a,b, * , E. Alves a,b , M.F. da Silva a,b , J.C. Soares a,b , A. Pa ul a,c , A. La Barbera d , B. Riccardi e a ITN, Departamento di F  õsica, EN10, 2686-953 Sacav em, Portugal b CFNUL, Av. Prof. Gama Pinto 2, 1699 Lisboa, Portugal c ICMSE, Universidad de Sevilla-CSIC, Avda. Am erico Vespuccio s/n, 41092 Sevilla, Spain d Association EURATOM-ENEA, CR-Casaccia, Rome, Italy e Association EURATOM-ENEA, CR-Frascati, Rome, Italy Abstract Among the advanced materials with potential interest for applications in fusion technology the SiC/SiC f composites are considered to be one of the most promising. We used microbeam RBS and PIXE techniques to follow the structural changes of several SiC/SiC f samples in contact with lithium orthosilicate and lithium titanate breeders at 800°C for dierent time intervals. After 216 h of exposure the strongest reaction taking place was the oxidation of the composites. The oxidation rate was faster in the samples exposed to the orthosilicate. Simultaneously, lithium diuses into all the composites and there is a noticeable loss of carbon. For longer exposure the thickness of the oxide layers extends to values above the depth of ion beam analysis. The formation of Ti-rich precipitates was also observed in the samples in contact with the Li titanate. Ó 2001 Elsevier Science B.V. All rights reserved. PACS: 28.52.Fa; 07.79.)v; 81.05.Je Keywords: Nuclear microprobe; Fusion materials 1. Introduction One of the problems in the realisation of nu- clear fusion power plants is the development of materials for the ®rst wall and breeding blanket. At present, among the available materials SiC-®bre reinforced ceramic SiC composites are potentially the best candidates for some of these applications. However there are several technological problems to be solved until it becomes completely reliable for its incorporation in the fusion programme [1,2]. Together with porosity problems, one of the main drawbacks of this material is its chemical com- patibility with other components like the ceramic breeders e.g. Li 4 SiO 4 ; Li 2 TiO 3 ) and Be pebbles as neutron multipliers. The knowledge of the impu- rity content is also important since one of the most Nuclear Instruments and Methods in Physics Research B 181 2001) 377±381 www.elsevier.com/locate/nimb * Corresponding author. Tel.: +351-21-99-46-112; fax: +351- 21-99-41-525. E-mail address: lcalves@itn1.itn.pt L.C. Alves). 0168-583X/01/$ - see front matter Ó 2001 Elsevier Science B.V. All rights reserved. PII:S0168-583X01)00331-7