Joining of surface modified carbon carbon composites using a barium-aluminum-borosilicate glass

Carbon/carbon composites (C/C) are known to be not wettable by most glass materials. in this paper, CIC have been joined by a barium-aluminum-borosilicate glass (SABB) after modifying the composite surface with the formation of a silicon carbide layer. The surface modification has been obtained by heating, in an inert atmosphere, a silicon slurry deposited on the composite surface at a temperature above the silicon melting point, to achieve its transformation to beta-SiC A 'sandwich-like' joined structure (composite/glass/composite) has been mane by putting a slurry of SABB glass between two beta-SiC surface modified CIC samples of approximately 10x12x2mm(3), then by heating them at a temperature above the SABB softening point, in an inert atmosphere. The obtained 'sandwich-like' joined structures were characterised by thermal analyses, X-ray diffraction, optical and scanning electron microscopy and compositional analysis. Mechanical characterisation was carried out using Vickers micro-indentation (at the glass/composite interface and in the glass joint) and with a shear stress test, performed on a compression test machine. The joined structures prepared with optimised conditions have shear strength values of up to 30 MPa at room temperature. (C) 1998 Elsevier Science Limited. All rights reserved.