Microstructure and frictional properties of C/SiC brake materials with sandwich structure

C/SiC brake materials with a sandwich structure were prepared by three step process, chemical vapor infiltration, slurry infiltration and liquid silicon infiltration process. The fabricated brake materials consist of a C-fiber rich main body and two SiC-rich frictional layers on the surface. The microstructure and frictional properties of C/SiC brake materials were investigated. The results indicated that the density and open porosity of the materials were 2.2 g/cm(3) and 4%, respectively. The phase distribution in the friction layers of C/SiC with sandwich structure was homogeneous, and the silicon was little and dispersed in the friction functional layers. The joining region between friction functional layer and mechanical functional layer has an inter-laminar shear strength of about 27 +/- 9 MPa, indicating its reliability. The frictional properties under wet condition of the C/SiC with the sandwich structure showed no fading, and were better than that of the 3D needled C/SiC. The static friction coefficient and linear wear rate of the C/SiC with the sandwich structure was higher than that of the 3D needled C/SiC. The C/SiC brake materials with sandwich structure would have higher brake efficiency. (C) 2011 Elsevier Ltd and Techna Group S.r.l. All rights reserved.