Preparation and tribological properties of C fibre reinforced C/SiC dual matrix composites fabrication by liquid silicon infiltration

Abstract

Three-dimensional needle carbon fibre reinforced carbon and silicon carbide dual matrix composite (C/C–SiC) is one of a new type of high performance brake material. The carbon fibre preform prepared by three-dimensional needling method was first densified by chemical vapour infiltration (CVI) to form porous carbon/carbon (C/C) composites. Then, the porous C/C composites were converted into C/C–SiC by liquid silicon infiltration (LSI), in which silicon carbide matrix was formed by reaction of carbon and melting silicon. The microstructure, mechanical properties and friction behaviour of C/C–SiC have been investigated. The results indicated that the composite was composed of 55 wt% C, 39 wt% SiC and 6 wt% Si. The density of C/C–SiC was 2.2 g cm−3 with 6.4% open porosity. The C/C–SiC exhibited good mechanical properties, especially excellent toughness which can help to avoid catastrophic brittle fracture. The flexural and compressive strength can reach to 214.6 MPa and 271.0 MPa, respectively. In addition, C/C–SiC had excellent impact damage tolerance of 25.2 kJ m−2. Compared to the self-friction, the C/C–SiC with steel opposing material shown higher static coefficient of friction (0.74) and better stability coefficient (0.28), while exhibited lower dynamic coefficient of friction (0.25), higher temperature of friction subsurface (444 °C), higher wear rate (2.88 μm cycle−1). The main wear mechanism of the C/C–SiC composites with different opposing material both includes adhesion and oxidation abrasion.