Patent ID: 7261846

Claim:
A process for producing a brake lining which is reinforced with carbon fibers and has a matrix which consists essentially of silicon carbide together with silicon and/or carbon, wherein the reinforcing fibers used are long fibers having a mean length of at least 10 mm which are aligned in the plane parallel to the friction surface, which process comprises the following steps: a) production of a fiber arrangement of carbon fibers arranged essentially in a plane, wherein the fibers may be present in the form of individual fibers, fiber bundles or fiber yarns and the fibers and/or fiber bundles or fiber yarns being bound by a carbonizable binder, b) shaping and/or curing of the bound fiber construction under pressure and/or at elevated temperature, if desired followed by further densification by means of carbonizable carbon precursors, c) carbonization or graphitization of the bound cured fiber construction to produce a shaped body comprising carbon reinforced with carbon fibers (C/C), d) at least one further densification of the C/C shaped body by means of pyrolytic carbon formed either by liquid-phase infiltration with carbonizable carbon precursors and subsequent carbonization or by gas-phase infiltration with carbon, and e) infiltration of the densified C/C shaped body with a silicon melt and partial reaction of the silicon with at least part of the carbon in the shaped body to form silicon carbide, so as to give a composite ceramic comprising carbon fibers embedded in a matrix comprising SiC, Si and C (C/SiC) such that the mass fraction of silicon in the material of the brake lining is at least 10%, and the mass fraction of silicon carbide is from 10% to 25%, and wherein the uppermost layer exposed to friction has a volume fraction of at least 50% of carbon fibres, and wherein the silicon content in the said friction layer is lower than the silicon carbide content in the said layer.