Brake system having a composite-material brake disc
A brake system includes a friction coupling having organically or inorganically bound metal-containing, sintered-metal-containing and/or CFC-containing brake linings and a brake disc of fiber-reinforced C/SiC ceramic composite material. A friction layer and/or a surface of the brake disc subject to friction has a proportion of SiC greater than 65% and material compositions in a core region and a surface region of the brake disc are different. The brake system may be used in motor vehicles, rail vehicles or aircraft.
1. A brake system, comprising a friction coupling, including:
organically or inorganically bound brake linings selected from at least one of the group consisting of metal-containing brake linings, sintered-metal-containing brake linings and CFC-containing brake linings; and
a multilayer rotor brake disc of fiber-reinforced C/Sic ceramic composite material that includes reinforcing carbon fibers and a ceramic matrix formed of SiC and Si, said rotor brake disc including a central layer forming a support body and at least one friction layer having a surface subject to friction, both said support body and said friction layer being obtained by providing a CFC molding comprising carbon, wherein said CFC molding is reinforced with chopped fiber strands, said fibers having been coated with carbon-containing pyrolyzable organic pitches and resins subjected to firing and subsequent graphitization, and siliconizing said CFC molding by infiltrating with silicon melt, said silicon melt including further metals or metalloids as alloy constituents, said metals and metalloids being selected from the group consisting of Mo, Ni, Cr, Ti, Fe, Cu, Al, and B, and chemically reacting at least some of said carbon to form said SiC in said ceramic matrix;
said support body and said at least one friction layer each having a different material composition, said at least one friction layer having a proportion of SiC of 70% to 99% and a proportion of Si of less than 20%, and said support body having a SiC content less than 65%, said at least one friction layer having a thickness greater than 0.5 mm, and wherein in said at least one friction layer a proportion by weight of 50% of said fibers have a length of less than 0.5 mm.
2. The brake system according to claim 1 , wherein said friction layer has a proportion of said SiC of 80 to 99%, a Si content of less than 9%, and remaining material predominantly composed of carbon.
3. The brake system according to claim 1 , wherein said fiber-reinforced C/Sic ceramic composite material has silicon phases, and said silicon phases of said C/Sic composite material are present in at least one of said support body and said at least one friction layer and contain up to 50% of said metals or metalloids.
4. An automobile brake system, comprising a brake system according to claim 1 .
5. A rail vehicle brake system, comprising a brake system according to claim 1 .
6. An aircraft brake system, comprising a brake system according to claim 1 .