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Composite which contains reinforcing fibers comprising carbon and whose matrix comprises silicon carbide, silicon and copper, with the mass fraction of copper in the composite being up to 55%, processes for producing it, in particular by liquid infiltration of C/C intermediate bodies with melts comp

Composite which contains reinforcing fibers comprising carbon and whose matrix comprises silicon carbide, silicon and copper, with the mass fraction of copper in the composite being up to 55%, processes for producing it, in particular by liquid infiltration of C/C intermediate bodies with melts comprising Si and/or Cu and Si, and also its use as friction lining in a friction pairing with ceramic brake discs or clutch discs comprising C/SiC.

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The invention claimed is: 1. A composite which contains coated reinforcing fibers comprising carbon and whose matrix comprises silicon carbide, silicon and copper and in which composite the mass fraction of copper is from 10% up to 55%, wherein isolated copper-containing regions are present which a

The invention claimed is: 1. A composite which contains coated reinforcing fibers comprising carbon and whose matrix comprises silicon carbide, silicon and copper and in which composite the mass fraction of copper is from 10% up to 55%, wherein isolated copper-containing regions are present which are surrounded completely by other phases, the volume fraction of the said isolated copper-containing regions in the composite being from 5% to 25%, wherein the material of the said isolated copper-containing regions is selected from the group consisting of alloys of copper with further metals which formmixed phases with copper, these metals being selected from the group consisting of zinc, tin, and lead, the mass fraction of the said further metals in the mass of copper and the said further metals being from 1% to 25%. 2. The composite as claimed in claim 1, wherein the copper in the matrix is present in isolated copper-containing regions which are completely surrounded by phases comprising silicon carbide. 3. The composite as claimed in claim 1, wherein the volume fraction of the copper-containing regions in the composite is up to 22%, based on the volume of the composite. 4. The composite as claimed in claim 1, wherein the matrix further comprises elements selected from the group consisting of boron, titanium, zirconium, vanadium, chromium, tungsten, iron, cobalt and nickel in a form selected from the group consisting of its elementary form, the form of its carbide, and the form of its silicide. 5. The composite as claimed in claim 4, wherein the sum of the mass fractions of these said elements, their carbides and silicides is up to 20% of the mass of the matrix. 6. The composite as claimed in claim 1 which further comprises preformed particulate additives which form separate phases in the composite. 7. The composite as claimed in claim 6, wherein the particulate additives are selected from the group consisting of silicon carbide, silicon nitride, titanium carbide, aluminum oxide, zirconium dioxide, silicon dioxide and zirconium silicate. 8. The composite as claimed in claim 6, wherein the mass fraction of the particulate additives is up to 15% of the mass of the matrix. 9. A process for producing composites as claimed in claim 1, which comprises the steps production of a porous carbon/carbon composite containing coated carbon fibers, melt infiltration of the porous C/C body with a metal melt comprising silicon and copper, wherein copper is present in the melt in such an amount that copper is present in the composite in a mass fraction of from 10% to 55%, and further metals selected from the group consisting of zinc, tin, and lead are present in the composite in such amount that the mass fraction of the said further metals in the mass of copper and the said further metals is from 1% up to 25%, reaction of at least part of the carbon of the C/C body with the silicon of the melt to form silicon carbide. 10. The process as claimed in claim 9, wherein the metal melt used comprises silicon and copper together with a mass fraction comprised in the metal melt of from 1% to 20% of further elements selected from the group consisting of boron, titanium, vanadium, chromium, iron, cobalt, and nickel. 11. The process as claimed in claim 9, wherein the C/C body prior to infiltration has a pore volume of at least 10% of the total volume of the body and a density of not more than 1.6 g/cm3. 12. The process as claimed in claim 9, wherein the C/C body prior to infiltration contains further particulate additives selected from the group consisting of grains of hard material and sintered metal particles. 13. The process as claimed in claim 12, wherein carbides or oxides having melting points above the melting point of silicon are used in mass fractions, with relation to the mass of the matrix, of up to about 15% as hard material additives. 14. The process as claimed in claim 9, wherein metallic copper or its alloys with mass fractions of up to 25% of other metals is/are introduced into the C/C body itself, wherein the mass fraction is based on the sum of masses of copper and the said further metals. 15. The process as claimed in claim 14, wherein the copper or its alloys are introduced in the form of powder or turnings. 16. The process as claimed in claim 9, wherein the metal melt used is a Cu/Si melt which further comprises additional carbide-forming elements selected from the group consisting of boron, titanium, vanadium, chromium, tungsten, iron, cobalt and nickel in mass fractions of from 1% to 15% of the melt. 17. The process as claimed in claim 9, wherein the metal melt is supplied via porous wicks made of carbon-containing material and/or via beds of metal particles. 18. The process as claimed in claim 9, wherein previously produced, finished alloys of Cu and Si are used for infiltration. 19. A process for producing composites as claimed in claim 1, which comprises the steps production of a porous carbon/carbon composite containing coated carbon fibers and copper, melt infiltration of the porous C/C body with a silicon melt, reaction of at least part of the carbon of the C/C body with the silicon of the melt to form silicon carbide. 20. A method of use of a composite as claimed in claim 1 in friction pairings with counterbodies having a friction surface in which at least the said friction surface is made of hard ceramic material, comprising combining the composite of claim 1 in the form of a friction pad with the said friction surface. 21. The method of use as claimed in claim 20 wherein the friction surface of the counterbody is the surface of a composite ceramic reinforced with carbon fibers and having an SiC-containing matrix. 22. The method of use as claimed in claim 21 wherein the friction surface of the counterbody is the surface of a ceramic brake disc which has a mass fraction of silicon carbide of at least 60% in the zone facing the composite of claim 1 in the form of a brake lining.