Friction bodies comprising metal-infiltrated, fiber-reinforced porous carbon
Friction bodies made of a fiber-reinforced porous carbon material in which the reinforcing fibers are present in the form of woven fabrics, short fibers and/or long fibers and whose pores are filled with metals, wherein carbides of the metals filling the pores are present in the material in a mass fraction of not more than 10%, a process for their production and the use thereof in brake and clutch systems.
1. A friction body comprising a fiber-reinforced porous carbon material in which the reinforcing fibers are present in the form selected from the group consisting of short fibers and long fibers and whose pores are filled with metals selected from the group consisting of Cu, Sn, Ti, Cr, Mo, V, Mg, Fe, Mn, Ni, Zr, Hf, Co and alloys thereof, wherein carbides of the said metals filling the pores are present in the material in a mass fraction of not more than 10%, based on the mass of the friction body.
2. The friction body as claimed in claim 1 , wherein the mass fraction of reinforcing fibers is at least 10%, based on the mass of the friction body.
3. The friction body as claimed in claim 1 , wherein the reinforcing fibers comprise carbon fibers.
4. The friction body as claimed in claim 1 , wherein the reinforcing fibers comprise inorganic fibers selected from the group consisting of silicon carbide fibers, silicon nitride fibers, silicon carbonitride fibers and fibers of compounds of silicon, boron, carbon and nitrogen in any ratios.
5. The friction body as claimed in claim 1 , wherein the matrix of the carbon material comprises metals selected from the group consisting of Cu, Sn, and alloys thereof.
6. The friction body as claimed in claim 1 , wherein lubricants in particle form are present in the material in a mass fraction of 0.5% to 20%, based on the mass of the friction body.
7. The friction body as claimed in claim 1 , wherein abrasives in particle form are present in the material in a mass fraction of 0.5% to 20%, based on the mass of the friction body.
8. A process for producing friction bodies as claimed in claim 1 , which compris
in a first step, producing a molding composition by mixing carbonizable materials selected from the group consisting of thermoset and thermoplastic polymers, resins and pitches with reinforcing fibers in the form of short fibers, long fibers or mixtures thereof, where the mass fraction of these reinforcing fibers in the molding composition is from 30% to 80%,
in a second step, producing a shaped part from the molding composition by molding at elevated temperature and/or under pressure,
in a third step, firing the shaped part by heating at a temperature of from about 750 □C to about 1100 □C in the absence of oxidizing gases to produce a porous body comprising reinforcing fibers and a porous carbon matrix which is formed by carbonization during the firing process, and
in a fourth step, infiltrating the porous body with liquid metal selected from the group consisting of Cu, Sn, Ti, Cr, Mo, V, Mg, Fe, Mn, Al, Ni, Zr, Hf, Co and alloys thereof, under reduced pressure or in vacuo.
9. The process as claimed in claim 8 , wherein abrasives and/or lubricants are mixed into the molding composition.
10. A brake system comprising the friction body as claimed in claim 1 .
11. A clutch system comprising the friction body as claimed in claim 1 .
12. The friction body of claim 1 which comprises a woven fabric made of reinforcing fibers.