Patent ID: 7413701

Claim:
A process for producing clutch linings comprising fiber-reinforced ceramic materials, said clutch linings having a largest area, and a friction surface, and having a thickness of from 2 mm to 6 mm and having the shape of rounded rectangles, rounded trapezoids or ring segments, which comprises producing in a mixer a mixture of short carbon fibers and a binder which binder consists of a carbonizable material which softens upon heating said mixture, introducing the mixture into a continuous screw extruder and extruding through a die which corresponds to the shape of the desired linings, then cutting up the extrudate to produce blanks and converting said blanks into porous carbon bodies with retention of the shape of blank by heating in the absence of oxidizing agents, and bringing the porous carbon bodies into contact with a silicon-containing melt under reduced pressure so that the melt penetrates into the porous carbon body and fills the pores of the porous carbon body under formation of a fiber-reinforced ceramic material with at least part of the porous carbon body formed in the converting step reacting with the silicon from the silicon-containing melt to form a matrix of the fiber-reinforced ceramic materials comprising silicon carbide, wherein the silicon-containing melt in the melt contacting step is used in such amount that said pores are not completely filled with the silicon-containing melt, so that incompletely filled pores remain, and then filling said incompletely filled pores with a second melt of metals or alloys which second melt has a melting point of at least 550° C., and wherein the matrix of the fiber-reinforced ceramic materials comprises mass fractions of from 60% to 90% of silicon carbide, from 0% to 30% of elemental silicon and from 0% to 10% of elemental carbon, wherein the fibers have a preferential orientation perpendicular to the friction surface of the linings, and wherein the length of the fibers is chosen such that the average of the projection of their length onto the normal to the largest area of the clutch linings is from 10% to 95% of the thickness of the lining.