Manufacture of carbon composites by hot pressing

Abstract

A mixture of carbon-containing fibers, such as mesophase or isotropic pitch fibers, a suitable matrix material, such as a milled pitch is compressed while resistively heating the mixture to form a carbonized composite material. Preferably, the carbonized material has a density of at least about 1.30 g/cm 3 . Preferably, the composite material is formed in less than ten minutes. This is a significantly shorter time than for conventional processes, which typically take several days and achieve a lower density material. A treating component may be impregnated into the composite. Consequently, carbon composite materials having final densities of about 1.6-1.8 g/cm 3 or higher are readily achieved with one or two infiltration cycles using a pitch or other carbonaceous material to fill voids in the composite and rebaking.

1 - 10 . (canceled)  
   
   
       11 . A vehicle friction brake assembly comprising: 
 a friction element having at least a metal surface which rotates with a wheel of a vehicle; and    a braking element having a surface aligned to movably engage said metal surface of said friction element, wherein at least said surface of said braking element comprises a carbon composite having a carbonized matrix impregnated with a treating component.    
   
   
       12 . The vehicle friction brake assembly according to  claim 11  wherein said surface further comprises at least one of a friction additive or a performance enhancer.  
   
   
       13 . The vehicle friction brake assembly according to  claim 12  wherein a concentration of said friction additive through a thickness of said surface comprises substantially uniform.  
   
   
       14 . The vehicle friction brake assembly according to  claim 11  wherein said treating component comprises at least one of a metal, a thermosett material, and combinations thereof.  
   
   
       15 . The vehicle friction brake assembly according to  claim 11  wherein said friction element comprises a brake drum or a brake rotor.  
   
   
       16 . The vehicle friction brake assembly according to  claim 11  wherein said braking element comprises a brake pad.  
   
   
       17 . The vehicle friction brake assembly according to  claim 11  wherein said treating component comprises a thermosett material.  
   
   
       18 . A method of making a vehicle friction brake assembly comprising: 
 rotatably attaching a friction element comprising a metal surface onto a vehicle; and    aligning a braking element to movably engage said friction element, said braking element comprising a surface comprised of a carbon composite having a carbonized matrix and a treating component, said surface of said braking element aligned to engage said metal surface.    
   
   
       19 . The method according to  claim 18 , wherein said treating component comprises at least one of a thermosett material, a metal, a metal alloy, and combinations thereof.  
   
   
       20 . The method according to  claim 18 , wherein said composite further comprise at least one of a friction additive or a performance enhancer.