Titanium carbide as a friction and wear modifier in friction materials

Abstract

Methods of making a carbon-carbon composite preforms, particularly suitable as brake discs in aircraft landing systems, by combining titanium carbide particles ranging in size from 0.01 to 10 microns in diameter, resinous binder, and carbon fibers or carbon fiber precursors in a mold, and subsequently subjecting the combined components to pressure and heat to carbonize the resinous binder by methods, thereby providing the carbon-carbon composite preform having particulate titanium carbide uniformly distributed throughout its mass. Prior to combining the titanium carbide and the binder with the fibers in this process, the particulate titanium carbide may be mixed with liquid binder, the resulting TiC/binder mixture may then solidified, and the resulting solid TiC/binder mixture may be ground into a fine powder for use in the process. Also, compositions for preparing a carbon-carbon composite friction materials, and methods of improving wear and dynamic stability in a carbon-carbon composite brake discs.

1 . A method of improving wear and dynamic stability in a carbon-carbon composite brake disc, which method comprises manufacturing said carbon-carbon composite brake disc from a preform comprising carbon-containing fibers, resin binder, and titanium carbide particles having a particle diameter in the range of from 0.01 to 10 microns.  
     
     
         2 . The method of  claim 1 , wherein the dynamic stability is characterized by a brake effectiveness μ of less than 0.200, wherein  
       
         
           
             
               μ 
               = 
               
                 
                   T 
                   Average 
                 
                 
                   
                     ( 
                     
                       
                         p 
                         Average 
                       
                       - 
                       bprt 
                     
                     ) 
                   
                   ⁢ 
                   
                     ( 
                     
                       2 
                       ⁢ 
                       
                         N 
                         R 
                       
                     
                     ) 
                   
                   ⁢ 
                   
                     A 
                     p 
                   
                   ⁢ 
                   
                     R 
                     m 
                   
                 
               
             
           
         
       
       where: 
 T Average—Average torque generated by the brake;    
 P Average—Average brake hydraulic fluid pressure;    
 bprt—Brake pressure rotors tight, lowest pressure at which brake generates torque;  
 2N R —Number of friction surfaces (twice the number of rotors N R );  
 A Ppl —Total hydraulic fluid piston surface area; and    
 R m —Mean brake radius.  
 
     
     
         3 . The method of  claim 2 , wherein the brake effectiveness μ is less than 0. 100.  
     
     
         4 . The method of  claim 1 , wherein said preform comprises from 15 to 80 weight-% carbon fiber, from 20 to 85 weight-% binder, and from 0.1 to 15 weight-% titanium carbide particles.  
     
     
         5 . The method of  claim 4 , wherein said preform comprises from 50 to 65 weight-% carbon fiber, from 30 to 45 weight-% binder, and from 2 to 8 weight-% titanium carbide particles, said titanium carbide particles ranging in size from 0.5 to 5 microns in diameter.  
     
     
         6 . A carbon-carbon composite brake disc preform comprising carbon fibers and resin binder, said preform having particulate titanium carbide uniformly distributed throughout its mass, wherein the particles of titanium carbide range in size from 0.01 to 10 microns in diameter.  
     
     
         7 . The preform of  claim 6 , wherein said particulate titanium carbide has an average particle size of 1-2 microns and an apparent porosity in the range 0.5-0.6.  
     
     
         8 . The preform of  claim 7 , wherein said particulate titanium carbide has an average particle size of 1.4 microns and an apparent porosity of 0.545.  
     
     
         9 . The preform of  claim 6 , comprising from 15 to 80 weight-% carbon fiber, from 20 to 85 weight-% binder, and from 0.1 to 15 weight-% titanium carbide particles.  
     
     
         10 . The preform of  claim 9 , comprising from 40 to 80 weight-% carbon fiber, from 20 to 65 weight-% binder, and from 1 to 15 weight-% titanium carbide particles.  
     
     
         11 . The preform of  claim 10 , comprising from 50 to 65 weight-% carbon fiber, from 30 to 45 weight-% binder, and from 2 to 8 weight-% titanium carbide particles, wherein said titanium carbide particles range in size from 0.5 to 5 microns in diameter.  
     
     
         12 . The preform of  claim 11 , comprising about 56 weight-% carbon fiber, about 38 weight-% binder, and about 5 weight-% titanium carbide particles, wherein said titanium carbide particles have an average particle size of about 1.4 microns.  
     
     
         13 . A method of making a carbon-carbon composite preform, wherein said method includes: 
 combining titanium carbide particles ranging in size from 0.01 to 10 microns in diameter, resinous binder, and carbon fibers or carbon fiber precursors in a mold, and    subjecting the combined components to pressure and heat to carbonize the resinous binder, thereby providing a carbon-carbon composite preform having particulate titanium carbide uniformly distributed throughout its mass.    
     
     
         14 . The method of  claim 13 , wherein the mold is selected to provide a preform configured as an aircraft landing system brake disc.  
     
     
         15 . The method of  claim 13 , wherein, prior to combination of the titanium carbide and the binder with the fibers, the particulate titanium carbide is mixed with liquid binder, the resulting TiC/binder mixture is solidified, and the resulting solid TiC/binder mixture is ground into a fine powder.  
     
     
         16 . The method of  claim 13 , wherein the titanium carbide particles have an average particle size of 1-2 microns and an apparent porosity in the range 0.5-0.6.  
     
     
         17 . The method of  claim 13 , which comprises combining 0.1 to 15 weight-% titanium carbide particles and 20 to 85 weight-% resinous binder with 15 to 80 weight-% carbon fiber or carbon fiber precursors.  
     
     
         18 . The method of  claim 17 , which comprises combining from 2 to 8 weight-% titanium carbide particles ranging in size from 0.5 to 5 microns in diameter with from 30 to 45 weight-% binder and from 50 to 65 weight-% carbon fiber.  
     
     
         19 . A composition for preparing a carbon-carbon composite friction material, said composition comprising carbon fibers or carbon fiber precursors, powdered or liquid resin binder, and titanium carbide particles ranging in size from 0.01 to 10 microns in diameter.  
     
     
         20 . The composition of  claim 19 , comprising 15 to 80 weight-% carbon fiber or carbon fiber precursors, 20 to 85 weight-% powdered or liquid resin binder, and 0.1 to 15 weight-% titanium carbide particles.