Petroleum pitch-based carbon foam

Abstract

Petroleum or coal tar pitch-based cellular or porous products having a density of preferably between about 0.1 g/cm 3 and about 0.8 g/cm 3 are produced by the controlled heating of mesophase carbon materials derived from coal tar or petroleum pitch having a softening point in excess of about 300° C. and preferably between about 300 and about 400° C. in a “mold” and under a non-oxidizing atmosphere. The porous product thereby produced, preferably as a net shape or near net shape, can be machined, adhered and otherwise fabricated to produce a wide variety of low cost, low density products.

What is claimed is:  
     
         1 . A semi-crystalline, largely isotropic, porous pitch-based foam produced from a mesophase carbon derived from a petroleum or coal tar pitch exhibiting a softening point above about 300° C., and having a density of between about 0.1 and about 0.8 g/cm 3 .  
     
     
         2 . The porous coal-based product of  claim 1  wherein said coal tar or petroleum pitch exhibits a softening point between about 300° C. and about 400° C.  
     
     
         3 . The porous coal-based product of  claim 1  having a compressive strength below about 6000 psi.  
     
     
         4 . The porous coal-based product of  claim 1  that has been carbonized.  
     
     
         5 . The porous coal-based product of  claim 1  that has been graphitized.  
     
     
         6 . A method for producing a carbon foam from a mesophase carbon particulate derived from a petroleum or coal tar pitch exhibiting a softening point above about 300° C., comprising: 
 A) placing said mesophase carbon particulate in a mold;  
 B) heating said mesophase carbon particulate in said mold under a non-oxidizing atmosphere to a temperature of between about 300° C. and about 700° C. and soaking at this temperature for a period of from about 10 minutes to about 1 hour to form a green foam; and  
 C) controllably cooling said green foam.  
 
     
     
         7 . The method of  claim 6  wherein said coal tar or petroleum pitch exhibits a softening point between about 300° C. and about 400° C.  
     
     
         8 . The method of  claim 6  wherein said inert atmosphere is applied at a pressure of from about 0 psi up to about 500 psi.  
     
     
         9 . The method of  claim 6  wherein said temperature is achieved using a heat-up rate of between about 2° C. to about 10° C. per minute.  
     
     
         10 . The method of  claim 6  wherein said controlled cooling is accomplished at a rate of less than about 10° C./min to a temperature of about 100° C.  
     
     
         11 . The method of  claim 6  wherein said mesophase carbon particulate derived from a petroleum or coal tar pitch exhibiting a softening point above about 300° C. is produced by thermal treatment or solvent extraction of said petroleum or coal tar pitch.  
     
     
         12 . A semi-crystalilne, largely isotropic, porous pitch-based foam produced from a mesophase carbon derived from a petroleum or coal tar pitch exhibiting a softening point above about 300° C., and having a density of between about 0.1 and about 0.8 g/cm 3  produced by a method comprising: 
 A) placing said mesophase carbon particulate in a mold;  
 B) heating said mesophase carbon particulate in said mold under a non-oxidizing atmosphere to a temperature of between about 300° C. and about 700° C. and soaking at this temperature for a period of from about 10 minutes to about 1 hour to form a green foam; and  
 C) controllably cooling said green foam.  
 
     
     
         13 . The-semi-crystalline, largely isotropic, porous pitch-based foam of  claim 12  wherein said coal tar or petroleum pitch exhibits a softening point between about 300° C. and about 400° C.  
     
     
         14 . The semi-crystalline, largely isotropic, porous pitch-based foam of  claim 12  wherein said inert atmosphere is applied at a pressure of from about 0 psi up to about 500 psi.  
     
     
         15 . The semi-crystalline, largely isotropic, porous pitch-based foam of  claim 12  wherein said temperature is achieved using a heat-up rate of between about 2° C. to about 10° C. per minute.  
     
     
         16 . The semi-crystalline, largely isotropic, porous pitch-based foam of  claim 12  wherein said controlled cooling is accomplished at a rate of less than about 10° C./min to a temperature of about 100° C.  
     
     
         17 . The semi-crystalline, largely isotropic, porous pitch-based foam of  claim 12  wherein said mesophase carbon particulate derived from a petroleum or coal tar pitch exhibiting a softening point above about 300° C. is produced by thermal treatment or solvent extraction of said petroleum or coal tar pitch.