Thermal protection system

Abstract

A thermal protection system (TPS) that combines a structural thermal insulator (carbon foam) with a high specific strength metal matrix composite. According to a specifically preferred embodiment, the structural thermal insulator is overcoated with a protective antioxidant layer or incorporates an antioxidant compound therein.

What is claimed is:  
     
         1 ) A thermal protection system comprising: 
 A) a carbonaceous core having a first and a second surface;    B) a layer of aluminum or an alloy of aluminum coated upon said at least said first surface;    C) a structural portion coated over said layer of aluminum or an aluminum alloy comprising at least one pair of alternating layers of: 
 i) an aluminum brazing alloy; and  
 ii) an aluminum metal matrix composite.  
   
     
     
         2 ) The thermal protection system of  claim 1  wherein said layer of aluminum or an aluminum alloy is coated upon said first surface.  
     
     
         3 ) The thermal protection system of  claim 2  wherein said carbonaceous core comprises a semi-crystalline, largely isotropic, porous coal-based product produced from particulate coal exhibiting a free swell index of between about 3.5 and about 5.0 and of a small diameter, having a density of between about 0.1 and about 0.8 g/cm 3  and a thermal conductivity below about 1 W/m/° K.  
     
     
         4 ) The thermal protection system of  claim 3  wherein said coal exhibits a free swell index of between about 3.75 and about 4.5.  
     
     
         4 ) The thermal protection system of  claim 2  wherein said carbonaceous core has a compressive strength below about 6000 psi.  
     
     
         5 ) The thermal protection system of  claim 2  wherein said carbonaceous core has been carbonized.  
     
     
         6 ) The thermal protection system of  claim 2  wherein said carbonaceous core has been graphitized.  
     
     
         7 ) The thermal protection system of  claim 2  further including a protective anti oxidant layer coated on said second surface.  
     
     
         8 ) The thermal protection system of  claim 7  wherein said protective antioxidant layer comprises a member selected from the group consisting of metallic layers, and glass forming metal-halide, carbide or nitride compounds.  
     
     
         9 ) The thermal protection system of  claim 7  wherein said protective antioxidant layer comprises a member selected from the group consisting of ZrB 2 , SiC, and B 4 C.  
     
     
         10 ) The thermal protection system of  claim 7  wherein said carbonaceous core comprises a semi-crystalline, largely isotropic, porous coal-based product produced from particulate coal exhibiting a free swell index of between about 3.5 and about 5.0 and of a small diameter, having a density of between about 0.1 and about 0.8 g/cm 3  and a thermal conductivity below about 1 W/m/° K.  
     
     
         9 ) The thermal protection system of  claim 10  wherein said coal exhibits a free swell index of between about 3.75 and about 4.5.  
     
     
         10 ) The thermal protection system of  claim 7  wherein said carbonaceous core has a compressive strength below about 6000 psi.  
     
     
         11 ) The thermal protection system of  claim 7  wherein said carbonaceous core has been carbonized.  
     
     
         12 ) The thermal protection system of  claim 7  wherein said carbonaceous core has been graphitized.  
     
     
         13 ) The thermal protection system of  claim 2  further including an anti oxidant blended into said carbonaceous core.  14 ) The thermal protection system of  claim 13  wherein said anti oxidant comprises a member selected from the group consisting of glass forming metal-halide, carbide or nitride compounds.  
     
     
         15 ) The thermal protection system of claim  14  wherein said protective antioxidant layer comprises a member selected from the group consisting of ZrB 2 , SiC, and B 4 C.