Method of Producing Hybrid Tubular Metal/Ceramic Composites and Resulting Products

Abstract

There are disclosed inventions relating to tubular hybrid metal/ceramic composites and the methods of making them wherein the ceramic chosen has a lower thermal expansion than that of the metal.

1 . A composite structure comprising: 
 a ceramic formed by pyrolysis of a ceramic precursor;    and a tubular metallic object directly adhering to said ceramic and partially exposed or protruding from said ceramic, said tubular metallic object having been partially covered by said ceramic precursor before pyrolysis.    
   
   
       2 . The composite structure of  claim 1  wherein said tubular metallic object comprises a gun barrel.  
   
   
       3 . The composite structure of  claim 1  wherein said ceramic precursor comprises one or more susceptors.  
   
   
       4 . The composite structure of  claim 3  wherein said susceptors comprise a form selected from the group consisting of continuous fibers, chopped fibers, milled fibers, whiskers, particulates, flakes, and powders.  
   
   
       5 . The composite structure of  claim 3  wherein said susceptors comprise a material selected from the group consisting of SiC, carbon, and graphite.  
   
   
       6 . The composite structure of  claim 3  wherein said susceptors become sufficiently hot when exposed to microwave radiation to induce pyrolysis of said ceramic precursor.  
   
   
       7 . The composite structure of  claim 1  wherein said ceramic precursor comprises a pre-impregnated fabric.  
   
   
       8 . The composite structure of  claim 7  wherein said fabric is placed about the tubular metallic object using a process selected from the group consisting of braiding, lay-up, convolute, and jellyroll wrap.  
   
   
       9 . The composite structure of  claim 1  wherein said ceramic precursor is pyrolyzed using microwave radiation.  
   
   
       10 . The composite structure of  claim 1  wherein during pyrolysis of said ceramic precursor said tubular metallic object is heated but remains substantially unaffected.  
   
   
       11 . The composite structure of  claim 1  wherein during pyrolysis of said ceramic precursor said tubular metallic object is grounded.  
   
   
       12 . The composite structure of  claim 1  wherein said ceramic precursor comprises a preceramic polymer.  
   
   
       13 . The composite structure of  claim 1  wherein said ceramic comprises a material selected from the group consisting of silicon carbide and silicon nitride.  
   
   
       14 . The composite structure of  claim 1  wherein said ceramic comprises a ceramic composite.  
   
   
       15 . The composite structure of  claim 1  wherein said ceramic has a lower thermal expansion than a thermal expansion of said tubular metallic object.  
   
   
       16 . The composite structure of  claim 15  wherein said ceramic is load bearing with respect to an expansion of said tubular metallic object during use.  
   
   
       17 . The composite structure of  claim 16  wherein said ceramic withstands hoop stresses of a gun barrel during firing.  
   
   
       18 . The composite structure of  claim 16  wherein said ceramic prevents deformation of said tubular metallic element during use.  
   
   
       19 . The composite structure of  claim 1  wherein a fiber reinforcement geometry of said ceramic precursor is chosen to enhance heat transfer from said tubular metallic object.  
   
   
       20 . The composite structure of  claim 1  wherein said ceramic comprises a thermochemical stability sufficient to withstand rapid or great continuous duration firing sequences without damage.  
   
   
       21 . The composite structure of  claim 1  wherein said ceramic has a higher thermal conductivity than a thermal conductivity of a thermal barrier coating.  
   
   
       22 . The composite structure of  claim 1  wherein said ceramic precursor comprises a sacrificial overcoat.  
   
   
       23 . The composite structure of  claim 22  wherein said sacrificial overcoat comprises V20 polysilazane.