Casting cores and methods for making

Abstract

Embodiments of the present invention include methods for forming ceramic articles, such as cores and core dies used in investment casting. The method may provide ceramic articles having improved strength and smoothness compared to articles manufactured by conventional methods. One embodiment is a method that comprises introducing a liquid comprising a silicon-bearing fluid into pores of a porous ceramic body; and heating the porous ceramic body in an oxygen-bearing atmosphere to form silica within the pores of the body.

1 . A method comprising:
 introducing a liquid comprising a silicon-bearing fluid into pores of a porous ceramic body; and   heating the porous ceramic body in an oxygen-bearing atmosphere to form silica within the pores of the body.   
     
     
         2 . The method of  claim 1 , wherein the fluid comprises a siloxane or a silane. 
     
     
         3 . The method of  claim 1 , wherein the liquid is neat. 
     
     
         4 . The method of  claim 1 , wherein the liquid further comprises a second fluid. 
     
     
         5 . The method of  claim 4 , wherein the second fluid has a lower viscosity than the silicon-bearing fluid. 
     
     
         6 . The method of  claim 4 , further comprising volatilizing the second fluid after the liquid has been introduced into the pores of the ceramic body. 
     
     
         7 . The method of  claim 1 , wherein reacting comprises heating the fluid to a temperature above about 200 degrees Celsius. 
     
     
         8 . The method of  claim 1 , wherein the liquid comprises a mixture of silicone monomers. 
     
     
         9 . The method of  claim 8 , further comprising curing the mixture of silicone monomers prior to the reacting step. 
     
     
         10 . The method of  claim 9 , wherein the liquid further comprises a catalyst, and wherein curing comprises thermally curing the mixture of silicone monomers in the presence of the catalyst. 
     
     
         11 . The method of  claim 1 , wherein the liquid further comprises a plurality of particles suspended within the silicon-bearing fluid. 
     
     
         12 . The method of  claim 11 , wherein the plurality of particles comprises oxide particles. 
     
     
         13 . The method of  claim 1 , wherein introducing comprises performing vacuum infiltration of the liquid into the pores of the body. 
     
     
         14 . The method of  claim 1 , wherein the porous ceramic body comprises a core for investment casting. 
     
     
         15 . The method of  claim 1 , wherein the ceramic body comprises silica, zirconium silicate, or a combination of zirconium silicate and silica.