Casting molds for use in a directional solidification process and methods of making

Abstract

Molds 16 for casting molten materials using a directional solidification process and methods for forming a barrier layer between a liquid cooling medium 20 and a molten material of a casting process are provided. According to an embodiment, a mold 16 for casting a molten material comprises an inner surface at least partially coated with a metal oxide slurry 32 comprising metal oxide particles, wherein the metal oxide slurry 32 is capable of inhibiting a liquid cooling medium 20 from contacting a molten metal or metal alloy when the molten metal or metal alloy is disposed within an interior of the mold 16 and the mold 16 is disposed in the liquid cooling medium 20.

1 . A mold for casting a molten material, comprising: an inner surface at least partially coated with a metal oxide slurry comprising metal oxide particles, wherein the metal oxide slurry is capable of inhibiting a liquid cooling medium from contacting a molten metal or metal alloy when the molten metal or metal alloy is disposed within an interior of the mold and the mold is disposed in the liquid cooling medium. 
     
     
         2 . The mold of  claim 1 , wherein the metal oxide particles comprise aluminum oxide, an alkaline earth metal oxide, a transition metal oxide, a rare earth element oxide, or a combination comprising at least one of the foregoing metal oxides. 
     
     
         3 . The mold of  claim 1 , wherein the metal oxide particles have a diameter of about 20 micrometers to about 500 micrometers. 
     
     
         4 . The mold of  claim 1 , further comprising a primary stucco layer or another metal oxide layer disposed upon the metal oxide slurry, wherein the another metal oxide layer and the metal oxide slurry have dissimilar compositions. 
     
     
         5 . The mold of  claim 5 , further comprising at least one additional metal oxide slurry and stucco layer stack disposed upon the primary stucco layer. 
     
     
         6 . A method for forming a barrier layer between a molten material and a liquid cooling medium of a casting process, comprising: disposing a metal oxide slurry comprising metal oxide particles upon the inner surface of the mold. 
     
     
         7 . The method of  claim 6 , wherein said disposing the metal oxide slurry comprises dip or spraying coating the inner surface of the mold. 
     
     
         8 . The method of  claim 6 , wherein the metal oxide particles comprise aluminum oxide, an alkaline earth metal oxide, a transition metal oxide, a rare earth element oxide, or a combination comprising at least one of the foregoing metal oxides. 
     
     
         9 . The method of  claim 6 , further comprising disposing a molten metal or metal alloy within an interior of the mold to cause the metal oxide slurry to react and form the barrier layer adjacent to the molten metal or metal alloy. 
     
     
         10 . The method of  claim 6 , wherein the metal oxide particles have a diameter of about 20 micrometers to about 500 micrometers. 
     
     
         11 . The method of  claim 6 , further comprising disposing a primary stucco layer or another metal oxide layer upon the metal oxide slurry, wherein the another metal oxide layer and the metal oxide slurry have dissimilar compositions. 
     
     
         12 . The method of  claim 11 , further comprising disposing at least one additional metal oxide slurry and stucco layer stack upon the primary stucco layer. 
     
     
         13 . A method of casting a molten material, comprising:
 disposing the molten material within an interior of a mold comprising an inner surface at least partially coated with a metal oxide slurry comprising metal oxide particles; and   disposing the mold in a liquid cooling medium to cause the molten material to solidify.   
     
     
         14 . The method of  claim 13 , wherein the molten material comprises a molten metal, a molten alloy, a molten superalloy, or a combination comprising at least one of the foregoing materials, and wherein the liquid cooling medium comprises a liquid metal having a melting point less than about 700° C., a liquid eutectic or near eutectic metal alloy, or a combination comprising at least one of the foregoing cooling mediums. 
     
     
         15 . The method of  claim 13 , wherein the mold is disposed in a hot zone at a temperature above a melting temperature of the molten material when the mold is filled such that the metal oxide slurry undergoes curing, and wherein the mold is moved progressively to a cold zone comprising the liquid cooling medium at a temperature below the melting temperature of the molten material, thereby effecting movement of a solidification interface through the molten material. 
     
     
         16 . The method of  claim 13 , wherein the metal oxide particles comprise aluminum oxide, an alkaline earth metal oxide, a transition metal oxide, a rare earth element oxide, or a combination comprising at least one of the foregoing metal oxides. 
     
     
         17 . The method of  claim 13 , wherein the mold further comprises a primary stucco layer or another metal oxide layer disposed upon the metal oxide slurry, wherein the another metal oxide layer and the metal oxide slurry have dissimilar compositions. 
     
     
         18 . The method of  claim 17 , wherein the mold further comprises at least one additional metal oxide slurry and stucco layer stack disposed upon the primary stucco layer. 
     
     
         19 . The method of  claim 13 , wherein the metal oxide particles have a diameter of about 20 micrometers to about 500 micrometers.