Ceramic porous bodies suitable for use with superalloys
AssigneeHowmet Turbine Components Corporation
InventorNick G. Lirones
Life of this patent
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Abstract
Ceramic porous bodies, including ceramic foam filters and smooth-faced ceramic objects, e.g., ceramic foam bricks, ceramic foam melting crucibles, and ceramic foam cores, made in accordance with the present invention are suitable for use with molten metal in general and molten superalloys in particular. The invention also provides a tundish for use with ceramic foam filters to filter metal en route from a metal furnace to a casting mold, and a melting device for use in casting metal which employs a ceramic foam filter as a bottom pour valve for a melting crucible such that the ceramic foam filter valve regulates the flow of molten metal therethrough in order to permit an entire ingot of metal to melt in the melting crucible before any metal begins to pour from the melting device into a casting mold.
Claims66
A process for making a ceramic foam filter suitable for use in filtering molten metals in general and molten superalloys in particular which comprises the steps of:
- providing an open-cell, flexible foam pattern;
- impregnating said foam pattern with a ceramic slurry;
- burning out said foam pattern at a temperature of between 1400.degree. F. and 2200.degree. F. to form a ceramic substrate;
- impregnating said ceramic substrate with additional ceramic slurry;
- and firing said impregnated ceramic substrate at a temperature of between 2200.degree. F. and 3400.degree. F.
The process of claim 31 wherein said viscosity is about 7 seconds.
A process for making a ceramic porous body suitable for use with molten metals in general and molten superalloys in particular having a solid, high density, high purity, smooth face which comprises the steps of:
- providing an open-cell, flexible, foam pattern and a face pattern the size of a face of said foam pattern to be smoothed;
- coating said face pattern with a ceramic slurry;
- stuccoing said face pattern with a coarse ceramic material;
- impregnating said foam pattern with said ceramic slurry;
- placing said impregnated foam pattern on said coated, stuccoed face pattern such that said impregnated foam pattern and said coated, stuccoed face pattern dry together and become attached;
- impregnating said attached impregnated foam pattern and coated, stuccoed face pattern with additional ceramic slurry;
- removing excess dried ceramic down to the edges of said foam pattern;
- burning out said foam pattern and said face pattern at a temperature of between 1400.degree. F. and 2200.degree. F. to form a ceramic substrate;
- impregnating said ceramic substrate with additional ceramic slurry;
- and firing said impregnated ceramic substrate at a temperature of between 2200.degree. F. and 3400.degree. F.
Dependencies are inferred from the claim text.