Ceramic shell mold
AssigneeRemet Corporation
InventorRoy C. Feagin
Life of this patent
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Abstract
Method for making a novel shell mold for use in directional solidification and for casting alloys containing reactive components, wherein a binder comprising a fibrous colloidal alumina in aqueous dispersion and being essentially free of silica, is employed. The resultant shell mold is particularly suitable for the casting of nickel and cobalt based alloys containing relatively reactive constituents such as zirconium, alumina and titanium.
Claims22
In a method for making a shell mold which comprises:
- a. making an expendable pattern of a part to be cast,
- b. dipping the expendable pattern into a slurry of a refractory material and a binder to form a moist coating on said pattern,
- c. sprinkling a coarse refractory powder on said moist coating,
- d. drying said moist coating, and
- e. repeating steps b, c and d, whereby said shell mold is built up to a desired thickness,
- the improvement wherein said binder consists essentially of an acid stabilized, fibrous colloidal alumina as an aqueous sol, said binder being essentially free of silica and said binder developing excellent green strength.
In a method for producing castings of alloys having directionally solidified grains wherein a molten alloy is poured into a shell mold, the improvement which comprises employing as the shell mold one produced by a method comprising:
- a. making an expendable pattern of a part to be cast,
- b. dipping the expendable pattern into a slurry of a refractory material and a binder to form a moist coating on said pattern,
- c. sprinkling a coarse refractory powder on said moist coating,
- d. drying said moist coating, and
- e. repeating steps b, c and d, whereby said shell mold is built up to a desired thickness,
- said binder consisting essentially of an acid stabilized, fibrous colloidal alumina as an aqueous sol, said binder being essentially free of silica, and said binder developing excellent green strength.
In method for casting an alloy comprising pouring a molten alloy in a shell mold, the improvement which comprises forming the shell mold from a slurry of binder and a refractory material, wherein said binder consists essentially of an acid stabilized, fibrous colloidal alumina as an aqueous sol, said binder being essentially free of silica, and said binder developing excellent green strength.
In a method of making a shell mold refractory coating comprising dipping a pattern into a slurry of binder and a refractory material, the improvement wherein said binder consists essentially of an acid stabilized, fibrous colloidal alumina as an aqueous sol, said binder being essentially free of silica, and said binder developing excellent green strength.
Dependencies are inferred from the claim text.