Refractory containing investment material and method of making
AssigneePrecision Metalsmiths, Inc.
InventorClaude Watts
Life of this patent
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Abstract
An improved refractory investment material for use in making refractory molds is provided. The material comprises an investment powder including a binder, a refractory selected from calcined mullite and pyrophyllite, additives for controlling setting and about 0.01 to about 0.04% by weight of a sulfate salt. The investment powder is formed into a slurry with a solution of a water based colloidal silica in an amount providing about 3% to about 6% by weight colloidal silica based on the weight of the water and a chloride salt in an amount of at least about 0.5% by weight based on the weight of said investment powder.
Claims16
In an aqueous slurry of investment powder for use in making investment molds, the powder including refractory and binder, the improvement comprising a sulfate salt in an amount of from about 0.01% to about 0.04% by weight based on the weight of investment powder, a chloride salt in an amount of at least about 0.5% by weight based on the weight of investment powder, and from about 3% to about 6% by weight colloidal silica based on the weight of water.
An aqueous slurry for use in making refractory molds comprising:
- a) an investment powder consisting essentially of at least one refractory selected from the class consisting of mullite and pyrophyllite, and in amounts by weight based on the total weight of investment powder, from about 25% to about 35% alpha gypsum, from about 0.01% to about 0.04% of a sulfate salt, and from about 0.07% to about 0.15% setting agents,
- b) colloidal silica in an amount of about 3% to about 6% based on the weight of water, and
- c) a chloride salt in an amount of from about 0.5% to about 2.0% by weight based on the weight of investment powder.
A method of preparing a refractory slurry for use in making investment molds comprising the steps of:
- a) preparing an investment powder by blending together at least one refractory selected from the class of mullite and pyrophyllite, alpha gypsum in an amount of from about 25% to about 35% by weight based on the weight of powder, a sulfate salt in an amount of from about 0.01% to about 0.04% by weight based on the weight of powder, and setting agents in an amount of from about 0.07% to 0.15% by weight based on the weight of powder,
- b) preparing an aqueous solution of silica sol in an amount providing about 3% to 6% by weight colloidal silica based on the weight of water, and a chloride salt in an amount of at least about 0.5% by weight based on the weight of powder, and
- c) mixing the investment powder and solution in a ratio of from about 28 to about 48 parts of solution to 100 parts of powder.
Dependencies are inferred from the claim text.