Refractory containing investment material and method of making

摘要

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.