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US 4,233,077 AGranted
Preparing extrudable refractory hard metal-wax blends
AssigneePPG Industries, Inc.
InventorJohn G. Hazel
Life of this patent
Estimating the term…
Abstract
Extrudable and injection-moldable blends of submicron refractory hard metal powders, i.e., carbides, borides, and nitrides of Groups III-V metals, with solid plasticizers, e.g., paraffin waxes or synthetic resins, are prepared by wetting the refractory powder with a solvent for the plasticizer, blending solvent-wetted powder with plasticizer at temperatures at which the resulting mixture is liquid, removing solvent from the mixture while blending is continued, and cooling the solvent-depleted mixture.
Claims12
A method of preparing an extrudable refractory powder composition which comprises:
- (a) mixing submicron refractory powder selected from the group consisting of borides, carbides, and nitrides of metals of Groups III, IV, and V of the Periodic Table of the Elements with organic solvent that is chemically inert to the refractory powder and liquid at room temperature to form an agglomerate-free slurry of submicron refractory powder and organic solvent,
- (b) mixing said slurry with between about 10 and 50 percent by weight of solvent-free powder of organic plasticizer at temperatures above the melting point of said organic plasticizer to obtain a liquid slurry, said plasticizer being solid at room temperature and a viscous liquid above 35.degree. C., said solvent being miscible with said plasticizer at the mixing temperatures and in the proportions used,
- (c) heating said slurry to remove substantially all of said solvent while avoiding vaporization of said plasticizer, and
- (d) cooling solvent-depleted slurry to form a solid, agglomerate-free extrudable refractory powder composition in which the refractory powder is well dispersed.
1 more element
Dependencies are inferred from the claim text.