# US 4,397,889 A · Process for producing refractory powder

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- Number: US 4,397,889 A
- Document ID: US4397889A
- Status: Granted
- Kind: A
- Application number: 06/365,685
- Filed: 1982-04-05
- Granted: 1983-08-09
- Earliest claimed: 1982-04-05
- Assignees: GTE Products Corporation
- Inventors: Mary Lou Benjamin; Robert J. Dobbs; Mary E. Shaffer
- Web page: https://patentgrep.com/patent/US4397889A

## CPC

- B22F 9/04: starting from solid material, e.g. by crushing, grinding or milling ({C22C1/1084 takes precedence}; crushing, grinding or milling, in general, see the relevant subclasses, e.g. B02C)
- B22F 1/10: Metallic powder containing lubricating or binding agents; Metallic powder containing organic material
- B22F 1/108: {Mixtures obtained by warm mixing}
- B22F 2998/00: Supplementary information concerning processes or compositions relating to powder metallurgy
- B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER

## Abstract

In a process for producing a refractory metal carbide grade powder, a metal carbide powder is heated above melting point of a wax prior to forming a blended mixture of metal carbide and wax which is subsequently milled with a metal binder in liquid milling medium incompatible with the wax and the mixture is dried to form a powder.

## Claims

### Claim 1

A process for producing a refractory powder containing an organic binder comprising heating particles of a refractory material to a temperature above the melting point and below the decomposition temperature of said organic binder to form a heated powder of refractory material, said organic binder consisting essentially of a wax, mixing said organic binder with said heated powder to form a blended mixture, milling said blended mixture with a liquid milling medium to produce a slurry, said organic binder being substantially insoluble in said liquid milling medium, and removing substantially all of said milling medium by evaporation below the decomposition temperature of said organic binder to form a refractory powder having an adherent coating of said organic binder.

### Claim 2

A process for producing a powder mixture of metal carbide particles, metal binder particles and wax suitable for making a cemented metal carbide comprising forming a mixture of metal carbide particles and wax at a temperature above the melting point of said wax, said metal carbide particles and wax being sufficiently mixed to form a blended mixture of wax and metal carbide particles, milling said blended mixture including metal binder particles with a liquid milling medium to substantially uniformly disperse said metal binder particles and to produce a slurry, said metal binder particles being added prior to or during milling, said wax being substantialy insoluble in said liquid milling medium, drying said slurry to remove said milling medium and produce a powder comprising particles of metal carbide, metal binder and wax.

### Claim 3 (depends on 2)

A process to claim 2 wherein said mixture of metal carbide particles and wax includes metal binder particles, and said mixture is sufficiently mixed in a non-oxidizing environment to form a blended mixture of wax, metal binder particles and metal carbide particles.

### Claim 4 (depends on 2)

A process according to claim 2 wherein said metal binder particles are added to said blended mixture of wax and metal carbide particles after mixing.

### Claim 5 (depends on 4)

A process according to claim 4 wherein said drying comprises spray drying to produce an agglomerated powder.

### Claim 6 (depends on 5)

A process according to claim 5 wherein said wax is water insoluble and said milling medium comprises water.

### Claim 7 (depends on 6)

A process according to claim 6 wherein said wax comprises a parafin wax.

### Claim 8 (depends on 5)

A process according to claim 5 wherein said milling medium comprises an organic solvent and said wax is insoluble in said organic solvent.

### Claim 9 (depends on 1)

A progress according to claim 1 wherein said temperature of heating is at least about 20 degrees centigrade above the melting point of said organic binder.

### Claim 10 (depends on 9)

A process according to claim 9 wherein said temperature of heating is at least about 30 degrees centigrade above the melting point of said organic binder.

### Claim 11 (depends on 10)

A process according to claim 10 wherein said blended mixture is cooled prior to milling.

### Claim 12 (depends on 11)

A process according to claim 11 wherein said milling comprises attritor milling.

### Claim 13 (depends on 12)

A process according to claim 12 wherein evaporation comprises spray drying.