# US 4,395,279 A · Plasma spray powder

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- Number: US 4,395,279 A
- Document ID: US4395279A
- Status: Granted
- Kind: A
- Application number: 06/325,267
- Filed: 1981-11-27
- Granted: 1983-07-26
- Earliest claimed: 1981-11-27
- Assignees: GTE Products Corporation
- Inventors: David L. Houck
- Web page: https://patentgrep.com/patent/US4395279A

## CPC

- C22C 29/08: based on tungsten carbide
- C23C 4/06: Metallic material
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)

## Abstract

A plasma spray powder having a substantially uniform composition consisting essentially of a metal selected from the group consisting of cobalt, nickel, iron, mixtures and alloys thereof the balance consisting essentially of tungsten and carbon in a ratio of about one mole of carbon per one mole of tungsten wherein the ratio of iron and nickel to cobalt is at least about 4 to one.

## Claims

### Claim 1

A plasma spray powder consisting essentially of metals selected from the group consisting of nickel, iron or cobalt, or mixtures and alloys thereof, with the balance being from about 50 to about 90 percent by weight tungsten and carbon, said tungsten and carbon being present in a one to one molar ratio and said iron and nickel being present in a weight ratio of at least about 4 parts by weight iron and nickel combined to 1 part by weight cobalt, said powder having a particle size distribution of about 60 to 90 percent minus 20 microns, and less than about 15 percent minus 5 microns and consisting essentially of homogeneous plasma densified and melt alloyed particles having a substantially uniform composition.

### Claim 2 (depends on 1)

A plasma spray powder according to claim 1 having a particle size distribution of about 100 percent minus 270 mesh and less than 15 percent -15 microns.

### Claim 3 (depends on 1)

A plasma spray powder according to claim 1 having a particle size distribution of about minus 200 plus 325 mesh.

### Claim 4

A process for producing a plasma spray powder comprising preparing a uniform powder blend consisting essentially of metals selected from the group consisting of iron, nickel or cobalt being present in a weight ratio of at least 4 parts iron or nickel to 1 part cobalt with the balance of said powder being from about 50 to about 90 percent by weight tungsten and carbon, said tungsten and said carbon being present in a one to one molar ratio, said powder blend having an average particle size less than about 10 microns, agglomerating the powder to produce agglomerated particles, sintering the agglomerated particles, entraining the sintered agglomerated powder in a carrier gas, feeding the entrained agglomerated powder through a high temperature reactor having a temperature above the melting point of the highest melting component of the powder material to densify said particles, wherein said densified particles consist essentially of particles having substantially uniform composition, and comminuting and classifying said densified particles to produce a powder having a particle size distribution of about 60 to 90 percent minus 20 microns, and less than about 15 percent minus 5 microns.

### Claim 5 (depends on 4)

A process for producing a plasma spray powder according to claim 4 wherein said densified particles have a particle size distribution of about 100 percent minus 270 mesh and less than 15 percent minus 15 microns.

### Claim 6 (depends on 4)

A process for producing a plasma spray powder according to claim 4 wherein said uniform powder blend is spray dried to form said agglomerates.