# US 9,518,308 B2 · High-density and high-strength WC-based cemented carbide

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- Number: US 9,518,308 B2
- Document ID: US9518308B2
- Status: Granted
- Kind: B2
- Application number: 14/138,177
- Filed: 2013-12-23
- Published: 2015-06-25
- Granted: 2016-12-13
- Earliest claimed: 2013-12-23
- Assignees: King Fahd University of Petroleum and Minerals
- Applicants: King Fahd University of Petroleum and Minerals
- Inventors: Khwaja Mohammad; Nouari Saheb; Tahar Laoui; Nasser Al-Aqeeli
- Web page: https://patentgrep.com/patent/US9518308B2

## CPC

- C22C 29/08: based on tungsten carbide
- B22F 3/105: by using electric current {other than for infrared radiant energy}, laser radiation or plasma (B22F3/11 takes precedence){; by ultrasonic bonding (B22F3/115 takes precedence)}
- B22F 2003/1051: {by electric discharge}
- B22F 2301/15: Nickel or cobalt
- B22F 2302/10: Carbide
- B22F 2304/054: Particle size between 1 and 100 nm
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- 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

The synthesis of high performance WC-Co cemented carbides which can be efficiently used in the cutting tool industry. WC with different particle sizes and different grain growth inhibitors were consolidated through spark plasma sintering technique and to form a cemented carbide with best combination of mechanical properties. VC and Cr3C2 are included as grain growth inhibitors in different amounts and combination to the WC-Co powder composition. Higher amount of inhibitors results in lower grain sizes and higher hardness values, however adding more than a crucial amount was observed to degrade the mechanical properties.

## Claims

### Claim 1

A spark plasma sintered tungsten carbide-cobalt cemented carbide, comprising:
tungsten carbide particles having an average particle size of no greater than 20 nm,
a cobalt metal matrix,
a vanadium carbide as a first grain growth inhibitor, and
a chromium carbide as a second grain growth inhibitor,
wherein the cobalt metal matrix is present in the cemented carbide in an amount of from 9 to 12% by weight based on the total weight of the tungsten carbide and the cobalt, and the total amount of the vanadium carbide and the chromium carbide is from 0.2 to 0.8 wt % based on the total weight of the tungsten carbide and the cobalt, and
wherein the tungsten carbide particles are dispersed in the cobalt metal matrix in disaggregated form.

### Claim 2 (depends on 1)

The cemented carbide according to claim 1, having a Vickers hardness (Hv30) of 800-1,750.

### Claim 3 (depends on 1)

The cemented carbide of claim 1, having a fracture toughness of from 11 to 13 MPam1/2.

### Claim 4 (depends on 1)

The cemented carbide of claim 1, having a relative densification of from 97.55 to 99.15%.

### Claim 5 (depends on 1)

The cemented carbide of claim 1, comprising from 0.2 to 0.8 wt % of the vanadium carbide.

### Claim 6 (depends on 1)

The cemented carbide of claim 1, comprising from 0.2 to 0.8 wt % of the chromium carbide.

### Claim 7 (depends on 1)

The cemented carbide of claim 1, wherein the total amount of the vanadium carbide and the chromium carbide is from 0.2 to 0.6 wt %.

### Claim 8 (depends on 1)

A process for forming the cemented carbide of claim 1, comprising:
spark plasma sintering a pulverulent mixture of WC particles, Co particles, VC particles and Cr3C2 particles.

### Claim 9 (depends on 8)

The process of claim 8, wherein the spark plasma sintering is carried out at a temperature of from 1,200 to 1,300° C.

### Claim 10 (depends on 8)

The process of claim 8, wherein the spark plasma sintering forms a product having a hardness of 1650-1700Hv30.

### Claim 11 (depends on 8)

The process of claim 8, wherein the spark plasma sintering is carried out at a pressure of 50 MPa or less.

### Claim 12 (depends on 8)

The process of claim 8, wherein the sintered tungsten carbide formed by the spark plasma sintering has a tungsten carbide grain size of 10 nm or less.

### Claim 13 (depends on 8)

The process of claim 8, wherein the spark plasma sintering forms a tungsten carbide cobalt comprising 0.1-0.3 wt % of vanadium carbide and 0.6-0.7 wt % chromium carbide, wherein wt % is based on the total weight of the tungsten carbide and the cobalt.