High-density and high-strength WC-based cemented carbide

Patent metadata

Field	Value
Publication number	US-9518308-B2
Application number	US-201314138177-A
Country	US
Kind code	B2
Filing date	Dec 23, 2013
Priority date	Dec 23, 2013
Publication date	Dec 13, 2016
Grant date	Dec 13, 2016

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 Cr 3 C 2 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.

First claim

The invention claimed is:

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.

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

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

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

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

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

7. 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 %.

8. 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 Cr 3 C 2 particles.

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

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

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

12. 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.

13. 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.

Assignees

• Univ King Fahd Pet & Minerals

Inventors

• Mohammad Khwaja
• Saheb Nouari
• Laoui Tahar
• Al-Aqeeli Nasser

Classifications

• C22C29/08 Primary

  based on tungsten carbide · CPC title

• B22F2304/054

  Particle size between 1 and 100 nm · CPC title

• B22F2003/1051

  by electric discharge · CPC title

• B22F2302/10

  Carbide · CPC title

• B22F2301/15

  Nickel or cobalt · CPC title