Composite material containing tungsten and bronze

• US 20030161751A1
• Filed: 10/16/2002
• Published: 08/28/2003
• Est. Priority Date: 10/16/2001
• Status: Active Grant

• Current Assignee: Elliott Cartridge Company (Canada), Ltd.
• Original Assignee: International Non-Toxic Composites Corporation
• Inventors: Elliott, Kenneth H.
• Granted Patent: US 7,232,473 B2
• Time in Patent Office: Days
• US Class Current: 419/36
• CPC Class Codes: A01K 95/005 Sinkers not containing lead
• CPC Class Codes: B22F 1/09 Mixtures of metallic powders
• CPC Class Codes: B22F 1/10 Metallic powder containing lubricating or binding agents; Metallic powder containing organic material
• CPC Class Codes: B22F 1/148 Agglomerating
• CPC Class Codes: B22F 2998/00 Supplementary information concerning processes or compositions relating to powder metallurgy
• CPC Class Codes: B22F 2998/10 Processes characterised by the sequence of their steps
• CPC Class Codes: B22F 3/10 Sintering only
• CPC Class Codes: B22F 3/1025 not by heating only
• CPC Class Codes: B22F 3/26 Impregnating making ferrous alloys by impregnation C22C33/0242
• CPC Class Codes: C22C 1/0425 Copper-based alloys
• CPC Class Codes: C22C 1/045 Alloys based on refractory metals
• CPC Class Codes: F42B 12/74 of the core or solid body
• CPC Class Codes: F42B 7/046 Pellets or shot therefor

Abstract

High-density composite materials comprising tungsten and bronze are useful as lead replacements in the production of ammunition, weights and other high density articles. The composition of the composite, articles manufactured using the composite, and a process for making the composite are disclosed.

Claims

1. A composite comprising tungsten and bronze.

2. The composite according to claim 1, wherein the composite comprises from about 40% to about 85% W by weight of the composite.

3. The composite according to claim 2, wherein in the bronze is an alloy of copper and tin comprising 80% to 95% copper and 5% to 20% tin by weight of the bronze.

4. The composite according to claim 3, wherein the bronze comprises copper and tin in a ratio of about 9:

1 by weight of the bronze.

5. The composite according to claim 4, wherein the composite comprises 50% to 55% W by weight of the composite.

6. The composite according to claim 5, wherein the composite further comprises iron (Fe).

7. The composite according to claim 6, wherein the composite comprises 0.5% to 5% Fe by weight of the composite.

8. The composite according to claim 7, wherein the composite comprises 0.8% Fe by weight of the composite.

9. An article comprising a composite according to claim 1.

10. The article of claim 9 which is ammunition, a wheel weight, a radiation shield or a high-density gyroscopic ballast.

11. The article of claim 9 which is a bullet, a bullet core, or a shot.

12. The article of claim 9 which is sintered.

13. The article of claim 12 which is plated with a powdered metal after sintering.

14. A composite consisting essentially of tungsten, bronze, and iron.

15. The composite according to claim 14, wherein the composite consists essentially of 52% tungsten, 47.2% bronze, and 0.8% iron by weight of the composite, the bronze consisting essentially of 90% copper and 10% tin by weight of the bronze.

16. An article comprising a composite according to claim 14.

17. The article of claim 16 which is ammunition, a wheel weight, a radiation shield or a high-density gyroscopic ballast.

18. The article of claim 16 which is a bullet, a bullet core, or a shot.

19. The article of claim 16 which is sintered.

20. The article of claim 16 which is plated with a powdered metal after sintering.

21. A process for producing a composite, the process comprising:

a) blending powdered tungsten, powdered bronze, and an organic binder, thereby forming a homogeneous mixture;

b) compounding the mixture at elevated temperature; and

,

c) cooling the mixture to form a composite having consistent characteristics throughout the composite.

22. A process according to claim 21, wherein step a) further includes blending powdered iron.

23. A process according to claim 21, wherein the organic binder can be de-bound at a temperature less than 375°

C.

24. The process according to claim 21, wherein the binder comprises a wax.

25. The process according to claim 21, wherein the binder comprises stearic acid and a mixture of paraffin waxes having a melting point between 50°

C. and 73°

C.

26. The process according to claim 21, wherein the binder is softened during compounding and compounding is conducted at a temperature less than the melting point of the binder.

27. The process according to claim 21, the process further comprising:

d) molding the composite at elevated temperature to form an article;

e) de-binding the organic binder from the article;

f) sintering the article at elevated temperature; and

,

g) cooling the article after sintering.

28. The process according to claim 27, wherein the binder is softened during molding and molding is conducted at a temperature less than the melting point of the binder.

29. The process according to claim 27, wherein de-binding comprises placing the articles in a wicking powder comprising alumina and elevating the temperature of the articles to about 350°

C.

30. The process according to claim 27, wherein the articles are sintered at a temperature of about 1000°

C. to about 1100°

C.

31. A process for producing an article, the process comprising:

a) providing a mold having a cavity with one open end;

b) placing a quantity of a homogeneous mixture of powders comprising tungsten and bronze in the cavity;

c) placing a quantity of a powdered infiltrant on the mixture of powders in the cavity;

d) sintering the mixture of tungsten and bronze powders at a first temperature followed by melting the infiltrant at a second temperature; and

,

e) cooling the mold and the articles formed therein.

32. A process according to claim 31, wherein the mixture of powders further comprises iron.

33. A process according to claim 31, wherein the quantity of infiltrant is less than the quantity of the mixture of powders.

34. A process according to claim 31, wherein the infiltrant is copper.

35. A process according to claim 31, wherein the first temperature is from 800-1100°

C. and wherein the second temperature is from 1000 to 1100°

C.

36. A process according to claim 31, wherein the mold is made from a ceramic material and has a plurality of cavities therein, each cavity in the shape of the article.

37. A process according to claim 31, wherein the article is a bullet or a bullet core.