Coinage alloy and processing for making coinage alloy

Patent metadata

Field	Value
Publication number	US-10344366-B2
Application number	US-201615295206-A
Country	US
Kind code	B2
Filing date	Oct 17, 2016
Priority date	Oct 17, 2016
Publication date	Jul 9, 2019
Grant date	Jul 9, 2019

Abstract

A coinage alloy for coinage includes nickel present in an amount from 13 wt. % to 16 wt. %, based on a total weight of the coinage alloy; zinc present in an amount from 25 wt. % to 32 wt. %, based on the total weight of the coinage alloy; manganese present in an amount from 1 wt. % to 4 wt. %, based on a total weight of the coinage alloy; copper; an electrical conductivity from 5% International Annealed Copper Standard (IACS) to 6% IACS; and a color comprising a yellowness vector b* that is from 5 to 10, based on a CIE L*a*b* color space and determined in accordance with ASTM Standard E308-15 (2015).

First claim

What is claimed is:

1. A coinage alloy for coinage comprising:
nickel present in an amount from 14.1 wt. % to 16 wt. %, based on a total weight of the coinage alloy;
zinc present in an amount from 25 wt. % to 32 wt. %, based on the total weight of the coinage alloy;
manganese present in an amount from 1 wt. % to 4 wt. %, based on a total weight of the coinage alloy;
copper;
an electrical conductivity from 5% International Annealed Copper Standard (IACS) to 6% IACS measured in accordance with ASTM E1004-09 (2009); and
a color comprising a yellowness vector b* that is from 5 to 10, based on a CIE L*a*b* color space and determined in accordance with ASTM Standard E308-15 (2015).

2. The coinage alloy of claim 1 , wherein the copper is present in an amount as a balance of the total weight of the coinage alloy.

3. The coinage alloy of claim 2 , wherein the copper is present in an amount from 46 wt. % to 61 wt. %, based on the total weight of the coinage alloy.

4. The coinage alloy of claim 1 , further comprising a disordered crystalline phase,
wherein atoms of the nickel, copper, zinc, and manganese are randomly arranged in the disordered crystalline phase at room temperature in a post-annealed state.

5. The coinage alloy of claim 4 , wherein the disordered crystalline phase comprises a single phase.

6. The coinage alloy of claim 5 , wherein the single phase is a face-centered cubic phase.

7. The coinage alloy of claim 1 , wherein the coinage alloy is an annealed alloy.

8. The coinage alloy of claim 5 , wherein the electrical conductivity is produced from quenching an annealing alloy from an annealing temperature at a cooling rate effective to produce the coinage alloy in the disordered crystalline phase.

9. The coinage alloy of claim 8 , wherein the cooling rate is greater than or equal to air cooling from the annealing temperature to room temperature.

10. The coinage alloy of claim 1 , wherein a yield strength of the coinage alloy is from 120 MPa to 180 MPa.

11. The coinage alloy of claim 1 , wherein a hardness of the coinage alloy is from 80 VHN to 250 VHN.

12. The coinage alloy of claim 1 , wherein the electrical conductivity is selected such that a coin comprising the coinage alloy is acceptable as currency in a vending machine that accepts the coin.

13. A coin comprising the coinage alloy of claim 1 .

14. The coin of claim 13 , wherein the electrical conductivity is selected such that a coin comprising the coinage alloy is acceptable as currency in a vending machine that accepts the coin.

15. A process for making the coinage alloy of claim 1 , the process comprising:
heating an alloying composition to a first temperature that is greater than or equal to an annealing temperature to form an annealing alloy, the alloying composition comprising:
nickel present in an amount from 14.1 wt. % to 16 wt. %, based on a total weight of the alloying composition;
zinc present in an amount from 25 wt. % to 32 wt. %, based on the total weight of the alloying composition;
manganese present in an amount from 1 wt. % to 4 wt. %, based on a total weight of the alloying composition; and
copper; and

quenching, by cooling the annealing alloy from the first temperature to a second temperature that is less than the annealing temperature, under a condition effective to form the coinage alloy comprising the electrical conductivity and the yellowness vector b*.

16. The process of claim 15 , wherein heating the alloying composition comprises melting the alloying composition to form a molten alloy; and
the process further comprises cooling the molten alloy to the first temperature to form the annealing alloy.

17. The process for making the coinage alloy of claim 16 , wherein the annealing temperature is from 700° to 800° C.; and
the condition comprises a cooling rate that is greater than or equal to air cooling from the first temperature to the second temperature.

18. The process for making the coinage alloy of claim 16 , further comprising casting the molten alloy to form the annealing alloy in a solid state.

19. The process for making the coinage alloy of claim 15 , wherein the copper is present in an amount as a balance of the total weight of the coinage alloy.

20. The process for making the coinage alloy of claim 19 , wherein the copper is present in an amount from 46 wt. % to 61 wt. %, based on the total weight of the coinage alloy.

21. The process for making the coinage alloy of claim 15 , wherein the coinage alloy further comprises a disordered crystalline phase,
wherein atoms of the nickel, copper, zinc, and manganese are randomly arranged in the disordered crystalline phase at room temperature in a post-annealed state.

22. The process for making the coinage alloy of claim 21 , wherein the disordered crystalline phase comprises a single phase.

23. The process for making the coinage alloy of claim 22 , wherein the single phase is a face-centered cubic phase.

24. The process for making the coinage alloy of claim 15 , wherein the electrical conductivity is produced from quenching an annealing alloy from the annealing temperature at a cooling rate effective to produce the coinage alloy in a disordered crystalline phase.

25. The process for making the coinage alloy of claim 24 , wherein the cooling rate is greater than or equal to air cooling from the annealing temperature to room temperature.

26. The process for making the coinage alloy of claim 15 , wherein a yield strength of the coinage alloy is from 120 MPa to 180 MPa.

27. The process for making the coinage alloy of claim 15 , wherein a hardness of the coinage alloy is from 80 VHN to 250 VHN.

28. The process for making the coinage alloy of claim 15 , wherein the electrical conductivity is selected such that a coin comprising the alloy is acceptable as currency in a vending machine that accepts the coin.

Assignees

• Us Commerce

Inventors

• Lass Eric A
• Stoudt Mark R
• Campbell Carelyn
• Ying Tsineng Tony

Classifications

• C22C1/02

  by melting {(C22C1/1036 takes precedence)} · CPC title

• B22D21/005

  with high melting point, e.g. Be 1280 degrees C, Ti 1725 degrees C · CPC title

• C22F1/08 Primary

  of copper or alloys based thereon · CPC title

• C22C9/04

  with zinc as the next major constituent · CPC title