FLUXING METHODS FOR NICKEL BASED CHROMIUM AND PHOSPHORUS BEARING ALLOYS TO IMPROVE GLASS FORMING ABILITY

• US 20150159248A1
• Filed: 12/09/2014
• Published: 06/11/2015
• Est. Priority Date: 12/09/2013
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Glassimetal Technology Inc.
• Inventors: Na, Jong Hyun, Floyd, Michael, Duggins, Danielle, Demetriou, Marios D., Johnson, William L.
• Granted Patent: US 9,828,659 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: C22C 1/11 Making amorphous alloys
• CPC Class Codes: C22C 19/05 with chromium
• CPC Class Codes: C22C 45/04 with nickel or cobalt as the major constituent
• CPC Class Codes: C22F 1/10 of nickel or cobalt or alloys based thereon

Abstract

The disclosure is directed to Ni-based glass-forming alloys bearing Cr and P, wherein the Cr atomic concentration is greater than 7 percent and the P atomic concentration is greater than 12 percent, and methods of fluxing such alloys such that their glass-forming ability is enhanced with respect to the glass-forming ability associated with their unfluxed state.

Claims

1. A method of fluxing a high purity Ni-based glass-forming alloy bearing Cr and P, wherein the Cr atomic concentration is greater than 7 percent and the P atomic concentration is greater than 12 percent, comprising:

heating the alloy with a fluxing agent comprising boron and oxygen to a fluxing temperature that is above the liquidus temperature of the alloy and above the softening or melting temperature of the fluxing agent to form an alloy melt and a fluxing agent melt;

allowing the alloy melt to interact with the fluxing agent melt at the fluxing temperature to form a fluxed alloy;

cooling the fluxed alloy to a temperature below the glass transition temperature of the alloy;

wherein the critical rod diameter of the fluxed alloy is increased by at least 50% as compared to the critical rod diameter of the alloy comprising the same composition in its unfluxed high-purity state.

2. The method of claim 1, wherein the critical rod diameter of the fluxed alloy is increased by at least 75% as compared to the critical rod diameter of the alloy comprising the same composition in its unfluxed high-purity state.

3. The method of claim 1, wherein the critical rod diameter of the fluxed alloy is increased by at least 100% as compared to the critical rod diameter of the alloy comprising the same composition in its unfluxed high-purity state.

4. The method of claim 1, wherein the critical rod diameter of the fluxed alloy is at least 14 mm.

5. The method of claim 1, wherein the critical rod diameter of the fluxed alloy is at least 16 mm.

6. The method of claim 1, wherein the fluxing temperature is at least 100°

C. above the liquidus temperature of the alloy.

7. The method of claim 1, wherein the fluxing temperature is at least 1150°

C.

8. The method of claim 1, wherein the alloy melt interacts with the fluxing agent at the fluxing temperature for a fluxing time of at least 60 seconds.

9. The method of claim 6, wherein the fluxing time is at least 1 hour.

10. The method of claim 1, wherein the fluxing agent is boron oxide.

11. The method of claim 1, wherein the fluxing agent is boric acid.

12. The method of claim 1, the fluxing agent has a purity of at least 98%.

13. The method of claim 1, wherein the cooling of the fluxed alloy is sufficiently fast such that the fluxed alloy solidifies in an amorphous phase.

14. The method of claim 1, wherein the fluxing method is performed in an inert atmosphere.

15. The method of claim 1, wherein the Cr atomic concentration is between 7 and 10, and the P atomic concentration is between 14 and 19.

16. The method of claim 1, wherein the alloy has a composition according to Formula (I):

Ni_{(100-a-b-c-d)}Cr_aX_bP_cY_d,  

 

(I)

wherein X is Mo, Mn, Nb, Ta, Fe or combinations thereof,

Y is B, Si, or combinations thereof,

the atomic percent of Cr (a) is greater than 7,

the atomic percent of X (b) is between 1 and 5,

the atomic percent of P (c) is greater than 12,

and the atomic percent of Y (d) is up to 5,

17. The method of claim 1, wherein the alloy has a composition according to Formula (II):

Ni_{100-a-b-c-d-e}Cr_aNb_bP_cB_dSi_e,  

 

(II)

wherein the atomic percent of Cr (a) is 7 and 10,

the atomic percent of Nb (b) is between 2.5 and 3.5,

the atomic percent of P (c) is between 14 and 17.5,

the atomic percent of B (d) is between 2.5 and 4, and

the atomic percent of Si (e) is up to 1.5.

18. A metallic glass formed according to the method of claim 1.

19. A fluxed Ni-based glass forming alloy bearing Cr and P, wherein the Cr atomic concentration is greater than 7 percent and the P atomic concentration is greater than 12 percent, wherein the glass forming ability of the fluxed alloy is increased by at least 50% as compared to the critical rod diameter of the alloy comprising the same composition in its unfluxed high-purity state, produced by a fluxing process comprising:

heating the alloy with a fluxing agent to a fluxing temperature that is above the liquidus temperature of the Ni-based glass forming alloy to form an alloy melt and a fluxing agent melt;

allowing the alloy melt to interact with the fluxing agent melt at the fluxing temperature;

cooling the alloy melt to a temperature below the glass transition temperature of the alloy to form the fluxed alloy.

20. A metallic glass article formed comprising the fluxed alloy of claim 19.