FLUXING METHOD TO REVERSE THE ADVERSE EFFECTS OF ALUMINUM IMPURITIES IN NICKEL-BASED GLASS-FORMING ALLOYS

• US 20150050181A1
• Filed: 08/12/2014
• Published: 02/19/2015
• Est. Priority Date: 08/16/2013
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Glassimetal Technology Inc.
• Inventors: Na, Jong Hyun, Floyd, Michael, Duggins, Danielle, Lee, David S., Demetriou, Marios D., Johnson, William L.
• Granted Patent: US 10,006,112 B2
• Time in Patent Office: Days
• US Class Current: 420/441
• CPC Class Codes: C22B 23/06 Refining
• CPC Class Codes: C22C 1/11 Making amorphous alloys
• CPC Class Codes: C22C 19/005 with Manganese as the next major constituent
• CPC Class Codes: C22C 19/03 based on nickel
• CPC Class Codes: C22C 19/05 with chromium
• CPC Class Codes: C22C 19/057 with the maximum Cr content being less 10%
• 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

A fluxing method is disclosed by which the melt of aluminum-contaminated Ni-based glass-forming alloys is fluxed using a fluxing agent based on boron and oxygen in order to reverse the adverse effects of aluminum impurities on the glass-forming ability and toughness.

Claims

1. A method of fluxing a Ni-based glass-forming alloy that contains an initial aluminum impurity, comprising:

heating the Ni-based glass-forming alloy with a fluxing agent based on boron and oxygen to a fluxing temperature that is at least 100°

C. above the liquidus temperature of the alloy;

allowing the alloy melt and the fluxing agent melt to interact while in contact at the fluxing temperature; and

cooling the melts to a room temperature to form a fluxed alloy with a final aluminum impurity lower than the initial aluminum impurity.

2. The method of claim 1, wherein the fluxed alloy has critical rod diameter that is at least 70% of the critical rod diameter of the alloy in the high purity state.

3. The method of claim 1, wherein a metallic glass formed from the fluxed alloy has notch toughness that is at least 70% of the notch toughness of the metallic glass formed from the alloy in the high purity state.

4. The method of claim 1, wherein the fluxing agent is boron oxide (B₂O₃).

5. The method of claim 1, wherein the fluxing agent is boric acid (H₃BO₃).

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

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

8. The method of claim 1, wherein the initial aluminum impurity has an atomic fraction ranging between 100 ppm and 10000 ppm.

9. The method of claim 1, wherein the final aluminum impurity has a weight fraction of less than 100 ppm.

10. The method of claim 1, wherein the final aluminum impurity has a weight fraction of less than 50 ppm.

11. The method of claim 1, wherein the final aluminum impurity has a weight fraction of less than 10 ppm.

12. The method of claim 1, wherein the final aluminum impurity has a weight fraction of less than 5 ppm.

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

14. The method of claim 1, wherein the fluxing temperature is at least 1100°

C.

15. The method of claim 1, wherein the fluxing temperature is at least 1200°

C.

16. The method of claim 1, wherein the two melts are allowed to interact at the fluxing temperature for at least 500 s.

17. The method of claim 1, wherein the two melts are allowed to interact at the fluxing temperature for at least 1000 s.

18. The method of claim 1, the two melts are allowed to interact at the fluxing temperature for at least 1500 s.

19. A fluxed alloy that contains an Al impurity with an atomic fraction of less than 100 ppm produced by a fluxing process, the process comprising:

heating a Ni-based glass-forming alloy that contains an Al impurity with an atomic fraction ranging between 100 ppm and 10000 ppm with a fluxing agent based on boron and oxygen in a crucible to a fluxing temperature that is at least 100°

C. above the liquidus temperature of the alloy;

allowing the alloy melt and the fluxing agent melt to interact while in contact at the fluxing temperature; and

cooling the melts to a room temperature to form the fluxed alloy.

20. A metallic glass article formed from the alloy of claim 19 by a process comprising:

heating the alloy to at least 100°

C. above the liquidus temperature of the alloy;

shaping the alloy; and

quenching the molten alloy at a rate fast enough such that crystallization is prevented thereby forming an article with an amorphous phase.