HIGH CORROSION RESISTANT Zr-Ti BASED METALLIC GLASSES

• US 20090014096A1
• Filed: 06/18/2008
• Published: 01/15/2009
• Est. Priority Date: 06/18/2007
• Status: Active Grant

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Johnson, William L., Wolfson, Nikolaj, Demetriou, Marios D., Wiest, Aaron
• Granted Patent: US 7,998,286 B2
• Time in Patent Office: Days
• US Class Current: 148/403
• CPC Class Codes: C22C 45/10 with molybdenum, tungsten, niobium, tantalum, titanium, or zirconium or Hf as the major constituent

Abstract

Bulk solidifying amorphous alloys (BMGs) having improved corrosion resistance properties; and more particularly a sub-set of Zr—Ti-based BMGs having improved corrosion resistance properties are provided. The BMG compositions are formed by carefully controlling the concentration of, or removing altogether, highly electronegative elements, such as Ni and Cu from Zr—Ti-based bulk solidifying amorphous alloys thereby producing BMG materials with corrosion resistance properties that far exceed those of current commercially available BMGs and most conventional alloys. The elimination of these electronegative materials also opens the possibility of new uses for BMGs, including in biological applications.

Claims

1. A bulk metallic glass having a high corrosion resistance comprising a composition in accordance with the following molecular formula:

(Zr_aTi_b)_1-z(Be_cX_d)_z

wherein x is an additive material selected from the group consisting of Y, Co, Fe, Cr, Mo, Mg, Al, Hf, Ta, Nb and V;

wherein z is from around 20 to 50 at %;

wherein the sum of c and d is equal to z and wherein c is at least around 25 at %; and

wherein elements having an electronegativity greater than 1.9 are present only in trace amounts.

2. The bulk metallic glass of claim 1, wherein the ratio of a to b is preferably around 1.16.

3. The bulk metallic glass of claim 1, wherein d is from around 2 to 7.5 at %.

4. The bulk metallic glass of claim 1, wherein a is around 35 at %, and b is around 30 at %.

5. The bulk metallic glass of claim 1, wherein c is from around 27.5 to 33 at %.

6. The bulk metallic glass of claim 1, wherein z is around 35 at %.

7. The bulk metallic glass of claim 1, wherein the alloy has a composition selected from the group consisting of Zr₃₅Ti₃₀Be₃₅, Zr₂₅Ti₄₀Be₃₀Cr₅, Zr₃₅Ti₃₀Be₃₃Fe₂, Zr₃₅Ti₃₀Be₃₁Fe₄, Zr₃₅Ti₃₀Be₂₉Fe₆, Zr₃₅Ti₃₀Be_27.5Fe_7.5, Zr₃₅Ti₃₀ Be₃₃Co₂, Zr₃₅Ti₃₀Be₃₁ Co₄, Zr₃₅Ti₃₀ Be₂₉Co₆, Zr₃₅Ti₃₀ Be_27.5Co_7.5

8. The bulk metallic glass of claim 1, wherein the alloy has an amorphous phase comprising at least around 25% of the alloy by volume.

9. The bulk metallic glass of claim 1, wherein the alloy may be net-shape formed.

10. The bulk metallic glass of claim 1, wherein the alloy may be micro-formed.

11. The bulk metallic glass of claim 1, wherein the alloy shows substantially no evidence of mass loss after a 3 month exposure to a solution of 0.6M NaCl.

12. The bulk metallic glass of claim 1, wherein the alloy shows substantially no evidence of mass loss after a 3 month exposure to a solution of 10×

PBS.

13. The bulk metallic glass of claim 1, wherein the alloy shows substantially no evidence of mass loss after a 3 month exposure to a solution of 50% NaOH.

14. The bulk metallic glass of claim 1, wherein the alloy shows substantially no evidence of mass loss after a 1 month exposure to a solution of 50% NaOH.

15. The bulk metallic glass of claim 1, wherein the alloy shows a mass loss equal to or less than around 0.1% after a 3 month exposure to a solution of 50% NaOH.

16. The bulk metallic glass of claim 1, wherein the alloy shows a mass loss equal to or less than around 0.2% after a 24 hour exposure to a solution of 37% HCl.

17. The bulk metallic glass of claim 1, wherein the alloy shows a mass loss equal to or less than around 10% after a 1 week exposure to a solution of 37% HCl.

18. The bulk metallic glass of claim 1, wherein the alloy is biocompatible.

19. A medical implant comprising:

an implant body formed of a bulk metallic glass having a composition in accordance with the following molecular formula;

(Zr_aTi_b)_1-z(Be_cX_d)_z

wherein x is an additive material selected from the group consisting of Y, Co, Fe, Cr, Mo, Mg, Al, Hf, Ta, Nb and V;

wherein z is from around 20 to 50 at %;

wherein the sum of c and d is equal to z and wherein c is at least around 25 at %; and

wherein elements having an electronegativity greater than 1.9 are present only in trace amounts.

20. The implant of claim 19, wherein the ratio of a to b is preferably around 1.16.

21. The implant of claim 19, wherein d is from around 2 to 7.5 at %.

22. The implant of claim 19, wherein a is around 35 at % and b is around 30 at %.

23. The implant of claim 19, wherein c is from around 27.5 to 33 at %.

24. The implant of claim 19, wherein z is around 35 at %.

25. The implant of claim 19, wherein the alloy has a composition selected from the group consisting of Zr₃₅Ti₃₀Be₃₅, Zr₂₅Ti₄₀Be₃₀Cr₅, Zr₃₅Ti₃₀Be₃₃Fe₂, Zr₃₅Ti₃₀Be₃₁Fe₄, Zr₃₅Ti₃₀Be₂₉Fe₆, Zr₃₅Ti₃₀Be_27.5Fe_7.5, Zr₃₅Ti₃₀Be₃₃Co₂, Zr₃₅Ti₃₀Be₃₁Co₄, Zr₃₅Ti₃₀Be₂₉Co₆, Zr₃₅Ti₃₀Be_27.5Cu_7.5.

26. The implant of claim 19, wherein the implant is net-shape formed.

27. The implant of claim 19, wherein the implant is micro-formed.