Cobalt alloy for medical implants and stent comprising the alloy

Patent metadata

Field	Value
Publication number	US-9757224-B2
Application number	US-201313910326-A
Country	US
Kind code	B2
Filing date	Jun 5, 2013
Priority date	Jun 18, 2012
Publication date	Sep 12, 2017
Grant date	Sep 12, 2017

Abstract

An embodiment of the invention relates to a cobalt-based alloy, which due to the composition exhibits twinning as the dominating deformation mechanism:
Cr: 13.0 to 30.0% by weight Mn: 2.0 to 10.0% by weight W: 2.0 to 18.0% by weight Fe: 5.0 to 15.0% by weight C: 0.002 to 0.5% by weight N: 0 to 0.2% by weight Si: 0 to 2.0% by weight Ni: 0 to 5.0% by weight

wherein the aforementioned alloying components and manufacturing-related impurities add up to 100% by weight, and the following restrictions according to formulas (1) and (2) apply to the contents of nitrogen and carbon, and the following restrictions according to formula (3) apply to the contents of oxygen, phosphorus and sulfur:

0.003%≦C+N≦0.5% weight  (1)

N/C(wt. %)≦1.00 for 0.07%<C<0.15% (weight)  (2)

O+P+S<0.10% weight  (3).

First claim

What is claimed is:

1. A cobalt alloy comprising a tensile strength of greater than 900 MPa and having the following composition:
Cr: 13.0 to 30.0% by weight
Mn: 2.0 to 10.0% by weight
W: 2.0 to 18.0% by weight
Fe: 5.0 to 15.0% by weight
C: 0.002 to 0.5% by weight
N: 0 to 0.2% by weight
Si: 0 to 2.0% by weight
Ni: 2.0 to 3.5% by weight
Co: balance,

wherein the aforementioned alloying components and manufacturing-related impurities add up to 100% by weight, and the following restrictions according to formulas (1) and (2) apply to the contents of nitrogen and carbon, and the following restrictions according to formula (3) apply to the contents of oxygen, phosphorus and sulfur:
0.003%≦C+N≦0.5% (by weight)  (1)

N/C(wt. %)≦1.00 for 0.07%<C<0.15% (by weight)  (2)

O+P+S<0.10% (by weight)  (3),

wherein the alloy is free from Mo.

2. The alloy according to claim 1 , wherein a content of Cr in the alloy is 17.0 to 25.0% by weight.

3. The alloy according to claim 1 , wherein a content of Mn in the alloy is 4.0 to 10.0% by weight.

4. The alloy according to claim 1 , wherein a content of W in the alloy is 9.0 to 18.0% by weight.

5. The alloy according to claim 1 , wherein a content of Fe in the alloy is 9.5 to 10.5% by weight.

6. The alloy according to claim 1 , wherein a content of Si in the alloy is less than 0.7% by weight.

7. The alloy according to claim 1 , wherein a content of C in the alloy is 0.002 to 0.15% by weight.

8. The alloy according to claim 1 , wherein a content of C in the alloy is 0.07 to 0.15% by weight and N/C (wt. %) ranges between 0.25 and 1.

9. The alloy according to claim 1 , wherein a content of Ni in the alloy is 2.5 to 3.5% by weight.

10. The alloy according to claim 1 , wherein a content of Ni in the alloy is 2.5 to 3.5% by weight, and the total weight % of C and N together is between 0.003 and 0.3.

11. The alloy according to claim 1 , wherein the total weight % of C and N together is between 0.003 and 0.1.

12. The alloy according to claim 1 wherein Cr is present in a weight % of between 19.0 and 21.0.

13. The alloy according to claim 1 wherein W is present in a weight % of between 14.5% to 15.5%.

14. The alloy according to claim 1 wherein the Si is present in a weight % between 0.05 to 0.5%.

15. The alloy according to claim 1 wherein the alloy is free of Ti, Ta, Nb and Al.

16. The alloy according to claim 1 wherein the content of O, S and P in alloy is below 0.07% weight in total.

17. A cobalt alloy, having the following composition:
Cr: 13.0 to 30.0% by weight
Mn: 2.0 to 10.0% by weight
W: 2.0 to 18.0% by weight
Fe: 5.0 to 15.0% by weight
C: 0.002 to 0.5% by weight
N: 0 to 0.2% by weight
Si: 0 to 2.0% by weight
Ni: 2.0 to 3.5% by weight
Co: balance,

wherein the aforementioned alloying components and manufacturing-related impurities add up to 100% by weight, and the following restrictions according to formulas (1) and (2) apply to the contents of nitrogen and carbon, and the following restrictions according to formula (3) apply to the contents of oxygen, phosphorus and sulfur:
0.003%≦C+N≦0.5% (by weight)  (1)

N/C(wt. %)≦1.00 for 0.07%<C<0.15% (by weight)  (2)

O+P+S<0.10% (by weight)  (3),

wherein the alloy is free from Mo; and
wherein the alloy has a stacking fault energy between 20 and 30 mJ/m 2 .

18. A stent comprising a filigree support structure made entirely or partially of a cobalt alloy comprising a tensile strength of greater than 900 MPa and having the following composition:
Cr: 13.0 to 30.0% by weight
Mn: 2.0 to 10.0% by weight
W: 2.0 to 18.0% by weight
Fe: 5.0 to 15.0% by weight
C: 0.002 to 0.5% by weight
N: 0 to 0.2% by weight
Si: 0 to 2.0% by weight
Ni: 0 to 3.5% by weight
Co: balance,
wherein the aforementioned alloying components and manufacturing-related impurities add up to 100% by weight, and the following restrictions according to formulas (1) and (2) apply to the contents of nitrogen and carbon, and the following restrictions according to formula (3) apply to the contents of oxygen, phosphorus and sulfur:
0.003%≦C+N≦0.5% (wt.)  (1)

N/C(wt. %)≦1.00 for 0.07%<C<0.15% (wt.)  (2)

O+P+S<0.10% (wt.)  (3)

wherein the alloy is free from Mo.

19. A stent as defined by claim 18 , wherein the stent further includes a generally tubular shaped base body that is made entirely of the alloy.

Assignees

• Biotronik Ag

Inventors

• Gerold Bodo

Classifications

• A61L31/022

  Metals or alloys · CPC title

• C22C19/07 Primary

  based on cobalt · CPC title

• C22F1/10

  of nickel or cobalt or alloys based thereon · CPC title

• A61F2/06 Primary

  Blood vessels · CPC title