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US 11,298,251 B2Granted
Radiopaque intraluminal stents comprising cobalt-based alloys with primarily single-phase supersaturated tungsten content
AssigneeAbbott Cardiovascular Systems Inc.
InventorsJohn A. Simpson, Puneet Kamal Singh Gill, Pamela A. Kramer-Brown
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Abstract
Embodiments are directed to radiopaque implantable structures (e.g., stents) formed of cobalt-based alloys that comprise cobalt, chromium, tungsten, and nickel. Tungsten is present above its solubility limit (about 15%), but is still only present as a super-saturated, primarily single-phase material exhibiting an FCC microcrystalline structure.
Claims22
A radiopaque stent, comprising:
- a cylindrical main body comprising a cobalt-chromium alloy including cobalt and chromium, the cobalt-chromium alloy including tungsten as a radiopacity increasing element, the tungsten comprising about 20% to about 35% by weight of the cobalt-chromium alloy, the tungsten content being super-saturated, above the solubility limit of tungsten in the cobalt-chromium alloy;
- wherein the cobalt-chromium alloy further comprises nickel, the nickel being present in a concentration of 5% to about 15% by weight;
- and
- wherein the cobalt-chromium alloy exhibits a primarily single-phase FCC solid solution, wherein a second phase of the tungsten is present and makes up no more than 10% volume fraction in the cobalt-chromium alloy, the second phase having an average particle size of less than 5 μm, even with the super-saturated tungsten content.
1 more element
A radiopaque stent, comprising:
- a cylindrical main body formed from a single homogenous cobalt-chromium alloy including cobalt, chromium, nickel, and tungsten, the cobalt-chromium alloy not including any other alloying elements in amounts greater than 3% by weight;
- the cobalt-chromium alloy including tungsten as a radiopacity increasing element, the tungsten comprising about 20% to about 35% by weight of the cobalt-chromium alloy, the tungsten content being super-saturated, above the solubility limit of tungsten in the cobalt-chromium alloy at ambient temperature;
- wherein the cobalt-chromium alloy comprises about 10% by weight nickel;
- and
- wherein the cobalt-chromium alloy exhibits a primarily single-phase FCC solid solution structure, a second phase of the tungsten is present in the cobalt-chromium alloy having a maximum particle size of less than 15 μm, even with the super-saturated tungsten content.
2 more elements
A radiopaque stent, comprising:
- a cylindrical main body comprising a cobalt-chromium alloy including cobalt and chromium, the cobalt-chromium alloy including tungsten as a radiopacity increasing element, the tungsten comprising about 20% to about 35% by weight of the cobalt-chromium alloy, the tungsten content being super-saturated, above the solubility limit of tungsten in the cobalt-chromium alloy;
- wherein the cobalt-chromium alloy further comprises nickel, the nickel being present in a concentration of 5% to about 15% by weight;
- wherein the cobalt-chromium alloy exhibits a primarily single-phase FCC solid solution, wherein no more than 10% volume fraction of a second phase of the tungsten is present in the cobalt-chromium alloy, the second phase having an average particle size of less than 5 μm, even with the super-saturated tungsten content;
- and
- at least one of (i) or (ii):
- (i) wherein a ratio of tungsten to cobalt is from 1.07 to 1.13;
- (ii) wherein the cobalt-chromium alloy further comprises both manganese and iron in a concentration of about 1.5% each, by weight.
4 more elements
Dependencies are inferred from the claim text.