IPC분류정보
국가/구분 |
United States(US) Patent
등록
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국제특허분류(IPC7판) |
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출원번호 |
US-0429341
(2009-04-24)
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등록번호 |
US-8808618
(2014-08-19)
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발명자
/ 주소 |
- Furst, Joseph G.
- Patel, Udayan
- Buckman, Jr., Raymond W.
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출원인 / 주소 |
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대리인 / 주소 |
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인용정보 |
피인용 횟수 :
1 인용 특허 :
228 |
초록
A method and process for at least partially forming a medical device that is at least partially formed of a novel metal alloy which improves the physical properties of the medical device.
대표청구항
▼
1. A method for forming an expandable medical device comprising the steps of: a) forming a rod or tube having a surface and an original outer cross-sectional area, said rod or tube being formed of a metal alloy, said metal alloy including two or more metals selected from the group consisting of calc
1. A method for forming an expandable medical device comprising the steps of: a) forming a rod or tube having a surface and an original outer cross-sectional area, said rod or tube being formed of a metal alloy, said metal alloy including two or more metals selected from the group consisting of calcium, chromium, cobalt, copper, gold, iron, lead, magnesium, molybdenum, nickel, niobium, platinum, rare earth metals, rhenium, silver, tantalum, titanium, tungsten, yttrium, zinc, and zirconium, said metal alloy including at least one metal selected from the group consisting of molybdenum, rhenium, tantalum, tungsten;b) drawing down said outer cross-sectional area of said rod or tube to a first drawn down cross-sectional area by a reducing mechanism, said rod or tube being drawn down at least once to obtain said first drawn down cross-sectional area, said outer cross-sectional area being reduced by no more than about 25% during each drawing down process;c) annealing said rod or tube during a first annealing step prior to said rod or tube having said original outer cross-sectional area drawn down by more than about 60%, said step of annealing performed at a first annealing temperature when said rod or tube is at said first drawn down cross-sectional area;d) drawing down said cross-sectional area of said rod or tube from said first drawn down cross-sectional area to a second drawn down cross-sectional area by the reducing mechanism after said rod or tube has been annealed, said second drawn down cross-sectional area smaller than said first drawn down cross-sectional area, said rod or tube being drawn down at least once to obtain said second drawn down cross-sectional area, said outer cross-sectional area reduced by no more than about 25% during each drawing down process;e) annealing said rod or tube during a second annealing step prior to said rod or tube having said first drawn down cross-sectional area being drawn down by more than about 60%, said step of annealing performed at a second annealing temperature when said rod or tube is at said second drawn down cross-sectional area, said second annealing temperature lower temperature than said first annealing temperature;f) controlling an atmosphere about said rod or tube during said steps of drawing and annealing so that said metal alloy of said rod or tube after final drawing and annealing steps includes less than about 30 ppm nitrogen, less than about 200 ppm carbon, and less than about 150 ppm oxygen; and,g) repeating steps d, e and f until said tube is at a desired thickness. 2. The method as defined in claim 1, wherein said step of forming said rod or tube includes a process of isostatically pressing metal powder together and subsequently sintering said metal power to form said rod or tube in a controlled atmosphere, said rod or tube having an average density of about 0.7-0.95 a minimum theoretical density of said metal alloy, said rod or tube have an average density of about 12-14 gm/cc, said controlled atmosphere including an inert atmosphere, an oxygen reducing atmosphere, or a vacuum. 3. The method as defined in claim 2, wherein said tube is formed by gun drilling, EDM cutting, and combinations thereof a passageway at least partially through a longitudinal length of said rod. 4. The method as defined in claim 1, wherein said step of forming said rod or tube includes a) forming an ingot of metal, b) extruding said ingot through a die to form a rod, c) hollowing out said rod to form a passageway at least partially through a longitudinal length of said rod, and d) polishing a surface of said passageway. 5. The method as defined in claim 4, wherein said step of hollowing includes gun drilling, EDM cutting, and combinations thereof said rod to form said passageway. 6. The method as defined in claim 1, wherein said metal alloy includes rhenium and molybdenum. 7. The method as defined in claim 6, wherein said metal alloy includes about 40-55 weight percent rhenium, about 45-60 weight percent molybdenum, and up to about 5 weight percent additional metal, said additional metal including one or more metals selected from the group consisting of titanium, yttrium, and zirconium. 8. The method as defined in claim 7, including the step of protecting said rod or tube from oxygen when said rod or tube is exposed to temperatures of greater than about 400-500° C. 9. The method as defined in claim 7, wherein said step of drawing down said cross-sectional area of said rod or tube by a reducing mechanism that reduces said cross-sectional area by less than about 20% each time said rod or tube is processed by said reducing mechanism. 10. The method as defined in claim 1, including the step of nitriding said rod or tube to form a nitride layer on said rod or tube prior to at least one drawing down step, said step of nitriding including a) exposing at least a portion of said rod or tube to a nitriding gas that includes nitrogen, nitrogen and hydrogen, and combinations thereof, and b) exposing at least a portion of said rod or tube to a nitriding gas at a temperature of at least about 400° C. for at least about 1 minute. 11. The method as defined in claim 7, including the step of nitriding said rod or tube to form a nitride layer on said rod or tube prior to at least one drawing down step, said step of nitriding including a) exposing at least a portion of said rod or tube to a nitriding gas that includes nitrogen, nitrogen and hydrogen, and combinations thereof, and b) exposing at least a portion of said rod or tube to a nitriding gas at a temperature of at least about 400° C. for at least about 1 minute. 12. The method as defined in claim 10, including the step of removing said nitride layer on said rod or tube prior to annealing said rod or tube. 13. The method as defined in claim 11, including the step of removing said nitride layer on said rod or tube prior to annealing said rod or tube. 14. The method as defined in claim 1, including the step of protecting said rod or tube from oxygen when said rod or tube is exposed to temperatures of greater than about 400-500° C. 15. The method as defined in claim 13, including the step of protecting said rod or tube from oxygen when said rod or tube is exposed to temperatures of greater than about 400-500° C. 16. The method as defined in claim 1, wherein said step of drawing down said cross-sectional area of said rod or tube by a reducing mechanism that reduces said cross-sectional area by less than about 20% each time said rod or tube is processed by said reducing mechanism. 17. The method as defined in claim 15, wherein said step of drawing down said cross-sectional area of said rod or tube by a reducing mechanism that reduces said cross-sectional area by less than about 20% each time said rod or tube is processed by said reducing mechanism. 18. The method as defined in claim 16, wherein said step of drawing down includes the step of inserting a close-fitting rod in a passageway of said tube prior to using said reducing mechanism on said tube, said close-fitting rod formed of tantalum and niobium. 19. The method as defined in claim 17, wherein said step of drawing down includes the step of inserting a close-fitting rod in a passageway of said tube prior to using said reducing mechanism on said tube, said close-fitting rod formed of tantalum and niobium. 20. The method as defined in claim 1, wherein said first step of annealing said rod or tube includes annealing said rod or tube at said first annealing temperature of at least about 1480° C. for a time period of at least about 5 minutes when said rod or tube has wall thickness of greater than about 0.015 inch, said second step of annealing said rod or tube includes annealing said rod or tube at said second annealing temperature of at least about 1450° C. for a time period of at least about 5 minutes when said rod or tube has all thickness of about 0.008-0.015 inch, and including the further step of annealing said rod or tube a third time at a third annealing temperature of less than about 1450° C. for a time period of at least about 5 minutes when said rod or tube has wall thickness of less than about 0.008 inch. 21. The method as defined in claim 17, wherein said first step of annealing said rod or tube includes annealing said rod or tube at said first annealing temperature of at least about 1480° C. for a time period of at least about 5 minutes when said rod or tube has wall thickness of greater than about 0.015 inch, said second step of annealing said rod or tube includes annealing said rod or tube at said second annealing temperature of at least about 1450° C. for a time period of at least about 5 minutes when said rod or tube has wall thickness of about 0.008-0.015 inch, and including the further step of annealing said rod or tube a third time at a third annealing temperature of less than about 1450° C. for a time period of at least about 5 minutes when said rod or tube has wall thickness of less than about 0.008 inch. 22. The method as defined in claim 1, wherein said tube having a grain size after said final drawing down step of up to 14 ASTM. 23. The method as defined in claim 21, wherein said tube having a gain size after said final drawing down step of up to 14 ASTM. 24. The method as defined in claim 1, wherein said medical device is a stent. 25. The method as defined in claim 23, wherein said medical device is a stent. 26. The method as defined in claim 24, including the step of cutting said tube to at least partially form said stent. 27. The method as defined in claim 25, including the step of cutting said tube to at least partially form said stent. 28. The method as defined in claim 26, wherein said step of cutting is at least partially by a laser, said laser cutting of said tube at least partially conducted in a vacuum or an inert atmosphere. 29. The method as defined in claim 27, wherein said step of cutting is at least partially by a laser, said laser cutting of said tube at east partially conducted in a vacuum or an inert atmosphere. 30. The method as defined in claim 26, including the step of electropolishing said stent after said cutting step. 31. The method as defined in claim 29, including the step of electropolishing said stent after said cutting step. 32. The method as defined in claim 1, including the step of using a lubricant during said drawing down of said tube, said lubricant including a molybdenum containing lubricant. 33. The method as defined in claim 31, including the step of using a lubricant during said drawing down of said tube, said lubricant including a molybdenum containing lubricant. 34. The method as defined in claim 1, wherein said first step of annealing said rod or tube includes annealing said rod or tube at said first annealing temperature of at least about 1480° C. for a time period of at least about 5 minutes when said rod or tube has wall thickness of greater than about 0.015 inch, said second step of annealing said rod or tube includes annealing said rod or tube at said second annealing temperature of at least about 1450° C. for a time period of at least about 5 minutes when said rod or tube has wall thickness of about 0.008-0.015 inch, and including the further step of annealing said rod or tube a third time at a third annealing temperature of less than about 1450° C. for a time period of at least about 5 minutes when said rod or tube has wall thickness of less than about 0.008 inch. 35. The method as defined in claim 1, wherein said first step of annealing said rod or tube includes annealing said rod or tube at said first annealing temperature of at least about 1480-1520° C. for a time period of about 5-40 minutes when said rod or tube has wall thickness of greater than about 0.015 inch, said second step of annealing said rod or tube includes annealing said rod or tube at said second annealing temperature of about 1450-1480° C. for a time period of about 5-60 minutes when said rod or tube has wall thickness of about 0.008-0.015 inch, and including the further step of annealing said rod or tube a third time at a third annealing temperature of about 1400-1450° C. for a time period of about 15-75 minutes when said rod or tube has wall thickness of less than about 0.008 inch.
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