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Development of a Platinum-Enhanced Radiopaque Stainless Steel (PERSS®) Pages: 11 Published: Jan 2003
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View License Agreement Source: STP1438-EB Abstract Balloon-expandable coronary stents may be made of stainless steel conforming to ASTM or ISO specifications, referred to by ASTM as UNS S31673 alloys. A need exists for an alloy with enhanced radiopacity to make stents more visible radiographically and more effective clinically. A research program was initiated with the objectives of enhancing fluoroscopic radiopacity while maintaining adherence to the ASTM and ISO specifications. These objectives were ultimately achieved by adding a noble metal, platinum, to UNS S31673 by vacuum induction melting a commercially-available alloy. Freedom of the resulting microstructure from formation of harmful topologically close packed phases was ensured by use of phase computation methodology (New PHACOMP), and confirmed by X-ray diffraction and transmission electron microscopy. Platinum was chosen since it is over twice as dense as nickel and, with approximately half its effect as an austenitizer, allows nickel content to be reduced to a minimum level.
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