TY - JOUR
T1 - Co-Cr-W-Pt alloys with high X-ray visibility for next-generation balloon-expandable stents
AU - Nakajima, Tomoki
AU - Ito, Yuri
AU - Ueki, Kosuke
AU - Numano, Tomokazu
AU - Ueda, Kyosuke
AU - Narushima, Takayuki
N1 - Publisher Copyright:
© 2025 The Authors
PY - 2025/6
Y1 - 2025/6
N2 - Balloon-expandable stents are deployed using radiography, necessitating materials with high X-ray visibility, excellent corrosion resistance, high strength and ductility, and low yield stress. In this study, we designed and developed Co-Cr-W-Pt alloys by replacing Ni with Pt in a Co-Cr-W-Ni (ASTM F90, L605) alloy, which is used for practical balloon-expandable stents, with the aim of achieving both high X-ray visibility and excellent mechanical properties. The brightness of the developed alloys, which was evaluated using an X-ray television system, decreased with an increase in the Pt content, indicating that Pt addition improved X-ray visibility. The developed Co-Cr-W-Pt alloys with grain sizes of 25–48 μm exhibited ductility similar to that of conventional Pt-Cr steel and ultimate tensile strength higher than that of Pt-Cr steel. Anodic-polarization tests revealed that the corrosion resistance of the Co-Cr-W-Pt alloys was comparable to that of the L605 alloy. The elution of metal ions in the simulated body fluid was decreased to an acceptable level, and the developed alloys exhibited lower magnetic susceptibility than the L605 alloy. The Co-Cr-W-Pt alloys with high X-ray visibility, excellent mechanical properties, high corrosion resistance, and low magnetic susceptibility are suitable materials for next-generation balloon-expandable stents.
AB - Balloon-expandable stents are deployed using radiography, necessitating materials with high X-ray visibility, excellent corrosion resistance, high strength and ductility, and low yield stress. In this study, we designed and developed Co-Cr-W-Pt alloys by replacing Ni with Pt in a Co-Cr-W-Ni (ASTM F90, L605) alloy, which is used for practical balloon-expandable stents, with the aim of achieving both high X-ray visibility and excellent mechanical properties. The brightness of the developed alloys, which was evaluated using an X-ray television system, decreased with an increase in the Pt content, indicating that Pt addition improved X-ray visibility. The developed Co-Cr-W-Pt alloys with grain sizes of 25–48 μm exhibited ductility similar to that of conventional Pt-Cr steel and ultimate tensile strength higher than that of Pt-Cr steel. Anodic-polarization tests revealed that the corrosion resistance of the Co-Cr-W-Pt alloys was comparable to that of the L605 alloy. The elution of metal ions in the simulated body fluid was decreased to an acceptable level, and the developed alloys exhibited lower magnetic susceptibility than the L605 alloy. The Co-Cr-W-Pt alloys with high X-ray visibility, excellent mechanical properties, high corrosion resistance, and low magnetic susceptibility are suitable materials for next-generation balloon-expandable stents.
KW - Co-Cr alloys
KW - Corrosion resistance
KW - Magnetic susceptibility
KW - Mechanical properties
KW - X-ray visibility
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U2 - 10.1016/j.msea.2025.148216
DO - 10.1016/j.msea.2025.148216
M3 - Article
AN - SCOPUS:105000287275
SN - 0921-5093
VL - 931
JO - Materials Science and Engineering: A
JF - Materials Science and Engineering: A
M1 - 148216
ER -