Alacrite

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Alacrite (also known as L-605, Cobalt L-605, Haynes 25, and occasionally F90[1][2][3]) is a family of cobalt-based alloys. The alloy exhibits useful mechanical properties and is oxidation- and sulfidation-resistant.[2]

One member of the family, XSH Alacrite,[4] is described as "a non-magnetic, stainless super-alloy whose high surface hardness enables one to achieve a mirror quality polish."[5] Originally developed for manufacturing aircraft components,[6] L-605 has also been used in aerospace components and turbine engines as well as drug-eluting and other kinds of stents due to its biocompatibility.[2] The Institut National de Métrologie in France has also used the material as a kilogram mass standard.[5][6]

Composition and standardization[edit]

L-605 is composed primarily of cobalt (Co), with a specified mixture of chromium (Cr), tungsten (W), nickel (Ni), iron (Fe) and carbon (C), as well as small amounts of manganese (Mn), silicon (Si), and phosphorus (P). The tungsten and nickel improve the alloy's machinability,[3] while chromium contributes to its solid-solution strengthening.[2] The following tolerances must be met to be considered an L-605 alloy:[1][2][4][6]

Tolerances for L-605 composition
Co Cr W Ni Fe C Mn Si P
Balance 19–21 14–16 9–11 < 3 0.05–0.015 1–2 < 1 < 0.4

When used for implantable medical devices, the ASTM F90-09 and ISO 5832-5:2005 specifications dictate how L-605 is manufactured and tested.[2][3][7][8]

References[edit]

  1. ^ a b "Nickel Alloy L-605, Cobalt® L-605, Haynes® 25". Continental Steel & Tube Company. Retrieved 11 March 2016. 
  2. ^ a b c d e f Poncin, P.; Gruez, B.; Missillier, P.; Comte-Gaz, P.; Proft, J.L. (2006). "L605 Precipitates and Their Effects on Stent Applications". In Venugopalan, R.; Wu, M. Medical Device Materials III - Proceedings of the Materials & Processes for Medical Devices Conference. ASTM International. pp. 85–92. ISBN 9781615031153. Retrieved 11 March 2016. 
  3. ^ a b c Brunski, J.B. (2009). "3.2.9 Metals". In Academic Press. Biomedical Engineering Desk Reference. Elsevier. pp. 230–247. ISBN 9780123746474. Retrieved 11 March 2016. 
  4. ^ a b Meury, P.A.; Molins, R.; Gosset, A. (June 2005). "Définition d'un nouvel alliage métallique pour la réalisation d'étalons de masse secondaires" (PDF). Actes du 12e congrès international de métrologie. Laboratoire national de métrologie et d’essais. Retrieved 11 March 2016. 
  5. ^ a b "BNM-INM/CNAM - M.G.A.". L'Institut National de Métrologie. Archived from the original on 30 March 2012. Retrieved 11 March 2016. 
  6. ^ a b c Jones, F.E.; Schoonover, R.M. (2002). "Chapter 3: Contamination of Mass Standards". Handbook of Mass Measurement. CRC Press. pp. 23–36. ISBN 9781420038453. Retrieved 11 March 2016. 
  7. ^ "ASTM F90-09: Standard Specification for Wrought Cobalt-20Chromium-15Tungsten-10Nickel Alloy for Surgical Implant Applications (UNS R30605)". ASTM.org. ASTM International. Retrieved 11 March 2016. 
  8. ^ "ISO 5832-5:2005: Implants for surgery -- Metallic materials -- Part 5: Wrought cobalt-chromium-tungsten-nickel alloy". ISO.org. International Organization for Standardization. 11 March 2016.