Continuing a tradition of technological excellence and innovation, NDC recently introduced an extra-low interstitial (ELI) version of its proven SE-508 alloy which has served as the medical device industry’s leading implantable Nitinol for nearly two decades. This revolution in material purity stems from ten years of research with their primary melting partner, ATI Wah Chang, to develop raw materials specifically formulated for ultra-pure Nitinol production, and enhance melting techniques to optimize the solidification thermodynamics to minimize the formation of impurities. As a result of these advancements, SE-508 ELI contains the fewest and smallest inclusions of any commercially available bulk Nitinol alloy while retaining the same desirable strength, ductility, transformation temperatures, superelasticity, formability, biocompatibility and corrosion-resistance as conventional Nitinol.
Like NDC’s flagship SE-508 alloy, SE-508 ELI is virtually carbon-free, thereby eliminating hard titanium-carbide (TiC) inclusions altogether. Furthermore, the oxygen levels are nominally 60 parts per million (ppm). Combined, these impurity levels are more than 10-times lower than the ASTM F2063 allowance, and 3- to 6-times lower than “standard” Nitinol alloys.
While the effect of inclusions on the durability and yields of Nitinol components remains unproven, a correlation has been established in other titanium alloys prompting the almost exclusive use of ELI-grade material in the medical industry (Saitova et al., Int J Fatigue 2009). Regardless, the use of this ultra-pure material will undoubtedly result in the lowest likelihood of inclusions residing in safety-critical regions of finished components.
The interest and demand for this revolutionary advancement in Nitinol purity has already been outstanding. Indeed, immediately upon the release of SE-508 ELI, 1,000 pounds of the material were purchased by a major medical device company for use in one of its implantable cardiovascular device products.
NDC offers SE-508 ELI to its customers in both a finished component form, as well as in its raw material form – tube, wire, sheet, and strip. For more information regarding SE-508 ELI, or any other Nitinol needs, NDC can be reached at www.nitinol.com or [email protected].