FAQ´s about Nitinol

There is Nickel in Nitinol and Nickel is considered toxic. Why does Nitinol get an FDA approval for instruments and even implants?

Nitinol alloys contain more nickel than stainless steels. However, as nitinol is an intermetallic compound and not an alloy in the metallurgical sense, the bonding force of nickel to titanium is much stronger in nitinol than to the alloy components in stainless steel. Moreover, as nitinol oxidizes after proper surface treatment, it forms a TiO2 layer with no nickel present at the surface.

For biocompatibility see en.wikipedia.org/wiki/Nitinol_Biocompatibility