Properties of nanostructured titanium nickelide and composite based on it

Abstract

The properties of nanostructured nitinol (Ni, 55.91 wt %; Ti, 44.03 wt %) in the initial state and after mechanical and the thermal treatment and a composite of nitinol with a tantalum surface layer obtained by magnetron sputtering have been studied. Compared with microstructured nitinol, the use of nanostructured nitinol for medical appliances, like stent, has great opportunities due to better corrosion resistance in solutions that model the physiological media of a human organism and the decreased diffusion of nickel ions into solution below the admitted average dietary intake of 200–300 mg/day in solutions of any acidity. Surface mechanical polishing increases its corrosion resistance by two to three times more. Compared with nitinol, the composite of nitinol with a tantalum surface layer is ∼7–11% better by strength, plasticity, and surface microhardness and characterized by the absence of a corrosion processes and diffusion of metal ions into solution.