Structure and Properties of the High Temperature Nitrided/Oxided Surface of Ni-Ti Alloy

Abstract

The nearly-equiatomic NiTi (50.6 at.%Ni, Af = 10°C) alloy was nitrided at 1073 K using glow discharge technique. Additionally, at the end of the nitriding some amount of oxygen was added. Phase identification and thickness of the nitrided/oxided layer was done using electron microscopy method and the X-ray reflectivity measurements. The chemical composition of the layers was determined using energy dispersive spectrometer. Combination of nitriding and oxidation of the NiTi surface produces nitride/oxide complex layer of a nanocrystalline structure. The average thickness of the obtained layer was about 0,5 μm. The potentiodynamical studies in Tyrod’s solution reveal good corrosion resistance of obtained nitrided/oxidized NiTi surface proving its high quality.