Effect of Zr and Cu Alloying on the Structure and Electrochemical Properties of TiNi

The detailed comparative XRD, TEM/EDS analysis of TiNi and TiNiCuZr samples revealed the formation of two isostructural B2 phases with different lattice parameters, chemical composition and microstructure. According to the experimental the lattice parameter value aB2(TiNiCuZr) in the TiNiCuZr sample is several times higher than aB2(TiNi) in the TiNi sample, indicating the formation of a new B2 phase. These variations in B2 lattice parameters strongly correlate with the changes in the chemical composition. The study of the electrochemical properties of the initial alloys (TiNi, Ti–Ni–Cu–Zr) in 0.9 wt % NaCl and artificial saliva showed that the TiNi alloy of binary composition exhibits significantly higher corrosion properties. In turn, the Ti–Ni–Cu–Zr alloy is prone to anodic polarization and corrosion destruction. It was found that under the same conditions of the corrosive media, the corrosion rate of the Ti–Ni–Cu–Zr alloy is ∼3.2 times higher than that of the TiNi alloys.