The electrochemical behavior of a Ti50Ni47Fe3 shape memory alloy

The corrosion performance of Ti50Ni47Fe3 alloy in 0.9% NaCl physiological, artificial saliva and Hank's solutions with different pH values at 37 °C was investigated by means of open circuit potential (OCP) measurement and linear polarization (LP) measurement techniques, respectively. The OCP stabilized at − 0.2925, − 0.3111 and − 0.3454 mV/SCE in sequence for 0.9% NaCl, artificial saliva and Hank's solutions, respectively. LP results demonstrated that the Ti50Ni47Fe3 alloy has a low passive current and a wide passive range. The surface roughness and in-depth distribution of the passive films after immersion in corrosion media was characterized by using Atomic Force Measurement (AFM) and X-ray electron spectroscopy (XPS). AFM results shows that the electrochemical measurements have little influence on the surface roughness of the Ti50Ni47Fe3 alloy, and the XPS analysis results revealed that the outer passive film consisting mainly of a layer of TiO2 which is deemed to be important for all biomaterials.