Although the corrosion behavior of austenite has been well established, the corrosion of martensite has not been fully characterized.  A detailed corrosion comparison between the different Nitinol phases was conducted and the results were evaluated.  The material specimens were thermally treated to ensure that one was austenite, and the other was martensite at 22ºC.  DSC, or differencial scanning calorimetry confirmed the material phases of each sample.   Cyclic potentiodynamic polarization (CPP) measurements yield information on corrosion rates, passivation abilities, and pitting tendencies.  CCP curves were obtained for the austenite, stress-induced martensite, and thermally-induced martensite phases in Hank’s simulated physiological solution.  The breakdown potential was similar for the thermally-induced martensite and austenite phases with more noble corrosion potentials.  By contrast, the stress-induced martensite exhibited a lower breakdown potential.  In addition, the stress-induced martensite phase exhibited a higher corrosion rate compared to the thermally-induced martensite and austenite phases. The corrosion behavior observed seemed to be primarily governed by changes in surface morphology.