INTERNATIONAL JOURNAL OF ELECTROCHEMICAL SCIENCE, cilt.10, ss.5291-5308, 2015 (SCI-Expanded)
In this study, Ni52Ti47.7Re0.3 shape memory alloy was subjected to solution treatment at 1000 °C for 24h (the tested alloy), followed by ageing at 300, 400, 500 and 600 °C for 3h. The objective is to investigate the effect of ageing temperature on the uniform and pitting corrosion characteristics of Ni52Ti47.7Re0.3 alloy. Measurements were conducted in 1.0 M H2SO4 solutions without and with 0.2 M NH4F, using polarization, impedance, and chronoamperometry measurements. Morphologies of the corroded surfaces were examined by SEM/EDX examinations. Results obtained from the employed electrochemical techniques were in good agreement and showed that the rates of the uniform and pitting corrosion processes of the tested alloy decrease with increase in the aging temperature, reaching their minimum values at an aging temperature of 400 oC. Further increase in the aging temperature up to 600 oC led to an obvious increase in the rates of corrosion. Experimental finding were interpreted adopting the effect of the aging temperature on the microstructure of the tested alloy.