Abstract
The corrosion of Incoloy (R) alloy 800 (TM) (Ni32.5/Cr21/Fe) in 1.0 M HCl pickling solutions after varied exposure periods, namely, 0.5 h, 2.0 h, 4.0 h, and 24 h were reported. The work was also extended to include the corrosion of the alloy at 20 degrees C, 30 degrees C, 40 degrees C, 50 degrees C, and 60 degrees C after 0.5 h immersion in the acid solution. The electrochemical impedance spectroscopy (EIS) measurements showed that the corrosion of Incoloy decreases when the exposure period increases and the highest surface and polarization resistances were recorded for the electrode after 24 h immersion. On the other hand, the increase of the temperature of the solution was found to highly increase the corrosion as a result of decreasing the resistance of the alloy under the increased corrosivity of the acid solution. The cyclic potentiodynamic polarization (CPP) measurements confirmed the EIS ones that the increase of immersion time decreases corrosion, while the increase of temperature pronouncedly increases it for the Incoloy in HCl solutions. This is because elongating the time of immersion leads to decreasing the values of j(Corr) and R-Corr but rising the temperature greatly increases them. CPP curves also indicated that the Incoloy dissolves in 1.0 M HCl solution as a result of the occurrence of the uniform corrosion.