Corrosion behaviour of Fe-C alloys in a sulfuric medium

Four different multiphase fe-xc alloys are prepared with different ferrite and cementite amounts. x-ray diffraction analysis is used to identify the present phases in the samples. the corrosion process was evaluated by dc measurements and electrochemical impedance spectroscopy (eis). behaviour of fe-xc alloys in sulfuric acid solution is greatly affected by increasing carbon concentration. carbon increases the corrosion rate,and influences the adherence of passive film. the synergic effect of cementite is highlighted; corrosion rate is dependent on the distribution of cementite in the microstructure. the rate of the corrosion reactions increased markedly,by decreasing the average pearlite lamellae spacing in a given alloy.