ELECTROCHEMICAL AND MICROSTRUCTURAL STUDIES OF SINTERED AND SINTERED-PLASMA NITRIDED STEEL CONTAINING DIFFERENT ALLOYING ELEMENTS

The corrosion of sintered and sintered-plasma nitrided steels containi ng different alloying elements was evaluated through analysis of the p otentiodynamic polarization curves of the samples at pH=7, with 1.25 M KNO3 as electrolyte. The Fe-3.0% Ni and Fe-0.1% C sintered alloys sho w better performance in relation to electrochemical corrosion, than si ntered pure iron samples. In addition, Fe-4.0% Mn, Fe-1.5% Mo and Fe-1 .5% Si alloys exhibited increased anodic current densities in relation to the pure iron sample. After the nitriding process the anodic curre nt densities of all samples containing an alloying element were consid erably diminished. The sintered-nitrided pure iron sample was the only nitrided part whose current density was higher than the current densi ty of the non-nitrided sample.