Effect of Plasma Nitriding and Oxidation on the Corrosion Resistance of 304 Stainless Steel in LiBr/H2O and CaCl2-LiBr-LiNO3-H2O Mixtures

The effect of plasma nitriding and oxidation on the corrosion resistance AISI 304 type stainless steel in LiBr/H2O CaCl2-LiBr-LiNO3-H2O mixtures at 80 °C has been evaluated by using potentiodynamic polarization curves electrochemical impedance spectroscopy techniques (EIS). Steel was treated 500 during 8 h under different atmospheres, nominally 20% N2 + 80% H2, 100% O2. X-ray diffraction analysis (XRD) showed presence a CrN layer nitrided specimens, whereas scanning electronic microscopy revealed that specimen H2 atmosphere thickest nitride layer. Specimens had noblest open circuit potential value both solutions, indicated formation passive These specimens exhibited lowest passivation current density values. Corrosion process charge transfer control solutions regardless treatment. suffered all treatments pitting corrosion. Pits for nitrides steels rather than untreated or pre-oxidized ones.