Effect of Nitriding on the Anodic Behavior of Iron and Its Significance in Pitting Corrosion of Iron-Based Alloys

Abstract

The anodic behavior of both pure iron and nitrided iron has been studied in chloride-containing aqueous solutions at neutral and acidic pH values. The structure of the nitride has been characterized by X-ray diffraction. Surface nitrides may modify the anodic kinetics of stainless steel at the stage of pitting initiation by inhibition of the anodic dissolution of iron. Micro-electrode measurements performed in simulated pits have provided supporting evidence.

Electrochemistry of TiN in 6 M KOH Solution

“…Thermodynamically, Ti" ions should not exist in water except at very low p11 21but the role of nitrogen (or oxynitrogen) on this chemistry, especially right at the TiN electrode surface, is unknown. The other possibility is that the TiN oxidizes to give Ti" ions first according to a reaction like TiN + 2 OIL + H,0 = HTiO; + NH3 + e [4] where the Ti" ions are incorporated in the titanate ion and the electrons are extracted either by an oxidant (probably dissolved 03) under open-circuit conditions or directly during anodic polarization. The titanate ions would then he free to react according to reaction 2 to give the hydrous titanate reaction product.…”

Facile preparation, formation mechanism and microwave absorption properties of porous carbonyl iron flakes

“…42 On the other hand, the corrosion potential for Fe 4 N is lowered by more than 150 mV and the corrosion current for Fe 4 N is about one order of magnitude larger than that for pure Fe in 1 M HCl. 43 Therefore it is reasonable to assume that the Fe 4 N phase, which was generated in the annealing process and is randomly dispersed within the CIF particles, is mainly responsible for the occurrence of pitting corrosion and the formation of the porous CIFs.…”

Investigation on Pitting Corrosion of Nickel-Free and Manganese-Alloyed High-Nitrogen Stainless Steels

“…This thus promotes the anodic dissolution of stainless steels. In addition, N has frequently been reported to accelerate the anodic dissolution of iron in acidic solution (Ref 5,(47)(48)(49), also to promote the selective dissolution of iron from stainless steels (Ref 26, 46). As a result, the HNSSs with combined addition of high Mn and N showed higher peaks of The sensitization treatment used in the present work caused significant degradation on pitting corrosion resistance of the HNSSs in both neutral and acidic NaCl solutions.…”