Loukaycheva M.Tzaneva B.Fachikov L.2024-07-162024-07-162024-07-162024-07-162014-01-011314-79781314-7471SCOPUS_ID:84901663445https://rlib.uctm.edu/handle/123456789/1050The corrosion behavior of Cr18Mn12N (0.61% N) and Cr18Ni9 steels in water solutions of sodium orthophosphates (NaH2PO4, Na2HPO4 u Na3PO4)-0.1 M, with sodium chloride addition (0.5M) have been investigated by potentiostatic and galvanostatic methods. Galvanostatic results reveal that both steels exhibit almost identical behaviors. The increase in the current density does not affect the value of the stationary potentials reached after 1 hour of polarization. In solutions of NaH2PO4 and Na2HPO4 both steels develop pitting corrosion. In Na3PO4 with added chloride, the steels show passive behavior at the applied current densities; there are indications of pitting occurrence on the chrome-nickel steel surface that subsequently repassivate. The potentiostatic dependencies provide a basis to determine the values of the pitting formation potentials, Epit and the incubation time, ti of the pitting nucleation. The recorded Epit for the nitrogen steel have more negative values than those obtained with the classical stainless steel. However, the nickel free steel demonstrates 5-10 times lower speed of pitting nucleation and growth compared to Cr18Ni9. In Na3PO4 solutions in presence of NaCl, the Cr18Mn12N steel shows better corrosion resistance-more positive Epit and longer incubation time.enArticle