Open AccessEffect of Molybdate on the Stability of Pit Growth in Duplex Stainless Steel 2205
Author(s) -
Razieh Tavassolian,
Mohammad Hadi Moayed,
Mostafa Mirjalili
Publication year - 2021
Publication title -
journal of the electrochemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.258
H-Index - 271
eISSN - 1945-7111
pISSN - 0013-4651
DOI - 10.1149/1945-7111/ac39dd
Subject(s) - molybdate , dissolution , sodium molybdate , chemistry , metal , molybdenum , inorganic chemistry , metallurgy , materials science
In the present study, the criteria of pit stabilization and salt formation have been investigated for DSS 2205 using the lead-in-pencil electrode in order to explore the contribution of molybdate in stable pit growth. Results show that the E pit shifts to positive values with increasing molybdate concentration. It is found that the increase in E pit could not be explained by the changes in DC crit and DC sat , since these values are slightly reduced by adding molybdate to the solution. In contrast, the active dissolution rate of the metal assessed by i diss,max is hindered in the presence of molybdate ions. Therefore, it is proposed that the mechanism for the inhibitory influence of molybdate can be attributed to an increment in the intersection point of i diss,max / i diff,crit (which reflects E crit ), and i diss,max / i lim (which reflects E sat ). Therefore, increasing the E crit and E sat at the pit growth process is responsible for the observed raising of the E pit in presence of molybdate.