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Application of potentiostatic pulse technique and statistical analysis in evaluating pitting resistance of aged 317L stainless steel
Author(s) -
Sun Yangting,
Sun Li,
Dai Nianwei,
Liu Yuanyuan,
Wu Jun,
Li Jin,
Jiang Yiming
Publication year - 2020
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.201810622
Subject(s) - materials science , metallurgy , pitting corrosion , microstructure , polarization (electrochemistry) , statistical analysis , chemistry , alloy , mathematics , statistics
Pitting potential (E p ) and potentiostatic critical pitting temperature (CPT) are two mainly applied electrochemical methods in pitting evaluation. However, the dispersive results make them difficult to distinguish specimens with similar pitting resistance. potentiostatic pulse technique (PPT) combined with statistical analysis can be a solution to this problem. In this work, potentiodynamic polarization curves of 317L stainless steel at different temperatures were measured to obtain the precise critical pitting condition, based on which the parameters of PPT tests were determined. Subsequently, statistical analysis and microstructure observation were carried out after PPT tests to compare the pitting resistance of 317L aged for different time. It was well revealed by PPT measurement that the specimens saw a degradation with the increase of aging time and this degradation was related to σ precipitation. On the other hand, E p and CPT of the same specimens were also measured. The results showed high dispersion, which was even larger than the difference among specimens.