Pitting Corrosion of Sensitized Ferritic Stainless Steel

CORROSION ◽  
1972 ◽  
Vol 28 (7) ◽  
pp. 255-258 ◽  
Author(s):  
C. R. RAREY ◽  
A. H. ARONSON
Keyword(s):  
Stainless Steel ◽  
Ferritic Stainless Steel ◽  
Pitting Corrosion

scholarly journals On the Application of Bipolar Electrochemistry to Characterise the Localised Corrosion Behaviour of Type 420 Ferritic Stainless Steel

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 794 ◽  
Author(s):  
Yiqi Zhou ◽  
Dirk Lars Engelberg
Keyword(s):  
Stainless Steel ◽  
Ferritic Stainless Steel ◽  
Pitting Corrosion ◽  
Corrosion Behaviour ◽  
General Corrosion ◽  
Full Spectrum ◽  
Nucleation Sites ◽  
Corrosion Pitting ◽  
Cathodic Region ◽  
Bipolar Electrochemistry

Bipolar electrochemistry has been applied to Type 420 ferritic stainless steel in order to determine the full spectrum of anodic-to-cathodic polarisation behaviour. The occurrence of crevice corrosion, pitting corrosion in combination with general corrosion, pitting corrosion only, general corrosion only, followed by a cathodic region has been observed. Instances of pitting corrosion initiated near chromium-rich carbides with Cr23C6, Cr3C2, and Cr7C3 identified as pit nucleation sites. The observed pit growth kinetics were independent of the electrochemical over-potential. Characterisation of the pit size distributions supports the presence of a critical dissolved volume for the transition of metastable to stable pit growth and pit coalescence.

Effect of cerium on the initiation of pitting corrosion of 444-type heat-resistant ferritic stainless steel

2020 ◽  
Vol 39 (1) ◽  
pp. 576-587
Author(s):  
Mingyu Ma ◽  
Houlong Liu ◽  
Liqing Chen
Keyword(s):  
Stainless Steel ◽  
Solid Oxide Fuel Cells ◽  
Ferritic Stainless Steel ◽  
Rare Earths ◽  
Pitting Corrosion ◽  
Electrochemical Impedance ◽  
Test Results ◽  
Heat Resistant ◽  
Service Environments ◽  
Metastable Pitting

AbstractThe 444-type heat-resistant ferritic stainless steel is widely utilized in automotive exhaust pipes and solid oxide fuel cells, due to its excellent properties at elevated temperature. To meet the demands of significantly harsh service environments, rare earths were added in 444-type ferritic stainless steel. For the purpose of evaluating the effect of rare earths on pitting corrosion initiation, the metastable pitting corrosion behavior in 444-type ferritic stainless steel was studied through potentiodynamic polarization and potentiostatic polarization tests. The results demonstrated that pitting corrosion was initiated at the inclusion/alloy interface. The cerium alloying in 444-type ferritic stainless steel decreased the amount of preferential dissolution sites. The beneficial effect of Ce on pitting corrosion resulted from the formation of stable cerium oxides, as well as from the reduction in the amount and size of inclusions in 444-type ferritic stainless steel. In addition, electrochemical impedance spectroscopy test results revealed that cerium alloying enhanced the polarization resistance of passive films through insignificant thickness alteration.

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