Mechanistic studies of atmospheric pitting corrosion of stainless steel for ILW containers

Abstract

Atmospheric pitting corrosion of stainless steel was examined with synchrotron X-ray microtomography, laboratory based tests and electrochemical measurements in order to provide a mechanistic basis for the development of corrosion prediction models. It was found that the morphology of corrosion pits was affected by the presence of residual ferrite, and some pits showed dense covers that may affect pit stability. Fluctuations in relative humidity may lead to partial or complete repassivation of pits, sometimes leading to the formation of new pits. Electrochemical measurements in artificial pits containing concentrated salt solutions show a strong dependence of the diffusion limited current density on chloride concentration.

Time-dependent in situ measurement of atmospheric corrosion rates of duplex stainless steel wires

“…17,18 State-of-theart characterisation techniques, such as X-ray computed tomography (X-ray CT), can provide non-destructive, in situ, information about the location, extent, and kinetics of damage evolution. 7,[17][18][19][20][21][22] Initial stages of localised corrosion and SCC can be visualised and quantified, with data providing the framework for life-time prediction models. 17,18,22 Corrosion characterisation so far has been limited to corrosion rate (CR) assessments derived from either electrochemical methods or weight loss measurements, which has become routine practice in quantifying aqueous CRs.…”

“…5 The surface of waste containers held in stores may experience the deposition of chloride-bearing particulates from sea-salt aerosols and/or industrial pollution, which may lead to localised corrosion. [7][8][9][10][11][12][13][14][15][16] A thorough understanding of localised corrosion and the nucleation of SCC under atmospheric exposure has significant importance for the use of DSS as candidate container materials. Quantitative assessment of the early stages of degradation is therefore required to be able to determine the life-time performance of structural components.…”

Engineering Science at the I12 Beamline at Diamond Light Source

“…Davenport et al [25] studied atmospheric corrosion of stainless steel, which is used as container material for radioactive waste of intermediate level. The initial corrosion attack is likely to be in the form of pits, and there is concern that stress corrosion cracking may develop from these pits.…”

Effect of H 3 BO 3 on corrosion in 0.01 M NaCl solution of the interface between low alloy steel A508 and alloy 52 M

“…Migration of Cl -onto active sites sustains pitting. Initiation and propagation of pits has received much attention [6,7,[11][12][13][14][15][16][17][18], as has pitting inhibition by inhibitors [19][20][21][22].…”