scholarly journals XANES-Based Determination of Redox Potentials Imposed by Steel Corrosion Products in Cement-Based Media

Author(s):  
Bin Ma ◽  
Alejandro Fernandez-Martinez ◽  
Benoît Madé ◽  
Nathaniel Findling ◽  
Ekaterina Markelova ◽  
...  
Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 241
Author(s):  
Xiaozhen Li ◽  
Hui Wang ◽  
Jianmin Wang ◽  
Junzhe Liu

In this work, the microstructure characteristics of corrosion products of reinforcement under a corrosive environment with chloride, carbonation and the combination of chloride-carbonization were studied by x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy/energy spectroscopy (SEM-EDX). The results indicate that the outside of the passivation film reacts with the cement slurry to produce Fe–SiO4 in all three corrosive environments. The inner side is not completely corroded. The morphology of the corrosion is different in the three environments. In a chloride environment, corrosion products have obvious cracks, and the local layered structure is dense. In a carbonation environment, the surface of the steel corrosion shows a uniform granular structure and loose texture. With the combination of chloride and combination, the surface of the structural layer of steel corrosion was uneven and accompanied by protrusions, cracking and spalling occurred. The composition of the corrosion substances in the three corrosion environments are mainly composed of FeO, Fe3O4, Fe2O3 and Fe–SiO4. The content of iron oxide increases from a chloride salt, carbonization to the composite environment, indicating that the corrosion degree intensifies successively.


1987 ◽  
Vol 112 ◽  
Author(s):  
Masaki Tsukamoto ◽  
Inga-Kari Björner ◽  
Hilbert Christensen ◽  
Hans-Peter Hermansson ◽  
Lars Werme

AbstractThe release of Am-241 during corrosion of the radioactive waste glass, JSS-A, has been studied in the presence of corrosion products and/or uncom-pacted bentonite. The corrosion behaviour of Am-241 has been analyzed using gamma spectrometry. Adsorption of Am-241 on bentonite is observed in all cases. The contents of Am-241 in centrifuged leachates are in most cases less than 1/100 of total values. The normalized elemental mass loss of Am increases initially with corrosion time, and the values in the presence of bentonite and corrosion products are larger than those in the presence of bentonite alone. This tendency is in agreement with results previously found for other elements. The release of Am is low, only about 10–20 % of the corresponding total mass loss.


CORROSION ◽  
10.5006/3912 ◽  
2021 ◽  
Author(s):  
Arthur Situm ◽  
Xiaoxuan Guo ◽  
Burke Barlow ◽  
Bao Guo ◽  
Ian Burgess ◽  
...  

Polymer coatings can be used to mitigate the corrosion of steel in high chloride environments. Obtaining speciation information from thin corrosion layers can be important for understanding corrosion mechanisms, including polymer coating failure. This study outlines the effectiveness of collecting glancing angle X-ray absorption near edge spectroscopy (GA-XANES) spectra at the Fe K-edge to obtain chemical speciation information at the polymer-steel interface without removal of the polymer film. The depth of penetration of the incident X-rays can be altered by changing the incidence angle, allowing for more fluorescence signal from corrosion products to be detected relative to the Fe metal fluorescence signal in GA-XANES spectra. This study demonstrates the use of GA-XANES to study thin layers of steel corrosion and obtain depth profile information of steel corrosion products beneath a polymethyl methacrylate polymer coating.


2003 ◽  
Vol 807 ◽  
Author(s):  
Lara Duro ◽  
Tiziana Missana ◽  
Sonia Ripoll ◽  
Mireia Grivé ◽  
Jordi Bruno

ABSTRACTWe have studied the surface interaction between tetravalent plutonium and two different steel corrosion products: magnetite, which is the final product of the anoxic corrosion of steel, and goethite, which exemplifies a further oxidation of the steel surface due to the presence of active oxidants in the system. The pH of the experiments has been varied from 2 to 10 and the ionic strength from 0.001 to 0.1 M NaClO4. All the sorption experiments were carried out under N2 atmosphere. No significant effect of ionic strength was observed under the conditions studied.The pHpcz of the solids (7.78 for goethite and 6.95 for magnetite) was determined by modelling potentiometric titration data.The results of the experiments show that the sorption edge of plutonium occurs between pH 3 and 4 when using goethite as a sorbing surface and between pH 4 and 5 when magnetite is used.We have modelled the sorption data by using a simple surface complexation approach with no electrostatic term. The model used involves a reduction process of Pu(IV) to Pu(III) in the presence of magnetite, which can be explained by the interaction of the actinide with the ferrous iron present in the solid. In the case of the experiments conducted with goethite, this reduction process is not possible and, therefore, in the model we have included the sorption of tetravalent Pu.


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