Electrochemical Behavior of Al/Mg Alloys Immobilized in a Magnesium Potassium Phosphate Cement-Based Mortar
Portland cement is extensively used for the conditioning of radioactive waste. However, its high alkalinity is a serious obstacle to the stabilization of waste containing aluminum metal since aluminum is oxidized by the pore solution with the production of dihydrogen. This work investigates the pote...
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MDPI AG
2023-08-01
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| Series: | Materials |
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| Online Access: | https://www.mdpi.com/1996-1944/16/15/5415 |
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| author | Gabriel Poras Céline Cau Dit Coumes Pascal Antonucci Céline Cannes Sylvie Delpech Stéphane Perrin |
| author_facet | Gabriel Poras Céline Cau Dit Coumes Pascal Antonucci Céline Cannes Sylvie Delpech Stéphane Perrin |
| author_sort | Gabriel Poras |
| collection | DOAJ |
| description | Portland cement is extensively used for the conditioning of radioactive waste. However, its high alkalinity is a serious obstacle to the stabilization of waste containing aluminum metal since aluminum is oxidized by the pore solution with the production of dihydrogen. This work investigates the potential of an alternative binder, magnesium potassium phosphate (MKP) cement, for the stabilization of Al–Mg alloys comprising 2 to 4.5 wt% of Mg and other metallic impurities. The objective is to assess the influence of the alloy composition on its reactivity in the cementitious matrix at earlier ages, as well as at later ages, when the cement has reached a significant reaction degree. Two complementary techniques are used. Gas chromatography shows that the dihydrogen release, resulting from the corrosion process, is not influenced by the magnesium content in the alloy. Electrochemical impedance spectroscopy provides qualitative information about the corrosion but also makes it possible to assess the corrosion current using an equivalent electrical circuit linked to the kinetic parameters of the postulated corrosion mechanism. Over a one-year period, the corrosion current of the alloys, regardless of their Mg content, is reduced by almost three orders of magnitude in MKP mortar as compared to Portland-cement-based mortar. |
| first_indexed | 2024-03-11T00:22:45Z |
| format | Article |
| id | doaj.art-b0415010ca8041b7b2f61f589560affc |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-11T00:22:45Z |
| publishDate | 2023-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Materials |
| spelling | doaj.art-b0415010ca8041b7b2f61f589560affc2023-11-18T23:13:00ZengMDPI AGMaterials1996-19442023-08-011615541510.3390/ma16155415Electrochemical Behavior of Al/Mg Alloys Immobilized in a Magnesium Potassium Phosphate Cement-Based MortarGabriel Poras0Céline Cau Dit Coumes1Pascal Antonucci2Céline Cannes3Sylvie Delpech4Stéphane Perrin5CEA, DES, ISEC, DPME, SEME, LFCM, Université de Montpellier, 30207 Bagnols-sur-Cèze, FranceCEA, DES, ISEC, DPME, SEME, LFCM, Université de Montpellier, 30207 Bagnols-sur-Cèze, FranceCEA, DES, ISEC, DPME, SEME, LFCM, Université de Montpellier, 30207 Bagnols-sur-Cèze, FranceIJCLab, CNRS/IN2P3, Université Paris-Saclay, 91405 Orsay, FranceIJCLab, CNRS/IN2P3, Université Paris-Saclay, 91405 Orsay, FranceCEA, DES, ISEC, DPME, SEME, LFCM, Université de Montpellier, 30207 Bagnols-sur-Cèze, FrancePortland cement is extensively used for the conditioning of radioactive waste. However, its high alkalinity is a serious obstacle to the stabilization of waste containing aluminum metal since aluminum is oxidized by the pore solution with the production of dihydrogen. This work investigates the potential of an alternative binder, magnesium potassium phosphate (MKP) cement, for the stabilization of Al–Mg alloys comprising 2 to 4.5 wt% of Mg and other metallic impurities. The objective is to assess the influence of the alloy composition on its reactivity in the cementitious matrix at earlier ages, as well as at later ages, when the cement has reached a significant reaction degree. Two complementary techniques are used. Gas chromatography shows that the dihydrogen release, resulting from the corrosion process, is not influenced by the magnesium content in the alloy. Electrochemical impedance spectroscopy provides qualitative information about the corrosion but also makes it possible to assess the corrosion current using an equivalent electrical circuit linked to the kinetic parameters of the postulated corrosion mechanism. Over a one-year period, the corrosion current of the alloys, regardless of their Mg content, is reduced by almost three orders of magnitude in MKP mortar as compared to Portland-cement-based mortar.https://www.mdpi.com/1996-1944/16/15/5415radioactive waste conditioningmagnesium potassium phosphate cementaluminummagnesiumcorrosionelectrochemical impedance spectroscopy |
| spellingShingle | Gabriel Poras Céline Cau Dit Coumes Pascal Antonucci Céline Cannes Sylvie Delpech Stéphane Perrin Electrochemical Behavior of Al/Mg Alloys Immobilized in a Magnesium Potassium Phosphate Cement-Based Mortar Materials radioactive waste conditioning magnesium potassium phosphate cement aluminum magnesium corrosion electrochemical impedance spectroscopy |
| title | Electrochemical Behavior of Al/Mg Alloys Immobilized in a Magnesium Potassium Phosphate Cement-Based Mortar |
| title_full | Electrochemical Behavior of Al/Mg Alloys Immobilized in a Magnesium Potassium Phosphate Cement-Based Mortar |
| title_fullStr | Electrochemical Behavior of Al/Mg Alloys Immobilized in a Magnesium Potassium Phosphate Cement-Based Mortar |
| title_full_unstemmed | Electrochemical Behavior of Al/Mg Alloys Immobilized in a Magnesium Potassium Phosphate Cement-Based Mortar |
| title_short | Electrochemical Behavior of Al/Mg Alloys Immobilized in a Magnesium Potassium Phosphate Cement-Based Mortar |
| title_sort | electrochemical behavior of al mg alloys immobilized in a magnesium potassium phosphate cement based mortar |
| topic | radioactive waste conditioning magnesium potassium phosphate cement aluminum magnesium corrosion electrochemical impedance spectroscopy |
| url | https://www.mdpi.com/1996-1944/16/15/5415 |
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