Effects of temperature and pH on uniform and pitting corrosion of aluminium alloy 6061-T6 and characterisation of the hydroxide layers

JOURNAL OF ALLOYS AND COMPOUNDS

卷:833

Article

L'Haridon-Quaireau, Sarah¹  Laot, Mathilde¹  Colas, Kimberly¹  Kapusta, Benedicte¹  Delpech, Sylvie²  Gosset, Dominique³ 

[1] Univ Paris Saclay, DEN Serv Etud Mat Irradies, CEA, F-91191 Gif Sur Yvette, France

[2] Paris Saclay Univ, IJCLab, Paris, France

[3] Univ Paris Saclay, DEN Serv Rech Met Appl, CEA, F-91191 Gif Sur Yvette, France

关键词: Aluminium hydroxide;    Corrosion;    Microstructure;    pH;   

DOI  :  10.1016/j.jallcom.2020.155146

来源: Elsevier

【 摘 要 】

During operation in material testing reactors (MTR), the AA-6061-T6 alloy used for core components is covered by aluminium hydroxide. In this work we investigate the effects of parameters on pitting and uniform corrosion of the aluminium alloy 6061-T6 in the conditions found in MTR for the core structures: temperature (70-100 degrees C) and pH (5 and 7.5). After corrosion experiments, characterisation techniques are used to observe the formed hydroxide, its composition and crystallographic structure (TEM, SEM, EDX, XRD, mu-Raman spectroscopy and electron diffraction) and formulate hypotheses on the mechanisms of corrosion at play. At low temperature (70 degrees C), the film is composed of two layers of different aluminium hydroxide phases. These two phases have different corrosion behaviours depending on the pH. The pH has a strong impact of the outer layer but not on the inner layer. PH increase is observed in deaerated medium, this pH variation is due to oxidation of magnesium of the alloy. In addition, corrosion models are used to predict the hydroxide thickness in MTR for a safe and efficient operation. These models are based on empirical correlations. The data obtained from this study allows to discuss the application of these models at low temperature (70 degrees C). (C) 2020 Elsevier B.V. All rights reserved.

【 授权许可】

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