Document IIF

Comportement de corrosion du "frigorigène magnétique" gadolinium dans une solution d'acide oxalique.

Corrosion behaviour of magnetic refrigerant gadolinium in oxalic acid solution.

Auteurs : CHEN J., CHEN Y. G., WU C. L., et al.

Résumé

In this paper, oxalic acid solutions with different pH values (pH=1.0, 2.0, 3.0 and 4.0, respectively) were investigated as the corrosion inhibitors for magnetic refrigerant gadolinium. The weight growth of gadolinium enhances with the increase of the pH values of the solutions. It implies that the oxidized film formed on the surface of the Gd plate becomes thicker with the increase of pH value. The coating is a mixture of most C(6)H(20)Gd(2)O(22) from XRD analysis. The corrosion current decreases with the increase of the pH value of the oxalic acid solutions, which indicates that Gd tends to be passivated, and the coating forming on the surface becomes much easier when pH value gets higher. When pH=1.0-2.0, the coating is relatively compact, and the grains of the products are integrated from SEM pictures. However, when pH>3.0, the coating on the gadolinium is not protective enough because of the appearance of some micro-cracks on the grains of the products on the surface after 30 hours. Meanwhile, the solutions become turbid when pH>3.0 after being immersed in the solutions for a longer time, which indicates that the coating flakes. Thus, the COOH(2) solutions with pH value of 1.0-2.0 might be suitable for gadolinium to form a protective layer.

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Pages : 2007-1

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Détails

  • Titre original : Corrosion behaviour of magnetic refrigerant gadolinium in oxalic acid solution.
  • Identifiant de la fiche : 2007-1574
  • Langues : Anglais
  • Source : 2nd International Conference on Magnetic Refrigeration at Room Temperature
  • Date d'édition : 11/04/2007

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