Oxide-Layer Formation and Stability on a Nickel-Base Alloy in Impure Helium at High Temperature

Fabien Rouillard (1) , Céline Cabet (2) , Michèle Pijolat (3, 4) , Krzysztof Wolski (5, 6)

1 SCCME - Service de la Corrosion et du Comportement des Matériaux dans leur Environnement
2 LECNA - Laboratoire d'Etude de la Corrosion Non Aqueuse
3 ProcESS-ENSMSE - Département Procédés et évolution des systèmes avec solides
4 LPMG-EMSE - Laboratoire des Procédés en Milieux Granulaires
5 MPI-ENSMSE - Département Mécanique physique et interfaces
6 PECM-ENSMSE - Plasticité, Endommagement et Corrosion des Matériaux

The corrosion behavior in impure helium of Haynes 230, a nickel base alloy candidate for heat exchangers in Very High Temperature Reactors (VHTR), has been investigated. The study focused on the formation and the subsequent destruction of the surface oxide layer at 900 °C and 980 °C. In-situ gas-phase analysis coupled to post-exposure surface analyses showed that a chromium-rich surface oxide formed on Haynes 230 at 900 °C but was unstable above a critical temperature T A : the chromium-rich oxide reacted with carbon in solution in the alloy to produce chromium and CO(g). The effect of carbon monoxide partial pressure in the gas phase as well as the influence of chromium and carbon activities in the alloy on T A are discussed taking thermodynamics and kinetics aspects into account.

Mots clés: High temperature; Corrosion; Oxidation; Nickel base alloy; Decarburization

Domaines: Matériaux; Génie des procédés

Fabien Rouillard, Céline Cabet, Michèle Pijolat, Krzysztof Wolski. Oxide-Layer Formation and Stability on a Nickel-Base Alloy in Impure Helium at High Temperature. Oxidation of Metals, 2007, 68 (3-4), pp.133-148. ⟨10.1007/s11085-007-9065-y⟩. ⟨hal-00293992⟩