Generalized corrosion of nickel base alloys in high temperature aqueous media: A contribution to the comprehension of the mechanisms
type: Dataset
description: In France, nickel base alloys, such as alloy 600 and alloy 690, are the materials constituting steam generators (SG) tubes of pressurized water reactors (PWR). The generalized corrosion resulting from the interaction between these alloys and the PWR primary media leads, on the one hand, to the formation of a thin protective oxide scale (circa 10 nm), and on the other hand, to the release of cations in the primary circuit, which entails an increase of the global radioactivity of this circuit. The goal of this work is to supply some new comprehension elements about nickel base alloys corrosion phenomena in PWR primary media, taking up with underlining the effects of metallurgical and physico-chemical parameters on the nature and the growth mechanisms of the protective oxide scale. In this context, the passive film formed during the exposition of alloys 600, 690 and Ni-30Cr, in conditions simulating the PWR primary media, has been analyzed by a set of characterization techniques (SEM, TEM, PEC and MPEC, XPS). The coupling of these methods leads to a fine description, in terms of nature and structure, of the multilayered oxide forming during the exposition of nickel base alloys in primary media. Thus, the protective part of the oxide scale is composed of a continuous layer of iron and nickel mixed chromite, and Cr2O3 nodules dispersed at the alloy / mixed chromite interface. The study of protective scale growth mechanisms by tracers and markers experiments reveals that the formation of the mixed chromite is the consequence of an anionic mechanism, resulting from short circuits like grain boundaries diffusion. Besides, the impact of alloy surface defects has also been studied, underlining a double effect of this parameter, which influences the short circuits diffusion density in oxide and the formation rate of Cr2O3 nodules. The sum of these results leads to suggest a description of the nickel base alloys corrosion mechanisms in PWR primary media and to tackle some kinet…
identifier: NNT: 2007EMSE0022
issued: 2026-05-05T11:05:03.494919
language: fr
modified: 2026-05-05T11:05:03.494924
contact point: Organization
  fn: CCSD
keyword: alliages-a-base-nickel
keyword: cinetique-doxydation
keyword: corrosion-generalisee
keyword: defauts-de-surface
keyword: generalized-corrosion
keyword: infoeu-reposemanticsdoctoralthesis
keyword: mecanismes-doxydation
keyword: milieu-primaire-des-rep
keyword: multilayer-oxide
keyword: nickel-base-alloys
keyword: oxidation-kinetics
keyword: oxidation-mechanisms
keyword: oxyde-multicouche
keyword: pwr-primary-media
keyword: spigprocengineering-sciences-physicschemical-and-process-engineering
keyword: surface-defects
keyword: theses
keyword: tracers
keyword: traceurs
landing page: https://theses.hal.science/tel-00991918

Generalized corrosion of nickel base alloys in high temperature aqueous media: A contribution to the comprehension of the mechanisms
type: Distribution
format: HTML
issued: 2026-05-05T11:05:03.511727
modified: 2026-05-05T11:05:03.474102
access URL: https://theses.hal.science/tel-00991918

test_moissonnage_selune
type: Agent