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RESEARCH PRODUCT

Mechanisms Involved by Reactive Elements upon High Temperature Chromia Scale Growth

Gilles BonnetSébastien ChevalierJean Pierre LarpinJ.c. ColsonGünter Borchardt

subject

Materials scienceAtmospheric pressureMechanical EngineeringDiffusionHigh-temperature corrosionMetallurgyAlloyAnalytical chemistrychemistry.chemical_elementengineering.materialCondensed Matter PhysicsChromiaSecondary ion mass spectrometryChromiumCoatingchemistryMechanics of MaterialsengineeringGeneral Materials Science

description

The influence of Y 2 O 3 , Pr 2 O 3 , Nd 2 O 3 , Sm 2 O 3 and Yb 2 O 3 coatings on Fe-30Cr alloy oxidation behaviour was investigated at 1000°C in air under atmospheric pressure. Isothermal exposures indicated that the Y 2 O 3 coating was the most protective after 100 hours. Pr 2 O 3 , Nd 2 O 3 and Sm 2 O 3 coatings were less effective, but the less beneficial effect was observed when Yb 2 O 3 coating was applied onto the Fe-Cr alloy surface. Two-stage oxidation experiments in 16 O 2 and then 18 O 2 were performed to get information about the chromia growth phenomena with and without reactive elements. The 18 O-tracer distribution was determined by secondary ion mass spectrometry (SIMS) and sputtered neutral mass spectrometry (SNMS). The experiments performed on uncoated samples clearly demonstrated that chromia growth mechanism was controlled by chromium cationic diffusion, whereas on reactive element coated samples the external diffusion of chromium ions was not predominant.

https://doi.org/10.4028/www.scientific.net/msf.369-372.327