The influence of reactive-element coatings on the high-temperature oxidation of pure-Cr and high-Cr-content alloys

Download
  1. Get@NRC: The influence of reactive-element coatings on the high-temperature oxidation of pure-Cr and high-Cr-content alloys (Opens in a new window)
DOIResolve DOI: http://doi.org/10.1007/BF01046989
AuthorSearch for: ; Search for:
TypeArticle
Journal titleOxidation of Metals
Volume45
Issue3-4
Pages349374; # of pages: 26
SubjectCr₂O₃ films on Cr and high-Cr-content alloys; reactive elements; ¹⁸O/SIMS; transport processes
AbstractThe influence of various reactive-element (RE) oxide coatings (Y₂O₃, CeO₂, La₂O₃, CaO, HfO₂, and Sc₂O₃) on the oxidation behavior of pure Cr, Fe-26Cr, Fe-16Cr and Ni-25Cr at 900ºC in O₂ at 5 x 10⁻³ torr has been investigated using the ¹⁸O/SIMS technique. Polished samples were reactively sputter-coated with 4 nm of the RE oxide and oxidized sequentially first in ¹⁶O₂ and then in ¹⁸O₂. the effectiveness of each RE on the extent of oxidation-rate reduction varied with the element used. Y₂O₃ and CeO₂ coatings were found to be the most beneficial, whereas Sc₂O₃ proved to be ineffective, for example, for the oxidation of Cr. SIMS sputter profiles showed that the maximum in the RE profile moved away from the substrate-oxide interface during the early stages of oxidation. After a certain time the RE maximum remained fixed in position with respect to this interface, it's final relative position being dependent on the particular RE. The position of the RE maximum within the oxide layer also varied with the substrate composition. For all coatings ¹⁸O was found to have diffused through the oxide to the substrate-oxide interface during oxidation, the amount of oxide at this interface increasing with increasing time. The SIMS data confirm that for coated substrates there has been a change in oxide-growth mechanism to predominantly anion diffusion. The RE most probably concentrates at the oxide grain boundaries, generally as the binary oxide (RE)CrO₃. Cr³⁺ diffusion is impeded, while oxygen diffusion remains unaffected.
Publication date
LanguageEnglish
AffiliationNRC Institute for Microstructural Sciences; National Research Council Canada
Peer reviewedYes
NPARC number20154415
Export citationExport as RIS
Report a correctionReport a correction
Record identifier407a4fbc-eb29-40a5-a23f-ac294c880447
Record created2012-06-22
Record modified2016-05-09
Bookmark and share
  • Share this page with Facebook (Opens in a new window)
  • Share this page with Twitter (Opens in a new window)
  • Share this page with Google+ (Opens in a new window)
  • Share this page with Delicious (Opens in a new window)