Please use this identifier to cite or link to this item:
Full metadata record
DC FieldValueLanguage
dc.contributor.authorSabioni, Antônio Claret Soares-
dc.contributor.authorHuntz, Anne Marie-
dc.contributor.authorPhilibert, J.-
dc.contributor.authorLesage, B.-
dc.identifier.citationSABIONI, A. C. S. et al. Relation between the oxidation growth rate of chromia scales and self-diffusion in Cr203. Journal of Materials Science, v. 27, n. 17, p. 4782-4790, set. 1992. Disponível em: <>. Acesso em: 08 mar. 2017.pt_BR
dc.description.abstractIn most cases, chromia scales are assumed to grow by predominant chromium diffusion. However, results of Atkinson and Taylor indicated that chromium bulk diffusion could not account for the growth rate of chromia scales. Moreover, recent results of Park et aL showed that oxygen diffusion in chromia was faster than chromium diffusion. So, at this date, the controlling process of the growth of chromia scales is not elucidated. To interpret such a phenomenon, oxygen and chromium self-diffusion coefficients in Cr203 single crystals and polycrystals were determined in the same materials and in the same experimental conditions, thus allowing a direct comparison. Tracers were introduced by ion implantation, thick film methods, and isotopic exchange, using the 54Cr, ~~ and 180 isotopes. Depth profiling was made by secondary ion mass spectroscopy (SIMS). The bulk diffusion coefficients were computed by using a general solution of the Fick's law taking into account evaporation and exchange at the surface. Grain-boundary diffusion coefficients were computed by using the Whipple-Le Claire equation for type B intergranular diffusion. Lattice and grain boundary self-diffusien coefficients were determined as a function of temperature and oxygen pressure. The diffusion coefficients are lower than results given in the literature and do not depend on the oxygen pressure. Moreover, it is found that oxygen diffusion is faster than chromium diffusion. These results are compared to the oxidation constants of chromia-forming alloys and it is shown that neither lattice self-diffusion, nor grain-boundary self-diffusion can justify the growth rate of chromia scales. Such a situation is compared to NiO case, for which authors found important differences in grain-boundary diffusivity, according to the elaboration mode of NiO (thermal oxidation or growth from the melt).pt_BR
dc.titleRelation between the oxidation growth rate of chromia scales and self-diffusion in Cr203.pt_BR
dc.typeArtigo publicado em periodicopt_BR
Appears in Collections:DEFIS - Artigos publicados em periódicos

Files in This Item:
File Description SizeFormat 
  Restricted Access
749,47 kBAdobe PDFView/Open

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.