SEGREGATION IN MULTICOMPONENT ALLOYS: ORDERED CrN AND CrC SURFACE PHASES ON AFe-15%Cr-C,N(100)SINGLE CRYSTAL

C. Uebing, V. Scheuch, M. Kiskinova and H. P. Bonzel
Additional contact information
C. Uebing: Institut für Festkörperforschung, Forschungszentrum Jülich, 52425 Jülich, Germany
V. Scheuch: Institut für Grenzflächenforschung und Vakuumphysik, Forschungszentrum Jülich, 52425 Jülich, Germany
M. Kiskinova: Institut für Grenzflächenforschung und Vakuumphysik, Forschungszentrum Jülich, 52425 Jülich, Germany
H. P. Bonzel: Institut für Grenzflächenforschung und Vakuumphysik, Forschungszentrum Jülich, 52425 Jülich, Germany

Surface Review and Letters (SRL), 1996, vol. 03, issue 05n06, 1721-1731

Abstract: In general the chemical composition of multicomponent alloy surfaces exhibits significant deviations from the bulk composition due to thermally activated segregation processes. Upon cosegregation epitaxially stabilized two-dimensional surface compounds are formed on substrate surfaces of suitable orientation, e.g.CrNonFe-15%Cr-N(100)andCrConFe-15%Cr-C(100). The important role of the epitaxial stabilization manifests itself by the fact that onFe-15%Cr-C(100)crystals the formation of cubicCrCsurface precipitates is possible upon nonequilibrium cosegregation of the constituent components. Such a chromium carbide with rocksalt structure is not stable in the bulk of bccFe-Cr-C alloys.Angle-resolved photoemission of Cr2p3/2, N 1s and C 1s core level photoelectrons is used to determine the structure of theCrNsurface compound and of theCrCsurface precipitate on aFe-15%Cr-C,N(100)single crystal. Both surface phases exhibit a sharp1×1LEED pattern. Polar angle intensity distributions of photoelectrons (x-ray photoelectron diffraction) are recorded in the [001] and [011] azimuths, respectively. ForCrNthe angular intensity distributions exhibit forward scattering peaks for Cr2p3/2but not for N 1s. Most likely, the CrN phase consists of aCrNcompound layer with significant N outward relaxation of about 0.6 Å and a second completedCrlayer. Single scattering cluster (SSC) calculations indicate that theCr-Crinterlayer distance is expanded by about 26% with respect to the bcc lattice. ForCrC, on the other hand,Cr2p3/2and C 1s show both strong forward scattering features in all distributions. TheCrCphase consists of at least three complete compound layers withNaClstructure.

Date: 1996
References: Add references at CitEc
Citations:

Downloads: (external link)
http://www.worldscientific.com/doi/abs/10.1142/S0218625X96002667
Access to full text is restricted to subscribers

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:wsi:srlxxx:v:03:y:1996:i:05n06:n:s0218625x96002667

Ordering information: This journal article can be ordered from

DOI: 10.1142/S0218625X96002667

Access Statistics for this article

Surface Review and Letters (SRL) is currently edited by S Y Tong

More articles in Surface Review and Letters (SRL) from World Scientific Publishing Co. Pte. Ltd.
Bibliographic data for series maintained by Tai Tone Lim ().