title: Structure of nickel layers in ni-C multilayer coatings: influence of annealing.
abstract: The structure of Ni-C multilayer and single nickel layer samples has been analyzed before and after annealing, using two techniques: fluorescence EXAFS (F1EXAFS) at the Ni-K. edge and CuKα reflection. Annealing at a temperature of 450°C resulted in a change in the structure of the nickel layers from amorphous like to crystalline like. A reduction of the Bragg reflectivity by a factor of 7 was also found. Comparison between the EXAFS data of the annealed sample and of a nickel foil show a difference in the amplitude of the EXAFS. This is ascribed to a non-Gaussian atomic distribution of the backscattering atoms in the annealed sample around their average positions, whereas the atomic distribution in the (polycrystalline) Ni foil is a Gaussian one. From the annealing experiments we conclude that no irreversible changes take place in the structure of the nickel layers at temperatures below 200°C.
authors.affiliation: Association Euratom-FOM, FOM Institute for Plasma Physics Rijnhuizen, P.O. Box 1207, 3430 BE Nieuwegein, the Netherlands.
authors.forename: G E
authors.initials: GE
authors.lastname: van Dorssen
authors.forename: E J
authors.initials: EJ
authors.lastname: Puik
authors.forename: M J
authors.initials: MJ
authors.lastname: van der Wiel
authors.forename: P
authors.initials: P
authors.lastname: Mackle
authors.forename: H A
authors.initials: HA
authors.lastname: Padmore
authors.forename: I H
authors.initials: IH
authors.lastname: Munro