Rapid structural and chemical characterization of ternary phase diagrams using synchrotron radiation
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A. Rar, G.M. Pharr, and E.P George Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 and Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996
P. Zschack and H. Hong Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
J. Ilavsky National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (Received 19 May 2003; accepted 31 July 2003)
A technique based on synchrotron radiation was developed that allows for rapid structural and chemical characterization of ternary alloys over a wide range of composition. The technique was applied to isothermal sections of the Cr–Fe–Ni system grown on Al2O3(0001) sapphire substrates by sequential deposition of layers of graded thickness followed by annealing to interdiffuse the elements. A film spanning the Cr–Fe–Ni ternary system was measured in 4 h at a resolution of 2 at.% by rastering the sample under a focused beam of synchrotron radiation while simultaneously measuring the diffraction pattern with a charge-coupled device detector to determine crystallographic phases, texture, and lattice parameters and also measuring the x-ray fluorescence with an energy-dispersive detector to determine elemental composition. Maps of phase composition and lattice parameter as a function of composition for several annealing treatments were found to be consistent with equilibrium values. The technique will be useful in combinatorial materials design. I. INTRODUCTION
Development of new materials by combinatorial synthesis and design has recently received much attention due to the potential it offers for discovering new materials and improving existing ones.1–3 Combinatorial materials science is based on two key elements: (i) simple synthesis techniques that can be used to create large libraries of specimens of varying composition and structure, and (ii) simple characterization techniques that can be used to rapidly assess the structure and properties of the material libraries. One popular method for synthesizing combinatorial material libraries uses vapor deposition or sputtering to make thin films in which the composition varies continuously in the plane of the film. The composition gradient is created by controlling the geometry and position of the component sources and/or the use of shutters and masks.1 Some techniques require that the specimen be annealed after deposition to intermix and react the components by
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J. Mater. Res., Vol. 18, No. 10, Oct 2003 Downloaded: 07 Apr 2015
solid-state diffusion. By these methods, high-quality films with compositions varying continuously across the binary or ternary phase system have been produced.4–7 Point-to-point characterization of the crystal structures and compositions of the phases in the thin-film material libraries can be used to determine the binary or ternary equilibrium ph
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