Elastic and nanostructural properties of Cu/Pd superlattices

1992 ◽  
Vol 7 (6) ◽  
pp. 1356-1369 ◽  
Author(s):  
B.M. Davis ◽  
D.X. Li ◽  
D.N. Seidman ◽  
J.B. Ketterson ◽  
R. Bhadra ◽  
...  
Keyword(s):  
Elastic Properties ◽  
Brillouin Scattering ◽  
High Resolution Electron Microscopy ◽  
Anomalous Behavior ◽  
Electron Beam Evaporation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Composition Modulation ◽  
Tension Tests ◽  
Resolution Electron

A series of Cu/Pd superlattices with composition modulation wavelengths (Λ's) ranging from 1.6 to 3.5 nm and a strong [111] growth texture were prepared by electron beam evaporation. The elastic properties of the films were examined using the methods of uniaxial tension tests [a Young's modulus (1/s11), where sij is an elastic compliance] with the applied load parallel to the plane of the Cu/Pd interface and Brillouin scattering [a shear modulus (1/s44) with the shear waves parallel to the plane of the Cu/Pd interface]. Also, the films were characterized using both x-ray diffraction and high-resolution electron microscopy; this was done to assess the effect of the nanostructure on a possible “supermodulus effect.” The films are nanostructurally very similar to the superlattice films employed in previous studies at Northwestern in which a supermodulus effect was reported. But, contrary to previous studies, no anomalous behavior was observed for the measured elastic properties of the thin films. Therefore the present results negate the earlier results and cast a serious doubt on the existence of a supermodulus effect.

Implications of Interface Structure on the Elastic Properties of Metallic Multilayers-The Case of the Supermodulus Effect

1991 ◽  
Vol 229 ◽  
Author(s):  
Alan F. Jankowski
Keyword(s):  
Electron Microscopy ◽  
Elastic Properties ◽  
High Resolution Electron Microscopy ◽  
Interface Structure ◽  
Metal Films ◽  
Metallic Multilayers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Resolution Electron ◽  
Detailed Nature

AbstractThe existence of the supermodulus effect, an enhancement in the elastic modulus of artificially layered metal films, was discovered more than a dozen years ago. Yet the detailed nature of this effect remains a puzzling phenomena. Implications of the interface structure on the elastic properties of gold-nickel multilayers are investigated using x-ray diffraction and high resolution electron microscopy.

Kinetic Study on the Formation of the Aragonite-Like Phase Ba(CuOx)1-Y(CO3)y

1995 ◽  
Vol 398 ◽  
Author(s):  
A. Tomasi ◽  
E. Galvanetto ◽  
F.C. Matacotta ◽  
P. Nozar ◽  
P. Scardi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
High Resolution Electron Microscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Analysis Techniques ◽  
Formation Kinetics ◽  
Resolution Electron ◽  
Thermal Analysis Techniques ◽  
Kinetics Of

ABSTRACTA systematic study on phase formation and stabilisation in the Ba-Cu-C-O system in the temperature range 20-500°C, under various atmospheres, by traditional thermal analysis techniques, high temperature X-ray diffraction and high resolution electron microscopy, has permitted to identify and characterise the formation kinetics of a new copper containing phase isomorphic to γ-BaCO3.

Elastic Properties and Structural Evolution of AgNi Superlattices

1991 ◽  
Vol 229 ◽  
Author(s):  
B. Rodmacq ◽  
V. Pelosin ◽  
J. Hillairet
Keyword(s):  
Young’S Modulus ◽  
Elastic Properties ◽  
Young's Modulus ◽  
Functional Dependence ◽  
Structural Evolution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Tension Tests ◽  
Prepared State ◽  
Dimensional Variation

AbstractSilver-nickel multilayers were prepared by sputtering at 100 K. X-ray diffraction, electrical resistivity and dimensional variation measurements were performed to structurally characterize these stratified materials, both in the as-prepared state and during the course of annealing cycles. Clearly, polycrystalline superlattices with marked (111) texture perpendicular to the strata are formed. We studied the elastic properties of these superlattices by performing uniaxial tension tests. No deviation from linear elasticity was observed, whatever the period. Young's modulus was found to be 130±15 GPa for all the periods studied. Thus no significant functional dependence of Young's modulus on the stacking periodicity exists in the AgNi superlattice, in the range of periods explored, 2.6 to 18 nm.

A structural model for charoite

2009 ◽  
Vol 73 (5) ◽  
pp. 883-890 ◽  
Author(s):  
I. V. Rozhdestvenskaya ◽  
T. Kogure ◽  
E. Abe ◽  
V. A. Drits
Keyword(s):  
Structural Model ◽  
High Resolution Electron Microscopy ◽  
Tubular Structures ◽  
X Ray Diffraction ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Resolution Electron ◽  
Xrd Patterns ◽  
Silicon Oxygen ◽  
Monoclinic Cell

AbstractThe crystal structure of charoite was investigated mainly by using selected-area electron diffraction (SAED), X-ray diffraction (XRD) and high-resolution electron microscopy (HREM). SAED and XRD patterns indicate that the structure has a monoclinic cell: a = 32.296, b = 19.651, c = 7.16 Å, β = 96.3° and V = 4517 Å3. The space group inferred from systematic absences and HREM images is P21/m. A model of the charoite structure is proposed that is based on the features of related Ca-alkaline silicate structures and HREM images. The structure of charoite consists of three different silicon-oxygen radicals (polymerized SiO4 tetrahedra) which are located between Ca polyhedra. Two of these radicals form continuous tubular structures comprising pectolite-like tetrahedral chains. Calcium polyhedra are joined to form blocks, each of which consists of four columns sharing edges and apices. Potassium and H2O molecules are probably located inside the tubular silicate radicals. From these results, a general formula is derived: K6-7(Ca,Na)18[(Si6O17)(Si12O30)(Si18O45)](OH,F)2.nH2O with two formula units in the unit cell (Z = 2).

Electron optical studies of the formation of vanadium pentoxide catalyst

1987 ◽  
Vol 45 ◽  
pp. 354-355
Author(s):  
A. Legrouri
Keyword(s):  
Electron Microscopy ◽  
Vanadium Pentoxide ◽  
High Resolution Electron Microscopy ◽  
X Ray Diffraction ◽  
Optical Studies ◽  
X Ray ◽  
Physicochemical Changes ◽  
Structural Correlation ◽  
Resolution Electron ◽  
Xrd Techniques

The oxides of vanadium, especially vanadium pentoxide, have been extensively studied because of their interesting physical properties particularly in catalysis. Vanadium pentoxide is generally used in the oxidation and ammoxidation of hydrocarbons.This catalyst has been prepared via the thermal decomposition of ammonium metavanadate (AMV) in air. Thermogravimetric analysis (TGA), infrared spectroscopy (IRS) and x-ray diffraction (XRD) techniques together with high resolution electron microscopy (HREM) and scanning electron microscopy (SEM) have enabled us to elucidate the physicochemical changes occurring during the decomposition process.According to TGA results, the decomposition of AMV commences at 150°C and is complete by 320°C leading to vanadium pentoxide by loss of ammonia and water with the formation of two intermediate compounds, namely at 190°C, ammonium bivanadate: (NH4)2V4 O11, and at 230°C, ammonium hexavanadate AHV: (NH4)2V6O16 . Samples for structural correlation studies were prepared by heating AMV in a stream of air for 2 hours at selected temperatures of 140, 190, 230, 320 and 400°C.

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