Intergrainular structure and deformation mechanism in nanocrystalline materials

1995 ◽  
Vol 53 ◽  
pp. 192-193
Author(s):  
H.Q. Ye ◽  
P.H. Ping ◽  
D.X. Li ◽  
J.Y. Huang ◽  
Y.K. Wu
Keyword(s):  
Deformation Mechanism ◽  
Structural Modification ◽  
Boundary Structure ◽  
X Ray Diffraction ◽  
Gas Condensation ◽  
Average Grain Size ◽  
Relationship Of ◽  
Structure Properties

It is recognized that boundary structure (GB) characterization is essential in order to understand the structure-properties relationship of nanocrystalline (NC). In most cases, NC materials have to suffer deformation during compacting or ball milling techniques, a deep and systematic study on deformation mechanism is also necessary. In this paper, characterization of microstructure in NC materials synthesized by three methods has been presented.1. Ordered and Disordered Regions at GBs of NC Pd The NC Pd samples were synthesized by the inert gas condensation and in situ compacting technique. The results of X-ray diffraction and HREM observations showed that the average grain size of the NC Pd is about 10 nm. It can be seen that most of the GBs have ordered structure and no 'gas-like' feature has been observed. Some disordered GB regions, such as nanovoid formed during compacting process, are also detected as marked by "V" in Fig.l. The structural modification from the disordered state was found during in situ HREM investigation.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Synthesis and Characterization of the PANI/ITO Conducting Nanocomposites

2010 ◽  
Vol 663-665 ◽  
pp. 542-545 ◽  
Author(s):  
Bing Jie Zhu ◽  
Xin Wei Wang ◽  
Mei Fang Zhu ◽  
Qing Hong Zhang ◽  
Yao Gang Li ◽  
...  
Keyword(s):  
Doping Concentration ◽  
In Situ Polymerization ◽  
Synthesis And Characterization ◽  
Conductivity Measurements ◽  
X Ray Diffraction ◽  
X Ray ◽  
Maximum Conductivity ◽  
Scanning Electron

The PANI/ITO conducting nanocomposites have been synthesized by in-situ polymerization. The obtained nanocomposites were characterized by X-ray diffraction pattern, scanning electron microscopy and Fourier transform infrared. Electrical conductivity measurements on the samples pressed into pellets showed that the maximum conductivity attained 2.0 ± 0.05 S/cm for PANI/ITO nanocomposites, at ITO doping concentration of 10 wt%. The results of the present work may provide a simple, rapid and efficient approach for preparing PANI/ITO nanocomposites.

scholarly journals Characterization of the Interface Between the Bulk Glass Forming Alloy Zr41Ti14Cu12Ni10Be23 with Pure Metals and Ceramics

2000 ◽  
Vol 15 (7) ◽  
pp. 1617-1621 ◽  
Author(s):  
Jan Schroers ◽  
Konrad Samwer ◽  
Frigyes Szuecs ◽  
William L. Johnson
Keyword(s):  
Sessile Drop ◽  
Bulk Glass ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Glass Forming ◽  
Processing Times ◽  
Thermal Stability Of

The reaction of the bulk glass forming alloy Zr41Ti14Cu12Ni10Be23 (Vit 1) with W, Ta, Mo, AlN, Al2O3, Si, graphite, and amorphous carbon was investigated. Vit 1 samples were melted and subsequently solidified after different processing times on discs of the different materials. Sessile drop examinations of the macroscopic wetting of Vit 1 on the discs as a function of temperature were carried out in situ with a digital optical camera. The reactions at the interfaces between the Vit 1 sample and the different disc materials were investigated with an electron microprobe. The structure and thermal stability of the processed Vit 1 samples were examined by x-ray diffraction and differential scanning calorimetry. The results are discussed in terms of possible applications for composite materials.

Synthesis and Characterization of Tetraphenylphosphonium Tetraazidoborate

2002 ◽  
Vol 57 (6) ◽  
pp. 621-624 ◽  
Author(s):  
Wolfgang Fraenk ◽  
Heinrich Nöth ◽  
Thomas M. Klapötke ◽  
Max Suter
Keyword(s):  
Single Crystal ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
X Ray

AbstractTetraphenylphosphonium tetraazidoborate, [P(C6H5)4][B(N3)4], was obtained from B(N3)3 - in situ prepared from BH3 · O(C2H5)2 and HN3 - and [P(C6H5)4][N3]. Recrystallization from an acetonitrile / hexane mixture yielded colorless crystals in 60% yield. The molecular structurewas determined by single crystal X-ray diffraction and the [B(N3)4]- anionwas shown to possess S4 symmetry.

scholarly journals Crystalline Swelling Process of Mg-Exchanged Montmorillonite: Effect of External Environmental Solicitation

2018 ◽  
Vol 2018 ◽  
pp. 1-18
Author(s):  
Marwa Ammar ◽  
Walid Oueslati
Keyword(s):  
Theoretical Models ◽  
Retention Mechanism ◽  
X Ray Diffraction ◽  
Interlayer Water ◽  
Hydration Properties ◽  
Crystalline Swelling ◽  
Low Charge ◽  
Interlayer Water Molecule

This work reports characterization of the possible effects that might distress the hydration properties of Mg-exchanged low-charge montmorillonite (SWy-2) when it undergoes external environmental solicitation. This perturbation was created by an alteration of relative humidity rates (i.e., RH%) over two hydration-dehydration cycles with different sequence orientations. Structural characterization is mainly based on the X-ray diffraction (XRD) profile-modeling approach achieved by comparing the “in situ” obtained experimental 00l reflections with other ones calculated from theoretical models. This method allows assessing the evolution of the interlayer water retention mechanism and the progress of diverse hydration state’s contributions versus external strain. Obtained results prove that the hydration behavior of the studied materials is strongly dependent on the RH sequence orientation which varied over cycles. The interlayer organization of Mg-exchanged montmorillonite (i.e., SWy-2-Mg) is characterized by a heterogeneous hydration behavior, which is systematically observed at different stages of both cycles. By comparing the interlayer water process evolution of Mg-exchanged montmorillonite with the observed SWy-2-Ni sample hydration behaviors, a same hysteresis thickness characterized by obvious fluctuations of interlayer water molecule abundances is observed. Nevertheless, in the case of Hg and Ba-saturated montmorillonite, the retention water process versus the applied cycles was steadier comparing with Mg ions.

In situ characterization of strain-induced crystallization of natural rubber by synchrotron radiation wide-angle X-ray diffraction: construction of a crystal network at low temperatures

Soft Matter ◽  
2019 ◽  
Vol 15 (4) ◽  
pp. 734-743 ◽  
Author(s):  
Pinzhang Chen ◽  
Jingyun Zhao ◽  
Yuanfei Lin ◽  
Jiarui Chang ◽  
Lingpu Meng ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Structural Evolution ◽  
X Ray Diffraction ◽  
In Situ Characterization ◽  
X Ray ◽  
Crystal Network ◽  
Strain Induced Crystallization ◽  
Induced Crystallization

The structural evolution of NR during stretching at −40 °C and in the strain–temperature space.

In-Situ Growth and Polygonization of Epitaxial Passive Oxide Films on Nanoparticles of Iron

2001 ◽  
Vol 7 (S2) ◽  
pp. 1234-1235
Author(s):  
K.K. Fung ◽  
X.X. Zhang ◽  
Y.S. Kwok ◽  
Boxiong Qin
Keyword(s):  
Shell Morphology ◽  
Iron Core ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gas Condensation ◽  
Transmission Electron ◽  
Image Position ◽  
Convergent Beam ◽  
Oxidation And Corrosion

Over the years, the study of the oxidation of nanoparticles of iron by transmission electron microscopy (TEM), Mossbauer spectroscopy and X-ray diffraction has established that nanoparticles of iron have a core-shell morphology in which the iron core is enclosed by shell of polycrystalline shell of ultrasmall γ-Fe2O3 and Fe3O4 crystallites. Recently, passivated nanoparticles of iron prepared by gas condensation of plasma evaporated vapor in Tianjin University exhibit remarkable resistance to further oxidation and corrosion in air and water. We have showed by TEM that these nanoparticles of iron are protected by a 4 nm epitaxial shell of γ-Fe2O3. The epitaxial orientation relationship, established by convergent beam electron diffraction from a nanoparticle, is as follows:The [001] diffraction pattern of the oxide is rotated by 45° about a cubic axis relative to that of iron.

X-RAY DIFFRACTION FOR SURFACES AND BURIED INTERFACES

2000 ◽  
Vol 07 (04) ◽  
pp. 437-446 ◽  
Author(s):  
G. RENAUD
Keyword(s):  
Grazing Incidence ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Grain Sizes ◽  
Buried Interfaces ◽  
Surfaces And Interfaces ◽  
Coherent Interfaces

The application of X-rays to the structural characterization of surfaces and interfaces, in situ and in UHV, is discussed on selected examples. Grazing incidence X-ray diffraction is not only a very powerful technique for quantitatively investigating the atomic structure of surfaces and interfaces, but is also very useful for providing information on the interfacial registry for coherent interfaces or on the strain deformation, island and grain sizes for incoherent epilayers.

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