Effect of Mechanical Activation on Ti-50Ni Powder Blends Reactivity

2010 ◽  
Vol 636-637 ◽  
pp. 544-549 ◽  
Author(s):  
Filipe Neves ◽  
Francisco Manuel Braz Fernandes ◽  
Jose Brito Correia
Keyword(s):  
Mechanical Activation ◽  
Energy Input ◽  
Exothermic Reaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Temperature Reaction ◽  
Short Period ◽  
Powder Blends ◽  
Different Levels

In the present study, equiatomic powder blends of Ni and Ti were mechanically activated for a short period of time in a planetary ball mill using different levels of energy input. The characterization of the mechanically activated materials was achieved by scanning electron microscopy, X-ray diffraction, differential thermal analysis and chemical analysis (oxygen and nitrogen measurements). During mechanical activation no phase transformation was induced and the high temperature reaction between Ni and Ti elemental powders was shifted to lower temperatures. Moreover, the temperature and the intensity of the exothermic reaction, i.e. the reactivity observed in the powder blends, decreased with the increase in the level of milling energy input. A maximum oxygen content of 0.39 wt% was measured after mechanical activation.

Ultra low energy SIMS, XTEM and X-ray diffraction methods for the characterization of a MBE grown short period (Si Ge )16 superlattices

2000 ◽  
Vol 367 (1-2) ◽  
pp. 176-179 ◽  
Author(s):  
O.A Mironov ◽  
D.J.F Fulgoni ◽  
C.P Parry ◽  
G.A Cooke ◽  
M.G Dowsett ◽  
...  
Keyword(s):  
Low Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Short Period

Preparation and characterization of a novel solid solution of aluminum in tungsten carbide by mechanically activated high-temperature reaction

2006 ◽  
Vol 21 (7) ◽  
pp. 1700-1703 ◽  
Author(s):  
Junmin Yan ◽  
Xianfeng Ma ◽  
Wei Zhao ◽  
Huaguo Tang ◽  
Changjun Zhu ◽  
...  
Keyword(s):  
Solid Solution ◽  
High Temperature ◽  
Substitutional Solid Solution ◽  
Phase Identification ◽  
Temperature Reaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Parameters ◽  
High Temperature Reaction

In this work, a novel substitutional solid solution (W0.8Al0.2)C was synthesized by mechanically activated high-temperature reaction. X-ray diffraction was used for phase identification during the whole reaction process. Environment scanning electronic microscopy–field emission gun and energy dispersive x-ray were used to investigate the microstructure and the quantitative material composition of the specimen. (W0.8Al0.2)C was found to crystallize in the WC-type, and the cell parameters were a = 2.907(1) Å and c = 2.837(1) Å. The hardness of (W0.8Al0.2)C was tested to be 19.3 ± 1 GPa, and the density was 13.19 ± 0.05 g cm−3.

Structural Characterization of Short-Period SimGEn Superlattices by Transmission Electron Microscopy and X-Ray Diffraction

1991 ◽  
Vol 220 ◽  
Author(s):  
W. Jäger ◽  
K. Leifer ◽  
P. Ehrhart ◽  
E. Kasper ◽  
H. Kibbel
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Interface Roughness ◽  
Buffer Layers ◽  
X Ray Diffraction ◽  
Average Composition ◽  
X Ray ◽  
Transmission Electron ◽  
Short Period

ABSTRACTHigh resolution and analytical transmission electron microscopy (TEM) and X-ray diffraction (XRD) were used to characterize short-period strained-layer Sim-Gen superlattices ( m monolayers Si, n monolayers Ge, total number of periods N≤ 145, total thickness ≃ 200 nm). The superlattices were grown by low-temperature molecular beam epitaxy (T = 300–400°C) on different SiGe alloy buffer layers on Si (100)substrates. The combination of these two methods shows that detailed informations can be obtained about superlattice periodicity, interface roughness, strain, and average composition.

Atomic Arrangements in Short period MO-GE Multilayers Determined by X-Ray Anomalous Scattering and EXAFS

1987 ◽  
Vol 103 ◽  
Author(s):  
Lane Wilson ◽  
Arthur Bienenstock
Keyword(s):  
Structural Characteristics ◽  
Composition Profile ◽  
Anomalous Scattering ◽  
X Ray Diffraction ◽  
Structural Variations ◽  
X Ray ◽  
Short Period ◽  
Wide Range ◽  
Transmission And Reflection

ABSTRACTStudies of atomic arrangements in amorphous and crystalline, short period Mo-Ge multilayers using synchrotron radiation X-ray diffraction (transmission and reflection), supplemented by EXAFS, are described. Differential anomalous scattering and EXAFS were utilized to determine the environment of each species. Intermixing, as well as a BCC epitaxial Ge structure, are among the observed structural characteristics. A wide range of structural variations is present indicating that specification of the layer thicknesses or composition profile alone is insufficient for characterization of the multilayers.

MECHANOCHEMICAL SYNTHESIS AND CHARACTERIZATION OF NANOSTRUCTURE FORSTERITE BIOCERAMICS

2008 ◽  
Vol 22 (18n19) ◽  
pp. 3082-3091 ◽  
Author(s):  
M. H. FATHI ◽  
M. KHARAZIHA
Keyword(s):  
Heat Treatment ◽  
Mechanical Activation ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
Mechanochemical Method ◽  
Bone Implant ◽  
X Ray ◽  
Nano Powder ◽  
Good Biocompatibility

Recent investigations suggest that forsterite ceramics possess good biocompatibility and mechanical properties and might be suitable for potential application like bone implant material. In this study, nanocrystalline forsterite ( Mg 2 SiO 4) powder was prepared by mechanochemical method and subsequent heat treatment and the effect of fluorine ion as catalyst was studied. Mechanochemical process and heat treatment were done on the MgCO 3, SiO 2 and ( NH 4)2 SiF 6 powders. The synthesized powders were characterized by X-ray diffraction (XRD), thermogravimetric (TG) analyses and scanning electron microscopy (SEM). The synthesized nano-powder had particle size smaller than 100 nm. The crystallite size of powders after 5 hours mechanical activation was 18 nm. Mechanical activation in the presence of fluorine ion affects the mechanism of forsterite formation and increase the rate of decomposition of MgO and fabrication of forsterite.

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.

High Resolution Replication of Organoclay Surfaces

1982 ◽  
Vol 40 ◽  
pp. 576-577
Author(s):  
W. W. Barker ◽  
W. E. Rigsby ◽  
V. J. Hurst ◽  
W. J. Humphreys
Keyword(s):  
Clay Mineral ◽  
Organic Molecule ◽  
Organic Molecules ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Naturally Occurring ◽  
Silicate Layers ◽  
Mineral Identification

Experimental clay mineral-organic molecule complexes long have been known and some of them have been extensively studied by X-ray diffraction methods. The organic molecules are adsorbed onto the surfaces of the clay minerals, or intercalated between the silicate layers. Natural organo-clays also are widely recognized but generally have not been well characterized. Widely used techniques for clay mineral identification involve treatment of the sample with H2 O2 or other oxidant to destroy any associated organics. This generally simplifies and intensifies the XRD pattern of the clay residue, but helps little with the characterization of the original organoclay. Adequate techniques for the direct observation of synthetic and naturally occurring organoclays are yet to be developed.

Interfacial properties of GaSb/InAs superlattices

1993 ◽  
Vol 51 ◽  
pp. 826-827
Author(s):  
M. E. Twigg ◽  
B. R. Bennett ◽  
J. R. Waterman ◽  
J. L. Davis ◽  
B. V. Shanabrook ◽  
...  
Keyword(s):  
Gaas Substrate ◽  
Molecular Beam ◽  
Infrared Detector ◽  
Interfacial Properties ◽  
Ex Situ ◽  
X Ray Diffraction ◽  
Absorption Coefficients ◽  
X Ray ◽  
Short Period ◽  
High Optical Absorption

Recently, the GaSb/InAs superlattice system has received renewed attention. The interest stems from a model demonstrating that short period Ga1-xInxSb/InAs superlattices will have both a band gap less than 100 meV and high optical absorption coefficients, principal requirements for infrared detector applications. Because this superlattice system contains two species of cations and anions, it is possible to prepare either InSb-like or GaAs-like interfaces. As such, the system presents a unique opportunity to examine interfacial properties.We used molecular beam epitaxy (MBE) to prepare an extensive set of GaSb/InAs superlattices grown on an GaSb buffer, which, in turn had been grown on a (100) GaAs substrate. Through appropriate shutter sequences, the interfaces were directed to assume either an InSb-like or GaAs-like character. These superlattices were then studied with a variety of ex-situ probes such as x-ray diffraction and Raman spectroscopy. These probes confirmed that, indeed, predominantly InSb-like and GaAs-like interfaces had been achieved.

Sign in / Sign up

Export Citation Format

Share Document