Observation of linear defects in Al particles below 7 nm in size

2006 ◽  
Vol 21 (6) ◽  
pp. 1347-1350 ◽  
Author(s):  
Dmitri V. Louzguine-Luzgin ◽  
Akihisa Inoue
Keyword(s):  
Melt Spinning ◽  
Glassy Matrix ◽  
X Ray ◽  
Al Nanoparticles ◽  
Linear Defects ◽  
Transmission Electron ◽  
Ribbon Sample ◽  
Highly Dispersed ◽  
Co Alloys ◽  
Melt Spinning Technique

An as-solidified structure of an Al-based ribbon sample produced by the melt-spinning technique was studied by x-ray diffractometry and transmission electron microscopy. The addition of Pd to Al-Y-Ni-Co alloys caused formation of the highly dispersed primary α-Al nanoparticles about 3–5 nm in size homogeneously embedded in the glassy matrix upon solidification. The first direct observation of microstrain and dislocations quenched in nanoparticles with a size below 7 nm is provided.

New, Experimental Powder Diffraction Data for Metastable Fe3B Phase Prepared According to ICDD Standards

2010 ◽  
Vol 163 ◽  
pp. 173-176
Author(s):  
Lucjan Pająk ◽  
E. Olszewska ◽  
Stanislaw Pikus ◽  
Grzegorz Dercz ◽  
Józef Rasek
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Melt Spinning ◽  
Powder Diffraction Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lattice Constants ◽  
Graphite Monochromator ◽  
Best Fitting ◽  
Melt Spinning Technique

In the present work X-ray studies were performed on annealed Fe78Nb2B20 amorphous alloy prepared by melt-spinning technique. All the samples were annealed in vacuum for 1 hour at temperatures up to 800°C. For the studied alloy -Fe and Fe2B are the stable, crystalline phases. The -Fe crystallized as the first crystalline phase in the sample annealed at 350°C. On the other hand, metastable Fe3B phase appeared to be stable during annealing in 425-800°C temperature range. The best fitting of the experimental X-ray data to as jet available ICDD files was obtained for Ni3P type structure (39-1315 – S.G.: I (82)). New, experimental powder diffraction data for metastable Fe3B phase prepared according to ICDD standards were elaborated for the sample annealed at 600°C. For this sample the best agreement between the calculated values of lattice constants and positions of experimental diffraction lines was obtained. The X-ray data were collected using X-Pert Philips diffractometer equipped with curved graphite monochromator on diffracted beam. The Treor program was applied for the analysis of X-ray diffraction data.

Hydrogenation Properties of Mg-Co and Its Related Alloys

2005 ◽  
Vol 475-479 ◽  
pp. 2453-2456
Author(s):  
Y. Zhang ◽  
Y. Tsushio ◽  
Hirotoshi Enoki ◽  
Etsuo Akiba
Keyword(s):  
Binary Alloys ◽  
Lattice Parameter ◽  
Ternary Alloys ◽  
Body Centered Cubic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Co Concentration ◽  
Bcc Structure ◽  
Co Alloys

Novel Mg-Co binary alloys with BCC (body-centered cubic) structure have been successfully synthesized by means of mechanical alloying technique. The formation of BCC structure was confirmed by X-ray diffraction and transmission electron microscopy. Mg-Co alloys were found in the range of Co concentration between 37 and 80 atomic %. All the Mg-Co alloys synthesized absorbed hydrogen below 373K. The maximum hydrogen capacity of these alloys reaches 2.7 mass %. However, desorption of hydrogen at 373 K has not been observed yet. Mg- Co-X (X = B and Ni) ternary alloys with BCC structure have also been synthesized. The lattice parameter of both alloys is lower than that of Mg-Co binary alloys, meanwhile the maximum hydrogen content of both alloys also decreased.

Recrystallization of Amorphous or Nanocrystalline NdBa2Cu3O7−x and GdBa2Cu3O7−x

1992 ◽  
Vol 275 ◽  
Author(s):  
T. J. Folkerts ◽  
S. I. Yoo ◽  
Youwen Xu ◽  
M. J. Kramer ◽  
K. W. Dennis ◽  
...  
Keyword(s):  
Melt Spinning ◽  
Amorphous Matrix ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Temperature Xrd ◽  
Melt Spun ◽  
Temperature Heat ◽  
Higher Temperature ◽  
Xrd Studies ◽  
Melt Spinning Technique

ABSTRACTUsing a novel melt-spinning technique, we have produced highly disordered NdBa2Cu3O7−x and GdBa2Cu3Oy−x materials. Samples which were melt-spun in an O2 environment consist of nanocrystals with the tetragonal REBa2Cu3O7−x structure: samples which were processed in an N2 environment consist of an amorphous matrix with small amounts of crystalline BaCu2O2, as shown by x-ray diffraction and electron microscopy. High temperature XRD studies indicate that the BaCu2O2 is eliminated during heating to 500°C in O2 and that the REBa2Cu3O7−x Phase recrystallizes directly from the amorphous matrix at temperatures below 800°C. Preliminary magnetization measurements show that higher temperature heat treatments are needed to restore superconductivity.

Nanocrystallization of Cobalt Based Metallic Glass

2009 ◽  
Vol 67 ◽  
pp. 25-32 ◽  
Author(s):  
A.P. Srivastava ◽  
Dinesh Srivastava ◽  
K.G. Suresh ◽  
G.K. Dey
Keyword(s):  
Metallic Glass ◽  
Melt Spinning ◽  
Amorphous Ribbon ◽  
X Ray Diffraction ◽  
X Ray ◽  
Copper Addition ◽  
Isothermal Analysis ◽  
Effect Of Copper ◽  
Melt Spinning Technique

Effect of copper addition in a Metallic glass 2714A on the nanocrystallization characteristics have been examined in this study. Amorphous ribbon of the alloy composition Co64.5 Fe3.5 Si16.5 B13.5 Ni1Cu1 were prepared by melt spinning technique. Nanocrystallization kinetics was studied using differential scanning calorimeter technique. The kinetic parameters such as activation energy and Avrami exponent were determined using two different non-isothermal analysis methods. The kinetic behavior of individual crystallization event has been rationalized on the basis of these results. The role of addition of copper on the crystallization behavior has been understood by comparing with Metallic glass 2714A. The isothermally annealed nanocrystallized microstructures were characterized by X-ray diffraction.

Controlled synthesis of highly dispersed and nano-sized Ru catalysts supported on carbonaceous materials via supercritical fluid deposition

RSC Advances ◽  
2016 ◽  
Vol 6 (20) ◽  
pp. 16851-16858 ◽  
Author(s):  
Yimin Zhang ◽  
Haoxi Jiang ◽  
Guiming Li ◽  
Minhua Zhang
Keyword(s):  
Electron Microscopy ◽  
Supercritical Fluid ◽  
Photoelectron Spectroscopy ◽  
Controlled Synthesis ◽  
Carbonaceous Materials ◽  
X Ray ◽  
Ru Nanoparticles ◽  
Transmission Electron ◽  
Highly Dispersed ◽  
Deposition Technology

Highly dispersed Ru nanoparticles supported on carbonaceous materials were fabricated by supercritical fluid deposition technology and characterized by high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy.

Anatase TiO2 Colloids Derived from the Peptization of TiO2 Precipitates with CF3COOH and their Photocatalytic Activities

2012 ◽  
Vol 465 ◽  
pp. 44-50 ◽  
Author(s):  
Su Jun Yuan ◽  
Yao Gang Li ◽  
Qing Hong Zhang ◽  
Hong Zhi Wang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Photocatalytic Property ◽  
X Ray Diffraction ◽  
Tio2 Nanocrystals ◽  
X Ray ◽  
Transmission Electron ◽  
Photocatalytic Activities ◽  
Highly Dispersed ◽  
Commercial Tio2

The highly dispersed TiO2 sols composed of anatase crystallites (ca.5 nm) were prepared by peptization of amorphous precipitates with trifluoroactic acid (TFA) during the synthesis. The size and crystallinity of the particles were tuned by the subsequent hydrothermal treatment. The prepared TiO2 nanocrystals were characterized by X-ray diffraction and transmission electron microscopy (TEM). The TEM results indicated that the growth of the crystallites could be inhibited by the increasing addition of TFA and the average sizes of TiO2 nanocrystals were all ultrafine. The degradation of phenol over the nanocrystals after calcination at 500 °C was investigated. The photocatalytic results showed that the sample with a high addition of TFA obtained a better photocatalytic property than that of the commercial TiO2

Preferred Orientation in Splat-Quenched Materials

1981 ◽  
Vol 8 ◽  
Author(s):  
N.W. Blake ◽  
F.A. Rames ◽  
R.W. Smith
Keyword(s):  
High Purity ◽  
Melt Spinning ◽  
Preferred Orientation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ribbon Plane ◽  
Extreme Degree ◽  
Melt Spinning Technique

ABSTRACTHigh purity, splat-quenched metal ribbons, produced by the melt spinning technique, were examined for preferred orientation using x-ray diffraction. Of the materials tested (Zn, Cd, Ag, Bi, Pb, Sb, Mg, Sn) all except Sn exhibited some degree of preferred orientation in the plane of the metal ribbon. the hcp metals Zn and Cd showed an extreme degree of preferred orientation with the 002 plane being closely parallel to the ribbon plane. The Zn ribbon was analysed more closely with a view to its use as a crystal monochromator for x-ray diffraction. The high purity Zn was found to have some instability of preferred orientation with increase in time and temperature. The orientation was found to be effectively stabilized by the intentional addition of impurities, or by the use of lower purity (99.99%) Zn. In this form, the Zn ribbon could be used as a crystal analyser for x-ray diffraction with both intensity and resolution comparable to that of the 1011 plane in Quartz.

Fractographic fingerprinting of proton-irradiation-induced disordering and amorphization of intermetallic compounds

1989 ◽  
Vol 4 (3) ◽  
pp. 565-578 ◽  
Author(s):  
J. Cheng ◽  
M. Yuan ◽  
C. N. J. Wagner ◽  
A. J. Ardell
Keyword(s):  
Intermetallic Compounds ◽  
Melt Spinning ◽  
Proton Irradiation ◽  
X Ray Diffraction ◽  
Electron Fractography ◽  
X Ray ◽  
Fracture Surfaces ◽  
Microstructural Alterations ◽  
Transmission Electron ◽  
Crystalline Matrix

The intermetallic compounds NiTi, NiTi2, CuZr, CuTi2, and Zr3Al were irradiated by 2 McV protons at various temperatures between –175 °C and –44 °C to a fluence of 1.9 × 1022 H+/m2. Transmission electron microscopy, electron diffraction, and x-ray diffraction were used to evaluate the extents of disordering and amorphization induced by irradiation in the samples. Both phenomena progressed to varying extents in the five compounds, depending on the irradiation temperature and dose. It was observed that the C-A transition began before the degree of long-range order was reduced significantly, and that the amorphous phase nucleated homogeneously throughout the crystalline matrix. A major finding of the current investigation is that the technique of scanning electron fractography provides a useful correlation between the features of the fractured surfaces and the microstructural alterations induced by the proton irradiations. When amorphization is complete the fracture surfaces are either featureless (e.g., NiTi2) or contain branching features resembling river patterns. In some cases (especially in CuZr) these are similar to the markings seen on the surfaces of fractured amorphous ribbons produced by melt-spinning. In general, however, there is not a particularly good correlation between the features on the fracture surfaces of the irradiated and melt-spun ribbons. When the microstructure consists of amorphous regions embedded in a partially disordered crystalline matrix, there is considerable evidence for irradiation-induced ductility. In such cases, exemplified by the results on NiTi and Zr3Al, the fracture surfaces contain dimples, characteristic of ductile fracture, suggesting that disordering promotes ductility.

Crystallization processes and magnetic properties of Fe78Co2Zr8Nb2B10-xGex (x = 0, 1, 2, 3) amorphous alloys

2014 ◽  
Vol 28 (20) ◽  
pp. 1450160
Author(s):  
Z. Hua ◽  
B. Zuo ◽  
Y. M. Sun ◽  
X. N. Wang ◽  
L. R. Dong ◽  
...  
Keyword(s):  
Magnetic Property ◽  
Amorphous Alloys ◽  
Melt Spinning ◽  
Crystallization Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Initial Stage ◽  
Different Temperatures ◽  
Change Trend

Fe 78 Co 2 Zr 8 Nb 2B10-x Ge x (x = 0, 1, 2, 3) amorphous alloys were prepared by melt-spinning and annealed at different temperatures. The microstructures and magnetic property were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM), respectively. The crystallization processes of Fe 78 Co 2 Zr 8 Nb 2 B 10 amorphous alloy at different quenching rates are similar and complex. The α- Fe ( Co ) and α- Mn type phases are observed in their initial stage of crystallization process. Hc increases with increasing annealing temperature in general. Only α- Fe ( Co ) phase is observed in the initial stage of the crystallization processes of Fe 78 Co 2 Zr 8 Nb 2 B 10-x Ge x (x = 0, 1, 2, 3) alloys. The change trend of coercivity is complex compared with Ge -free samples. The magnetic property of Fe 78 Co 2 Zr 8 Nb 2 B 7 Ge 3 is better.

Irreversible transformation in as-cast FeAl B2-ordered alloy obtained by melt spinning

2000 ◽  
Vol 15 (3) ◽  
pp. 659-664 ◽  
Author(s):  
E. Bonetti ◽  
R. Montanari ◽  
C. Testani ◽  
G. Valdrè
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Melt Spinning ◽  
Al Alloy ◽  
Microstructural Stability ◽  
X Ray Diffraction ◽  
Repeated Heating ◽  
X Ray ◽  
Transmission Electron ◽  
Stage Process

The aim of the work described in the present paper was to investigate the microstructural stability during annealing treatments of a Fe–Al alloy obtained by melt spinning. To this purpose internal friction (IF) and dynamic modulus (Md) measurements were employed, and the results correlated with x-ray diffraction, optical microscopy, and scanning and transmission electron microscopy observations. In particular, the B2-ordered Fe–38A1–2Cr–0.015C–0.003B (in at.%) alloy was studied during repeated heating runs from room temperature to 823 K by IF and Md. The modulus exhibited a broad maximum (in the range of 600–800 K) only in the first run. On the basis of transmission electron microscopy and x-ray diffraction analysis, the irreversible transformation was explained by considering a two-stage process that occurs when vacancies in supersaturation move toward dislocations. The first stage is connected to dislocation locking; the second one is due to annihilation of some vacancies by dislocation climb.

Sign in / Sign up

Export Citation Format

Share Document