Microstructure of a high strength alumina glass composite

1996 ◽  
Vol 11 (4) ◽  
pp. 855-858 ◽  
Author(s):  
Helga Hornberger ◽  
Peter M. Marquis ◽  
Silke Christiansen ◽  
Horst P. Strunk
Keyword(s):  
Electron Microscopy ◽  
Strain Relaxation ◽  
High Strength ◽  
Average Diameter ◽  
Strength Properties ◽  
Ring Test ◽  
Glass Composite ◽  
Transmission Electron ◽  
Trade Name ◽  
Faceted Particles

The morphology and microstructure of an Al2O3 glass composite (trade name In-Ceram, Vita Zahnfabrik) were studied using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The composite was produced by infiltration of a lanthanum-based glass throughout a porous Al2O3 body. This alumina body was formed by three classes of particles differing in size and shape: faceted particles typically ≤4 μm in diameter, platelets of average diameter 8 μm, 1.5 μm thickness, and small spheres 0.4 μm in diameter. The outstanding strength properties of the composite (600 MPa, ball-on-ring test) are a result of the high wetting capability of the glass phase on the Al2O3 surface. In addition, plastic strain relaxation in the faceted particles by dislocation formation compensates partially for residual stresses and impedes crack formation at the glass/Al2O3 interface.

Antifungal Effectiveness of Nanosilver Colloid against Rose Powdery Mildew in Greenhouses

2008 ◽  
Vol 135 ◽  
pp. 15-18 ◽  
Author(s):  
Hae Sic Kim ◽  
Hyun Suk Kang ◽  
Gyo Jin Chu ◽  
Hong Sik Byun
Keyword(s):  
Electron Microscopy ◽  
Powdery Mildew ◽  
Colloidal Solution ◽  
Physical Method ◽  
Average Diameter ◽  
Optical Microscope ◽  
Size Analysis ◽  
Large Area ◽  
Transmission Electron ◽  
Antifungal Effects

The antifungal effectiveness against rose powdery mildew using antimicrobial nanosilver colloidal solution was investigated. Double-capsulized nanosilver was prepared by chemical reaction of silver ion with aid of physical method, reducing agent and stabilizers. The average diameter of nanosilver was about 1.5 nm. They were highly stable and very well dispersive in aqueous solution. The Transmission electron microscopy and UV-vis spectrometer were used for measurements of size analysis and their stability, respectively. The nanosilver colloidal solution of concentration of 5000 ppm was diluted in 10 ppm of 500 kg and sprayed at large area of 3306 m2polluted by rose powdery mildew. The white rose powdery mildew fade out above 95 % after 2 days and was not recurred for a week. The antifungal effects were observed by an optical microscope and photographs.

Characterization of Al65.0Cu32.9Co2.1 Alloy Containing Nanofibres

2012 ◽  
Vol 186 ◽  
pp. 212-215
Author(s):  
Jacek Krawczyk ◽  
Włodzimierz Bogdanowicz ◽  
Grzegorz Dercz ◽  
Wojciech Gurdziel
Keyword(s):  
Electron Microscopy ◽  
Average Diameter ◽  
Chemical Compositions ◽  
X Ray ◽  
Transmission Electron ◽  
Orthogonal Set ◽  
T Phase ◽  
Terminal Area ◽  
Scanning Electron

Microstructure of terminal area of Al65Cu32.9Co2.1ingots (numbers indicate at.%), obtained via directional solidification was studied. Scanning Electron Microscopy, Transmission Electron Microscopy and X-ray powder diffraction were applied. Point microanalysis by Scanning Electron Microscope was used for examination of chemical compositions of alloy phases. It was found that tetragonal θ phase of Al2Cu stoichiometric formula was the dominate phase (matrix). Additionally the alloy contained orthogonal set of nanofibres of Al7Cu2Co T phase with the average diameter of 50-500 nm and oval areas of hexagonal Al3(Cu,Co)2H-phase, surrounded by monoclinic AlCu η1phase rim. Inside some areas of H-phase cores of decagonal quasicrystalline D phase were observed.

scholarly journals The formation of self-assembled structures of C60 in solution and in the volume of an evaporating drop of a colloidal solution

2020 ◽  
Vol 60 (3) ◽  
Author(s):  
Urol Kudratovich Makhmanov ◽  
Abdulmutallib Kokhkharov ◽  
Sagdilla Bakhramov ◽  
Donats Erts
Keyword(s):  
Electron Microscopy ◽  
Colloidal Solution ◽  
Substrate Surface ◽  
Flat Glass ◽  
Dissipative System ◽  
Average Diameter ◽  
Flat Substrate ◽  
Transmission Electron ◽  
Physical Features ◽  
Self Aggregation

The results of experiments on the self-aggregation of C60 fullerene molecules both inside a two-component solvent (xylene/tetrahydrofuran) and in the volume of an evaporating drop of C60 colloidal solution on a flat substrate surface are presented. The investigations of C60 solutions using dynamic light scattering, transmission electron microscopy and UV–Vis absorption spectroscopy methods revealed the possibility of synthesis of fractal nanoaggregates with a diameter of up to ~135 nm at low concentrations of C60 in the solutions. The final geometric dimensions of C60 nanoaggregates were determined by the initial concentration of fullerene in the solvent medium. Using the scanning electron microscopy method, we have shown that in an open dissipative system – in the volume of an evaporating droplet of the colloidal solution of fullerene C60 sessile on the surface of a flat glass substrate, large quasispherical nanoaggregates with an average diameter of ~380–800 nm are formed. The physical features and regularities that characterize the processes of self-aggregation of fullerene particles in the volume of a drying drop were determined.

Transmission electron microscopy of misfit dislocation and strain relaxation in lattice mismatched III-V heterostructures versus substrate surface treatment

2011 ◽  
Vol 1324 ◽  
Author(s):  
Y. Wang ◽  
P. Ruterana ◽  
L. Desplanque ◽  
S. El Kazzi ◽  
X. Wallart
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Surface Treatment ◽  
Substrate Surface ◽  
Strain Relaxation ◽  
Dislocation Core ◽  
Misfit Dislocations ◽  
Heteroepitaxial Growth ◽  
Transmission Electron ◽  
Growth Initiation

ABSTRACTHigh resolution transmission electron microscopy in combination with geometric phase analysis is used to investigate the interface misfit dislocations, strain relaxation, and dislocation core behavior versus the surface treatment of the GaAs for the heteroepitaxial growth of GaSb. It is pointed out that Sb-rich growth initiation promotes the formation of a high quality network of Lomer misfit dislocations that are more efficient for strain relaxation.

scholarly journals Gas Sensing Properties of NiSb2O6 Micro- and Nanoparticles in Propane and Carbon Monoxide Atmospheres

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Verónica-M. Rodríguez-Betancourtt ◽  
Héctor Guillén Bonilla ◽  
Martín Flores Martínez ◽  
Alex Guillén Bonilla ◽  
J. P. Moran Lazaro ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Monoxide ◽  
Gas Sensing ◽  
Average Diameter ◽  
Cell Parameters ◽  
Sensing Applications ◽  
Transmission Electron ◽  
Colloidal Method ◽  
Antimony Chloride ◽  
20 Nm

Micro- and nanoparticles of NiSb2O6 were synthesized by the microwave-assisted colloidal method. Nickel nitrate, antimony chloride, ethylenediamine, and ethyl alcohol were used. The oxide was obtained at 600°C and was analyzed by X-ray diffraction (XRD) and Raman spectroscopy, showing a trirutile-type structure with cell parameters a = 4.641 Å, c = 9.223 Å, and a space group P42/mnm (136). Average crystal size was estimated at ~31.19 nm, according to the XRD-peaks. The microstructure was scrutinized by scanning electron microscopy (SEM), observing microrods measuring ~3.32 μm long and ~2.71 μm wide, and microspheres with an average diameter of ~8 μm; the size of the particles shaping the microspheres was measured in the range of ~0.22 to 1.8 μm. Transmission electron microscopy (TEM) revealed that nanoparticles were obtained with sizes in the range of 2 to 20 nm (~10.7 nm on average). Pellets made of oxide’s powders were tested in propane (C3H8) and carbon monoxide (CO) atmospheres at different concentrations and temperatures. The response of the material increased significantly as the temperature and the concentration of the test gases rose. These results show that NiSb2O6 may be a good candidate for gas sensing applications.

scholarly journals First identification of nanoparticles on thorax, abdomen and wings of the worker bee Apis dorsata Fabricius

2016 ◽  
Vol 60 (1) ◽  
pp. 87-96
Author(s):  
Atanu Bhattacharyya ◽  
Shashidhar Viraktamath ◽  
Fani Hatjina ◽  
Santanu Bhattacharyya ◽  
Bhaktibhavana Rajankar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Average Diameter ◽  
The Body ◽  
Apis Dorsata ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Calcium Phosphate Nanoparticles ◽  
First Time

Abstract The presence of nanoparticles on the body of the honeybee Apis dorsata Fabricius, was investigated for the first time to better understand the bee’s behaviour. These have been observed by using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and confirmed by Atomic Force Microscopy (AFM). Our study clearly denotes that the Indian rock honey bee Apis dorsata possess calcium silicate and calcium phosphate nanoparticles on its body surface of 5-50 nm in diameter. In particular, the nanoparticles on the abdomen and thorax of A. dorsata have an average diameter of about 10 nanometers and they are smaller than those found on wings of the same bees which are about 20 nanometers. The nanoparticles found are different of the ones previously observed on honey bees or other insects. The origin and role of these natural nanoparticles on the body of the Indian rock bee need to be to be further investigated; more research in the subject might raise important aspects in relation to the conservation of these unique pollinators.

Mechanisms of misfit strain relaxation in epitaxially grown BLT (Bi4-xLaxTi3O12, x = 0.75) thin films

2003 ◽  
Vol 779 ◽  
Author(s):  
Hyung Seok Kim ◽  
Sang Ho Oh ◽  
Ju Hyung Suh ◽  
Chan Gyung Park
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Strain Relaxation ◽  
Lattice Misfit ◽  
Misfit Strain ◽  
Misfit Dislocations ◽  
Transmission Electron ◽  
Means Of Transmission ◽  
20 Nm

AbstractMechanisms of misfit strain relaxation in epitaxially grown Bi4-xLaxTi3O12 (BLT) thin films deposited on SrTiO3 (STO) and LaAlO3 (LAO) substrates have been investigated by means of transmission electron microscopy (TEM). The misfit strain of 20 nm thick BLT films grown on STO substrate was relaxed by forming misfit dislocations at the interface. However, cracks were observed in 100 nm thick BLT films grown on the same STO. It was confirmed that cracks were formed because of high misfit strain accumulated with increasing the thickness of BLT, that was not sufficiently relaxed by misfit dislocations. In the case of the BLT film grown on LAO substrate, the magnitude of lattice misfit between BLT and LAO was very small (~1/10) in comparison with the case of the BLT grown on STO. The relatively small misfit strain formed in layered structure of the BLT films on LAO, therefore, was easily relaxed by distorting the film, rather than forming misfit dislocations or cracks, resulting in misorientation regions in the BLT film.

scholarly journals Investigation of Interfacial Layer for Friction Stir Scribe Welded Aluminum to Steel Joints

2018 ◽  
Vol 140 (11) ◽  
Author(s):  
Kaifeng Wang ◽  
Piyush Upadhyay ◽  
Yuxiang Wang ◽  
Jingjing Li ◽  
Xin Sun ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Driving Force ◽  
Bond Formation ◽  
Welding Process ◽  
High Strength ◽  
Bimaterial Interface ◽  
Joint Interface ◽  
Friction Stir ◽  
Transmission Electron ◽  
Steel Joints

Friction stir scribe (FSS) welding as a recent derivative of friction stir welding (FSW) has been successfully used to fabricate a linear joint between automotive Al and steel sheets. It has been established that FSS welding generates a hook-like structure at the bimaterial interface. Beyond the hook-like structure, there is a lack of fundamental understanding on the bond formation mechanism during this newly developed FSS welding process. In this paper, the microstructures and phases at the joint interface of FSS welded Al to ultra-high-strength steel were studied using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found that both mechanical interlocking and interfacial bonding occurred simultaneously during the FSS welding process. Based on SEM observations, a higher diffusion driving force in the advancing side was found compared to the retreating side and the scribe swept zone, and thermally activated diffusion was the primary driving force for the interfacial bond formation in the scribe swept region. The TEM energy-dispersive X-ray spectroscopy (EDXS) revealed that a thin intermetallic compound (IMC) layer was formed through the interface, where the thickness of this layer gradually decreased from the advancing side to the retreating side owing to different material plastic deformation and heat generations. In addition, the diffraction pattern (or one-dimensional fast Fourier transform (FFT) pattern) revealed that the IMC layer was composed of Fe2Al5 or Fe4Al13 with a Fe/Al solid solution depending on the weld regions.

In Situ Electron Microscopy Studies of Surface Dynamical Processes

1998 ◽  
Vol 4 (S2) ◽  
pp. 608-609
Author(s):  
Ruud M. Tromp
Keyword(s):  
Electron Microscopy ◽  
Strain Relaxation ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Relaxation Phase ◽  
Transmission Electron ◽  
In Situ Electron Microscopy ◽  
Low Energy Electron ◽  
New Machine

To obtain a full and detailed understanding of the spatiotemporal dynamics of surface processes such as epitaxial growth, strain relaxation, phase transformations and phase transitions, chemisorption and etching, in situ real-time observations have proven to be invaluable. The development of two experimental techniques, i.e. Low Energy Electron Microscopy (LEEM) typically operating at electron energies below 10 eV, and Ultra-High-Vacuum Transmission Electron Microscopy (UHV-TEM) at several 100 keV, has made such in situ studies routinely possible. In many cases, the videodata obtained from such experiments are amenable to detailed, quantitative analysis, yielding statistical, kinetic and thermodynamic information that cannot be obtained in any other way.I will discuss recent experimental developments, including the design and construction of a new and improved LEEM instrument. Figure 1 shows a schematic diagram of this new machine. There are several features that distinguishes this design from most other LEEMs. One is the use of a 90 degree deflection magnetic prism array,

Synthesis and Thermal Stability of Nontransformable Tetragonal (ZrO2)0.96(REO1.5)0.04 (Re=Sc3+, Y3+) Nanocrystals

2013 ◽  
Vol 334-335 ◽  
pp. 60-64 ◽  
Author(s):  
Mohammad Reza Loghman-Estark ◽  
Reza Shoja Razavi ◽  
Hossein Edris
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Scanning Electron Microscopy ◽  
Sol Gel ◽  
Average Diameter ◽  
X Ray ◽  
Transmission Electron ◽  
20 Nm ◽  
Thermal Stability Of ◽  
Scanning Electron

Scandia, yttria doped zirconia ((ZrO2)0.96(REO1.5)0.04(RE=Sc3+, Y3+)) nanoparticles were prepared by the modified sol-gel method. The microstructure of the products was characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. Thermal stabillity of SYSZ nanocrystals were also investigated. The SYSZ nanocrystals synthesized with EGM:Zr+4mole ratio 4:1, calcined at 700°C, have average diameter of ~20 nm.

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