SLEEM Study of MgAl2O4 at Interface betweeen Al2O3 and Matrix in Al2O3/Al Alloy Composite Materials

2007 ◽  
Vol 539-543 ◽  
pp. 779-784
Author(s):  
Susumu Ikeno ◽  
Kenji Matsuda ◽  
I. Müllerová ◽  
Luděk Frank
Keyword(s):  
Electron Microscope ◽  
Composite Materials ◽  
Low Energy ◽  
Al Alloy ◽  
Alloy Composite ◽  
Orientation Relationships ◽  
Small Particles ◽  
Interaction Volume ◽  
Low Energy Electron ◽  
Scanning Electron

In the present talk, MgAl2O4 in the Al2O3/Al-1.0mass%Mg2Si alloy composite was also observed by a scanning electron microscope equipped with the low energy electron (SLEEM) adaptation aiming at examination of its morphology and orientation relationships to the Al2O3 particles. Owing to its much smaller interaction volume of signal exciting electrons in the target and hence more localized information, together with a favorable combination of secondary (SE) and backscattered (BSE) electron signals, the SLEEM method provided much better readable and detailed images of all particles, their shapes and mutual orientations, in comparison with conventional SE and BSE images at the electron energies usually used in the SEM. MgAl2O4 (spinels) were formed on facets of Al2O3 as small particles, and their shape well corresponded to an octahedron consisting of 8 equiaxial triangles.

High Resolution Scanning Electron Microscopy

1991 ◽  
Vol 49 ◽  
pp. 478-479
Author(s):  
David Joy ◽  
James Pawley
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Beam ◽  
Electron Microscope ◽  
High Resolution ◽  
Scanning Electron Microscope ◽  
Electron Probe ◽  
Impact Point ◽  
Interaction Volume ◽  
Scanning Electron

The scanning electron microscope (SEM) builds up an image by sampling contiguous sub-volumes near the surface of the specimen. A fine electron beam selectively excites each sub-volume and then the intensity of some resulting signal is measured. The spatial resolution of images made using such a process is limited by at least three factors. Two of these determine the size of the interaction volume: the size of the electron probe and the extent to which detectable signal is excited from locations remote from the beam impact point. A third limitation emerges from the fact that the probing beam is composed of a finite number of discrete particles and therefore that the accuracy with which any detectable signal can be measured is limited by Poisson statistics applied to this number (or to the number of events actually detected if this is smaller).

Performance Evaluation of a Novel Type of Low-Energy Electron Microscope

1990 ◽  
Vol 48 (1) ◽  
pp. 354-355
Author(s):  
Bertholdand Senftinger ◽  
Helmut Liebl
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Field Strength ◽  
Numerical Aperture ◽  
Low Energy ◽  
Energy Electron ◽  
High Resolution Imaging ◽  
Lens System ◽  
Resolution Imaging ◽  
Low Energy Electron

During the last few years the investigation of clean and adsorbate-covered solid surfaces as well as thin-film growth and molecular dynamics have given rise to a constant demand for high-resolution imaging microscopy with reflected and diffracted low energy electrons as well as photo-electrons. A recent successful implementation of a UHV low-energy electron microscope by Bauer and Telieps encouraged us to construct such a low energy electron microscope (LEEM) for high-resolution imaging incorporating several novel design features, which is described more detailed elsewhere.The constraint of high field strength at the surface required to keep the aberrations caused by the accelerating field small and high UV photon intensity to get an improved signal-to-noise ratio for photoemission led to the design of a tetrode emission lens system capable of also focusing the UV light at the surface through an integrated Schwarzschild-type objective. Fig. 1 shows an axial section of the emission lens in the LEEM with sample (28) and part of the sample holder (29). The integrated mirror objective (50a, 50b) is used for visual in situ microscopic observation of the sample as well as for UV illumination. The electron optical components and the sample with accelerating field followed by an einzel lens form a tetrode system. In order to keep the field strength high, the sample is separated from the first element of the einzel lens by only 1.6 mm. With a numerical aperture of 0.5 for the Schwarzschild objective the orifice in the first element of the einzel lens has to be about 3.0 mm in diameter. Considering the much smaller distance to the sample one can expect intense distortions of the accelerating field in front of the sample. Because the achievable lateral resolution depends mainly on the quality of the first imaging step, careful investigation of the aberrations caused by the emission lens system had to be done in order to avoid sacrificing high lateral resolution for larger numerical aperture.

Fabrication and Properties of Lignin/Castor Oil-Based Composites

2011 ◽  
Vol 311-313 ◽  
pp. 1535-1538 ◽  
Author(s):  
Hong Juan Wang ◽  
Hai Yan Xiao ◽  
Feng Qiang Sun ◽  
Jian Hua Zhang
Keyword(s):  
Fourier Transform ◽  
Electron Microscope ◽  
Free Radical ◽  
Composite Materials ◽  
Scanning Electron Microscope ◽  
Castor Oil ◽  
Morphology And Structure ◽  
The Matrix ◽  
Facile Route ◽  
Scanning Electron

Novel bio-based composites were developed from maleate castor oil (MACO) and lignin through free radical initiated copolymerization between MACO and diluent monomer styrene(St). The morphology and structure of the composites were characterized by Fourier transform infrared spectroscope (FTIR) and scanning electron microscope (SEM). The mechanical and thermal behaviors of the composites were investigated, which showed the incorporation of a little of lignin in the castor oil based polymer can enhance the tensile properties of the matrix polymer greatly. This work provides a facile route to prepare bio-based composite materials from castor oil and lignin and can be extended to prepare other bio-based materials from reproducible resources.

scholarly journals A design for a subminiature, low energy scanning electron microscope with atomic resolution

2009 ◽  
Vol 105 (1) ◽  
pp. 014702 ◽  
Author(s):  
D. A. Eastham ◽  
P. Edmondson ◽  
S. Greene ◽  
S. Donnelly ◽  
E. Olsson ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Low Energy ◽  
Atomic Resolution ◽  
Scanning Electron

Double aberration correction in a low-energy electron microscope

2010 ◽  
Vol 110 (11) ◽  
pp. 1358-1361 ◽  
Author(s):  
Th. Schmidt ◽  
H. Marchetto ◽  
P.L. Lévesque ◽  
U. Groh ◽  
F. Maier ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Low Energy ◽  
Energy Electron ◽  
Aberration Correction ◽  
Low Energy Electron
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