Impurity-controlled contrast in secondary-electron images of reaction-bonded silicon carbide

1990 ◽  
Vol 48 (4) ◽  
pp. 888-889
Author(s):  
R.A. Youngman
Keyword(s):  
Secondary Electron ◽  
Microstructural Characterization ◽  
Optical Microscope ◽  
The Past ◽  
Contrast Mechanism ◽  
Backscattered Electron ◽  
In Situ Formation ◽  
Secondary Ion

Reaction-bonded SiC is formed by the high temperature (>2100°C) heat treatment of a mixture of alpha-SiC powder and organic binders in the presence of elemental Si. The bonding occurs by the in-situ formation of beta-SiC from the reaction of the pyrolyzed binder and the Si. Substantial microstructural characterization of these materials has been carried out in the past. A particular feature of these analyses is the so-called trace-impurity-controlled contrast of secondary electron (SE) images of uncoated specimens. This report describes further attempts to elucidate the origin of this contrast mechanism.Samples of reaction-bonded SiC (Hexoloy KT, The Carborundum Co.) were prepared for multiple-technique analysis. This was accomplished by preparing an optical thin section for reflected and transmitted optical microscopy. Regions of interest were diamond-scribed on the optical microscope (Leitz, Orthoplan) and then SE and backscattered electron (BE) microscopy (CamScan, Series IV) of the same areas (both coated and uncoated with evaporated carbon) was conducted. Finally, the same areas were imaged in a secondary ion mass spectrometer (SIMS) (Cameca, IMS3F) to detect trace and major impurity levels.

Resolution Limits of Secondary Electron Dopant Contrast in Helium Ion and Scanning Electron Microscopy

2011 ◽  
Vol 17 (4) ◽  
pp. 637-642 ◽  
Author(s):  
Mark Jepson ◽  
Xiong Liu ◽  
David Bell ◽  
David Ferranti ◽  
Beverley Inkson ◽  
...  
Keyword(s):  
Secondary Electron ◽  
Electrical Potential ◽  
Helium Ion ◽  
Resolution Limits ◽  
Contrast Mechanism ◽  
Material Contrast ◽  
Dopant Atoms ◽  
Scanning Electron

AbstractAs the miniaturization of semiconductor devices continues, characterization of dopant distribution within the structures becomes increasingly challenging. One potential solution is the use of the secondary electron signal produced in scanning electron (SEMs) or helium ion microscopes (HeIMs) to image the changes in electrical potential caused by the dopant atoms. In this article, the contrast mechanisms and resolution limits of secondary electron dopant contrast are explored. It is shown that the resolution of the technique is dependent on the extent of electrical potential present at a junction and that the resolution of dopant contrast can be improved in the HeIM after an in-situ plasma cleaning routine, which causes an oxide to form on the surface altering the contrast mechanism from electrical potential to material contrast.

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.

Polysulfide Networks. In Situ Formation and Characterization of the Elastomeric Behavior

2007 ◽  
Vol 40 (14) ◽  
pp. 5141-5149 ◽  
Author(s):  
Giona Kilcher ◽  
Lei Wang ◽  
Craig Duckham ◽  
Nicola Tirelli
Keyword(s):  
In Situ Formation

scholarly journals CAAC Boranes. Synthesis and characterization of cyclic (alkyl) (amino) carbene borane complexes from BF3 and BH3

2010 ◽  
Vol 6 ◽  
pp. 709-712 ◽  
Author(s):  
Julien Monot ◽  
Louis Fensterbank ◽  
Max Malacria ◽  
Emmanuel Lacôte ◽  
Steven J Geib ◽  
...  
Keyword(s):  
Silica Gel ◽  
Synthesis And Characterization ◽  
Gel Chromatography ◽  
Nmr Analysis ◽  
X Ray ◽  
X Ray Crystallography ◽  
In Situ Formation ◽  
Silica Gel Chromatography

In situ formation of two cyclic (alkyl) (amino) carbenes (CAACs) followed by addition of BF3•Et2O provided the first two examples of CAAC–BF3 complexes: 1-(2,6-diisopropylphenyl)-3,5,5-trimethyl-3-phenylpyrrolidin-2-ylidene trifluoroborane, and 2-(2,6-diisopropylphenyl)-3,3-dimethyl-2-azaspiro[4.5]decan-1-ylidene trifluoroborane. These CAAC–BF3 complexes are robust compounds that are stable to ambient laboratory conditions and silica gel chromatography. They were characterized by spectroscopy and X-ray crystallography. In contrast, a CAAC complex with borane (BH3) was readily formed in situ according to 1H and 11B NMR analysis, but did not survive the workup conditions. These results set the stage for further studies of the chemistry of CAAC boranes.

scholarly journals Microstructural Characterization Of Laser Heat Treated AISI 4140 Steel With Improved Fatigue Behavior

2015 ◽  
Vol 60 (2) ◽  
pp. 1331-1334 ◽  
Author(s):  
M.C. Oh ◽  
H. Yeom ◽  
Y. Jeon ◽  
B. Ahn
Keyword(s):  
Fatigue Strength ◽  
Alloy Steel ◽  
Microstructural Evolution ◽  
Fatigue Behavior ◽  
Microstructural Characterization ◽  
Optical Microscope ◽  
Heat Treated ◽  
Aisi 4140 ◽  
Ultrasonic Fatigue

Abstract The influence of surface heat treatment using laser radiation on the fatigue strength and corresponding microstructural evolution of AISI 4140 alloy steel was investigated in this research. The AISI 4140 alloy steel was radiated by a diode laser to give surface temperatures in the range between 600 and 800°C, and subsequently underwent vibration peening. The fatigue behavior of surface-treated specimens was examined using a giga-cycle ultrasonic fatigue test, and it was compared with that of non-treated and only-peened specimens. Fatigue fractured surfaces and microstructural evolution with respect to the laser treatment temperatures were investigated using an optical microscope. Hardness distribution was measured using Vickers micro-hardness. Higher laser temperature resulted in higher fatigue strength, attributed to the phase transformation.

Effect of Post Weld Heat Treatment on Al 5052-SS 316 Explosive Cladding with Copper Interlayer

2018 ◽  
Vol 910 ◽  
pp. 35-40
Author(s):  
Eswaran Elango ◽  
Somasundaram Saravanan ◽  
Krishnamorthy Raghukandan
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Intermetallic Compounds ◽  
Microstructural Characterization ◽  
Optical Microscope ◽  
Post Weld Heat Treatment ◽  
Inclination Angles ◽  
Copper Interlayer ◽  
Weld Heat

This study focuses on effect of post weld heat treatment (PWHT) on interfacial and mechanical properties of Al 5052-SS 316 explosive clad with copper interlayer at varied loading ratios and inclination angles. The use of interlayer is proposed for the control of additional kinetic energy dissipation and to alleviate the formation of intermetallic compounds at the interface. The Al-Steel clads are subjected to PWHT at varied temperatures (300°C-450°C) for 30 minutes and the results are presented. The microstructural characterization of as-clad and PWHT samples is observed by an optical microscope and Scanning Electron Microscope (SEM). Maximum hardness is obtained at the interface of the as-clad and PWHT samples. Increase in PWHT temperature enhances the tensile strength of the composite, whereas, the tensile strength decreases at 300°C due to the diffusion of Al and Cu elements and the formation of detrimental intermetallic compounds.

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