Correlation of Electric Parameters Change and Structural Changes Induced in Silicon Systems by Pulsed Magnetic Field Treatment

1993 ◽  
Vol 319 ◽  
Author(s):  
Mark N. Levin ◽  
Vladimir M. Maslovsky
Keyword(s):  
Magnetic Field ◽  
Structural Changes ◽  
Vacancy Concentration ◽  
Surface Region ◽  
Lattice Parameter ◽  
Pulsed Magnetic Field ◽  
Crystal Lattice Parameter ◽  
Free Electrons ◽  
Near Surface ◽  
Electric Parameters

AbstractThe results of comparison investigations of structural and electric parameters changes in silicon systems induced by pulsed magnetic field (MF) treatment (PMFT) are presented for the first time. The characteristics of (PMFT) that can induce considerable parameters changes of the silicon system were determined. Amplitudc of thc magnctic impulscs is 0.1-0.3 MA/m and duration of thc impulscs is 10-30 ms. The investigations were carried out by means of scanning electron microscope (SEM), X-ray diffraction analysis, C-V and DLTS spectroscopies. The PMFT induces the generation of A-centers in the near-surface region of silicon, the changes of the crystal lattice parameter and the concentration of free electrons and results in emergence of an extent structural microdefects in subsurface. The obtained experimental data testifies that PMFT is possible to increase the vacancy concentration at subsurface region of silicon.

scholarly journals ON WHEEL–RAIL CONTACT SURFACE PHENOMENA WITH STRUCTURAL CHANGES AND ‘WHITE ETCHING LAYERS’ GENERATION

Transport ◽  
2012 ◽  
Vol 27 (2) ◽  
pp. 196-205 ◽  
Author(s):  
Libor Beneš
Keyword(s):  
Structural Changes ◽  
Surface Region ◽  
Rolling Contact ◽  
Contact Friction ◽  
Surface Phenomena ◽  
Wheel Surface ◽  
Near Surface ◽  
High Microhardness ◽  
Stress Formation ◽  
Surface Changes

The main aim of this work was a study of the microstructure transformations with the residual stress formation that is induced by rolling contact friction and adhesive wore in the wheel–rail system. Several small railsurface samples, we term them as the ‘chips’, and a piece of wheel sample were chosen for the analyses of the surface changes on the wheel–rail surface. A multitude of different experiments were carried out in order to analyse the microstructure changes at the surface and the near-surface region of the material samples and, thus, to contribute to the understanding of the complex wheel–rail rolling contact phenomena – and its degradation mechanisms. The formation of nano-structured martensite and carbides on the rail and wheel surface causes the extremely high microhardness valuees and the strong corrosion resistance of the so called White Etching Layers (WEL).

Modelling structural changes in the near-surface region in amorphous silica

1995 ◽  
Vol 31 (1) ◽  
pp. 37-39
Author(s):  
G. S. Yablonskii ◽  
D. V. Kundirenko ◽  
L. A. Kulabukhova ◽  
N. Ya. Barash
Keyword(s):  
Amorphous Silica ◽  
Structural Changes ◽  
Surface Region ◽  
Near Surface

scholarly journals Перестройка дефектной структуры тетрабората лития (Li-=SUB=-2-=/SUB=-B-=SUB=-4-=/SUB=-O-=SUB=-7-=/SUB=-) во внешнем электрическом поле

2019 ◽  
Vol 61 (4) ◽  
pp. 671
Author(s):  
А.Г. Куликов ◽  
Ю.В. Писаревский ◽  
А.Е. Благов ◽  
Н.В. Марченков ◽  
В.А. Ломонов ◽  
...  
Keyword(s):  
Electric Field ◽  
Integral Intensity ◽  
Surface Region ◽  
Lattice Parameter ◽  
Diffraction Peak ◽  
Near Surface ◽  
Rocking Curve ◽  
Structure Rearrangement ◽  
Structure Changes ◽  
Distorted Structure

The process of the defect structure rearrangement in a lithium tetraborate single crystal under the influence of high voltage external electric field applied along the polar direction [001] is studied with use of X-ray diffractometry. The results are supplemented by measurements of the conductivity kinetics. Under conditions of electric field of 300-500 V/mm strength, a sharp broadening of the 004 reflection diffraction peak and its integral intensity increasing by several times are observed, however its position and shape practically do not change. Under the influence of DC field with a strength in range of 500 to 1500 V/mm, the broadening process slows down, but the rocking curve asymmetry appears as well as its sharp shift to the smaller angles associated with an increase in the lattice parameter along the c-axis. This process is quasi-reversible, since the distorted structure is partially restored at a very slow rate (for several months). Two types of the diffraction peak parameters variation dependencies on the external field are interpreted as the manifestation of two ionic conductivity mechanisms: mobile lithium ions (Li+) at low-intensity electric field and oxygen vacancies (VO2+) at stronger fields. The process of charge carriers’ migration causes the increase of defects concentration and structure changes in the near-surface region of the crystal.

Shot Peening - A New Method for Improving Mechanical Properties of Structural Ceramics

2006 ◽  
Vol 317-318 ◽  
pp. 277-280 ◽  
Author(s):  
Henryk Tomaszewski ◽  
K. Godwod ◽  
Ryszard Diduszko ◽  
F. Carrois ◽  
J.M. Duchazeaubeneix
Keyword(s):  
Compressive Stress ◽  
Shot Peening ◽  
Structural Changes ◽  
Treatment Time ◽  
Surface Region ◽  
Microplastic Deformation ◽  
Material Surface ◽  
Near Surface ◽  
Compressive Stresses ◽  
Ultrasonic Shot Peening

Shot peening is commonly used to modify material surface layers and improve the strength of metal components. As it occurred the same technique can be applied for brittle ceramics. High compressive stresses up to 2.4 GPa were introduced into near surface region of alumina and zirconia ceramics by ultrasonic shot peening maintaining its surface integrity. Dependence between diameter of tungsten balls, treatment time (at constant mass of balls in the housing and vibration amplitude) and level of compressive stress introduced was determined for both ceramics with nano and micrograins. Coarser grained ceramics was found to be more sensible to structural changes responsible for stress creation than the smaller one. High microplastic deformation in shot peened surface layer of ceramics was observed by X-ray diffraction. An increase of hardness and surface resistance to fracture with increasing level of compressive stress was found.

Computational Modeling For Magnetic-Sensor-Based Three-Dimensional Visualization Of Microcracks

2001 ◽  
Vol 674 ◽  
Author(s):  
Leonid Muratov ◽  
David Lederman ◽  
Bernard R. Cooper
Keyword(s):  
Magnetic Field ◽  
Three Dimensional ◽  
Magnetic Tunnel Junction ◽  
Phase Segregation ◽  
Surface Region ◽  
Electrical Current ◽  
Element Analysis ◽  
Near Surface ◽  
Fast Recognition ◽  
The Magnetic Field

ABSTRACTThe presence of cracks, phase segregation, or even submicron-sized grain boundaries creates a disruption of the magnetic field response to an externally applied electrical current running through the material. These effects can be detected through the magnetic field leakage in the external near-surface region. Using a computer model of an array of magnetic tunnel junction detectors, magnetic “signatures” of various faults and/or material borders and domains have been calculated using finite element analysis and portrayed by icons. We have considered a number of typical cracks and flaws, of different dimensions and orientations, within the bulk of the component. The database of “signatures” thus generated allows fast recognition of faults and generation of their images in real time. Significant efforts have been made to provide an adequate three-dimensional visualization of the shape and distribution of microcracks, the magnetic field lines, and delineation of the position of the faults in relation to the surface.

Calibration of the Au Labeling Technique to Measure Vacancy Defects in Si

2000 ◽  
Vol 610 ◽  
Author(s):  
R. Kalyanaraman ◽  
T. E. Haynes ◽  
V. C. Venezia ◽  
D. C. Jacobson ◽  
H.-J. Gossmann ◽  
...  
Keyword(s):  
Vacancy Concentration ◽  
Surface Region ◽  
High Energy ◽  
Calibration Factor ◽  
Medium Energy ◽  
Near Surface ◽  
Vacancy Defects ◽  
Vacancy Clusters ◽  
Projected Range

AbstractIt has been shown recently that Au labeling can be used to profile vacancy-type defects located near half the projected range (½Rp) in MeV-implanted Si. In this work we have quantified the technique by determining the ratio of vacancies annihilated to decrease in the number of Au atoms trapped (calibration factor ‘k’) for the Au labeling technique. The 3 step experiment involved: 1) a high-energy Si-self implant (HEI) followed by an anneal to form stable vacancy clusters, 2) a controlled removal of vacancies via a medium energy Si self implant and interstitial-cluster dissolution anneal, and finally 3) Au labeling to count the change in vacancy concentration in the near surface region (0.1-1.6μm). It is seen that the Au concentration decreases linearly with increasing interstitial injection and the slope of this decrease determined the number of vacancies per trapped Au atom. The value of k was determined to be 1.2±0.2 vacancies per trapped Au atom.

Preparation of cross-sectional samples for near-surface TEM studies

1987 ◽  
Vol 45 ◽  
pp. 380-381
Author(s):  
R.C. Dickenson ◽  
K.R. Lawless
Keyword(s):  
Standard Sample ◽  
Surface Region ◽  
Specimen Preparation ◽  
Thick Sheet ◽  
Drill Bit ◽  
Sample Holder ◽  
Metal Interface ◽  
Cross Sectional ◽  
Near Surface ◽  
Cold Worked

In thermal oxidation studies, the structure of the oxide-metal interface and the near-surface region is of great importance. A technique has been developed for constructing cross-sectional samples of oxidized aluminum alloys, which reveal these regions. The specimen preparation procedure is as follows: An ultra-sonic drill is used to cut a 3mm diameter disc from a 1.0mm thick sheet of the material. The disc is mounted on a brass block with low-melting wax, and a 1.0mm hole is drilled in the disc using a #60 drill bit. The drill is positioned so that the edge of the hole is tangent to the center of the disc (Fig. 1) . The disc is removed from the mount and cleaned with acetone to remove any traces of wax. To remove the cold-worked layer from the surface of the hole, the disc is placed in a standard sample holder for a Tenupol electropolisher so that the hole is in the center of the area to be polished.

The Effects of Ion Implantation on the Surface Features of Inconel 600

1985 ◽  
Vol 43 ◽  
pp. 288-289
Author(s):  
John D. Rubio
Keyword(s):  
Grain Boundary ◽  
Ion Implantation ◽  
Nuclear Power ◽  
Power Plants ◽  
Surface Region ◽  
Selective Dissolution ◽  
Boundary Region ◽  
Near Surface ◽  
Inconel 600 ◽  
Steam Generator Tubing

The degradation of steam generator tubing at nuclear power plants has become an important problem for the electric utilities generating nuclear power. The material used for the tubing, Inconel 600, has been found to be succeptible to intergranular attack (IGA). IGA is the selective dissolution of material along its grain boundaries. The author believes that the sensitivity of Inconel 600 to IGA can be minimized by homogenizing the near-surface region using ion implantation. The collisions between the implanted ions and the atoms in the grain boundary region would displace the atoms and thus effectively smear the grain boundary.To determine the validity of this hypothesis, an Inconel 600 sample was implanted with 100kV N2+ ions to a dose of 1x1016 ions/cm2 and electrolytically etched in a 5% Nital solution at 5V for 20 seconds. The etched sample was then examined using a JEOL JSM25S scanning electron microscope.

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