Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 203 (Feb. 1996), p. 43-46 
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Advances in science and technology Vol. 48 (Oct. 2006), p. 61-66 
    ISSN: 1662-0356
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Natural Sciences in General , Technology
    Notes: Structural defects and degree of order of natural and synthetic moissanite have been investigated byXRD Topography and TEM. XRDT analyses of synthetic 6H-SiC wafers allowed to study extendeddefects and to identify and localize coalescence of polytypes. The observed linear defects are microchannelsand dislocations. Axial screw dislocations, either parallel or slightly inclined to the c-axis,suggest that the growth mechanism for the bulk crystals was mainly by spiral growth. Moreover, thestudy of line orientations of the dislocations allow to reconstruct the growth sector evolution of thesample. Therefore, the convex shape of the growing surface is attained by the development ofgrowth sectors (10l) neighbouring growth sector (001).The coalescence of a thin lamella of a different polytype has been also localized and investigated.The contrast analysis and the diffraction pattern of the lamella are consistent with a 15R-SiCcrystal. Such coalescence indicates local variations of growth conditions.TEM images and selected area electron diffractions (SAEDs) strongly differentiate natural fromsynthetic samples. SAED patterns with [010] incidence of natural crystals are consistent with the6H polytype and do not show streaks along the [001] stacking direction. Synthetic samples arecomparatively much more disordered. Conventional images show high density of (001) faults, notobserved in natural samples. Consistently, SAED patterns of the [100] zone are streaked along c*.High resolution (HR) imaging shows that synthetic samples mainly consist of (001) stackingsequence described as (32)3. Locally mixed stacking sequence described by notation 23(3233)5,probably referred to a long period polytype, are present
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 483-485 (May 2005), p. 311-314 
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: X-Ray Diffraction Topography (XRDT) and Optical Microscopy (OM) are adopted to study extended structural defects in 6H-SiC bulky crystals. Topographs are taken by means of White Beam Synchrotron Radiation Source (WB-SRS-XRDT) and by means of monochromatic radiation (MoKα1) with conventional source (Lang method). All studied samples are characterised by the presence of linear defects, dislocations and microchannels, uniformly distributed in the crystal. Such defects draw a net of independent systems of parallel lines, with different orientation and different contrast widths. Micro-channels are parallel to the c axis, whereas dislocations are perpendicular or nearly parallel to the c axis. The last are unit screw dislocations. It has been concluded that the growth mechanism is driven by screw dislocations and that channels results from the coalescence of parallel dislocations
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Physics and chemistry of minerals 17 (1990), S. 379-384 
    ISSN: 1432-2021
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Abstract Growth marks of pegmatite beryls can be divided into general and specific in relation to their types and distributions. Dislocation absence and growth bands have been recognized as general growth marks of the environment while minor element concentrations and optical anomalies as specific to the local growth medium.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...