The Study of Planar Interfaces by Means of Electron Microscopy

Amelinckx, S.; Landuyt, J. van

doi:10.1016/b978-0-444-85128-4.50008-4

Cited by 63 publications

(56 citation statements)

References 28 publications

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“…However, other precipitate-like features now appear. The contrast is considered to arise from absorption effects and is consistent with the features being cavities [Amelinckx, 1970]; we therefore shall refer to them as 'bubbles.' The contrast is considered to arise from absorption effects and is consistent with the features being cavities [Amelinckx, 1970]; we therefore shall refer to them as 'bubbles.'…”

Section: A Complex Absorption Band Of Intermediate Width Peaking At mentioning

confidence: 98%

An Experimental Study of the Role of Water in Quartz Deformation

Kekulawala

Paterson

Boland

2013

Mechanical Behavior of Crustal Rocks

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Basic equilibrium and kinetic properties of water in quartz are elucidated in a combined mechanical, infrared absorption, and electron microscope study on a hydroxylbearing synthetic quartz crystal. Changes in yield strength and nature of infrared absorption observed after heating specimens at 900øC and various pressures are correlated with the precipitation or redissolution of water in bubbles visible in the electron microscope. From these observations it is concluded that the solubility of water in quartz at 900øC and 300 MPa pressure is between 200 and 400 H per 106Si and that the diffusivity of the dissolved hydroxyl-bearing species is very low, probably less than 10 -•9 m •' s -• at 900øC in initially dry quartz but increasing significantly with hydroxyl concentration. These results explain the sluggishness and associated experimental difficulties in studies on hydrolytic weakening in this pressure range. They indicate that equilibrium may not be attained in many such experiments and pose pertinent questions concerning extrapolation to geological conditions. 49 MPa) is an important factor. A similar conclusion follows from observations of lower strength in quartzite at higher pressures by Tullis et al. [1979]. The reasons for the pressure effect have not yet been elucidated, but pressure is clearly an important variable.The present study, combining mechanical, infrared absorption, and electron microscope approaches, attempts to separate and to identify some basic equilibrium and kinetic aspects of the role of OH in the properties of quartz. Preliminary accounts of the findings have been given in Kekulawala et al. [1978] and in Paterson and Kekulawala [1979]. The latter paper also gives a review setting out the background in some detail, which therefore need not be repeated here. We shall now describe observations on the mechanical properties of synthetic quartz crystals subjected to various histories of heat treatment and relate these observations to infrared absorption spectra measured at low temperature and to electron microscope observations on bubbles. The observations will then be discussed in terms of the solubility and diffusivity of the kinetically effective hydroxyl species responsible for hydrolytic weakening. Finally, some implications for the mechanical properties of quartz under other conditions are considered. Apparatus and ProceduresDeformation tests were carried out in an argon gas-medium high pressure apparatus, previously described [Pa- terson, 1970]. The apparatus has an internal furnace and an internal load cell. Displacements are determined with an externally mounted LVDT, correcting for apparatus

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Section: A Complex Absorption Band Of Intermediate Width Peaking At mentioning

confidence: 98%

An Experimental Study of the Role of Water in Quartz Deformation

Kekulawala

Paterson

Boland

2013

Mechanical Behavior of Crustal Rocks

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“…Twins induced upon losing point group symmetry are reflection, rotation, and centrosymmetry type 1–4 . Both crystal parts (or individuals, components) are related crystallographically by the operation of a mirror plane in reflection twins, a twofold (or less commonly 1,4 threefold, fourfold, and sixfold) rotation axis in rotation twins, and an inversion center in centrosymmetry twins (or inversion twins).…”

Section: Introductionmentioning

confidence: 99%

“…Both the herringbone and square‐net domain patterns were found in BaTiO 3 ceramics 9–11 under a microscope, with the former most commonly 11 observed in undoped samples. Lamellar (or stripe) domains 3,9,10 are almost always identified to be the 90° type; they were further divided into 90° a – a and 90° a – c depending on the viewing direction, 9,10 although geometrically equivalent. The conventional domains of 90° a – a and 90° a – c are illustrated schematically in Figs.…”

Section: Introductionmentioning

confidence: 99%

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Transformation‐Induced Twinning: The 90° and 180° Ferroelectric Domains in Tetragonal Barium Titanate

Cheng

2006

Journal of the American Ceramic Society

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Ferroelectric twin domains resulting from the cubic (c) to tetragonal (t) phase transformation at the Curie point TC≈130°C in pressureless‐sintered BaTiO3 ceramics, using TiO2‐excess powder, have been investigated using scanning and transmission electron microscopy. Both 90° and 180° domains were identified by spot splitting along characteristic crystallographic directions in the selected‐area diffraction patterns and/or from the shape of domain boundaries. Lamellar domains were found predominantly with the 90° types. The 180° domain boundaries mostly appeared wavy in shape, while the 90° ones, having sharpened ends, attained a dagger shape. Failure of Friedel's law in the non‐centrosymmetric t‐BaTiO3 was adopted to validate the existence of the 180° domains. The 90° domains with boundaries lying in are reflection–inversion twins, and the 180° domains lying in {100)t and }220)t are inversion twins. Convergent‐beam electron diffraction was performed to ensure that changing of the polar direction [001]t across the 90° and the 180° domain boundaries was consistent with the domain type. It was also used to confirm whether the 180°‐type walls are inversion domain boundaries produced by the loss of an inversion center when the cubic phase transforms into tetragonal symmetry. The formation of such ferroelectric domains is discussed with reference to the crystal symmetry reduction from (c‐phase) to P4mm (t‐phase) with a loss of mirror plane (m) and roto‐inversion axis upon c→t phase transformation.

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“…fragment amorphous. The second type of particle exhibited a prominent cleavage and had planar defects lying in the cleavage plane (AMELINCKX, 1970); the d-spac ing of the planes containing the defects was -9 .5A which corresponded with (100) in the Structure From an analysis of over 100 Laue zones, no single lattice could be found to fit all the zones.…”

Section: X-ray and Optical Datamentioning

confidence: 99%

High pressure synthesis of a new aluminium silicate: Al5Si5O17(OH).

1978

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NOTE (Received February 17, 1978) A new aluminium silicate has been produced under hydrous conditions from A1203-Si02 oxide mixes with Si/Al ratios close to unity, at pressures greater than 100 kilobars and at about 1,000°C. X-ray powder photographs indicated one dominant new phase. From analyses of the electron diffraction Laue zones of minute fragments (^'1µm), a monoclinic structure that fitted the X-ray powder results was identified. This monoclinic structure is described in terms of nine close-packed layers of oxygen with the unit cell containing 72 oxygen atoms. Assuming Si/Al equals 1, the composition of this phase is A120Si2OO72H4 The calculated density of 4.03 g/cc is in good agreement with the value of 4.02 g/cc estimated from the refractive index measurements.

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The Study of Planar Interfaces by Means of Electron Microscopy

Cited by 63 publications

References 28 publications

An Experimental Study of the Role of Water in Quartz Deformation

An Experimental Study of the Role of Water in Quartz Deformation

Transformation‐Induced Twinning: The 90° and 180° Ferroelectric Domains in Tetragonal Barium Titanate

High pressure synthesis of a new aluminium silicate: Al5Si5O17(OH).

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