Pretreatment of Fithian illite for oxygen isotope analysis

Oxygen isotope analysis of clay minerals presents several practical difficulties. These include their very fine grain size, the presence of both hydroxyl and non-hydroxyl oxygen, adsorbed water and, where clays from oil reservoirs are concerned, the possibility of hydrocarbon contamination. To develop routines which would minimize these problems while leaving the isotope systematics of the clay undisturbed, a series of oxygen isotope analyses were made under different running conditions of the API Standard Illite–the Fithian illite.

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Hydrolysis of ceramic materials: neoformation or rehydroxylation of clay minerals. Oxygen stable isotope analysis

Clay Minerals ◽

10.1180/0009855023720038 ◽

2002 ◽

Vol 37 (2) ◽

pp. 345-349 ◽

Cited By ~ 2

Author(s):

R. Nuñez ◽

J . Capel ◽

E. Reyes ◽

A. Delgado

Keyword(s):

Oxygen Isotope ◽

Clay Minerals ◽

Isotope Composition ◽

Isotope Analysis ◽

Size Fraction ◽

Ceramic Materials ◽

X Ray Diffraction ◽

X Ray ◽

Fired Bricks ◽

Oxygen Stable Isotope

AbstractHand-made bricks were manufactured from natural sediments by firing at 700°C and 800°C after which they were hydrothermally altered at 150°C in a high-pressure reactor for 1200 h. Sediments and fired pieces were studied by X-ray diffraction. The <2 μm size-fraction of fired and hydrolysed samples were also studied by X-ray diffraction and oxygen isotope analysis. The oxygen isotope composition of the samples became depleted in 18O by alteration. Our results are consistent with a process of hydration and hydroxylation of the partially destroyed clay minerals in the fired bricks. The work is relevant to understanding the origins and alteration processes in old ceramic materials.

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Laser oxygen isotope analysis of silicate/oxide grain separates: Evidence for a grain size effect?

Chemical Geology ◽

10.1016/0009-2541(96)00004-6 ◽

1996 ◽

Vol 130 (1-2) ◽

pp. 31-54 ◽

Cited By ~ 30

Author(s):

Anne-Marie Fouillac ◽

Jean-Pierre Girard

Keyword(s):

Grain Size ◽

Size Effect ◽

Oxygen Isotope ◽

Isotope Analysis ◽

Grain Size Effect

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Aspects of microanalysis in a transmission electron microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100109690 ◽

1978 ◽

Vol 36 (1) ◽

pp. 510-511

Author(s):

R. Sinclair ◽

B.E. Jacobson

Keyword(s):

Grain Size ◽

Electron Beam ◽

Electron Microscope ◽

Chemical Analysis ◽

Transmission Electron Microscope ◽

Vapor Deposition ◽

Critical Currents ◽

X Ray ◽

Fine Grain ◽

Transmission Electron

INTRODUCTIONThe prospect of performing chemical analysis of thin specimens at any desired level of resolution is particularly appealing to the materials scientist. Commercial TEM-based systems are now available which virtually provide this capability. The purpose of this contribution is to illustrate its application to problems which would have been intractable until recently, pointing out some current limitations.X-RAY ANALYSISIn an attempt to fabricate superconducting materials with high critical currents and temperature, thin Nb3Sn films have been prepared by electron beam vapor deposition [1]. Fine-grain size material is desirable which may be achieved by codeposition with small amounts of Al2O3 . Figure 1 shows the STEM microstructure, with large (∽ 200 Å dia) voids present at the grain boundaries. Higher quality TEM micrographs (e.g. fig. 2) reveal the presence of small voids within the grains which are absent in pure Nb3Sn prepared under identical conditions. The X-ray spectrum from large (∽ lμ dia) or small (∽100 Ǻ dia) areas within the grains indicates only small amounts of A1 (fig.3).

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Hydrated form of some clay minerals observed using a film sealed environmental cell

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100107502 ◽

1978 ◽

Vol 36 (1) ◽

pp. 72-73

Author(s):

N. Kohyama ◽

K. Fukushima ◽

A. Fukami

Keyword(s):

Clay Minerals ◽

Morphological Changes ◽

Carbon Film ◽

Electron Microscopic Observation ◽

Adsorbed Water ◽

Electron Microscopic ◽

Hydrated Form ◽

Thin Carbon ◽

Environmental Cell ◽

Thin Carbon Film

Since the interlayer or adsorbed water of some clay minerals are quite easily dehydrated in dried air, in vacuum, or at moderate temperatures even in the atmosphere, the hydrated forms have not been observed by a conventional electron microscope(TEM). Recently, specific specimen chambers, “environmental cells(E.C.),” have been developed and confirmed to be effective for electron microscopic observation of wet specimen without dehydration. we observed hydrated forms of some clay minerals and their morphological changes by dehydration using a TEM equipped with an E.C..The E.C., equipped with a single hole copper-microgrid sealed by thin carbon-film, attaches to a TEM(JEM 7A) with an accelerating voltage 100KV and both gas pressure (from 760 Torr to vacuum) and relative humidity can be controlled. The samples collected from various localities in Japan were; tubular halloysite (l0Å) from Gumma Prefecture, sperical halloysite (l0Å) from Tochigi Pref., and intermediate halloysite containing both tubular and spherical types from Fukushima Pref..

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