Oxidation mechanism of nickel particles studied in an environmental transmission electron microscope

Cécile Hébert, Aïcha Hessler-Wyser, Quentin Thomas Jeangros, Jan Van Herle
Pergamon-Elsevier Science Ltd, 2014
Journal paper

The oxidation of nickel particles was studied in situ in an environmental transmission electron microscope in 3.2 mbar of O-2 between ambient temperature and 600 degrees C. Several different transmission electron microscopy imaging techniques, electron diffraction and electron energy-loss spectroscopy were used to study the evolution of the microstructure and the local chemical composition of the particles during oxidation. Our results suggest that built-in field effects control the initial stages of oxidation, with randomly oriented NiO crystallites and internal voids then forming as a result of outward diffusion of Ni2+ along NiO grain boundaries, self-diffusion of Ni2+ ions and vacancies, growth of NiO grains and nucleation of voids at Ni/NiO interfaces. We also observed the formation of transverse cracks in a growing NiO film in situ in the electron microscope. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

About this result

This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.

Related concepts

Related publications

Cécile Hébert, Aïcha Hessler-Wyser, Quentin Thomas Jeangros, Jan Van Herle
Pergamon-Elsevier Science Ltd, 2014
Journal paper

Abstract

Official source

https://infoscience.epfl.ch/record/198569?ln=en

About this result

Related concepts (19)

Related concepts

Related publications (101)

Related publications

Transmission electron microscopy

Transmission electron microscopy (TEM) is a microscopy technique in which a beam of electrons is transmitted through a specimen to form an image. The specimen is most often an ultrathin section les

Electron microscope

An electron microscope is a microscope that uses a beam of electrons as a source of illumination. They use electron optics that are analogous to the glass lenses of an optical light microscope. As

Scanning electron microscope

A scanning electron microscope (SEM) is a type of electron microscope that produces images of a sample by scanning the surface with a focused beam of electrons. The electrons interact with atoms

Effect of vanadium addition on the microstructure and mechanical properties of the ODS ferritic steels

Nadine Baluc, Zbigniew Oksiuta

In this work, the effects of vanadium addition in the range of 0.3-3% (in weight percent) for an oxide dispersion strengthened reduced activation ferritic (ODS RAF) steel were investigated. Samples of the V-modified steel have been prepared using elemental (Fe, Cr, W, Ti) and Y2O3 powders with the nominal composition of Fe-14Cr-2W-0.3Ti-0.3Y(2)O(3). Consolidated and heat treated samples were investigated using Scanning Electron Microscopy and Scanning Transmission Electron Microscopy equipped with Electron Energy Loss Spectroscopy detector. Hardness and Charpy impact tests (KLST specimens) were also performed. The microstructure investigations revealed numerous particles of the size up to 0.5 mu m. They are primarily Ti-Cr-V oxides located at the grain boundaries and inside the grains. These particles increase hardness and significantly reduce fracture resistance of the ODS RAF alloys developed here. However, it should be noted that the 0.3% V-ODS steel has unexpectedly the lowest transition temperature of about 282 K and that the 1-3% V-ODS steels, in spite of the transition temperature about 373 K, exhibit almost two times higher the lower shelf energy values in comparison with the 0.3% V-ODS and 0% V-ODS steels. (C) 2012 Elsevier B. V. All rights reserved.

Elsevier Science Bv2013

A proposal for dichroic experiments in the electron microscope

Cécile Hébert

Building upon the similarities between inelastic electron scattering and X-ray absorption we show that dichroism can be observed in electron energy loss spectrometry (EELS) in the transmission electron microscope (TEM). Natural or magnetic linear dichroism can be studied in electron scattering experiment with definite wave vector transfer in the interaction. The detection of circular dichroism in the TEM relies on interferometric EELS in a particular scattering geometry that allows extraction of the mixed dynamic form factor from energy loss spectra. Similarities between dichroic signals in energy loss near edge structures and X-ray absorption near edge structures are discussed, and a new experimental setup for dichroic measurements in the TEM is proposed.

2003

Magnetic circular dichroism in electron microscopy

Cécile Hébert

Although the analogies between the electron energy loss spectra and X-ray absorption spectra were recognized long ago, the possibility to observe the magnetic circular dichroism in the electron microscope was demonstrated only recently. This technique combines the atom specificity with the high spatial resolution of the transmission electron microscope. Being a very young technique, there are still many open questions concerning the optimization of the signal to noise ratio. In this paper we study the dichroic signal dependence on the sample thickness, acceleration voltage and incoming beam tilt angle of bcc-Fe and fcc-Ni.

2008