Quantitative valence plasmon mapping in the TEM: viewing physical properties at the nanoscale

Daniels, H.; Brydson, Rik; Brown, Andy; Rand, B.

doi:10.1016/s0304-3991(03)00115-3

Cited by 68 publications

(52 citation statements)

References 17 publications

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“…For example, Figure 1 shows there is no significant variation in the (π+σ) plasmon peak energy with sample orientation for a collection semi-angle of 3.7mrad for 60kV over an angular (tilt) range of ca. 15 degrees similar to the results of Daniels et al at 200kV [17]. Therefore, operating at a collection angle of > 3.7mrad at 60kV during EEL spectroscopy ensures a consistency in plasmon peak position, where any changes are a direct result of varying density.…”

Section: Experimental Procedures and Sample Preparationsupporting

confidence: 83%

“…At 200kV the (magic angle) collection conditions were determined and published by Daniels et al [17] for the microscopes used in these TEM experiments. For the EELS measurements at 60 kV, although the conditions did not satisfy the magic angle criterion, there was found to be only a small variation in plasmon peak position within a limited tilt range.…”

Section: Experimental Procedures and Sample Preparationmentioning

confidence: 99%

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On the nature of cracks and voids in nuclear graphite

Freeman

Jones

Ward

et al. 2016

Carbon

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Microcracks in neutron-irradiated nuclear grade graphite have been examined in detail for the first time using a combination of transmission electron microscopy (TEM), electron energy loss spectroscopy (EELS), energy dispersive X-ray (EDX), and energy filtered TEM (EFTEM). Filler particles from both unirradiated Pile Grade A (PGA) and three irradiated British Experimental Pile 'O' (BEPO) graphite specimens were investigated with received doses ranging from 0.4 to 1.44 displacements per atom (dpa) and an irradiation temperature of between 20-120°C. We suggest that the concentration and potentially the size of microcracks increase with increasing neutron irradiation and show that disordered carbon material is present in a range of microcracks (of varying size and shape) in all specimens including unirradiated material. EFTEM and EELS data showed that these cracks contained carbon material of lower density and graphitic character than that of the surrounding bulk graphite. The presence of partially filled microcracks has potentially significant implications for the development of microstructural models for the prediction of radiation-induced dimensional and property changes in nuclear graphite.

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Section: Experimental Procedures and Sample Preparationsupporting

confidence: 83%

Section: Experimental Procedures and Sample Preparationmentioning

confidence: 99%

On the nature of cracks and voids in nuclear graphite

Freeman

Jones

Ward

et al. 2016

Carbon

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“…[13][14][15] In consequence, it was not surprising to find after closer examination of the small spheroidal graphite nodules, that they could comprise of an amorphous central region surrounded by a more crystalline graphitic mantle. This was determined using a quantitative method of mapping EELS plasmon energy loss shifts within graphitising carbon systems using EFTEM [22]. The plasmon feature results from a collective oscillation of the valence electrons, and the absolute energy loss of this feature (Ep) is dependent upon the valence electron density (Ep  (valence electron density) 1/2 ).…”

Section: Fig 10mentioning

confidence: 99%

“…Provided that the sample thickness is less than 2.2 times the inelastic mean free path (i.e. 200-250nm) [22], then in the final grey-scale plasmon ratio image, lighter regions of high intensity indicate areas with a higher degree of graphitisation at a resolution measured to be between 1-2 nm.…”

Section: Fig 10mentioning

confidence: 99%

High-Resolution Metallography of a Coarse Microstructure: Graphite Formation in the Solid-State in Steel

Edmonds

Brydson

Inam

2016

Materials Performance and Characterization

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ABSTRACT:The equilibrium form of carbon in iron and steel is graphite. In higher carbon cast irons graphite is normally formed from the liquid state. In lower carbon steels carbon invariably exists in the form of metastable cementite, due to slow graphitisation kinetics in the solid, but in fact, graphite formation is also more likely to be prevented by alloying to stabilise the microstructure for service. Relatively few high-resolution studies of graphite formation have thus been made, in the past also because of probable difficulties associated with specimen preparation of a relatively coarse aggregate microstructure. More recently, new investigative techniques and methods have allowed closer examination of graphite formation in steels. Examples are given of HRTEM, EELS, ELNES, EFTEM and FIB/FEGSEM recently applied to observations of graphite nucleation and growth in the solid state in steel. This has importance, for example, in the potential development of more economic and user-friendly machining steels which would rely upon internal lubrication by graphite particles in the microstructure.

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“…It allows a clear distinction of diamond-and graphite-like materials with different crystallization degrees [6]. Plasmon energy values are closely related to physical properties of graphite-like materials [7,8,9]. Therefore, in the present work, the crack bridging mechanism is studied by analytical TEM coupled with EELS in the low-loss region and by combining high-resolution SEM and TEM.…”

Section: Introductionmentioning

confidence: 99%

Electron microscopy and electron-energy-loss spectroscopy study of crack bridging in carbon–carbon composites

Резник

Fotouhi

2008

Composites Science and Technology

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To cite this version:B. Reznik, M. Fotouhi. Electron microscopy and electron-energy-loss spectroscopy study of crack bridging in carbon-carbon composites. Composites Science and Technology, Elsevier, 2009, 68 (5), pp.1131. <10.1016/j.compscitech.2007.06.020>. E l e c t r o n m i c r o s c o p y a n d e l e c t r o n -e n e r g y -l o s s s p e c t r o s c o p y s t u d y o f c r a c k b r i d g i n g i n c a r b o n -c a r b o n c o m p o s i t Accepted Manuscript AbstractCrack bridging within pyrolytic carbon matrix of a carbon-fiber/carbon-matrix composite was studied by scanning electron microscopy and transmission electron microscopy combined with electron-energy-loss spectroscopy. An extensive propagation of concentric cracks around carbon fibers is observed in the matrix. The crack propagation is bridged by bent lamellae. The analysis of low-energy-electron losses in cracked regions shows that the bulk ( + ) plasmon of planar lamellae lies close to those of graphite while the bulk ( + ) plasmon in bent areas is shifted towards lower energy positions and is comparable with the plasmon resonance of a polymer film. The morphology of bridging areas is discussed by considering the degradation of the atomic structure of planar graphite by the presence of lattice defects and hydrogen atoms.

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Quantitative valence plasmon mapping in the TEM: viewing physical properties at the nanoscale

Cited by 68 publications

References 17 publications

On the nature of cracks and voids in nuclear graphite

On the nature of cracks and voids in nuclear graphite

High-Resolution Metallography of a Coarse Microstructure: Graphite Formation in the Solid-State in Steel

Electron microscopy and electron-energy-loss spectroscopy study of crack bridging in carbon–carbon composites

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