Working with the ESEM at high temperature

Podor, Renaud; Bouala, G.I. Nkou; Ravaux, Johann; Lautru, Joseph; Clavier, Nicolas

doi:10.1016/j.matchar.2019.02.036

Cited by 32 publications

(30 citation statements)

References 67 publications

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“…Orientation images also show that these variants are dominant in the samples. The above observation also shows that variants related to pink colour (11,13) are within the cluster 10-20°, while variants with shades of blue and green are within the cluster of 50-60°. Martensite variants which formed after cooling within the austenite grains, with higher misorientation gradient (figure 9b) and different orientations, in the C 55 sample are shown in figure 10.…”

Section: Resultssupporting

confidence: 52%

“…The bias box controls the voltage applied to the top shield plate with respect to earth potential. Biasing voltage is bipolar and can be used differently: either as a filter by trapping the lower energy thermionic electrons by positive biasing or as an amplifier by increasing the contribution of secondary electron in imaging using a negative bias [11]. The bias was altered and the brightness and contrast were readjusted to record the best possible images at different temperatures.…”

Section: (B) In Situ Heatingmentioning

confidence: 99%

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Study of diffusionless and diffusional transformations usingin situcooling and heating techniques in a scanning electron microscope

Kumar

Sarkar

Singh

et al. 2020

Phil. Trans. R. Soc. A.

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In situ electron microscopy can be an effective tool to investigate the underlying science of many transformation mechanisms in materials science. Useful utilization of these experimentations will provide greater insight into many of the existing theories, as microstructural changes can be visualized in real time under some applied constraints. In this study, we have investigated two basic phase transformation phenomena: diffusionless and diffusional mechanisms with the help of in situ cooling and heating techniques in scanning electron microscope (SEM). In situ cooling experiments have been carried out on secondary hardening ultra-high-strength steels to understand the diffusionless transformation of austenite to martensite. Nucleation and growth of the martensites have been observed with cooling in different steps to −194°C. Details of the formation of different variants of martensites in steel were studied with the help of orientation imaging microscopy. Diffusional transformations were studied in terms of oxidation of pure copper in SEM using in situ heating technique. Different heating cycles were adopted for different samples by in situ heating to a maximum temperature of 950°C for the oxidation study. Nucleation of copper oxides and subsequent growth of the copper oxides at different temperatures were studied systematically. Raman spectroscopy and orientation imaging were done to confirm the formation of oxides and their orientations. The thermal cycling phenomenon was replicated inside SEM with heating and cooling and it has been demonstrated how the nature of copper and its oxides changes with the thermal cycle. This article is part of a discussion meeting issue ‘Dynamic in situ microscopy relating structure and function’.

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Section: Resultssupporting

confidence: 52%

Section: (B) In Situ Heatingmentioning

confidence: 99%

Study of diffusionless and diffusional transformations usingin situcooling and heating techniques in a scanning electron microscope

Kumar

Sarkar

Singh

et al. 2020

Phil. Trans. R. Soc. A.

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“…For indexation of the EBSD patterns, we used the data for the pure Li crystal with a BCC lattice structure. We list the challenges to perform high-temperature SEM-EBSD experiments below (20). 1) Hardware: The SEM stage has temperature sensitive components (plastic or polymer-based materials) that can be damaged at high temperature.…”

Section: In Situ Sem-ebsd Mappingmentioning

confidence: 99%

On high-temperature evolution of passivation layer in Li–10 wt % Mg alloy via in situ SEM-EBSD

et al. 2020

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Li–10 wt % Mg alloy (Li–10 Mg) is used as an anode material for a solid-state battery with excellent electrochemical performance and no evidence of dendrite formation during cycling. Thermal treatment of Li metal during manufacturing improves the interfacial contact between a Li metal electrode and solid electrolyte to achieve an all solid-state battery with increased performance. To understand the properties of the alloy passivation layer, this paper presents the first direct observation of its evolution at elevated temperatures (up to 325°C) by in situ scanning electron microscopy. We found that the morphology of the surface passivation layer was unchanged above the alloy melting point, while the bulk of the material below the surface was melted at the expected melting point, as confirmed by in situ electron backscatter diffraction. In situ heat treatment of Li-based materials could be a key method to improve battery performance.

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“…High resolution images were acquired at a typical frequency of 1-60 frame per minute, which mainly depended on the scanning rate considered. Also, a significant loss of resolution was generally observed above 1100°C, due to the progressive increase of the thermal electrons emission with temperature [21,24]. As high magnification images (i.e.…”

Section: Ht-esemmentioning

confidence: 99%

Early stages of UO2+x sintering by in situ high-temperature environmental scanning electron microscopy

Trillaud

Podor

Gossé

et al. 2020

Journal of the European Ceramic Society

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Early stages of various uranium oxides sintering were monitored in situ through High Temperature Environmental Scanning Electron Microscopy. Systems composed of two UO 2+x microspheres were heated up to 900-1200°C under P O 2 ranging from 10-10 to 25 Pa. The oxide phases stabilized were assessed through thermodynamic calculations and powder X-ray diffraction. In all the conditions tested, the formation and the development of a neck was evidenced and image processing led to quantitative data describing the morphological changes. The evolution of the sintering degree was fitted using an exponential law and allowed the evaluation of the activation energy. When P O 2 led to stabilize hyper-stoichiometric UO 2+x oxides, the values obtained increased with x, typically in the 200-400 kJ•mol-1 range. Under air atmosphere, the stabilization of U 3 O 8 led to E A = 260 ± 40 kJ•mol-1. Finally, the main diffusion mechanism driving neck formation was found to be volume diffusion, independently from the oxide stoichiometry.

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Working with the ESEM at high temperature

Cited by 32 publications

References 67 publications

Study of diffusionless and diffusional transformations usingin situcooling and heating techniques in a scanning electron microscope

Study of diffusionless and diffusional transformations usingin situcooling and heating techniques in a scanning electron microscope

On high-temperature evolution of passivation layer in Li–10 wt % Mg alloy via in situ SEM-EBSD

Early stages of UO2+x sintering by in situ high-temperature environmental scanning electron microscopy

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