Jean Di Martino

Publications (3)4 Total impact

• Article: Prediction and limitation of polymer degradation in Environmental SEM.

  Claire Arnoult, Jean Di Martino, David Ruch
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  ABSTRACT: Polymer materials degradation is a well-known limitation to their characterization in SEM. In this paper authors present an additional possibility for polymer imaging offered by the Environmental SEM applied to the PMMA with micrometric relief. As shown by the so-called double-scan procedure, increasing the pressure enables to delay the degradation of the polymer surface. To evaluate quantitatively this observation, the classical formula to calculate the electron dose is adapted to ESEM characteristic. It is shown first that pressure enables to decrease the electron dose and all that takes place as if the skirt electrons do not participate in the irradiation. Secondly this procedure allows to obtain the critical dose of topographic degradation, applied to the PMMA with micrometric relief D(C) was found to be 1.31±0.28Cm(-2). Finally it becomes then possible, knowing the D(C) for a given sample, to evaluate the limit of investigation without topographic surface degradation: for example, the maximal field of view (linked to the magnification) depending on the other parameters.
  Ultramicroscopy 07/2012; 122C:32-36. · 2.47 Impact Factor
• Article: Pressure and scattering regime influence on the EDS profile resolution at a composite interface in environmental SEM.

  Claire Arnoult, Jean Di Martino, Lahcen Khouchaf, Valérie Toniazzo, David Ruch
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  ABSTRACT: Gas impact on the EDS profile resolution at the interface of composite interface resin/Al was investigated with two gaseous environments: helium and water vapor. Two main components of the global profile at the interface were investigated: the contrast of the profile and the spatial resolution. A complementary approach was developed by comparing gas nature impact versus the pressure and versus the scattering regime. The results show that the unscattered electron beam mainly governs EDS profile spatial resolution as long as the scattering regime is single or oligo scattering. Then for plural scattering, spatial resolution is dramatically degraded. In addition, the contrast is degraded since a gas is introduced, whatever the gas, the pressure and so the scattering regime. This approach would enable to better understand the respective contributions of the unscattered beam and the skirt and the influence of the gases nature on them.
  Micron 06/2011; 42(8):877-83. · 1.53 Impact Factor
• Article: Characterization of the interphase in an aluminium/epoxy joint by using controlled pressure scanning electron microscopy coupled with an energy dispersive X-ray spectrometer

  Caroline Sperandio, Claire Arnoult, Abdelghani Laachachi, Jean Di Martino, David Ruch
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  ABSTRACT: The aim of this work is to introduce the use of low vacuum scanning electron microscopy (LVSEM) coupled with an X-ray energy dispersive spectrometer (EDS) in the field of structural adhesives, more precisely aluminium/epoxy resin assembly. Such assembly is characterized by the creation of an interphase resulting from the metal diffusion inside the resin during cross-linking. As the performance of the final bond is strongly links by the interphase properties, fine characterization of this interphase, in particularity the evaluation of its thickness is essential to understand the macroscopic properties of the adhesive assembly. First, the EDS acquisition parameters were investigated in order to limit the sample/resin damage/degradation due to the incident electrons beam irradiation. Then a specific methodology of stacked profiles was defined to improve the precision of the measures. To evaluate the true Al diffusion profile, the impact of the interaction volume of incident electron in the material on the Al signal variation during the interface crossing was calculated and the effect of the gas pressure on the electron beam characteristic and so on the measured profiles was examinated.According to our developed methodology and data treatments, Al diffusion profile was interpreted and interphase thickness was qualitatively determined by comparison with an experimental baseline. This innovative methodology promotes the use of LVSEM–EDS in the field of adhesive structural assemblies, but also, deals with a comparative study on the effect of the gas pressure on the EDS profile analysis.
  Micron.