TY - JOUR A1 - Hodoroaba, Vasile-Dan A1 - Motzkus, C. A1 - Macé, T. A1 - Vaslin-Reimann, S. T1 - Performance of high-resolution SEM/EDX systems equipped with transmission mode (TSEM) for imaging and measurement of size and size distribution of spherical nanoparticles N2 - The analytical performance of high-resolution scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX) for accurate determination of the size, size distribution, qualitative elemental analysis of nanoparticles (NPs) was systematically investigated. It is demonstrated how powerful high-resolution SEM is by using both mono- and bi-modal distributions of SiO2 airborne NPs collected on appropriate substrates after their generation from colloidal suspension. The transmission mode of the SEM (TSEM) is systematically employed for NPs prepared on thin film substrates such as transmission electron microscopy grids. Measurements in the transmission mode were performed by using a 'single-unit' TSEM transmission setup as manufactured and patented by Zeiss. This alternative to the 'conventional' STEM detector consists of a special sample holder that is used in conjunction with the in-place Everhart–Thornley detector. In addition, the EDX capabilities for imaging NPs, highlighting the promising potential with respect to exploitation of the sensitivity of the new large area silicon drift detector energy dispersive X-ray spectrometers were also investigated. The work was carried out in the frame of a large prenormative VAMAS (Versailles Project on Advanced Materials and Standards) project, dedicated to finding appropriate methods and procedures for traceable characterization of NP size and size distribution. KW - Transmission scanning electron microscopy/microscope (TSEM, T-SEM, STEM) KW - High-resolution scanning electron microscope (SEM) KW - Transmission KW - SiO2 KW - Nanoparticles KW - Size KW - Size distribution KW - EDX KW - Large area SDD PY - 2014 DO - https://doi.org/10.1017/S1431927614000014 SN - 1431-9276 SN - 1435-8115 VL - 20 IS - 2 SP - 602 EP - 612 PB - Cambridge University Press CY - New York, NY AN - OPUS4-30612 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hodoroaba, Vasile-Dan A1 - Rackwitz, Vanessa T1 - Gaining improved chemical composition by exploitation of compton-to-rayleigh intensity ratio in XRF analysis N2 - The high specificity of the coherent (Rayleigh), as well as incoherent (Compton) X-ray scattering to the mean atomic number of a specimen to be analyzed by X-ray fluorescence (XRF), is exploited to gain more information on the chemical composition. Concretely, the evaluation of the Compton-to-Rayleigh intensity ratio from XRF spectra and its relation to the average atomic number of reference materials via a calibration curve can reveal valuable information on the elemental composition complementary to that obtained from the reference-free XRF analysis. Particularly for matrices of lower mean atomic numbers, the sensitivity of the approach is so high that it can be easily distinguished between specimens of mean atomic numbers differing from each other by 0.1. Hence, the content of light elements which are “invisible” for XRF, particularly hydrogen, or of heavier impurities/additives in light materials can be calculated 'by difference' from the scattering calibration curve. The excellent agreement between such an experimental, empirical calibration curve and a synthetically generated one, on the basis of a reliable physical model for the X-ray scattering, is also demonstrated. Thus, the feasibility of the approach for given experimental conditions and particular analytical questions can be tested prior to experiments with reference materials. For the present work a microfocus X-ray source attached on an SEM/EDX (scanning electron microscopy/energy dispersive X-ray spectroscopy) system was used so that the Compton-to-Rayleigh intensity ratio could be acquired with EDX spectral data for improved analysis of the elemental composition. PY - 2014 DO - https://doi.org/10.1021/ac5000619 SN - 0003-2700 SN - 1520-6882 VL - 86 IS - 14 SP - 6858 EP - 6864 PB - American Chemical Society CY - Washington, DC AN - OPUS4-31179 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan A1 - Yamamoto, K. A1 - Grulke, E. A. A1 - Maurino, V. ED - Bosse, H. ED - Buhr, E. ED - Dziomba, T. ED - Hodoroaba, Vasile-Dan ED - Klein, T. ED - Krumrey, M. T1 - Shape controlled TiO2 nanoparticles as candidates for nano-CRM’s – an ISO case study N2 - Extraction of true, 3D shape (and size) of non-spherical nanoparticles (NPs) is associated with Errors by conventional 2D electron microscopy using projection images. Significant efforts within the ISO technical committee TC 229 ‘Nanotechnologies’ are aimed at establishing accurate TEM and SEM measurement of NP size and shape as robust, standard procedures. Study groups have been organizing inter-laboratory comparisons on well-selected NP systems according to the market needs, such as aggregated titania nano-powder for which size and shape distribution of primary crystallites of irregular shape must be measured accurately. To be noticed is e. g. the fact that the measurement procedure allows only manual selection of the particles clearly distinguishable for analysis as well as manual definition of the contour of the imaged NPs. An inter-laboratory exercise on titania NPs (pure anatase, grown by hydrothermal synthesis) of well-defined non-spherical shape, i.e. bipyramidal, has been recently started within ISO/TC 229 under similar conditions as for the irregular shaped titania. In the TEM micrograph the particles tracked manually according to the measurement protocol. Overlapped particles were allowed to be considered, as long as they are clearly distinguishable. One decisive NP selection criterion was to analyze only those NPs with a roundness value below 0.7, i.e. the NPs laying on the support foil and, hence, with projection areas clearly deviating from perfect circles (R=1). The overall evaluation (for 15 labs) of the size descriptors (area, Feret, minFeret, perimeter) and shape descriptors (aspect ratio, roundness, compactness, extent) by analysis of variance is just to be finished and included in ISO/WD 21363 Nanotechnologies -- Protocol for particle size distribution by transmission electron microscopy. T2 - NanoWorkshop 2018: Workshop on Reference Nanomaterials CY - Berlin, Germany DA - 14.05.2018 KW - Titanium dioxide KW - Nanoparticles KW - Shape-controlled KW - Electron microscopy PY - 2019 SN - 978-3-95606-440-1 DO - https://doi.org/https://doi.org/10.7795/110.20190412 SN - 0179-0609 VL - F-61 SP - 245 EP - 255 PB - Physikalisch-Technische Bundesanstalt CY - Braunschweig und Berlin AN - OPUS4-49990 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hodoroaba, Vasile-Dan A1 - Steers, E.B.M. A1 - Hoffmann, V. A1 - Wetzig, K. T1 - The effect of small quantities of hydrogen on a glow discharge in neon. Comparison with the argon case N2 - In order to gain an insight into the numerous effects caused by the addition of hydrogen to an argon glow discharge, comparison experiments have been made with neon as carrier gas. In some cases the effects are diminished or even disappear. Using various bulk samples, such as copper, steel and titanium, sputtered in a neon glow discharge, the intensities of the analytical lines are affected by the presence of hydrogen in different ways from argon; the dependent parameter (the discharge current in this work) and the sputtering rate vary less than in argon. The crater shape and roughness are also affected and these effects are discussed qualitatively. Probably the most important spectral feature caused by hydrogen in the case of a discharge in argon is the emission of a continuous background. This does not appear in neon under similar discharge conditions and only weakly at high hydrogen concentrations. This supports the suggestion, made in previous work, that an effective quenching process of the argon metastables (11.55 and 11.72 eV) is Penning excitation of the hydrogen molecules, and subsequent decay to a repulsive state with emission of the continuum; in neon the energy match does not occur. It was found with neon, as with argon, that similar features occur as when hydrogen is introduced in different ways into the glow discharge: as a molecular gas contamination or as a constituent of the sample. Glow discharge mass spectrometry (GD-MS) experiments carried out with both argon and neon support the results obtained by optical emission spectrometry (OES) and provide further relevant information. PY - 2001 DO - https://doi.org/10.1039/b007527m SN - 0267-9477 SN - 1364-5544 VL - 16 SP - 43 EP - 49 PB - Royal Society of Chemistry CY - London AN - OPUS4-6887 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mrkwitschka, Paul A1 - Mühlbauer, Michaela A1 - Rossi, Andrea A1 - Pellegrino, Francesco A1 - Zurutuza, Amaia A1 - Radnik, Jörg A1 - Meier, Florian A1 - Hodoroaba, Vasile-Dan T1 - Morphological Analysis of Graphene Oxide by Scanning Electron Microscopy and Correlative Field-flow Fractionation Coupled with Multi-angle Light Scattering N2 - In this paper graphene related 2D materials (GR2M) arre investigated by centrifugal field flow fractioning (CF3) and SEM. Three materials were selected as case studies (CS): graphene „HD-G (CS I), graphene oxide UniTo“ (CS II), and graphene oxide „Graphenea“ (CS III). For CS I particles were evaluated as constituent particles in agglomerates, for the other two materials only isolated (non aggregated/agglomerated) flakes were considered for determination of the area equivalent circular diameter (ECD). Size analysis of all three materials was carried out by CF3 coupled with MALS (Multi-Angle Light Scattering). For evaluation, it was found that the data obtained was best suited to a disc model. Results are in good agreement when compared to the sizes obtained before CF3 analysis. CS II material is too heterogenous to accurately determine flake size by imaging. CF3 coupled with MALS enables to assess fractions within the highly heterogenous material of CS II. Imaging of the material in CS III after CF3 measurement indicates that the procedure is non-destructive. This could not be verified for the CS‘s I & II As a next step we plan to analyse the fractionated samples by imaging them within a SEM wet-cell. KW - 2D Materials KW - SEM KW - Centrifugal field flow fractionation (CF3) KW - Imaging KW - Size distribution PY - 2025 DO - https://doi.org/10.1093/mam/ozaf048.222 VL - 31 IS - 7 SP - 442 EP - 443 PB - Oxford Academic AN - OPUS4-63804 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan T1 - Quantitative microstructural analysis - VAMAS/TWA 37 N2 - The 44th Meeting of the Versailles Project on Advanced Materials and Standards (VAMAS) Steering Committee has just taken place at NIST in Boulder (CO, USA). BAM participates with significant contributions in Technical Working Areas on nanoparticle and surface chemistry characterization, but also has positioned itself to new global material challenges and trends in the developement of advanced materials and their characterization, such as thermal properties, self-healing materials, and micro- and nanoplastic. T2 - Annual Meeting of the Versailles Project on Advanced Materials and Standards (VAMAS) Steering Committee CY - Boulder, CO, USA DA - 22.05.2019 KW - VAMAS KW - Nanoparticles KW - Microbeam analysis KW - Advanced materials PY - 2019 AN - OPUS4-48184 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan T1 - Towards accurate analysis of particle size distribution for non-spherically shaped nanoparticles as quality control materials N2 - Measurement of nanoparticle size (distribution) becomes a challenging analytical problem when non-spherical nanoparticles must be accurately measured. Most industrial nanoparticles have not only non-spherical shapes but also possess polydisperse size distributions, and due to their agglomeration/aggregation state are difficult (or even impossible) to be addressed individually. Moreover, driven by regulatory purposes related to the identification of a material as a nanomaterial, the accurate measurement of the smallest dimension of a (nano)particulate material makes the analysis even more complex. In the first phase of the EU Project nPSize - Improved traceability chain of nanoparticle size measurements (https://www.bam.de/Content/DE/Projekte/laufend/nPSize/npsize.html), the efforts are focused on synthesis of nanoparticles of well-defined, non-spherical shape. Following candidates of reference materials (CRM) with certifiable particle size (distribution) are under characterization with respect to their homogeneity and stability: (i) titania nanoplatelets (10-15 nm thickness x 50-60 nm lateral), (ii) titania bipyramides (~60 nm length x 40 nm width), (iii) titania acicular particles (100 nm length x 15-20 nm width; aspect ratio 5.5/6), (iv) gold nanorods (~10 nm width x 30 nm length), and (v) gold nanocubes (~55 nm x 55 nm x 55 nm). T2 - Microscopy & Microanalysis 2019 CY - Portland, OR, USA DA - 03.08.2019 KW - Nanoparticles KW - Reference materials KW - Traceability KW - Non-spherical shape KW - Titanium dioxide PY - 2019 AN - OPUS4-48671 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan T1 - Liaison Report ISO/TC 229 Nanotechnology for ISO/TC 202 Microbeam Analysis and vice-versa N2 - The liaison between the ISO technical committees TC 229 Nanotechnologies and TC 202 Microbeam analysis is described in detail with highlight on the projects under development and published since 2024 and which involve input /knowledge from ISO/TC 202. T2 - 32nd Plenary Meeting of ISO/TC 202 Microbeam Analysis CY - London, United Kingdom DA - 28.10.2025 KW - Nanotechnology KW - Microabeam analysis KW - Standardisation KW - ISO PY - 2025 AN - OPUS4-64551 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Hodoroaba, Vasile-Dan A1 - Fontanges, Richard T1 - A new deep-learning AI tool for analysing images of complex nanoparticles N2 - A thousand times thinner than a human hair, nanoparticles (NPs) are finding applications in a range of modern products. However, as some can affect human health or the environment, knowing the types present is essential. Electron microscopy is the ‘gold standard’ for NP analysis, allowing identification based on manual size analysis, but a new method was required to analyse these particles quickly, accurately and in a consistent way. KW - Nanoparticles KW - Imaging KW - AI tool KW - Particle size and shape distribution PY - 2024 UR - https://www.euramet.org/casestudies/casestudiesdetails/news/a-new-deep-learning-ai-tool-for-analysing-images-of-complex-nanoparticles SP - 1 EP - 2 PB - EURAMET CY - Braunschweig AN - OPUS4-60095 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ren, L. A1 - Pollard, A. A1 - Hodoroaba, Vasile-Dan T1 - Measurement of Lateral Size of Graphene Oxide Flakes by SEM - An Update of the VAMAS TWA 41 Project P13 N2 - The progress of the VAMAS interlaboratory comparison Project P13 "Lateral size of graphene oxide flakes by SEM" within the Technical Working Area 41 "Graphene and Related 2D Materials" is presented. The challenges at sample preparation on substrates for accurate measurement and image analysis as well as two different image analysis approaches, containing exact guidance how to measure the main descriptors for the lateral size measurement of the imaged graphene oxide flakes with Scanning Electron Microscopy are described. The implementation of the results into the corresponding ISO technical specification AWI/TS 23879 is also discussed and planned, in relation with the AFM part. T2 - Versailles Project on Advanced Materials and Standards (VAMAS) 49th Steering Committee Meeting CY - Rio de Janeiro, Brazil DA - 23.09.2024 KW - VAMAS KW - Graphene oxide KW - SEM KW - Lateral size KW - Interlaboratory comparison PY - 2024 UR - http://www.vamas.org/twa41/documents/2023_vamas_twa41_project13_GO_SEM.pdf AN - OPUS4-61434 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -