BAM-Publica - Publikationsserver der Bundesanstalt für Materialforschung und -prüfung
Not a member yet
58839 research outputs found
Sort by
SI-traceable total analysis of nitrate and nitrite by isotope dilution optical spectroscopy and its application to Berlin surface waters
No full textAccurate nitrate and nitrite data support water-quality regulation, yet routine methods rely on external calibration and rarely achieve SI traceability. We report a calibration-free determination of nitrate and nitrite by combining isotope dilution with high-resolution continuum-source graphite furnace molecular absorption spectrometry (ID-HR-CS-GF-MAS). A 15N-enriched nitrate spike (its concentration verified by reverse isotope dilution against the standard reference material NIST 3185) provides the SI link, and it is gravimetrically added to samples; nitrate and residual nitrite are converted in situ to nitric oxide (NO), whose 215 nm band is recorded at a pixel resolution of λ/Δλ ≈ 140 000. The 0.2127 nm shift between 14NO and 15NO electronic spectra is resolved, and a three-latent-variable partial least squares regression model yields the 15N/14N ratio with 0.3% precision. Instrumental LoD values of 4.8 ng (14N) and 3.2 ng (15N) translate to a method LoD of 4.8 ng of nitrogen (equivalent to 1.05 mg L−1 NO3− for a 20 μL aliquot). The furnace program allows for successive drying/pyrolysis loops, so additional 20 μL aliquots can be layered onto the graphite platform. Alternatively, a 10 mL anion-exchange solid-phase extraction step concentrates nitrate and nitrite fivefold, allowing for the analysis of even lower sample concentrations. Results for four certified reference materials (2.9 to 1000 mg L−1 NO3−) agreed with certified values, giving relative expanded uncertainties of 2 to 4%. Analysis of twenty Berlin surface-water samples revealed concentrations ranging from 0.10 to 7.3 mg L−1 NO3−, indicating that the Panke River and Teltow Canal are the primary sources of nitrogen. ID-HR-CS-GF-MAS thus delivers ID-MS-level accuracy in a few minutes per run with bench-top optics, and, with optional on-platform or SPE pre-concentration, extends SI-traceable nitrate/nitrite monitoring into the low-ng regime
Rare Mononuclear Lithium-Carbene Complex for Atomic Layer Deposition of Lithium Containing Thin Films
No full textLithium is the core material of modern battery technologies and fabricating the lithium‐containing materials with atomic layer deposition (ALD) confers significant benefits in control of film composition and thickness. In this work, a new mononuclear N‐heterocyclic carbene (NHC) stabilized lithium complex, [Li(tBuNHC)(hmds)], is introduced as a promising precursor for ALD of lithium‐containing thin films. Structural characterization is performed, comparing density functional theory (DFT) and single‐crystal X‐ray diffraction (SC‐XRD), confirming a rare mononuclear structure. Favorable thermal properties for ALD applications are evidenced by thermogravimetric analysis (TGA). The compound exhibits a low melting point, clean evaporation, and its volatility parameters are encouraging compared to other lithium precursors. ALD trials using [Li(tBuNHC)(hmds)] with ozone demonstrate its effectiveness in depositing LiSixOy films. The ALD process exhibits a saturated growth per cycle (GPC) of 0.95 Å. Compositional analysis using Rutherford backscattering spectrometry/nuclear reaction analysis (RBS/NRA), X‐ray photoelectron spectrometry (XPS), and glow discharge optical emission spectrometry (GD‐OES), confirms the presence of lithium and silicon in the expected ratios. This work not only presents a new ALD precursor but also contributes to the understanding of lithium chemistry, offering insights into the intriguing coordination chemistry and thermal behavior of lithium complexes stabilized by NHC ligands
Glow discharge techniques applied to lithium ion battery analysis
No full textGlow Discharge Techniques Applied to Lithium-Ion Battery Analysis
Beatrice Battistella, V. Hoffmann, A. Revill, S. Richter, S. Recknagel, C. Abad
Seit ihrer Einführung haben Lithium-Ionen-Batterie (LIB) Technologien die Welt der tragbaren Elektronik und der nachhaltigen Mobilität revolutioniert [1] und sind dank ihrer langen Lebensdauer und ihrer unübertroffenen Energiedichte in vielen Bereichen nach wie vor unersetzlich. Angesichts des kontinuierlich wachsenden Marktvolumens der LIBs [2,3] und der begrenzten Verfügbarkeit der für ihre Herstellung benötigten Ressourcen ist die Entwicklung verbesserter Batterien der nächsten Generation erforderlich. Eine wesentliche Voraussetzung für diese Entwicklung ist ein tieferes Verständnis der Degradationsmechanismen in LIB-Zellen, das jedoch häufig durch die Komplexität der Systeme und die gleichzeitig ablaufenden Prozesse, die zum Versagen beitragen, erschwert wird.
In diesem Zusammenhang zeigt unsere Arbeit, wie Glimmentladungstechniken dazu beitragen können, grundlegende Fragestellungen in der LIB-Analyse zu beantworten. Einerseits hat sich die GD OES als wertvolles Werkzeug zur Qualitätskontrolle bei der Elektrodenherstellung erwiesen und zeigt Potential bei der Analyse von Fluor für diagnostische Zwecke an Zellen. Andererseits wurde die GD MS in Post-Mortem-Analysen eingesetzt, um die Korrelation zwischen Veränderungen in der elementaren und isotopischen Verteilung an den Elektroden und der elektrochemischen Leistung der Zellen zu untersuchen. Insbesondere ermöglichte der Einsatz von GD-MS bei LIBs die Detektion und Lokalisierung einer Lithium-Isotopenfraktionierung innerhalb der Elektroden und setzte damit einen neuen Maßstab für die Untersuchung der Grenzflächen zwischen Elektrode und Elektrolyt.
_____________________________
Since their introduction, lithium-ion battery (LIB) technologies have revolutionized the world of portable electronics and sustainable mobility [1], and they remain irreplaceable in several sectors thanks to their long cycle life and unmatched energy density. In view of the continuously growing LIB market [2,3] and the limited availability of the resources required for their manufacture, the development of improved next-generation batteries is needed. This requires a deeper understanding of degradation pathways in LIB cells, which is often hindered by the complexity of these systems and the concurrent processes that contribute to failure.
In this context, our work demonstrates how glow discharge techniques can help address fundamental questions in LIB analysis. On one hand, GD-OES has proven to be a valuable tool for quality control in electrode manufacturing, showing potential in the analysis of fluorine for cell diagnostics. On the other hand, GD-MS applied in post-mortem analysis enabled correlation of changes in elemental and isotopic distributions within electrodes and the electrochemical performance of the cells. In particular, GD-MS analysis on LIBs allowed detection and depth localization of lithium isotope fractionation in the electrodes, establishing a new benchmark for the study of electrode-electrolyte interfaces
ISO TC 261 / JG 85 Projects
No full textDieser Vortrag fasst die laufenden Aktivitäten der ISO TC 261 JG 85 zusammen. Insbesondere die Gewinnung und Verarbeitung von PBF-LB/M Prozessdaten steht im Fokus
Normungsaktivitäten in QI-Digital
No full textDer Vortrag thematisiert die Normungsaktivitäten in QI-Digital. Insbesondere die entwickelte Datenstruktur in der ISO/ASTM 52970 und die Anknüpfungspunkte zur Verwaltungsschale. Die ISO TC 261 / JG 85 und ihr entsprechender Scope werden vorgestellt
Aktuelle Themen aus dem Fachbeirat der BAM
No full textDie Anforderungen an Geokunststoffprodukte und deren Qualitätssicherung unterliegen einem stetigen Wandel, der sowohl durch technische Veränderungen als auch durch normative und organisatorische Entwicklungen geprägt ist. Insbesondere der Fachbeirat der BAM gemäß Deponieverordnung (DepV) spielt hier im Bereich der Deponietechnik eine wichtige Rolle. An dieser Stelle sollen aktuelle Themen aus dem Fachbeirat der BAM vorgestellt werden, die wesentliche Änderungen in der Zulassungs- und Anwendungspraxis betreffen.
Der Beitrag beleuchtet unter anderem Veränderungen innerhalb der BAM, die Modernisierung der Publikationsformate sowie die fachliche Weiterentwicklung der Zulassungsrichtlinien. Besondere Aufmerksamkeit gilt der Diskussion um die Einbauhilfe im Schutzschichtsystem, der Einführung einer europäischen Zugversuchsnorm für Kunststoffdichtungsbahnen sowie der Fremdüberwachung der Produktion geosynthetischer Komponenten. Darüber hinaus werden neue Anforderungen an Edelstahlelektroden in Dichtungskontrollsystemen und die Spannungsrissbeständigkeit von PE-HD-Dichtungsbahnen thematisiert
Designing Co–N/C Cathode Catalysts with Dense Atomic Cobalt Sites for Enhanced PEMFC Performance
No full textMetal-nitrogen/carbon (M-N/C) catalysts, particularly those incorporating Fe,Co, or Mn, are among the most promising non-platinum group catalysts forthe acidic oxygen reduction reaction (ORR) in fuel cells. This study reports aCo-N/C catalyst featuring high (3 wt%) cobalt content exclusively present asatomic sites. Extended X-ray absorption fine structure analysis confirms atetrapyridinic Co-N4 coordination environment in the optimized (3.0)Co-N/Ccatalyst. The high cobalt loading leads to a significant density ofelectrochemically accessible active sites, 3.58 × 10 19 sites g−1 , quantified viathe nitrite stripping method. The catalyst demonstrates excellent ORR activityin a rotating ring-disk electrode setup, achieving a half-wave potential (E 1/2 ) of0.76 V at a low loading of 0.2 mg cm−2 and a mass activity of 3.5 A g−1 at 0.80VRHE . Single-cell hydrogen-oxygen PEMFC tests achieve a peak power densityexceeding 1.3 W cm−2 (iR-corrected). Under hydrogen-air condition, thecatalyst delivers 0.54 A cm−2 at 0.60 V (0.39 W cm−2 ). Despite the intrinsicallyhigher turnover frequency of Fe-based sites, the optimized(3.0)Co-N/C catalyst achieves similar fuel cell performance to that of Fe-N/C,highlighting the critical role of site density in overall activity
Influence of Internal Pressure Regulation During Filament Winding on Failure Mechnism in Type 4 Pressure Vessels: A Case Study
No full textHydrogen storage is a crucial part of the hydrogen value chain, particularly in terms of safety and social acceptance of hydrogen technologies. For on-board and transportation applications, hydrogen is commonly stored as a compressed gas in pressure vessels. Full composite wrapped Type 4 pressure vessels are especially beneficial due to their high weight-saving potential and their capability to withstand high working pressures. To maintain an appropriate safety level, the mechanical behavior of the composite structure has been the subject of investigation in numerous studies. In this study, the failure mechanisms of two designs of Type 4 cylinders are investigated. The two designs differ solely in the manufacturing process parameters, particularly the internal pressure applied during the filament winding process. Variations in internal pressure result in different residual stress states and changes in the quality of the composite structure. The stacking sequence, materials used, and other manufacturing parameters remain unchanged. The cylinders show different failure mechanisms in slow burst tests: one design fails in hoop windings, while the other one fails in helical windings, despite no stress exaggeration in the fiber direction being observed with embedded optical fibers or in numerical simulations. To explain the failure mechanisms, the quality of the cylinders is investigated. The results of X-ray computed tomography and pulse-echo investigation, highlight the complexity of the interactions between manufacturing process parameters, residual stresses, manufacturing quality, and the mechanical behavior of composite pressure vessels. Resin-rich areas in the composite material are identified as a possible cause of the differing failure mechanisms
Corrosion and Soiling in the 21st Century: Insights from ICP Materials and Impact on Cultural Heritage
No full textThis paper reviews results published by the International Co-operative Programme on Effects on Materials including Historic and Cultural Monuments (ICP Materials) with emphasis on those obtained after the turn of the century. Data from ICP Materials come from two main sources. The first is through exposures of materials and collection of environmental data in a network of atmospheric exposure test sites mainly distributed across Europe. Corrosion of carbon steel has continued to decrease during the period 2000–2020 but corrosion of zinc only up until 2014, and the trend in zinc corrosion is only visible when examining four-year data. Surface recession of limestone as well as soiling of modern glass show no decreasing trend during 2000–2020. The second is through case studies performed at heritage sites across Europe. Risk analysis of corrosion and soiling for twenty-six sites indicate that currently soiling is a more significant maintenance trigger than corrosion. Costs for maintaining heritage sites are substantial and costs attributable to air pollution is estimated from 40% to as much as 80% of the total cost. Future directions of the program are work on effects of particulate matter, improving the scientific basis for the work, and making the monitoring data publicly available
Auf dem Weg in die digitale Transformation
No full textDie Digitalisierung in der Laborbranche stellt eine komplexe Herausforderung dar – nicht zuletzt aufgrund zahlreicher Einzelprojekte und vieler proprietärer Insellösungen. Um eine konsequente und wirkungsvolle Labordigitalisierung und Prozessautomatisierung zu erreichen, braucht es eine übergreifende Sichtbarkeit und Vernetzung bestehender Initiativen. Diese Notwendigkeit haben verschiedene Akteure der Laborbranche erkannt und, angestoßen durch die Initiative QI-Digital, den Digital LabHub ins Leben gerufen. Ziel ist es, eine Plattform für Wissensaustausch und -transfer, gegenseitige Unterstützung und praxisnahe Umsetzung zu schaffen – offen für Labore aller Branchen und Anwendungsfelder. Der Digital LabHub soll gezielte Hilfestellung beim Einstieg in die Digitalisierung bieten, Labore zukunftssicher aufstellen und dabei helfen, regulatorische Anforderungen zu erfüllen