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Eingeladener Vortrag
- nein (23)
New applications of ceramic multilayers, for example, in biotechnology, sensor technology, and chemical micro-reaction technique, call for cavities with complex geometries. Hot embossing offers a promising, cost-effective way to generate these structures on the surfaces of green tapes or laminates. Cavities inside low-temperature co-fired ceramic multilayer were manufactured by a combination of hot embossing, lamination by a special adhesive technique, and zero shrinkage sintering. The edge and surface quality in the green state as well as the sintered multilayers with surface structures and cavities were extensively characterized by laser surface scanning, optical and ultrasound microscopy. Sintering shrinkage of hot-embossed laminates could be reduced in the x and y directions to less than 0.5%.
Reliable measurement of the size of polydisperse, complex-shaped commercial nanopowders is a difficult but necessary task, e.g., for regulatory requirements and toxicity risk assessment. Suitable methods exist for the accurate characterization of the size of non-aggregated, stabilized, spherical and monodisperse nanoparticles. In contrast, industrial nanoscale powders usually require dedicated sample preparation procedures developed for the analysis method of choice. These nano-powders tend to agglomerate and/or aggregate, a behavior which in combination with an innate broad particle size distribution and irregular shape often significantly alters the achievable accuracy of the measured size parameters. The present study systematically tests two commercially available nanoscale powders using different sample preparation methods for correlative analysis by scanning electron microscopy, dynamic light scattering, Brunauer–Emmet–Teller method and differential mobility analysis. One focus was set on the sample preparation by embedding nanoparticles in carbon-based hot-mounting resin. Literature on this topic is scarce and the accuracy of the data extracted from cross sections of these particles is unclearly stated. In this paper systematic simulations on the deviation of the size parameters of well-defined series of nanoparticles with different shapes from the nominal value were carried out and the contributing factors are discussed.
The publicly available document encapsulates the first version of the Catalogue of Services of the future EC4Safenano Centre (CoS 2019).
The CoS 2019 is structured in 12 Service Categories and 27 Service Topics, for each of the 12 categories considered. This architecture configures a 12 x 27 matrix that allows ordering the potential EC4Safenano offer in 324 types of services/groups of services.
Each type of service/group of services is described, in a simple and friendly way, by means of a specific service sheet: the EC4Safenano - Service Data Sheet (EC4-SDS). These EC4-SDSs allow structuring and summarizing the information of each service, providing the customer with a concise view of characteristics of the service and also the contact details with the service provider.
The CoS 2019 deploys a map of services consisting of a set of 100 EC4-SDSs, covering 7 of the 12 Service Categories and 17 of the 27 Service Topics.
The harmonization of services is visualized as a future necessary step in EC4Safenano, in order to strengthen the offer and provide added value to customers with a growing offer of harmonized services in future versions of the CoS.
The information contained in this document is structured in 3 main sections, as follows:
• Catalogue structure. This section describes in short the main characteristics of the CoS 2019.
• Catalogue content. This section represents the core part of the document and encapsulates the set of 100 SDSs displaying the offer proposed by the CoS 2019.
• Online Catalogue. This section describes the resources implemented by EC4Safenano to facilitate the on-line consultation of the CoS 2019 by customers and other interested parties.
This is the final report on the proficiency test (PT) „Measurement of the particle size distribution of ceramic powders by laser diffraction”. The PT was organized by the Federal Institute for Materials Research and Testing (BAM), division 5.5 “Advanced technical ceramics”. The measurements took place from 12/2021 to 03/2022. The aim of the interlaboratory comparison was the proficiency assessment of the participating laboratories.
Management and realization of PT were performed in accordance with DIN EN ISO/IEC 17043:2010.
The basis of the harmonized measuring procedure and the instructions for the interlaboratory comparison was the standard ISO 13320:2020.
The statistical analysis was performed in accordance with DIN ISO 13528:2020 by use of the software PROLab Plus (QuoData GmbH, Dresden, Germany).
A group of 44 laboratories from 17 countries participated in the PT. Laser diffraction analyzers produced by 7 different manufacturers were used. The three test materials were commercial products. Overall, the measured characteristic values of the particle distributions (d10, d50 and d90) were in the size range between 0.5 and 25 μm. The final report contains all individual results in an anonymous way.
Particle size determination of a commercially available CeO2 nano powder - SOPs and reference data
(2023)
Compilation of detailed SOPs for characterization of a commercially available CeO2 nano powder including
- suspension preparation (indirect and direct sonication),
- particle size determination (Dynamic Light Scattering DLS and Centrifugal Liquid Sedimentation CLS) with reference data, respectively.
For sample preparation and analysis by Scanning Electron Microscopy (SEM) of this powder see related works (submitted, coming soon).
Presented are results of an inter-laboratory study (ILS) for measurements of the particle size distribution of fine powders in wet dispersion by laser diffraction. In this proficiency test 32 participants from four countries took part. They utilized 13 different devices from 7 manufacturers.
Three commercial powders (glass spheres and two silicon carbide powders) showing a median diameter of about 30, 10 and 1 µm (volume distribution), respectively, were chosen for the procedure. A homogeneity study was carried out after the units had been separated and bottled.
All participants received their test samples including a description of the standard operating procedures based on ISO 13320:2009 – to ensure that experiments were performed in a consistent manner. Results were calculated using the Mie Theory. The general means and the precision of the results were estimated in accordance with ISO 5725-2:2002.
The evaluation showed excellent values of repeatability standard deviation. Values of 4 to 21?% of the reproducibility standard deviation of the results were found in the particle size range above 1 µm. Much larger deviation between the labs was detected in the case of smaller particles. Differences in the design of the analyzers were unambiguously identified as the main reason for the large deviations.
Die Bestimmung der Partikelgrößenverteilung mittels Laserstreulichtverfahren hat sich bei den verschiedensten Pulvern im Mikrometer- und Submikrometerbereich insbesondere wegen der kurzen Messdauer und des breiten Messbereichs zu einem der führenden Verfahren entwickelt. In den letzten Jahren gab es eine Reihe von gerätetechnischen Weiterentwicklungen durch die Hersteller, die der Tatsache Rechnung tragen, dass die Anwender immer feinere Ausgangsprodukte einsetzen und damit auch charakterisieren wollen. Die aktualisierte Fassung der ISO 13320 von 2009, welche die normative Basis der Methode bildet, gilt grundsätzlich im Größenbereich von 3000 gm bis hinunter zu 0,1 gm. Es sind aber zusätzliche Ausstattungsmerkmale beschrieben, die diesen Bereich unter Umständen erweitern können.
Weltweit gibt es etwa zehn etablierte Hersteller von Lasergranulometern, deren modernste Modelle jeweils über derartige Zusatzeinrichtungen verfügen. Die eingesetzten Geräte unterscheiden sich in ihrem Aufbau damit nicht nur zwischen den einzelnen Herstellern, sondern auch innerhalb verschiedener Gerätegenerationen ein und desselben Herstellers. Hinzu kommt der mathematische Prozess der Konvertierung der gewonnenen Streulichtdaten in eine Partikelgrößenverteilung (Dekonvolution), bei dem die Hersteller verschiedene Ansätze und Glättungsmethoden nutzen. Seit 2004 hat die Bundesanstalt für Materialforschung und -prüfung drei Ringversuche zur Bestimmung der Partikelgrößenverteilung mittels Laserstreulichtverfahren initiiert. Neben dem eigentlichen Zweck - der Eignungsbewertung der teilnehmenden Labore - wurden die erhobenen Daten genutzt, um Aussagen zur Präzision der Ergebnisse zu gewinnen und Ursachen für Abweichungen zu finden.
Die Wiederholbarkeit der Messergebnisse innerhalb der Labore war unabhängig vom eingesetzten Gerätetyp sehr gut und erfüllte die Anforderungen der ISO 13320. Geringe Abweichungen bei der Reproduzierbarkeit wurden nur zwischen Laboren gefunden, die identische Gerätetypen desselben Herstellers verwendeten. Über alle Labore betrachtet, ergaben sich Vergleichstandardabweichungen, die in Abhängigkeit von der Größe der gemessenen