TY - JOUR A1 - Hu, Y. A1 - Neumann, C. A1 - Scholtz, Lena A1 - Turchanin, A. A1 - Resch-Genger, Ute A1 - Eigler, S. T1 - Polarity, intramolecular charge transfer, and hydrogen bond comediated solvent effects on the optical properties of graphene quantum dots N2 - Graphene quantum dots (GQDs) have attracted increasing attention due to their favorable optical properties and have been widely used, e.g., in the biomedical field. However, the properties related to the chemical structure of GQDs, resulting in solventdependent optical properties, still remain unclear. Herein, we present the synthesis of long-wavelength emitting GQDs with a size of about 3.6 nm via a solvothermal method using oxo-functionalized graphene (oxo-G) and p-phenylenediamine as precursors and their structural and surface chemical analysis by transmission electron and atomic force microscopy (TEM; AFM) as well as Fourier-transform infrared, Raman, and X-ray photoelectron spectroscopy (FTIR; Raman; XPS). Subsequently, the influence of solvent polarity and proticity on the optical properties of the as-prepared GQDs bearing –OH, –NH2, –COOH and pyridine surface groups was investigated. Based on the results of the absorption and fluorescence (FL) studies, a possible luminescence mechanism is proposed. The observed solvent-induced changes in the spectral position of the FL maximum, FL quantum yield, and FL decay kinetics in protic and aprotic solvents of low and high polarity are ascribed to a combination of polarity effects, intramolecular charge transfer (ICT) processes, and hydrogen bonding. Moreover, the potential of GQDs for the optical sensing of trace amount of water was assessed. The results of our systematic spectroscopic study will promote the rational design of GQDs and shed more light on the FL mechanism of carbon based fluorescent nanomaterials. KW - Graphene quantum dots KW - Solvent polarity KW - solvent-induced changes KW - Charge transfer PY - 2022 DO - https://doi.org/10.1007/s12274-022-4752-1 SN - 1998-0124 SP - 1 EP - 8 PB - Springer AN - OPUS4-56030 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Winkler, Nicolas P. A1 - Neumann, Patrick P. A1 - Schaffernicht, E. A1 - Lilienthal, A. J. T1 - Heterogeneous Sensor Networks: Challenges and Insights from an Industrial Scenario N2 - Monitoring airborne pollutants is critical for occupational health, particularly in industrial environments where workers are exposed to hazardous emissions. Traditional measurements are typically limited to single-day campaigns, resulting in extremely sparse temporal data. Low-cost sensor networks offer a way to increase spatial and temporal resolution but are limited by issues of accuracy and reliability. To address this, we present a wireless heterogeneous sensor network that integrates low-cost stationary nodes with high-quality sensors on mobile platforms, including ground and aerial robots. We deploy this system in a hot rolling mill facility and evaluate its performance under real-world conditions. Field experiments reveal dynamic pollutant patterns, such as altitude-dependent PM2.5 gradients and temperature fluctuations. By introducing synchronized “rendezvous” events between mobile and stationary nodes, we demonstrate correlation capabilities of sensors. Our spatiotemporal analysis shows that, despite limitations of mobile sensing, strategically combining heterogeneous data sources enables capturing pollutant dynamics in complex industrial settings. T2 - IEEE SENSORS 2025 CY - Vancouver, BC, Kanada DA - 19.10.2025 KW - Environmental monitoring KW - Sensor data fusion KW - Sensor system networks KW - Mobile robotics PY - 2025 SN - 979-8-3315-4467-6 SP - 1 EP - 4 PB - IEEE CY - Piscataway, NJ, USA AN - OPUS4-64501 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rütters, H. A1 - Fischer, S. A1 - Le, Quynh A1 - Bettge, Dirk A1 - Bäßler, Ralph A1 - Maßmann, J. A1 - Ostertag-Henning, C. A1 - Wolf, J. Lennard A1 - Pumpa, M. A1 - Lubenau, U. A1 - Knauer, S. A1 - Jaeger, P. A1 - Neumann, A. A1 - Svensson, K. A1 - Lempp, C. A1 - Menezes, F. A1 - Hagemann, B. T1 - Towards defining reasonable minimum composition thresholds – impacts of variable CO2 stream compositions on transport, injection and storage N2 - The collaborative project “Impacts of impurities in CO2 streams captured from different emitters in a regional cluster on transport, injection and storage (CLUSTER)” aimed to set up recommendations on how to define “reasonable minimum composition thresholds” that CO2 streams should meet when accessing CO2 transport pipeline networks. Within CLUSTER, we investigated potential impacts of CO2 streams with different and temporally variable compositions and mass flow rates along the whole CCS chain. Investigations included, amongst others, impacts on: Corrosion of pipeline steel, pipeline network design and related transport costs, alteration of well bore cements, pressure development and rock integrity, geochemical reactions, and petrophysical and geomechanical rock properties. All investigations are based on a generic CCS chain scenario. In this scenario, CO2 streams are captured from a spatial cluster of eleven emitters and collected in a regional pipeline network. Emitters comprise seven fossil fuel-fired power plants equipped with different capture technologies, two cement plants, one refinery and one integrated iron and steel plant. In total, 19.78 Mio t CO2 (including impurities) are captured in the emitter cluster annually. The combined CO2 stream is transported in a trunk line with a length of 400 km (100 km of these offshore) and is injected into five generic storage structures. The storage reservoirs are saline aquifers of the Buntsandstein. The investigations revealed beneficial and deteriorating impacts of different impurities and combinations thereof. Overall, no fundamental technical obstacles for transporting, injecting and storing CO2 streams of the modelled variable compositions and mass flow rates were observed. Based on the results, the CLUSTER project team recommends not to define “minimum composition thresholds” for CO2 streams as strict threshold values for each individual impurity in the stream. Instead, CO2 stream compositions and variabilities for specific CCS projects should be constrained with regard to a set of parameters including i) the overall CO2 content, ii) maximum contents of relevant impurities or elements, iii) acceptable variability of CO2 stream composition, and iv) impurity combinations to be avoided. T2 - 15th International Conference on Greenhouse Gas Control Technologies, GHGT-15 CY - Online meeting DA - 15.03.2021 KW - Corrosion KW - Impurities KW - CO2 quality KW - Pipeline network KW - Whole-chain CCS scenario KW - Recommendations PY - 2021 DO - https://doi.org/10.2139/ssrn.3816427 SP - 1 EP - 18 AN - OPUS4-52418 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rütters, H. A1 - Fischer, S. A1 - Le, Quynh Hoa A1 - Bettge, Dirk A1 - Bäßler, Ralph A1 - Maßmann, J. A1 - Ostertag-Henning, C. A1 - Lennard Wolf, J. A1 - Pumpa, M. A1 - Lubenau, U. A1 - Knauer, S. A1 - Jaeger, P. A1 - Neumann, A. A1 - Svensson, K. A1 - Pöllmann, H. A1 - Lempp, C. A1 - Menezes, F. A1 - Hagemann, B. T1 - Towards Defining Reasonable Minimum Composition Thresholds – Impacts of Variable CO2 Stream Compositions on Transport, Injection and Storage N2 - The collaborative project “Impacts of impurities in CO2 streams captured from different emitters in a regional cluster on transport, injection and storage (CLUSTER)” aimed to set up recommendations on how to define “reasonable minimum composition thresholds” that CO2 streams should meet when accessing CO2 transport pipeline networks. Within CLUSTER, we investigated potential impacts of CO2 streams with different and temporally variable compositions and mass flow rates along the whole CCS chain. Investigations included, amongst others, impacts on: • corrosion of pipeline steel, • pipeline network design and related transport costs, • alteration of well bore cements, • pressure development and rock integrity, • geochemical reactions, and • petrophysical and geomechanical rock properties. All investigations are based on a generic CCS chain scenario. In this scenario, CO2 streams are captured from a spatial cluster of eleven emitters and collected in a regional pipeline network. Emitters comprise seven fossil fuel-fired power plants equipped with different capture technologies, two cement plants, one refinery and one integrated iron and steel plant. In total, 19.78 Mio t CO2 (including impurities) are captured in the emitter cluster annually. The combined CO2 stream is transported in a trunk line with a length of 400 km (100 km of these offshore) and is injected into five generic storage structures. The storage reservoirs are saline aquifers of the Buntsandstein. The investigations revealed beneficial and deteriorating impacts of different impurities and combinations thereof. Overall, no fundamental technical obstacles for transporting, injecting and storing CO2 streams of the modelled variable compositions and mass flow rates were observed. Based on the results, the CLUSTER project team recommends not to define “minimum composition thresholds” for CO2 streams as strict threshold values for each individual impurity in the stream. Instead, CO2 stream compositions and variabilities for specific CCS projects should be constrained with regard to a set of parameters including i) the overall CO2 content, ii) maximum contents of relevant impurities or elements, iii) acceptable variability of CO2 stream composition, and iv) impurity combinations to be avoided. T2 - The 15th Greenhouse Gas Control Technologies Conference CY - Online meeting DA - 15.03.2021 KW - Corrosion KW - Impurities KW - CO2 quality KW - Pipeline network KW - Whole-chain CCS scenario KW - Recommendations PY - 2021 DO - https://doi.org/10.2139/ssrn.3816427 SP - 1 EP - 18 PB - Elservier AN - OPUS4-52940 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zocca, Andrea A1 - Wilbig, Janka A1 - Waske, Anja A1 - Günster, Jens A1 - Widjaja, Martinus Putra A1 - Neumann, C. A1 - Clozel, M. A1 - Meyer, A. A1 - Ding, J. A1 - Zhou, Z. A1 - Tian, X. T1 - Challenges in the Technology Development for Additive Manufacturing in Space N2 - Instead of foreseeing and preparing for all possible scenarios of machine failures, accidents, and other challenges arising in space missions, it appears logical to take advantage of the flexibility of additive manufacturing for “in-space manufacturing” (ISM). Manned missions into space rely on complicated equipment, and their safe operation is a great challenge. Bearing in mind the absolute distance for manned missions to the Moon and Mars, the supply of spare parts for the repair and replacement of lost equipment via shipment from Earth would require too much time. With the high flexibility in design and the ability to manufacture ready-to-use components directly from a computer-aided model, additive manufacturing technologies appear to be extremely attractive in this context. Moreover, appropriate technologies are required for the manufacture of building habitats for extended stays of astronauts on the Moon and Mars, as well as material/feedstock. The capacities for sending equipment and material into space are not only very limited and costly, but also raise concerns regarding environmental issues on Earth. Accordingly, not all materials can be sent from Earth, and strategies for the use of in-situ resources, i.e., in-situ resource utilization (ISRU), are being envisioned. For the manufacturing of both complex parts and equipment, as well as for large infrastructure, appropriate technologies for material processing in space need to be developed. KW - Additive manufacturing KW - Space KW - Process PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549204 DO - https://doi.org/10.1016/j.cjmeam.2022.100018 SN - 2772-6657 VL - 1 IS - 1 SP - 1 EP - 13 PB - Elsevier Ltd. AN - OPUS4-54920 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Neumann, Patrick P. A1 - Asadi, S. A1 - Lilienthal, A.J. A1 - Bartholmai, Matthias A1 - Schiller, J.H. T1 - Autonomous gas-sensitive microdrone - wind vector estimation and gas distribution mapping N2 - This article presents the development and validation of an autonomous, gas sensitive microdrone that is capable of estimating the wind vector in real time using only the onboard control unit of the microdrone and performing gas distribution mapping (DM). Two different sampling approaches are suggested to address this problem. On the one hand, a predefined trajectory is used to explore the target area with the microdrone in a real-world gas DM experiment. As an alternative sampling approach, we introduce an adaptive strategy that suggests next sampling points based on an artificial potential field (APF). Initial results in real-world experiments demonstrate the capability of the proposed adaptive sampling strategy for gas DM and its use for gas source localization. KW - Anemometric sensor KW - Autonomous micro UAV KW - Chemical sensing KW - Gas distribution modelling KW - Gas source localization KW - Gas sensors KW - Mobile sensing system KW - Quadrocopter KW - Sensor planning KW - Artificial potential field PY - 2012 DO - https://doi.org/10.1109/MRA.2012.2184671 SN - 1070-9932 VL - 19 IS - 1 SP - 50 EP - 61 PB - IEEE CY - New York, NY, USA AN - OPUS4-25773 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hüllmann, Dino A1 - Neumann, Patrick P. A1 - Scheuschner, Nils A1 - Bartholmai, Matthias A1 - Lilienthal, A.J. T1 - Experimental Validation of the Cone-Shaped Remote Gas Sensor Model N2 - Remote gas sensors mounted on mobile robots enable the mapping of gas distributions in large or hardly accessible areas. A challenging task, however, is the generation of threedimensional distribution maps from these gas measurements. Suitable reconstruction algorithms can be adapted, for instance, from the field of computed tomography (CT), but both their performance and strategies for selecting optimal measuring poses must be evaluated. For this purpose simulations are used, since, in contrast to field tests, they allow repeatable conditions. Although several simulation tools exist, they lack realistic models of remote gas sensors. Recently, we introduced a model for a Tunable Diode Laser Absorption Spectroscopy (TDLAS) gas sensor taking into account the conical shape of its laser beam. However, the novel model has not yet been validated with experiments. In this paper, we compare our model with a real sensor device and show that the assumptions made hold. T2 - IEEE Sensors 2019 CY - Montreal, Canada DA - 27.10.2019 KW - Remote gas sensor model KW - TDLAS KW - Gas dispersion simulation PY - 2019 SN - 978-1-7281-1634-1 SP - 104 EP - 107 PB - IEEE AN - OPUS4-49548 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Neumann, Martin A1 - Schilling, O. A1 - Kuschke, Christian A1 - Darnstädt, A. A1 - Schubert, Sven A1 - Günther, U. A1 - Wille, Frank T1 - Requirements for management systems for manufacturing of transport packages: the new revision of BAM-GGR 011 guideline N2 - In accordance with IAEA SSR-6 para 306 a management system shall be established and implemented to ensure compliance with the relevant provisions of the IAEA regulations. BAM has issued an update of the guideline: the BAM-GGR 011. The new revision describes necessary quality assurance measures for design, manufacture, testing, documentation, use, maintenance and inspection of packagings for package designs requiring competent authority approval for the transport of radioactive material. The measures can be categorised as system-related and design-related. They are independently approved and monitored by the German competent authority BAM and its authorised expert (BAM/T). The qualification of the organisation applying for the design approval certificate is reviewed in the context of the design approval procedure. The quality assurance measures for manufacture consist of three main steps. Pre-assessment of manufacturing documents such as quality plans, specifications etc., Manufacturing inspections according the pre-assessed documents and inspection before commissioning including documentation review. Periodic inspections during operation as well as relevant specifications for use and maintenance ensure that the properties specified in the approval certificate are preserved over the package life time. Special provisions for the return on experience regarding operational feedback for design, manufacture, use, maintenance and inspection are given. Special focus shall be given here to the rearranged and meanwhile established system of manufacturing inspections. This includes more transparent roles for a) the Producers authorised inspection 11282 representative, b) the independent inspection expert (S), acting on behalf of the manufacturer with acceptance of BAM, and c) BAM or its authorised expert (BAM/T). Additional attention shall be drawn to the management of deviations during manufacturing and provisions for maintenance and periodic inspections. T2 - 19th International Symposium on the Packaging and Transportation of Radioactive Materials PATRAM 2019 CY - New Orleans, LA, USA DA - 04.08.2019 KW - Quality assurance KW - Transport KW - Manufacturing KW - Surveillance KW - Radioactive material PY - 2019 SP - Paper 1128, 1 AN - OPUS4-49059 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Winkler, Nicolas P. A1 - Lilienthal, A. J. A1 - Neumann, Patrick P. ED - Zemčík, R. ED - Krystek, J. T1 - Boosting a Low-Cost Sensor Network with Mobile High-Quality Sensors N2 - Occupational health is an important topic, especially in industry, where workers are exposed to airborne by-products (e.g., dust particles and gases). Therefore, continuous monitoring of the air quality in industrial environments is crucial to meet safety standards. For practical and economic reasons, high-quality, costly measurements are currently only carried out sparsely, both in time and space, i.e., measurement data are collected in single day campaigns at selected locations only. Recent developments in sensor technology enable cost-efficient gas monitoring in real-time for long-term intervals. This knowledge of contaminant distribution inside the industrial environment would provide means for better and more economic control of air impurities, e.g., the possibility to regulate the workspace’s ventilation exhaust locations, can reduce the concentration of airborne contaminants by 50%. This paper describes a concept proposed in the project “Robot-assisted Environmental Monitoring for Air Quality Assessment in Industrial Scenarios“ (RASEM). RASEM aims to bring together the benefits of both – low- and high-cost – measuring technologies: A stationary network of low-cost sensors shall be augmented by mobile units carrying high-quality sensors. Additionally, RASEM will develop procedures and algorithms to map the distribution of gases and particles in industrial environments. T2 - 36th Danubia-Adria Symposium on Advances in Experimental Mechanics CY - Pilsen, Czech Republic DA - 24.09.2019 KW - RASEM KW - Sensor network KW - Low-cost KW - Occupational health KW - Mobile Robot Olfaction PY - 2019 SP - 61 EP - 62 CY - Plzeň AN - OPUS4-49630 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hüllmann, Dino A1 - Neumann, Patrick P. A1 - Monroy, J. A1 - Lilienthal, A. J. T1 - A realistic remote gas sensor model for three-dimensional olfaction simulations N2 - Remote gas sensors like those based on the Tunable Diode Laser Absorption Spectroscopy (TDLAS) enable mobile robots to scan huge areas for gas concentrations in reasonable time and are therefore well suited for tasks such as gas emission surveillance and environmental monitoring. A further advantage of remote sensors is that the gas distribution is not disturbed by the sensing platform itself if the measurements are carried out from a sufficient distance, which is particularly interesting when a rotary-wing platform is used. Since there is no possibility to obtain ground truth measurements of gas distributions, simulations are used to develop and evaluate suitable olfaction algorithms. For this purpose several models of in-situ gas sensors have been developed, but models of remote gas sensors are missing. In this paper we present two novel 3D ray-tracer-based TDLAS sensor models. While the first model simplifies the laser beam as a line, the second model takes the conical shape of the beam into account. Using a simulated gas plume, we compare the line model with the cone model in terms of accuracy and computational cost and show that the results generated by the cone model can differ significantly from those of the line model. T2 - 2019 IEEE International Symposium on Olfaction and Electronic Nose (ISOEN) CY - Fukuoka, Japan DA - 26.05.2019 KW - Remote gas sensor KW - Gas detector KW - TDLAS KW - Sensor modelling PY - 2019 SN - 978-1-5386-8327-9 SN - 978-1-5386-8328-6 DO - https://doi.org/10.1109/ISOEN.2019.8823330 SP - 1 EP - 3 PB - IEEE AN - OPUS4-48919 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Neumann, Patrick P. A1 - Kohlhoff, Harald A1 - Hüllmann, Dino A1 - Krentel, Daniel A1 - Kluge, Martin A1 - Dzierliński, M. A1 - Lilienthal, A. J. A1 - Bartholmai, Matthias T1 - Aerial-based gas tomography – from single beams to complex gas distributions N2 - In this paper, we present and validate the concept of an autonomous aerial robot to reconstruct tomographic 2D slices of gas plumes in outdoor environments. Our platform, the so-called Unmanned Aerial Vehicle for Remote Gas Sensing (UAV-REGAS), combines a lightweight Tunable Diode Laser Absorption Spectroscopy (TDLAS) gas sensor with a 3-axis aerial stabilization gimbal for aiming at a versatile octocopter. While the TDLAS sensor provides integral gas concentration measurements, it does not measure the distance traveled by the laser diode’s beam nor the distribution of gas along the optical path. Thus, we complement the set-up with a laser rangefinder and apply principles of Computed Tomography (CT) to create a model of the spatial gas distribution from a set of integral concentration measurements. To allow for a fundamental ground truth evaluation of the applied gas tomography algorithm, we set up a unique outdoor test environment based on two 3D ultrasonic anemometers and a distributed array of 10 infrared gas transmitters. We present results showing its performance characteristics and 2D plume reconstruction capabilities under realistic conditions. The proposed system can be deployed in scenarios that cannot be addressed by currently available robots and thus constitutes a significant step forward for the field of Mobile Robot Olfaction (MRO). KW - Aerial robot olfaction KW - Mobile robot olfaction KW - Gas tomography KW - TDLAS KW - Plume PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-487843 DO - https://doi.org/10.1080/22797254.2019.1640078 SP - 1 EP - 16 PB - Taylor & Francis CY - London AN - OPUS4-48784 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Winkler, Nicolas P. A1 - Neumann, Patrick P. A1 - Hüllmann, Dino A1 - Kohlhoff, Harald A1 - Bartholmai, Matthias A1 - Bennetts, V. H. A1 - Lilienthal, A. J. T1 - Remote Gas Sensing with Multicopter-Platforms N2 - This presentation gives an introduction to the gas-sensitive aerial robots developed at BAM, including various application examples in the field of mobile robot olfaction: gas source localization and gas distribution mapping. T2 - Zweites Innovationsforum "Autonome, mobile Dienste; Services für Mobilität" CY - Berlin, Germany DA - 04.06.2019 KW - Tunable Diode Laser Absorption Spectroscopy (TDLAS); UAV-REGAS KW - Localization of gas sources KW - Mobile Robot Olfaction KW - Nano UAV Swarm KW - Tomographic reconstruction of gas plumes PY - 2019 UR - http://modisem.de/files/Ereignisse/2019-06/Innovationsforum_Downloads/IF2_2019_Tagungsband_WEB.pdf SN - 978-3-942709-22-4 N1 - Tagungsband auf Deutsch, Beitrag auf Englisch. VL - 2019 SP - 24 EP - 34 AN - OPUS4-48699 LA - mul AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hüllmann, Dino A1 - Neumann, Patrick P. A1 - Lilienthal, A. J. T1 - Gas Dispersion Fluid Mechanics Simulation for Large Outdoor Environments N2 - The development of algorithms for mapping gas distributions and localising gas sources is a challenging task, because gas dispersion is a highly dynamic process and it is impossible to capture ground truth data. Fluid-mechanical simulations are a suitable way to support the development of these algorithms. Several tools for gas dispersion simulation have been developed, but they are not suitable for simulations of large outdoor environments. In this paper, we present a concept of how an existing simulator can be extended to handle both indoor and large outdoor scenarios. T2 - 36th Danubia Adria Symposium on Advances in Experimental Mechanics CY - Pilsen, Czech Republic DA - 24.09.2019 KW - Gas dispersion simulation KW - CFD KW - Gas tomography PY - 2019 SN - 978-80-261-0876-4 SP - 49 EP - 50 CY - Pilsen, Czech Republic AN - OPUS4-49224 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Epishin, A. A1 - Link, T. A1 - Svetlov, I. L. A1 - Nolze, Gert A1 - Saliwan Neumann, Romeo A1 - Lucas, H. T1 - Mechanism of porosity growth during homogenisation in single crystal nickel-based superalloys N2 - Several mechanisms for porosity growth in single crystal nickel-based superalloys during homogenisation heat treatment have been proposed in the literature. They were carefully checked using different experimental methods, namely quantitative light microscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction and density measurements. It is shown that the main mechanism is the Kirkendall–Frenkel effect, i.e. generation of voids due to uncompensated efflux of Al atoms from dissolving γ/γ′-eutectic areas. The Al diffusion is supported by the afflux of vacancies from surrounding γ-matrix which results in porosity growth. This conclusion is confirmed by the estimation of the vacancy afflux towards the dissolving eutectic. KW - Ni-base superalloy KW - Eutectic KW - Vacancies KW - Porosity PY - 2013 VL - 104 IS - 8 SP - 776 EP - 782 PB - Carl Hanser Verlag AN - OPUS4-37983 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -