“Quantified contribution of β&Prime, and β&prime, precipitates to the strengthening of an aged Al–Mg–Si alloy”. Yang M, Chen H, Orekhov A, Lu Q, Lan X, Li K, Zhang S, Song M, Kong Y, Schryvers D, Du Y, Materials Science And Engineering A-Structural Materials Properties Microstructure And Processing 774, 138776 (2020). http://doi.org/10.1016/j.msea.2019.138776
Abstract: It is generally believed that β00 precipitates, rather than β0 precipitates, are the major strengthening precipitates in
aged Al–Mg–Si alloys. The reason for this difference is not well understood. To clarify this, two samples of the
same Al–Mg–Si alloy but with different aging states were prepared. The under-aged sample only contains nanoprecipitates
of the β00 type, while the peak-aged one contains nearly equal volumes of β00 and β0 precipitates. We
have, for the first time, separated the strengthening effect of the contribution from βʺ and βʹ precipitates,
respectively, by an indirect approach based on high-precision measurements of volume fractions, number densities,
sizes, proportions of the precipitates, their lattice strains, the composition and grain size of the matrix. The
β0 precipitates, which take 45.6% of the total precipitate volume in the peak-aged sample, contribute to the entire
precipitation strengthening by only 31.6%. The main reason why they are less useful compared to β00 precipitates
has been found to be associated with their smaller lattice strains relative to the matrix, which is 0.99% versus
2.10% (for β00 ).
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 6.4
DOI: 10.1016/j.msea.2019.138776
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“Glycogen as a biodegradable construction nanomaterial for in vivo use”. Filippov SK, Sedlacek O, Bogomolova A, Vetrik M, Jirak D, Kovar J, Kucka J, Bals S, Turner S, Stepanek P, Hruby M;, Macromolecular bioscience 12, 1731 (2012). http://doi.org/10.1002/mabi.201200294
Abstract: It is demonstrated that glycogen as a biodegradable and inexpensive material coming from renewable resources can be used as a carrier for the construction of in vivo imaging nanoagents. The model system considered is composed of glycogen modified with gadolinium and fluorescent labels. Systematic studies of properties of these nanocarriers by a variety of physical methods and results of in vivo tests of biodegradability are reported. This represents, to the authors' best knowledge, the first such use of glycogen.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.238
Times cited: 22
DOI: 10.1002/mabi.201200294
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““Branched&rdquo, structural transformation of the L12-Al3Zr phase manipulated by Cu substitution/segregation in the Al-Cu-Zr alloy system”. Ding L, Zhao M, Ehlers FJH, Jia Z, Zhang Z, Weng Y, Schryvers D, Liu Q, Idrissi H, Journal of materials science &, technology 185, 186 (2024). http://doi.org/10.1016/j.jmst.2023.11.015
Abstract: The effect of Cu on the evolution of the Al3Zr phase in an Al-Cu-Zr cast alloy during solution treatment at 500 °C has been thoroughly studied by combining atomic resolution high-angle annular dark-field scanning transmission electron microscopy, energy-dispersive X-ray spectroscopy and first-principles cal- culations. The heat treatment initially produces a pure L12-Al3Zr microstructure, allowing for about 13 % Cu to be incorporated in the dispersoid. Cu incorporation increases the energy barrier for anti-phase boundary (APB) activation, thus stabilizing the L12 structure. Additional heating leads to a Cu-induced “branched”path for the L12 structural transformation, with the latter process accelerated once the first APB has been created. Cu atoms may either (i) be repelled by the APBs, promoting the transformation to a Cu-poor D023 phase, or (ii) they may segregate at one Al-Zr layer adjacent to the APB, promoting a transformation to a new thermodynamically favored phase, Al4CuZr, formed when these segregation layers are periodically arranged. Theoretical studies suggest that the branching of the L12 transformation path is linked to the speed at which an APB is created, with Cu attraction triggered by a comparatively slow process. This unexpected transformation behavior of the L12-Al3Zr phase opens a new path to understanding, and potentially regulating the Al3Zr dispersoid evolution for high temperature applications.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 10.9
DOI: 10.1016/j.jmst.2023.11.015
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“Addition of yttrium into HfO2 films: microstructure and electrical properties”. Dubourdieu C, Rauwel E, Roussel H, Ducroquet F, Hollaender B, Rossell M, Van Tendeloo G, Lhostis S, Rushworth S, Journal of vacuum science and technology: A: vacuum surfaces and films 27, 503 (2009). http://doi.org/10.1116/1.3106627
Abstract: The cubic phase of HfO2 was stabilized by addition of yttrium in thin films grown on Si/SiO2 by metal-organic chemical vapor deposition. The cubic phase was obtained for contents of 6.5 at. % Y or higher at a temperature as low as 470 °C. The complete compositional range (from 1.5 to 99.5 at. % Y) was investigated. The crystalline structure of HfO2 was determined from x-ray diffraction, electron diffraction, and attenuated total-reflection infrared spectroscopy. For cubic films, the continuous increase in the lattice parameter indicates the formation of a solid-solution HfO2Y2O3. As shown by x-ray photoelectron spectroscopy, yttrium silicate is formed at the interface with silicon; the interfacial layer thickness increases with increasing yttrium content and increasing film thickness. The dependence of the intrinsic relative permittivity r as a function of Y content was determined. It exhibits a maximum of ~30 for ~8.8 at. % Y. The cubic phase is stable upon postdeposition high-temperature annealing at 900 °C under NH3.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.374
Times cited: 29
DOI: 10.1116/1.3106627
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“Crystalline structure of very hard tungsten carbide thin films obtained by reactive pulsed laser deposition”. Mihailescu IN, Gyorgy E, Marin G, Popescu M, Teodorescu VS, van Landuyt J, Grivas C, Hatziapostolou A, Journal of vacuum science and technology: A: vacuum surfaces and films 17, 249 (1999). http://doi.org/10.1116/1.581579
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.374
Times cited: 8
DOI: 10.1116/1.581579
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“Electromagnetic effects in high-frequency large-area capacitive discharges : a review”. Liu Y-X, Zhang Y-R, Bogaerts A, Wang Y-N, Journal of vacuum science and technology: A: vacuum surfaces and films 33, 020801 (2015). http://doi.org/10.1116/1.4907926
Abstract: In traditional capacitively coupled plasmas, the discharge can be described by an electrostatic model, in which the Poisson equation is employed to determine the electrostatic electric field. However, current plasma reactors are much larger and driven at a much higher frequency. If the excitation wavelength k in the plasma becomes comparable to the electrode radius, and the plasma skin depth d becomes comparable to the electrode spacing, the electromagnetic (EM) effects will become significant and compromise the plasma uniformity. In this regime, capacitive discharges have to be described by an EM model, i.e., the full set of Maxwells equations should be solved to address the EM effects. This paper gives an overview of the theory, simulation and experiments that have recently been carried out to understand these effects, which cause major uniformity problems in plasma processing for microelectronics and flat panel display industries. Furthermore, some methods for improving the plasma uniformity are also described and compared.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.374
Times cited: 10
DOI: 10.1116/1.4907926
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“Fluid simulation of the bias effect in inductive/capacitive discharges”. Zhang Y-R, Gao F, Li X-C, Bogaerts A, Wang Y-N, Journal of vacuum science and technology: A: vacuum surfaces and films 33, 061303 (2015). http://doi.org/10.1116/1.4928033
Abstract: Computer simulations are performed for an argon inductively coupled plasma (ICP) with a capacitive radio-frequency bias power, to investigate the bias effect on the discharge mode transition and on the plasma characteristics at various ICP currents, bias voltages, and bias frequencies. When the bias frequency is fixed at 13.56 MHz and the ICP current is low, e.g., 6A, the spatiotemporal averaged plasma density increases monotonically with bias voltage, and the bias effect is already prominent at a bias voltage of 90 V. The maximum of the ionization rate moves toward the bottom electrode, which indicates clearly the discharge mode transition in inductive/capacitive discharges. At higher ICP currents, i.e., 11 and 13 A, the plasma density decreases first and then increases with bias voltage, due to the competing mechanisms between the ion acceleration power dissipation and the capacitive power deposition. At 11 A, the bias effect is still important, but it is noticeable only at higher bias voltages. At 13 A, the ionization rate is characterized by a maximum at the reactor center near the dielectric window at all selected bias voltages, which indicates that the ICP power, instead of the bias power, plays a dominant role under this condition, and no mode transition is observed. Indeed, the ratio of the bias power to the total power is lower than 0.4 over a wide range of bias voltages, i.e., 0300V. Besides the effect of ICP current, also the effect of various bias frequencies is investigated. It is found that the modulation of the bias power to the spatiotemporal distributions of the ionization rate at 2MHz is strikingly different from the behavior observed at higher bias frequencies. Furthermore, the minimum of the plasma density appears at different bias voltages, i.e., 120V at 2MHz and 90V at 27.12 MHz.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.374
Times cited: 9
DOI: 10.1116/1.4928033
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“Influence of sticking coefficients on the behavior of sputtered atoms in an argon glow discharge: modeling and comparison with experiment”. Bogaerts A, Naylor J, Hatcher M, Jones WJ, Mason R, Journal of vacuum science and technology: A: vacuum surfaces and films 16, 2400 (1998). http://doi.org/10.1116/1.581359
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.374
Times cited: 12
DOI: 10.1116/1.581359
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“Modeling and experimental investigation of the plasma uniformity in CF4/O2 capacitively coupled plasmas, operating in single frequency and dual frequency regime”. Zhang Y-R, Tinck S, De Schepper P, Wang Y-N, Bogaerts A, Journal of vacuum science and technology: A: vacuum surfaces and films 33, 021310 (2015). http://doi.org/10.1116/1.4906819
Abstract: A two-dimensional hybrid Monte Carlofluid model, incorporating a full-wave solution of Maxwell's equations, is employed to describe the behavior of high frequency (HF) and very high frequency capacitively coupled plasmas (CCPs), operating both at single frequency (SF) and dual frequency (DF) in a CF4/O2 gas mixture. First, the authors investigate the plasma composition, and the simulations reveal that besides CF4 and O2, also COF2, CF3, and CO2 are important neutral species, and CF+3 and F− are the most important positive and negative ions. Second, by comparing the results of the model with and without taking into account the electromagnetic effects for a SF CCP, it is clear that the electromagnetic effects are important, both at 27 and 60 MHz, because they affect the absolute values of the calculation results and also (to some extent) the spatial profiles, which accordingly affects the uniformity in plasma processing. In order to improve the plasma radial uniformity, which is important for the etch process, a low frequency (LF) source is added to the discharge. Therefore, in the major part of the paper, the plasma uniformity is investigated for both SF and DF CCPs, operating at a HF of 27 and 60 MHz and a LF of 2 MHz. For this purpose, the authors measure the etch rates as a function of position on the wafer in a wide range of LF powers, and the authors compare them with the calculated fluxes toward the wafer of the plasma species playing a role in the etch process, to explain the trends in the measured etch rate profiles. It is found that at a HF of 60 MHz, the uniformity of the etch rate is effectively improved by adding a LF power of 2 MHz and 300 W, while its absolute value increases by about 50%, thus a high etch rate with a uniform distribution is observed under this condition.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.374
Times cited: 3
DOI: 10.1116/1.4906819
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“Modeling of the target surface modification by reactive ion implantation during magnetron sputtering”. Depla D, Chen ZY, Bogaerts A, Ignatova V, de Gryse R, Gijbels R, Journal of vacuum science and technology: A: vacuum surfaces and films 22, 1524 (2004). http://doi.org/10.1116/1.1705641
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.374
Times cited: 13
DOI: 10.1116/1.1705641
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“Reaction mechanisms for atomic layer deposition of aluminum oxide on semiconductor substrates”. Delabie A, Sioncke S, Rip J, Van Elshocht S, Pourtois G, Mueller M, Beckhoff B, Pierloot K, Journal of vacuum science and technology: A: vacuum surfaces and films 30, 01a127 (2012). http://doi.org/10.1116/1.3664090
Abstract: In this work, we have studied the TMA/H(2)O (TMA Al(CH(3))(3)) atomic layer deposition (ALD) of Al(2)O(3) on hydroxyl (OH) and thiol (SH) terminated semiconductor substrates. Total reflection x-ray fluorescence reveals a complex growth-per-cycle evolution during the early ALD reaction cycles. OH and SH terminated surfaces demonstrate growth inhibition from the second reaction cycle on. Theoretical calculations, based on density functional theory, are performed on cluster models to investigate the first TMA/H(2)O reaction cycle. Based on the theoretical results, we discuss possible mechanisms for the growth inhibition from the second reaction cycle on. In addition, our calculations show that AlCH(3) groups are hydrolyzed by a H(2)O molecule adsorbed on a neighboring Al atom, independent of the type of backbonds (Si-O, Ge-O, or Ge-S) of AlCH(3). The coordination of Al remains four-fold after the first TMA/H(2)O reaction cycle. (C) 2012 American Vacuum Society. [DOI: 10.1116/1.3664090]
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.374
Times cited: 41
DOI: 10.1116/1.3664090
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“Thermal recrystallization of short-range ordered WS2 films”. Heyne MH, de Marneffe J-F, Radu I, Neyts EC, De Gendt S, Journal of vacuum science and technology: A: vacuum surfaces and films 36, 05g501 (2018). http://doi.org/10.1116/1.5036654
Abstract: The integration of van der Waals materials in nanoelectronic devices requires the deposition of few-layered MX2 films with excellent quality crystals covering a large area. In recent years, astonishing progress in the monolayer growth of WS2 and MoS2 was demonstrated, but multilayer growth resulted often in separated triangular or hexagonal islands. These polycrystalline films cannot fully employ the specific MX2 properties since they are not connected in-plane to the other domains. To coalesce separated islands, ultrahigh-temperature postdeposition anneals in H2S are applied, which are not compatible with bare silicon substrates. Starting from the deposition of stoichiometric short-ordered films, the present work studies different options for subsequent high-temperature annealing in an inert atmosphere to form crystalline films with large grains from stoichiometric films with small grains. The rapid thermal annealing, performed over a few seconds, is compared to excimer laser annealing in the nanosecond range, which are both able to crystallize the thin WS2. The WS2 recrystallization temperature can be lowered using metallic crystallization promoters (Co and Ni). The best result is obtained using a Co cap, due to the circumvention of Co and S binary phase formation below the eutectic temperature. The recrystallization above a critical temperature is accompanied by sulfur loss and 3D regrowth. These undesired effects can be suppressed by the application of a dielectric capping layer prior to annealing. A SiO2 cap can suppress the sulfur loss successfully during annealing and reveals improved material quality in comparison to noncapped films Published by the AVS.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.374
Times cited: 2
DOI: 10.1116/1.5036654
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“Corrosion protection of Cu by atomic layer deposition”. Cremers V, Rampelberg G, Baert K, Abrahami S, Claes N, de Oliveira TM, Terryn H, Bals S, Dendooven J, Detavernier C, Journal of vacuum science and technology: A: vacuum surfaces and films 37, 060902 (2019). http://doi.org/10.1116/1.5116136
Abstract: Atomic layer deposition (ALD) is a vapor phase technique that is able to deposit uniform, conformal thin films with an excellent thickness control at the atomic scale. 18 nm thick Al2O3 and TiO2 coatings were deposited conformaly and pinhole-free onto micrometer-sized Cu powder, using trimethylaluminum and tetrakis(dimethylamido)titanium(IV), respectively, as a precursor and de-ionized water as a reactant. The capability of the ALD coating to protect the Cu powder against corrosion was investigated. Therefore, the stability of the coatings was studied in solutions with different pH in the range of 0–14, and in situ raman spectroscopy was used to detect the emergence of corrosion products of Cu as an indication that the protective coating starts to fail. Both ALD coatings provide good protection at standard pH values in the range of 5–7. In general, the TiO2 coating shows a better barrier protection against corrosion than the Al2O3 coating. However, for the most extreme pH conditions, pH 0 and pH 14, the TiO2 coating starts also to degrade.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.374
Times cited: 7
DOI: 10.1116/1.5116136
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“Controllable nitrogen doping in as deposited TiO2 film and its effect on post deposition annealing”. Deng S, Verbruggen SW, Lenaerts S, Martens JA, Van den Berghe S, Devloo-Casier K, Devulder W, Dendoover J, Deduytsche D, Detavernier C, Journal of vacuum science and technology: A: vacuum surfaces and films 32, 01a123 (2014). http://doi.org/10.1116/1.4847976
Abstract: In order to narrow the band gap of TiO2, nitrogen doping by combining thermal atomic layer deposition (TALD) of TiO2 and plasma enhanced atomic layer deposition (PEALD) of TiN has been implemented. By altering the ratio between TALD TiO2 and PEALD TiN, the as synthesized TiOxNy films showed different band gaps (from 1.91 eV to 3.14 eV). In situ x-ray diffraction characterization showed that the crystallization behavior of these films changed after nitrogen doping. After annealing in helium, nitrogen doped TiO2 films crystallized into rutile phase while for the samples annealed in air a preferential growth of the anatase TiO2 along (001) orientation was observed. Photocatalytic tests of the degradation of stearic acid were done to evaluate the effect of N doping on the photocatalytic activity.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 1.374
Times cited: 10
DOI: 10.1116/1.4847976
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“A scanning electron microscopy study on hollow silica microspheres: defects and influences of the synthesis composition”. Liu S, Wei M, Sui X, Cheng X, Cool P, Van Tendeloo G, Journal of sol-gel science and technology 49, 373 (2009). http://doi.org/10.1007/s10971-008-1875-0
Abstract: Defects on hollow silica spheres synthesized in a tetraethylorthosilicate-octylamine-HCl-H2O system were recorded by scanning microscope. Based on the results, influences of synthesis composition on the formation of these defects are discussed. It is evidenced that products prepared with different octylamine-to-tetraethylorthosilicate ratios may have surface depressions, cracks and non-hollow microspheres. However, by changing water and acid additions, these defects could be reduced or eliminated. Generally, samples synthesized with a large octylamine addition commonly exhibit surface depressions. A small octylamine or a large water addition benefits the formation of solid silica microspheres among the product. Acid, although is not indispensable for the formation of hollow spheres, helps to eliminate or reduce depressions on the hollow shells. It is explained that the added acid gives rise to a relative localized fast hydrolysis versus condensation, facilitating an easy mobility of hydrolyzed silica species, and consequently the shell surface is smoothened.
Keywords: A1 Journal article; Laboratory of adsorption and catalysis (LADCA); Electron microscopy for materials research (EMAT)
Impact Factor: 1.575
Times cited: 1
DOI: 10.1007/s10971-008-1875-0
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“Numerical study of the sputtering in a dc magnetron”. Kolev I, Bogaerts A, Journal of vacuum science and technology: A: vacuum surfaces and films 27, 20 (2009). http://doi.org/10.1021/jp8058992
Abstract: Molecular dynamics simulations were used to investigate the size-dependent melting mechanism of nickel nanoclusters of various sizes. The melting process was monitored by the caloric curve, the overall cluster Lindemann index, and the atomic Lindemann index. Size-dependent melting temperatures were determined, and the correct linear dependence on inverse diameter was recovered. We found that the melting mechanism gradually changes from dynamic coexistence melting to surface melting with increasing cluster size. These findings are of importance in better understanding carbon nanotube growth by catalytic chemical vapor deposition as the phase state of the catalyst nanoparticle codetermines the growth mechanism.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 66
DOI: 10.1021/jp8058992
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“Multistep loading of titania nanoparticles in the mesopores of SBA-15 for enhanced photocatalytic activity”. de Witte K, Cool P, de Witte I, Ruys L, Rao J, Van Tendeloo G, Vansant EF, Journal of nanoscience and nanotechnology 7, 2511 (2007). http://doi.org/10.1166/jnn.2007.445
Keywords: A1 Journal article; Laboratory of adsorption and catalysis (LADCA); Electron microscopy for materials research (EMAT)
Impact Factor: 1.483
Times cited: 13
DOI: 10.1166/jnn.2007.445
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“Nanoscale Characterization of Growth of Secondary Phases in Off-Stoichiometric CZTS Thin Films”. Vishwakarma M, Karakulina OM, Abakumov AM, Hadermann J, Mehta BR, Journal of nanoscience and nanotechnology 18, 1688 (2018). http://doi.org/10.1166/jnn.2018.14261
Abstract: The presence of secondary phases is one of the main issues that hinder the growth of pure kesterite Cu2ZnSnS4 (CZTS) based thin films with suitable electronic and junction properties for efficient solar cell devices. In this work, CZTS thin films with varied Zn and Sn content have been prepared by RF-power controlled co-sputtering deposition using Cu, ZnS and SnS targets and a subsequent sulphurization step. Detailed TEM investigations show that the film shows a layered structure with the majority of the top layer being the kesterite phase. Depending on the initial thin film composition, either about ~1 μm Cu-rich and Zn-poor kesterite or stoichiometric CZTS is formed as top layer. X-ray diffraction, Raman spectroscopy and transmission electron microscopy reveal the presence of Cu2−x S, ZnS and SnO2 minor secondary phases in the form of nanoinclusions or nanoparticles or intermediate layers.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 1.483
DOI: 10.1166/jnn.2018.14261
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“Unravelling the solvent flux behaviour of ceramic nanofiltration and ultrafiltration membranes”. Buekenhoudt A, Bisignano F, De Luca G, Vandezande P, Wouters M, Verhulst K, Journal of membrane science 439, 36 (2013). http://doi.org/10.1016/j.memsci.2013.03.032
Abstract: In order to increase the understanding of the underlying processes in organic solvent nanofiltration (OSN), a study has been undertaken aimed at clarifying the solvent flux behaviour of ceramic nanofiltration and ultrafiltration membranes. Ceramic membranes were chosen for their non-swelling character. Pure water and a variation of 11 different organic solvents were measured on a series of different ceramic membranes with pore-size diameters ranging from 0.9 nm up to 100 nm. To avoid any historical effects, each flux measurement was carried out on a new membrane. The flux results were analysed in a phenomenological way, and a common very simple linear relationship was observed between the product of flux and viscosity of the solvent, and the total Hansen solubility parameter of the solvent. The linear relationship was found for all membranes, independent of the membrane pore size and the membrane material. The slope of the linear relationship was found to depend exponentially on the pore-size diameter and on the polarity of the membrane surface. This result emphasizes the importance of viscosity in the solvent transport, but also of the polarity difference between membrane surface and solvent. The very simple flux model deduced, allows a straightforward prediction of the flux of any solvent or solvent mixture, once the water flux of the membrane is known. At the high pore-size end, the phenomenological model naturally transforms into the viscous-flow or pore-flow behaviour as required. A tentative physical explanation of the model takes into account the presence and extension of a water layer adsorbed to the total pore surface of these membranes. This work also shows that the water flux of a hydrophilic membrane gives a good indication of its molecular weight cut-off (MWCO), and therefore of its separation performance in water. (C)0 2013 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Applied Electrochemistry & Catalysis (ELCAT)
Impact Factor: 6.035
Times cited: 55
DOI: 10.1016/j.memsci.2013.03.032
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“The role of MOFs in Thin-Film Nanocomposite (TFN) membranes”. Van Goethem C, Verbeke R, Pfanmoeller M, Koschine T, Dickmann M, Timpel-Lindner T, Egger W, Bals S, Vankelecom IFJ, Journal of membrane science 563, 938 (2018). http://doi.org/10.1016/J.MEMSCI.2018.06.040
Abstract: Incorporation of MOFs in interfacially polymerized Thin-Film Nanocomposite (TFN) membranes has widely been shown to result in increased membrane performance. However, the exact functioning of these membranes is poorly understood as large variability in permeance increase, filler incorporation and rejection changes can be observed in literature. The synthesis and functioning of TFN membranes (herein exemplified by ZIF-8 filled polyamide (PA) membranes prepared via the EFP method) was investigated via targeted membrane synthesis and thorough characterization via STEM-EDX, XRD and PALS. It is hypothesized that the acid generated during the interfacial polymerization (IP) at least partially degrades the crystalline, acid-sensitive ZIF-8 and that this influences the membrane formation (through so-called secondary effects, i.e. not strictly linked to the pore morphology of the MOF). Nanoscale HAADF-STEM imaging and STEM-EDX Zn-mapping revealed no ZIF-8 particles but rather the presence of randomly shaped regions with elevated Zn-content. Also XRD failed to show the presence of crystalline areas in the composite PA films. As the addition of the acid-quenching TEA led to an increase in the diffraction signal observed in XRD, the role of the acid was confirmed. The separate addition of dissolved Zn2+ to the synthesis of regular TFC membranes showed an increase in permeance while losing some salt retention, similar to observations regularly made for TFN membranes. While the addition of a porous material to a TFC membrane is a straightforward concept, all obtained results indicate that the synthesis and performance of such composite membranes is often more complex than commonly accepted.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.035
Times cited: 84
DOI: 10.1016/J.MEMSCI.2018.06.040
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“Development, performance and stability of sulfur-free, macrovoid-free BSCF capillaries for high temperature oxygen separation from air”. Buysse C, Kovalevsky A, Snijkers F, Buekenhoudt A, Mullens S, Luyten J, Kretzschmar J, Lenaerts S, Journal of membrane science 372, 239 (2011). http://doi.org/10.1016/J.MEMSCI.2011.02.011
Abstract: Capture and storage of CO2 (CCS) from fossil-fuel power plants is vital in order to counteract a pending anthropogenic global warming. High temperature oxygen transport perovskite membranes can fulfill an important role in the separation of oxygen from air needed in the oxy-fuel technologies for CCS. In this study we present the development, performance and stability of gastight, macrovoid-free and sulfur-free Ba0.5Sr0.5Co0.8Fe0.2O3 − δ (BSCF) mixed conductor capillary membranes prepared by phase-inversion spinning and sintering. A sulfur-free phase-inversion polymer was chosen in order to obtain a phase-pure BSCF crystal phase. Special attention was given to the polymer solution and ceramic spinning suspension in order to avoid macrovoids and achieve gastight membranes. The sulfur-free BSCF capillaries showed an average 4-point bending strength of 64 ± 8 MPa and a maximum oxygen flux of not, vert, similar5.3 Nml/(cm2 min) at 950 °C for an argon sweep flow rate of 125 Nml/min. The comparison of the performance of sulfur-free and sulfur-containing BSCF capillaries with similar dimensions revealed a profound impact of the sulfur contamination on both the oxygen flux and the activation energy of the overall oxygen transport mechanism. Both long-term oxygen permeation at different temperatures and post-operation analysis of a sulfur-free BSCF capillary were performed and discussed.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 6.035
Times cited: 32
DOI: 10.1016/J.MEMSCI.2011.02.011
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“Fabrication and oxygen permeability of gastight, macrovoid-free Ba0.5Sr0.5Co0.8Fe0.2O3-\delta capillaries for high temperature gas separation”. Buysse C, Kovalevsky A, Snijkers F, Buekenhoudt A, Mullens S, Luyten J, Kretzschmar J, Lenaerts S, Journal of membrane science 359, 86 (2010). http://doi.org/10.1016/J.MEMSCI.2009.10.030
Abstract: Oxygen-permeable perovskites with mixed ionic-electronic conducting properties can play an important role in the separation of oxygen from air which is needed in the oxy-fuel and pre-combustion technologies for the removal and capture of CO2. In this work, gastight, macrovoid-free Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF) capillaries were successfully shaped by a phase-inversion spinning technique, followed by calcination and sintering. It was found that both the rheology of the ceramic suspension and the composition of bore liquid and coagulation bath are key factors for making macrovoid-free green capillaries. Gastight BSCF capillaries were obtained by sintering for 5 h at 1100 °C. The sintered BSCF capillaries contained a significant amount of BaSO4 due to a reaction with the polysulfone binder during calcination. The oxygen permeation flux through the BSCF capillaries was measured and compared to literature data on BSCF disk and hollow fiber membranes measured in similar conditions.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 6.035
Times cited: 38
DOI: 10.1016/J.MEMSCI.2009.10.030
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“Oxygen exchange-limited transport and surface activation of Ba0.5Sr0.5Co0.8Fe0.2O3-\delta capillary membranes”. Kovalevsky A, Buysse C, Snijkers F, Buekenhoudt A, Luyten J, Kretzschmar J, Lenaerts S, Journal of membrane science 368, 223 (2011). http://doi.org/10.1016/J.MEMSCI.2010.11.034
Abstract: Analysis of oxygen permeation fluxes through Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF) capillary membranes, fabricated via a phase-inversion spinning technique using polysulfone as binder, showed a significant limiting role of the surface-oxygen exchange kinetics. Within the studied temperature and oxygen partial pressure ranges, the activation of core and shell sides of the BSCF capillary with praseodymium oxide (PrOx) resulted in an increase in permeation rate of about 300%. At 11231223 K the activated BSCF membranes demonstrate almost 3-times lower activation energies for the overall oxygen transport (not, vert, similar35 kJ/mol) than the non-activated capillaries, indicating that the mechanism of oxygen transport through the activated capillaries becomes significantly controlled by bulk diffusion limitations, allowing further improvement of the overall performance by decreasing the wall thickness. XRD, EDS and EPMA studies revealed the formation of (Pr,Ba,Sr)(Co,Fe)O3−δ perovskite-type oxides on the surface of the PrOx-modified membranes, which may be responsible for the drastic increase in oxygen exchange rate. At T > 1123 K both non-activated and activated Ba0.5Sr0.5Co0.8Fe0.2O3−δ membranes demonstrate stable performance with time, while at 1073 K only a small initial decrease in permeation was observed.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 6.035
Times cited: 21
DOI: 10.1016/J.MEMSCI.2010.11.034
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“Cross-section transmission electron microscopy characterization of the near-surface structure of medical Nitinol superelastic tubing”. Potapov PL, Tirry W, Schryvers D, Sivel VGM, Wu M-Y, Aslanidis D, Zandbergen H, Journal of materials science: materials in medicine 18, 483 (2007). http://doi.org/10.1007/s10856-007-2008-y
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.325
Times cited: 14
DOI: 10.1007/s10856-007-2008-y
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“Composition and crystal structure of resorbable calcium phosphate thin films”. Tuck L, Sayer M, Mackenzie M, Hadermann J, Dunfield D, Pietak A, Reid JW, Stratilatov AD, Journal of materials science 41, 4273 (2006). http://doi.org/10.1007/s10853-005-5532-5
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.599
Times cited: 2
DOI: 10.1007/s10853-005-5532-5
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“Compositional characterization of nickel silicides by HAADF-STEM imaging”. Verleysen E, Bender H, Richard O, Schryvers D, Vandervorst W, Journal of materials science 46, 2001 (2011). http://doi.org/10.1007/s10853-010-5191-z
Abstract: A methodology for the quantitative compositional characterization of nickel silicides by high angle annular dark field scanning transmission electron microscopy (HAADF-STEM) imaging is presented. HAADF-STEM images of a set of nickel silicide reference samples Ni3Si, Ni31Si12, Ni2Si, NiSi and NiSi2 are taken at identical experimental conditions. The correlation between sample thickness and HAADF-STEM intensity is discussed. In order to quantify the relationship between the experimental Z-contrast intensities and the composition of the analysed layers, the ratio of the HAADF-STEM intensity to the sample thickness or to the intensity of the silicon substrate is determined for each nickel silicide reference sample. Diffraction contrast is still detected on the HAADF-STEM images, even though the detector is set at the largest possible detection angle. The influence on the quantification results of intensity fluctuations caused by diffraction contrast and channelling is examined. The methodology is applied to FUSI gate devices and to horizontal TFET devices with different nickel silicides formed on source, gate and drain. It is shown that, if the elements which are present are known, this methodology allows a fast quantitative 2-dimensional compositional analysis.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.599
Times cited: 1
DOI: 10.1007/s10853-010-5191-z
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“Hydrothermal processing of barium strontium titanate sol-gel composite thin films”. Zelonka K, Sayer M, Freundorfer AP, Hadermann J, Journal of materials science 41, 3885 (2006). http://doi.org/10.1007/s10853-005-5525-4
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.599
Times cited: 10
DOI: 10.1007/s10853-005-5525-4
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“Multiple-step martensitic transformations in the Ni51Ti49 single crystal”. Khalil-Allafi J, Amin-Ahmadi B, Journal of materials science 45, 6440 (2010). http://doi.org/10.1007/s10853-010-4729-4
Abstract: Multiple-step martensitic transformations of an aged Ni51Ti49 single crystal using calorimetric method were investigated. Results show that for short aging times (1045 min) multiple-step martensitic transformations on cooling occur in two steps. Applying intermediate aging times (1.254 h) results in three steps and long aging times (more than 8 h) lead to two-step martensitic transformations again. This behavior has not been recognized in NiTi single crystals in literatures. It can be related to the heterogeneity of composition and stress fields around Ni4Ti3 precipitates.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.599
Times cited: 5
DOI: 10.1007/s10853-010-4729-4
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“Multiwalled carbon nanotubes functionalized with 7-octenyltrichlorosilane and n-octyltrichlorosilane: dispersion in Sylgard®184 silicone and Youngs modulus”. Vast L, Carpentier L, Lallemand F, Colomer J-F, Van Tendeloo G, Fonseca A, Nagy JB, Mekhalif Z, Delhalle J, Journal of materials science 44, 3476 (2009). http://doi.org/10.1007/s10853-009-3464-1
Abstract: Sylgard®184/multiwalled carbon nanotube (MWNT) composites have been prepared by in situ polymerization using purified and functionalized multiwalled carbon nanotubes (f-MWNTs) as fillers. Surface modification of the MWNTs has been carried out by silanization with 7-octenyltrichlorosilane (7OTCS) and n-octyltrichlorosilane (nOTCS). The modification and dispersion of the carbon nanotubes in composites were characterized by X-ray photoelectron spectroscopy (XPS), transmission electron spectroscopy (TEM), and high-resolution transmission electron spectroscopy (HRTEM). Youngs modulus results were derived from indentation testing. It is shown that the terminal-vinyl group of 7OTCS molecules plays an essential role for both the dispersion of the f-MWNTs in the composite and its mechanical properties. At loading as low as 0.2 wt%, the Youngs modulus is shown to increase up to 50%. This is interpreted as resulting from a combination of the good compatibility in the forming silicone matrix of the MWNTs coated with a siloxane network, on the one hand, and the covalent links created between the terminal-vinyl groups and the host matrix in formation, on the other hand.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.599
Times cited: 16
DOI: 10.1007/s10853-009-3464-1
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“Study of the Q&prime, (Q)-phase precipitation in Al–Mg–Si–Cu alloys by quantification of atomic-resolution transmission electron microscopy images and atom probe tomography”. Ding L, Orekhov A, Weng Y, Jia Z, Idrissi H, Schryvers D, Muraishi S, Hao L, Liu Q, Journal of materials science 54, 7943 (2019). http://doi.org/10.1007/s10853-019-03427-6
Abstract: The precipitation mechanism of the Q phase in Al-Mg-Si-Cu alloys has long been the subject of ambiguity and debate since its metastable phase (Q 0) has the same crystal structure and similar lattice parameters as its equilibrium counterparts. In the present work, the evolution of the Q 0 (Q) phase during aging is studied by combination of quantitative atomic-resolution scanning transmission electron microscopy and atom probe tomography. It was found that the transformation from the Q 0 to the Q phase involves changes of the occupancy of Al atoms in atomic columns of the Q 0 (Q) phase. The Al atoms incorporated in the Cu, Si and Mg columns are gradually released into the Al matrix, while mixing between Cu and Si atoms occurs in the Si columns. This transformation process is mainly attributed to the low lattice misfit of the equilibrium Q phase. Besides, the formation of various compositions of the Q phase is due to the different occupancy in the atomic columns of the Q phase. The occupancy changes in the columns of the Q phase are kinetically controlled and are strongly influenced by the alloy composition and aging temperature.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.599
Times cited: 1
DOI: 10.1007/s10853-019-03427-6
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