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“Cavity nucleation and growth in Cu-Zn-Al irradiated with Cu+ ions at different temperatures”. Zelaya E, Schryvers D, Tolley A, Fitchner PFP, Intermetallics 18, 493 (2010). http://doi.org/10.1016/j.intermet.2009.09.010
Abstract: The effects of high dose ion irradiation in β CuZnAl were investigated between room temperature and 150 °C. Single crystal samples with surface normal close to [001]β were irradiated with 300 keV Cu+ ions. Microstructural changes were characterized using transmission electron microscopy. Irradiation induced cavities located on the surface exposed to the irradiation were observed. The morphology, size and density distribution of these cavities were analyzed as a function of different irradiation conditions. The shape and location of the cavities with respect to the irradiation surface were not affected by irradiation temperature or irradiation dose. Instead, the cavity size distribution showed a bi-modal shape for a dose of 15 dpa, regardless of irradiation temperature. For a dose of 30 dpa the bi-modal distribution was only observed after room temperature irradiation. The diffusion effects of vacancies produced by irradiation are analyzed in shape memory CuZnAl alloys, which main characteristic is the diffusionless martensitic transformation. Particularly, the cavity size distributions were analyzed in terms of nucleation, growth and coalescence.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.14
Times cited: 1
DOI: 10.1016/j.intermet.2009.09.010
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“Grain growth and precipitation in an annealed cold-rolled Ni50.2Ti49.8 alloy”. Srivastava AK, Schryvers D, van Humbeeck J, Intermetallics 15, 1538 (2007). http://doi.org/10.1016/j.intermet.2007.06.003
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.14
Times cited: 37
DOI: 10.1016/j.intermet.2007.06.003
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“Phase transformations and precipitation in amorphous Ti50Ni25Cu25 ribbons”. Satto C, Ledda A, Potapov P, Janssens JF, Schryvers D, Intermetallics 9, 395 (2001). http://doi.org/10.1016/S0966-9795(01)00015-2
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.14
Times cited: 16
DOI: 10.1016/S0966-9795(01)00015-2
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“Recrystallization and grain growth in a B2 iron aluminide alloy”. Samajdar I, Ratchev P, Verlinden B, Schryvers D, Intermetallics 6, 419 (1998). http://doi.org/10.1016/S0966-9795(97)00092-7
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.14
Times cited: 17
DOI: 10.1016/S0966-9795(97)00092-7
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“Transmission electron microscopy study of combined precipitation of Ti2Ni(Pd) and Ti2Pd(Ni) in a Ti50Ni30Pd20 alloy”. Delville R, Schryvers D, Intermetallics 18, 2353 (2010). http://doi.org/10.1016/j.intermet.2010.08.006
Abstract: We report a new mode of precipitation in a B19 martensitic Ti50Ni30Pd20 shape memory alloy consisting of a central Ti2Ni(Pd) precipitate surrounded by an austenite area containing Ti2Pd(Ni) precipitates. The morphology and crystallography of the precipitation area is investigated using conventional and high resolution electron microscopy. In particular, the orientation relationship and the coherency strain between the Ti2Pd(Ni) precipitate and the surrounding retained B2 matrix are discussed. A study of local composition in relation with a ternary phase diagram using X-ray energy dispersive spectroscopy with a nanoprobe gives evidences of the formation mechanism.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.14
Times cited: 9
DOI: 10.1016/j.intermet.2010.08.006
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“Twinned b.c.c. sherical particles in a partially crystallised Ti50Ni25Cu25 melt-spun ribbon”. Santamarta R, Schryvers D, Intermetallics 12, 341 (2004). http://doi.org/10.1016/j.intermet.2003.12.002
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.14
Times cited: 14
DOI: 10.1016/j.intermet.2003.12.002
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“Microstructures and interfaces in Ni-Al martensite: comparing HRTEM observations with continuum theories”. Schryvers D, Boullay P, Potapov PL, Kohn RV, Ball JM, International journal of solids and structures 39, 3543 (2002). http://doi.org/10.1016/S0020-7683(02)00167-1
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.76
Times cited: 13
DOI: 10.1016/S0020-7683(02)00167-1
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“Advanced TEM investigation of the plasticity mechanisms in nanocrystalline freestanding palladium films with nanoscale twins”. Wang B, Idrissi H, Galceran M, Colla MS, Turner S, Hui S, Raskin JP, Pardoen T, Godet S, Schryvers D, International journal of plasticity 37, 140 (2012). http://doi.org/10.1016/j.ijplas.2012.04.003
Abstract: Nanocrystalline palladium thin films deposited by electron-beam evaporation and deformed by on-chip tensile testing reveal a surprisingly large strain hardening capacity when considering the small similar to 25 nm grain size. The as-grown films contain several coherent single and multifold twin boundaries. The coherency of the twin boundaries considerably decreases with deformation due to dislocation/twin boundary interactions. These reactions are described based on a detailed analysis of the number and the type of dislocations located at the twin boundaries using high-resolution TEM, including aberration corrected microscopy. Sessile Frank dislocations were observed at the twin/matrix interfaces, explaining the loss of the TB coherency due to the Burgers vector pointing out of the twinning plane. Grain boundary mediated processes were excluded as a mechanism dominating the plastic deformation based on the investigation of the grain size distribution as well as the crystallographic texture using Automated Crystallographic Orientation Indexation TEM. Other factors influencing the plastic deformation such as impurities and the presence of a native passivation oxide layer at the surface of the films were investigated using analytical TEM. The twin boundaries observed in the present work partly explain the high strain hardening capacity by providing both increasing resistance to dislocation motion with deformation and a source for dislocation multiplication. (C) 2012 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 5.702
Times cited: 44
DOI: 10.1016/j.ijplas.2012.04.003
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“Transmission electron microscopy investigation of dislocation slip during superelastic cycling of NiTi wires”. Delville R, Malard B, Pilch J, Sittner P, Schryvers D, International journal of plasticity 27, 282 (2011). http://doi.org/10.1016/j.ijplas.2010.05.005
Abstract: Superelastic deformation of thin NiTi wires containing various nanograined microstructures was investigated by tensile cyclic loading with in situ evaluation of electric resistivity. Defects created by the superelastic cycling in these wires were analyzed by transmission electron microscopy. The role of dislocation slip in superelastic deformation is discussed. NiTi wires having finest microstructures (grain diameter <100 nm) are highly resistant against dislocation slip, while those with fully recrystallized microstructure and grain size exceeding 200 nm are prone to dislocation slip. The density of the observed dislocation defects increases significantly with increasing grain size. The upper plateau stress of the superelastic stressstrain curves is largely grain size independent from 10 up to 1000 nm. It is hence claimed that the HallPetch relationship fails for the stress-induced martensitic transformation in this grain size range. It is proposed that dislocation slip taking place during superelastic cycling is responsible for the accumulated irreversible strains, cyclic instability and degradation of functional properties. No residual martensite phase was found in the microstructures of superelastically cycled wires by TEM and results of the in situ electric resistance measurements during straining also indirectly suggest that none or very little martensite phase remains in the studied cycled superelastic wires after unloading. The accumulation of dislocation defects, however, does not prevent the superelasticity. It only affects the shape of the stressstrain response, makes it unstable upon cycling and changes the deformation mode from localized to homogeneous. The activity of dislocation slip during superelastic deformation of NiTi increases with increasing test temperature and ultimately destroys the superelasticity as the plateau stress approaches the yield stress for slip. Deformation twins in the austenite phase ({1 1 4} compound twins) were frequently found in cycled wires having largest grain size. It is proposed that they formed in the highly deformed B19′ martensite phase during forward loading and are retained in austenite after unloading. Such twinning would represent an additional deformation mechanism of NiTi yielding residual irrecoverable strains.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 5.702
Times cited: 157
DOI: 10.1016/j.ijplas.2010.05.005
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“Effect of structural defects on the hydriding kinetics of nanocrystalline Pd thin films”. Delmelle R, Amin-Ahmadi B, Sinnaeve M, Idrissi H, Pardoen T, Schryvers D, Proost J, International journal of hydrogen energy 40, 7335 (2015). http://doi.org/10.1016/j.ijhydene.2015.04.017
Abstract: While the microstructure of a metal is well-known to affect its equilibrium hydrogen uptake and therefore the hydriding thermodynamics, microstructural effects on the hydriding kinetics are much less documented. Moreover, for thin film systems, such microstructural effects are difficult to separate from the internal stress effect, since most defects generate internal stresses. Such a decoupling has been achieved in this paper for nanocrystalline Pd thin film model systems through the use of a high-resolution, in-situ curvature measurement set-up during Pd deposition, annealing and hydriding. This set-up allowed producing Pd thin films with similar internal stress levels but significantly different microstructures. This was evidenced from detailed defect statistics obtained by transmission electron microscopy, which showed that the densities of grain boundaries, dislocations and twin boundaries have all been lowered by annealing. The same set-up was then used to study the hydriding equilibrium and kinetic behaviour of the resulting films at room temperature. A full quantitative analysis of their hydriding cycles showed that the rate constants of both the adsorption- and absorption-limited kinetic regimes were strongly affected by microstructure. Defect engineering was thereby shown to increase the rate constants for hydrogen adsorption and absorption in Pd by a factor 40 and 30, respectively. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 3.582
Times cited: 13
DOI: 10.1016/j.ijhydene.2015.04.017
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“Composition gradients surrounding Ni4Ti3 precipitates in a NiTi alloy studied by EELS, EFTEM and EDX”. Yang Z, Schryvers D, International journal of applied electromagnetics and mechanics 23, 17 (2006)
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 0.769
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“Martensitic and related transformations in Ni-Al alloys”. Schryvers D, Journal de physique: 4
T2 –, IIIrd European Symposium on Martensitic Transformations (ESOMAT 94), SEP 14-16, 1994, BARCELONA, SPAIN 5, 225 (1995). http://doi.org/10.1051/jp4:1995235
Abstract: The present paper gives a review of results of recent studies investigating the fundamentals of the martensitic and related phase transformations in Ni-Al. For the former case, the emphasis will be on the microstructure of martensite plates. The latter include the metastable Ni2Al omega-like and stable Ni5Al3 bainitic phases. These phases will be discussed in view of their atomic structure, nucleation, growth and effect on the martensitic transformation. A separate chapter will deal with precursor effects.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 21
DOI: 10.1051/jp4:1995235
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“Nucleation and growth of the Ni5Al3 phase in Ni-Al austenite and martensite”. Schryvers D, Toth L, Ma Y, Tanner L, Journal de physique: 4
T2 –, IIIrd European Symposium on Martensitic Transformations (ESOMAT 94), SEP 14-16, 1994, BARCELONA, SPAIN 5, 299 (1995). http://doi.org/10.1051/jp4:1995246
Abstract: The nucleation and growth mechanisms of Ni5Al3 precipitates and microtwinned plates in B2 austenite and 2M (3R) martensite phases are described on the basis of conventional and high resolution electron microscopy. In the Ni62.5Al37.5 B2 austenite matrix short annealings at 550 degrees C introduce three-pointed star shaped precipitates consisting of twin related parts of different variants of the Ni5Al3 structure. Longer annealings result in plates growing separately from these wings and developing microtwinning in order to accommodate stress built-up at the interfaces with the surrounding matrix. Annealing of Ni65Al35 2M martensite plates induces simple reordering into the Ni5Al3 phase, increasing the fct c/a ratio by about 1%. As a result stracking faults are introduced in the smallest twin variants.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 3
DOI: 10.1051/jp4:1995246
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“Fabrication and characterization of functionally graded Ni-Ti multilayer thin films”. Tian H, Schryvers D, Mohanchandra KP, Carman GP, van Humbeeck J, Functional materials letters 2, 61 (2009). http://doi.org/10.1142/S1793604709000570
Abstract: A functionally graded multilayer NiTi thin film was deposited on a SiO2/Si substrate by d.c. sputtering using a ramped heated NiTi alloy target. The stand-alone films were crystallized at 500°C in vacuum better than 10-7 Torr. Transmission electron microscopy micrographs taken along the film cross section show two distinct regions, thin and thick, with weak R and B2 phases, respectively. The film compositions along the thickness were measured and quantified using the standard-less EELSMODEL method. The film deposited during the initial thermal ramp (thin regions) displays an average of 54 at.% Ni while the film deposited at a more elevated target temperature (thick regions) shows about 51 at.% Ni.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.234
Times cited: 9
DOI: 10.1142/S1793604709000570
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“Microstructure and functional property changes in thin Ni-Ti wires heat teated by electric current: high energy X-ray and TEM investigations”. Malard B, Pilch J, Sittner P, Gartnerova V, Delville R, Schryvers D, Curfs C, Functional materials letters 2, 45 (2009). http://doi.org/10.1142/S1793604709000557
Abstract: High energy synchrotron X-ray diffraction, transmission electron microscopy and mechanical testing were employed to investigate the evolution of microstructure, texture and functional superelastic properties of 0.1 mm thin as drawn NiTi wires subjected to a nonconventional heat treatment by controlled electric current (FTMT-EC method). As drawn NiTi wires were prestrained in tension and exposed to a sequence of short DC power pulses in the millisecond range. The annealing time in the FTMT-EC processing can be very short but the temperature and force could be very high compared to the conventional heat treatment of SMAs. It is shown that the heavily strained, partially amorphous microstructure of the as drawn NiTi wire transforms under the effect of the DC pulse and tensile stress into a wide range of annealed nanosized microstructures depending on the pulse time. The functional superelastic properties and microstructures of the FTMT-EC treated NiTi wire are comparable to those observed in straight annealed wires.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.234
Times cited: 21
DOI: 10.1142/S1793604709000557
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“Ni cluster formation in low temperature annealed Ni50.6Ti49.4”. Pourbabak S, Wang X, Van Dyck D, Verlinden B, Schryvers D, Functional materials letters 10, 1740005 (2017). http://doi.org/10.1142/S1793604717400057
Abstract: Various low temperature treatments of Ni50.6Ti49.4 have shown an unexpected effect on the martensitic start temperature. Periodic diffuse intensity distributions in reciprocal space indicate the formation of short pure Ni strings along the <111> directions in the B2 ordered lattice, precursing the formation of Ni4Ti3 precipitates formed at higher annealing temperatures.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Impact Factor: 1.234
Times cited: 4
DOI: 10.1142/S1793604717400057
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“TEM and Raman characterisation of diamond micro- and nanostructures in carbon spherules from upper soils”. Yang ZQ, Verbeeck J, Schryvers D, Tarcea N, Popp J, Rösler W, Diamond and related materials 17, 937 (2008). http://doi.org/10.1016/j.diamond.2008.01.104
Abstract: Carbonaceous spherules of millimeter size diameter and found in the upper soils throughout Europe are investigated by TEM, including SAED, HRTEM and EELS, and Raman spectroscopy. The spherules consist primarily of carbon and have an open cell-like internal structure. Most of the carbon appears in an amorphous state, but different morphologies of nano- and microdiamond particles have also been discovered including flake shapes. The latter observation, together with the original findings of some of these spherules in crater-like structures in the landscape and including severely deformed rocks with some spherules being embedded in the fused crust of excavated rocks, points towards unique conditions of origin for these spherules and particles, possibly of exogenic origin. (C) 2008 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.561
Times cited: 26
DOI: 10.1016/j.diamond.2008.01.104
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“A versatile lab-on-chip test platform to characterize elementary deformation mechanisms and electromechanical couplings in nanoscopic objects”. Pardoen T, Colla M-S, Idrissi H, Amin-Ahmadi B, Wang B, Schryvers D, Bhaskar UK, Raskin J-P, Comptes rendus : physique 17, 485 (2016). http://doi.org/10.1016/j.crhy.2015.11.005
Abstract: A nanomechanical on-chip test platform has recently been developed to deform under a variety of loading conditions freestanding thin films, ribbons and nanowires involving submicron dimensions. The lab-on-chip involves thousands of elementary test structures from which the elastic modulus, strength, strain hardening, fracture, creep properties can be extracted. The technique is amenable to in situ transmission electron microscopy (TEM) investigations to unravel the fundamental underlying deformation and fracture mechanisms that often lead to size-dependent effects in small-scale samples. The method allows addressing electrical and magnetic couplings as well in order to evaluate the impact of large mechanical stress levels on different solid-state physics phenomena. We had the chance to present this technique in details to Jacques Friedel in 2012 who, unsurprisingly, made a series of critical and very relevant suggestions. In the spirit of his legacy, the paper will address both mechanics of materials related phenomena and couplings with solids state physics issues.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.048
Times cited: 7
DOI: 10.1016/j.crhy.2015.11.005
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“Transmission electron microscopy study of complex oxide scales on DIN 1.4970 steel exposed to liquid Pb-Bi eutectic”. Charalampopoulou E, Delville R, Verwerft M, Lambrinou K, Schryvers D, Corrosion science 147, 22 (2019). http://doi.org/10.1016/j.corsci.2018.10.018
Abstract: The deployment of Gen-IV lead-cooled fast reactors requires a good compatibility between the selected structural/cladding steels and the inherently corrosive heavy liquid metal coolant. An effective liquid metal corrosion mitigation strategy involves the in-situ steel passivation in contact with the oxygen-containing Pb-alloy coolant. Transmission electron microscopy was used in this work to study the multi-layered oxide scales forming on an austenitic stainless steel fuel cladding exposed to oxygen-containing (CO ≈ 10−6 mass%) static liquid leadbismuth eutectic (LBE) for 1000 h between 400 and 500 °C. The oxide scale constituents were analyzed, including the intertwined phases comprising the innermost biphasic layer.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Times cited: 5
DOI: 10.1016/j.corsci.2018.10.018
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“Stress-assisted crystallisation in anodic titania”. Vanhumbeeck J-F, Tian H, Schryvers D, Proost J, Corrosion science 53, 1269 (2011). http://doi.org/10.1016/j.corsci.2010.12.020
Abstract: The relationship between the microstructural and internal stress evolution during Ti anodising is discussed. Samples anodised galvanostatically to 12 V and 40 V, corresponding to different stages of the internal stress evolution, were examined by in-plane and cross-section transmission electron microscopy. Electron diffraction patterns have been complemented with stoichiometry data obtained from energy loss near edge structure spectra. The sample anodised to 40 V was observed to consist of two regions, with a crystallised inner region adjacent to the metal/oxide interface. Crystallisation of this region is associated with the presence of large compressive internal stresses which build up during anodising up to 12 V.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 5.245
Times cited: 11
DOI: 10.1016/j.corsci.2010.12.020
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“Crack initiation in tapered high Si stainless steel specimens : stress threshold analyses”. Penders A, Konstantinovic MJ, Bosch RW, Schryvers D, Corrosion Engineering Science And Technology , 1 (2020). http://doi.org/10.1080/1478422X.2020.1785651
Abstract: Tapered specimens were used for an accelerated test technique to study the crack initiation of high Si stainless steel by means of constant elongation rate tensile testing in a simulated pressurised water reactor environment. Detailed crack density distributions were obtained by applying an advanced crack detection algorithm on iteratively displaced scanning electron microscopy pictures featuring stress corrosion cracks along the specimen's gauge length. By means of finite-element analysis, prominent peaks in the crack density graphs are demonstrated to be related to stress relief and stress build-up during the crack initiation phase. Intrinsic scatter related to the crack detection suggests that stress corrosion cracking is independent of the strain-rate for strain-rates lower than 10(-6 )s(-1). Based on the extrapolation to constant load conditions, the critical threshold value for the duplex high Si stainless steel is estimated to be around 580 MPa.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 1.8
Times cited: 1
DOI: 10.1080/1478422X.2020.1785651
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“TEM investigation of SCC crack tips in high Si stainless steel tapered specimens”. Penders A, Konstantinovic MJ, Van Renterghem W, Bosch RW, Schryvers D, Corrosion Engineering Science And Technology (2021). http://doi.org/10.1080/1478422X.2021.1961665
Abstract: The stress corrosion cracking (SCC) mechanism is investigated in high Si duplex stainless steel in a simulated PWR environment based on TEM analysis of FIB-extracted SCC crack tips. The microstructural investigation in the near vicinity of SCC crack tips illustrates a strain-rate dependence in SCC mechanisms. Detailed analysis of the crack tip morphology, that includes crack tip oxidation and surrounding deformation field, indicates the existence of an interplay between corrosion- and deformation-driven failure as a function of the strain rate. Slow strain-rate crack tips exhibit a narrow cleavage failure which can be linked to the film-induced failure mechanism, while rounded shaped crack tips for faster strain rates could be related to the strain-induced failure. As a result, two nominal strain-rate-dependent failure regimes dominated either by corrosion or deformation-driven cracking mechanisms can be distinguished.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 0.879
DOI: 10.1080/1478422X.2021.1961665
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“Optical encoding of luminescent carbon nanodots in confined spaces”. Bartholomeeusen E, De Cremer G, Kennes K, Hammond C, Hermans I, Lu J-B, Schryvers D, Jacobs PA, Roeffaers MBJ, Hofkens J, Sels BF, Coutino-Gonzalez E, Chemical Communications 57, 11952 (2021). http://doi.org/10.1039/D1CC04777A
Abstract: Stable emissive carbon nanodots were generated in zeolite crystals using near infrared photon irradiation gradually converting the occluded organic template, originally used to synthesize the zeolite crystals, into discrete luminescent species consisting of nano-sized carbogenic fluorophores, as ascertained using Raman microscopy, and steady-state and time-resolved spectroscopic techniques. Photoactivation in a confocal laser fluorescence microscope allows 3D resolved writing of luminescent carbon nanodot patterns inside zeolites providing a cost-effective and non-toxic alternative to previously reported metal-based nanoclusters confined in zeolites, and opens up opportunities in bio-labelling and sensing applications.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.319
DOI: 10.1039/D1CC04777A
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“Towards biolubricant compatible vegetable oils by pore mouth hydrogenation with shape-selective Pt/ZSM-5 catalysts”. Van Aelst J, Philippaerts A, Bartholomeeusen E, Fayad E, Thibault-Starzyk F, Lu J, Schryvers D, Ooms R, Verboekend D, Jacobs P, Sels B, Catalysis science &, technology 6, 2820 (2016). http://doi.org/10.1039/C6CY00498A
Abstract: Pt/ZSM-5 catalysts with various crystal sizes were prepared via competitive ion-exchange, followed by a slow activation procedure. Even when using very large ZSM-5 crystals, highly dispersed Pt nano-clusters were contained within the zeolite crystal's voids, as ascertained by 2D pressure-jump IR spectroscopy of adsorbed CO and focussed ion-beam transmission electron microscopy. The shape-selective properties of the Pt/ZSM-5 catalysts were evaluated in the partial hydrogenation of soybean oil. Unique hydrogenation selectivities were observed, as the fatty acids located at the central position of the triacylglycerol (TAG) molecules were preferentially hydrogenated. The resulting oil has therefore high levels of intermediately melting TAGs, which are compatible with biolubricants due to their improved oxidative stability and still appropriate low-temperature fluidity. The TAG distribution in the partially hydrogenated soybean oil samples was independent from the zeolite crystal size, while the hydrogenation activity linearly increases with the crystal's external surface area. This trend was confirmed with a Pt loaded mesoporous ZSM-5 zeolite, obtained via a mild alkaline treatment. These observations imply and confirm a genuine pore mouth catalysis mechanism, in which only one fatty acid chain of the TAG is able to enter the micropores of ZSM-5, where the double bonds are hydrogenated by the crystal encapsulated Pt-clusters.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 5.773
Times cited: 5
DOI: 10.1039/C6CY00498A
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“Critical assessments and thermodynamic modeling of BaO-SiO2 and SiO2-TiO2 systems and their extensions into liquid immiscibility in the BaO-SiO2-TiO2 system”. Boulay E, Nakano J, Turner S, Idrissi H, Schryvers D, Godet S, Calphad computer coupling of phase diagrams and thermochemistry 47, 68 (2014). http://doi.org/10.1016/j.calphad.2014.06.004
Abstract: This study discusses rational reproduction of liquid immiscibility in the BaO-SiO2-TiO2 system. While a ternary assessment requires sub-binary descriptions in the same thermodynamic model, the related sub-binary systems BaO-SiO2, BaO-TiO2 and SiO2-TiO2 liquid and solid phases have been evaluated using different thermodynamic models in the literature. In this study, BaO-SiO2 and SiO2-TiO2 were assessed using the Ionic Two Sublattice model (I2SL) based on experimental data from the literature. BaO-TiO2 was already assessed using this model. Binary descriptions developed were then used for the assessment of liquid immiscibility in the BaO-SiO2-TiO2 system. Ternary interaction parameters were found necessary for rational reproduction of the new ternary experimental data gathered in the present work. The model parameters for each system were evaluated using a CAPLHAD approach. A set of parameters is proposed. They show good agreement between the calculated and experimental equilibrium liquidus, liquid immiscibility and thermochemical properties in the BaO-SiO2-TiO2 system. (C) 2014 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.6
Times cited: 9
DOI: 10.1016/j.calphad.2014.06.004
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“The influence of surface oxides on the distribution and release of nickel from Nitinol wires”. Shabalovskaya SA, Tian H, Anderegg JW, Schryvers DU, Carroll WU, van Humbeeck J, Biomaterials 30, 468 (2009). http://doi.org/10.1016/j.biomaterials.2008.10.014
Abstract: The patterns of Ni release from Nitinol vary depending on the type of material (NiTi alloys with low or no processing versus commercial wires or sheets). A thick TiO2 layer generated on the wire surface during processing is often considered as a reliable barrier against Ni release. The present study of Nitinol wires with surface oxides resulting from production was conducted to identify the sources of Ni release and its distribution in the surface sublayers. The chemistry and topography of the surfaces of Nitinol wires drawn using different techniques were studied with XPS and SEM. The distribution of Ni into surface depth and the surface oxide thickness were evaluated using Auger spectroscopy, TEM with FIB and ELNES. Ni release was estimated using either ICPA or AAS. Potentiodynamic potential polarization of selected wires was performed in as-received state with no strain and in treated strained samples. Wire samples in the as-received state showed low breakdown potentials (200 mV); the improved corrosion resistance of these wires after treatment was not affected by strain. It is shown how processing techniques affect surface topography, chemistry and also Ni release. Nitinol wires with the thickest surface oxide TiO2 (up to 720 nm) showed the highest Ni release, attributed to the presence of particles of essentially pure Ni whose number and size increased while approaching the interface between the surface and the bulk. The biological implications of high and lasting Ni release are also discussed.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 8.402
Times cited: 102
DOI: 10.1016/j.biomaterials.2008.10.014
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“High resolution transmission electron microscopy characterization of fcc ->, 9R transformation in nanocrystalline palladium films due to hydriding”. Amin-Ahmadi B, Idrissi H, Delmelle R, Pardoen T, Proost J, Schryvers D, Applied physics letters 102, 071911 (2013). http://doi.org/10.1063/1.4793512
Abstract: Sputtered nanocrystalline palladium thin films with nanoscale growth twins have been subjected to hydriding cycles. The evolution of the twin boundaries has been investigated using high resolution transmission electron microscopy. Surprisingly, the Sigma 3{112} incoherent twin boundaries dissociate after hydriding into two phase boundaries bounding a 9R phase. This phase which corresponds to single stacking faults located every three {111} planes in the fcc Pd structure was not expected because of the high stacking fault energy of Pd. This observation is connected to the influence of the Hydrogen on the stacking fault energy of palladium and the high compressive stresses building up during hydriding. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4793512]
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.411
Times cited: 14
DOI: 10.1063/1.4793512
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“Plasticity mechanisms in ultrafine grained freestanding aluminum thin films revealed by in-situ transmission electron microscopy nanomechanical testing”. Idrissi H, Kobler A, Amin-Ahmadi B, Coulombier M, Galceran M, Raskin J-P, Godet S, Kuebel C, Pardoen T, Schryvers D, Applied physics letters 104, 101903 (2014). http://doi.org/10.1063/1.4868124
Abstract: In-situ bright field transmission electron microscopy (TEM) nanomechanical tensile testing and in-situ automated crystallographic orientation mapping in TEM were combined to unravel the elementary mechanisms controlling the plasticity of ultrafine grained Aluminum freestanding thin films. The characterizations demonstrate that deformation proceeds with a transition from grain rotation to intragranular dislocation glide and starvation plasticity mechanism at about 1% deformation. The grain rotation is not affected by the character of the grain boundaries. No grain growth or twinning is detected. (C) 2014 AIP Publishing LLC.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.411
Times cited: 24
DOI: 10.1063/1.4868124
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“Quantitative Landau potentials for the martensitic transformation in Ni-Al”. Salje EKH, Zhang H, Schryvers D, Bartova B, Applied physics letters 90, 221903 (2007). http://doi.org/10.1063/1.2743927
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.411
Times cited: 9
DOI: 10.1063/1.2743927
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“A TEM study of nanoparticles in lustre glazes”. Fredrickx P, Helary D, Schryvers D, Darque-Ceretti E, Applied physics A : materials science &, processing 79, 283 (2004). http://doi.org/10.1007/s00339-004-2515-3
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.455
Times cited: 16
DOI: 10.1007/s00339-004-2515-3
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