No (438)
Yes (4)
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442
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Study of lithium encapsulation in porous membrane using ion and neutron beams
Ceccio, Giovanni; Cannavó, Antonino; Horák, Pavel; Torrisi, Alfio; Tomandl, Ivo; Hnatowicz, Vladimír; Vacík, Jiří
2019 - English
Ion track-etched membranes are porous systems obtained by etching of the latent ion tracks using a suitable etchant solution. In this work, control of the pores' spatial profiles and dimensions in PET polymers was achieved by varying etching temperature and etching time. For determination of the pores' shape, Ion Transmission Spectroscopy technique was employed. In this method, alterations of the energy loss spectra of the transmitted ions reflect alterations in the material density of the porous foils, as well as alterations of their thickness. Simulation code, developed by the team, allowed the tomographic study of the ion track 3D geometry and its evolution during chemical etching. From the doping of porous membranes with lithium-based solution and its analysis by Thermal Neutron Depth Profiling method, the ability of porous PET membranes to encapsulate nano-sized material was also inspected. The study is important for various applications, e.g., for catalysis, active agents, biosensors, etc.
Keywords:
doping; etching; ion transmission spectroscopy; thermal neutron depth profiling
Available at various institutes of the ASCR
Study of lithium encapsulation in porous membrane using ion and neutron beams
Ion track-etched membranes are porous systems obtained by etching of the latent ion tracks using a suitable etchant solution. In this work, control of the pores' spatial profiles and dimensions in PET ...
Mechanical properties of WN43 magnesium alloy prepared by spark plasma sintering
Knapek, Michal; Minárik, P.; Greš, A.; Zemková, M.; Cinert, Jakub; Král, R.
2019 - English
The spark plasma sintering (SPS) method was used to prepare bulk materials form WN43 magnesium alloy atomized powder. Compression tests were carried out in order to investigate the effect of different sintering regimes (10 min at 400, 450, or 500 degrees C) on the mechanical properties of the material. Furthermore, complementary in-situ acoustic emission (AE) recording was employed to reveal the dynamics of deformation processes during compression. It was shown that by increasing the sintering temperature, the ultimate compressive strength and ductility were significantly improved. The AE data and microstructure observations suggest that pronounced twin nucleation takes place around the yield point whereas twin growth and dislocation activity are the dominant deformation mechanisms in the later stages of deformation.
Keywords:
spark plasma sintering; magnesium; deformation; twinning; acoustic emission
Available at various institutes of the ASCR
Mechanical properties of WN43 magnesium alloy prepared by spark plasma sintering
The spark plasma sintering (SPS) method was used to prepare bulk materials form WN43 magnesium alloy atomized powder. Compression tests were carried out in order to investigate the effect of different ...
Instrumentation for study of nanomaterials in NPI REZ (New laboratory for material study in Nuclear Physics Institute in REZ)
Bejšovec, Václav; Cannavó, Antonino; Ceccio, Giovanni; Hnatowicz, Vladimír; Horák, Pavel; Lavrentev, Vasyl; Macková, Anna; Tomandl, Ivo; Torrisi, Alfio; Vacík, Jiří
2019 - English
Nano-sized materials become irreplaceable component of a number of devices for every aspect of human life. The development of new materials and deepening of the current knowledge require a set of specialized techniques-deposition methods for preparation/modification of the materials and analytical tools for proper understanding of their properties. A thoroughly equipped research centers become the requirement for the advance and development not only in nano-sized field. The Center of Accelerators and Nuclear Analytical Methods (CANAM) in the Nuclear Physics Institute (NPI) comprises a unique set of techniques for the synthesis or modification of nanostructured materials and systems, and their characterization using ion beam, neutron beam and microscopy imaging techniques. The methods are used for investigation of a broad range of nano-sized materials and structures based on metal oxides, nitrides, carbides, carbon-based materials (polymers, fullerenes, graphenes, etc.) and nano-laminate composites (MAX phases). These materials can be prepared at NPI using ion beam sputtering, physical vapor deposition and molecular beam epitaxy. Based on the deposition method and parameters, the samples can be tuned to possess specific properties, e.g., composition, thickness (nm-μm), surface roughness, optical and electrical properties, etc. Various nuclear analytical methods are applied for the sample characterization. RBS, RBS-channeling, PIXE, PIGE, micro-beam analyses and Transmission Spectroscopy are accomplished at the Tandetron 4130MC accelerator, and additionally the Neutron Depth Profiling (NDP) and Prompt Gamma Neutron Activation (PGNA) analyses are performed at an external neutron beam from the LVR-15 research reactor. The multimode AFM facility provides further surface related information, magnetic/electrical properties with nano-metric precision, nano-indentation, etc.
Keywords:
AFM; ion beam analysis; LEIF
Available at various institutes of the ASCR
Instrumentation for study of nanomaterials in NPI REZ (New laboratory for material study in Nuclear Physics Institute in REZ)
Nano-sized materials become irreplaceable component of a number of devices for every aspect of human life. The development of new materials and deepening of the current knowledge require a set of ...
Neutron investigation of Nitinol stents and massive samples before and after PIRAC coating
Rogante, M.; Buhagiar, J.; Cassar, G.; Debono, M.; Lebedev, V.; Mikula, Pavol; Ryukhtin, Vasyl
2019 - English
Nitinol, a thermoelastic Ni-Ti Shape Memory Alloy (SMA) with approximately 50 at. % Ti, is adopted in a wide range of medical equipment and devices used in interventional radiology, orthopaedics, neurology and cardiology, in particular as a smart material for stents. In this work, NiTi real stents and massive samples before and after different Powder Immersion Reaction Assisted Coating (PIRAC) treatments have been investigated by using two neutron techniques: (1) Small and Ultra-Small Angle Neutron Scattering (SANS, USANS) for nano- and micro-scale characterization, obtaining information on structure and the effects due to the coating treatment, and (2) High-Resolution Neutron Diffraction (HRND), evaluating the macrostrain components resulting from angular shifts of diffraction peaks and the micro-strains in the plastically deformation region by means of profile-broadening analysis. The obtained results contribute: improving knowledge of defects and other key features of the materials complementary to those achieved by using traditional examination techniques. helping to better understand the functional characteristics of Nitinol parts and predict the material's mechanical behaviour.
Keywords:
high-resolution neutron diffraction; nanostructure; Nitinol; SANS
Available at various institutes of the ASCR
Neutron investigation of Nitinol stents and massive samples before and after PIRAC coating
Nitinol, a thermoelastic Ni-Ti Shape Memory Alloy (SMA) with approximately 50 at. % Ti, is adopted in a wide range of medical equipment and devices used in interventional radiology, orthopaedics, ...
Investigation of deformation mechanisms in textured magnesium alloy
Dittrich, J.; Čapek, J.; Knapek, Michal; Minárik, P.
2019 - English
Advanced in-situ and ex-situ methods were used to reveal active deformation mechanisms during deformation of magnesium alloy with a strong texture. Three sets of samples were prepared from the rolled sheet of commercial AZ31 alloy with respect to its strong basal texture - normal direction (ND), rolling direction (RD) and 45 degrees between RD and ND, and were deformed in both compression and tension. The signal of acoustic emission (AE) was measured concurrently during the deformation. Electron backscattered diffraction (EBSD) was used to study the microstructure after the selected stages of the deformation. It is shown that the extension twinning played an important role during the plastic deformation in the samples having favorably oriented basal texture component, whereas in the unfavorably oriented samples, the role of twinning was marginal. Pronounced activation of twinning only in some samples caused a considerable variation in the deformation behavior and AE response. A consistent link between the energy and amplitudes of the AE signal and the microstructure changes investigated by EBSD was established.
Keywords:
magnesium; deformation; twinning; acoustic emission; EBSD
Available at various institutes of the ASCR
Investigation of deformation mechanisms in textured magnesium alloy
Advanced in-situ and ex-situ methods were used to reveal active deformation mechanisms during deformation of magnesium alloy with a strong texture. Three sets of samples were prepared from the rolled ...
Effect of aluminum content and precipitation on the corrosion behavior and acoustic emission response of AZ31 and AZ80 magnesium alloys
Veverková, E.; Knapek, Michal; Minárik, P.
2019 - English
In this study, we investigated the effect of aluminum content and precipitation on the corrosion behavior of the AZ31 and AZ80 magnesium alloys. The investigated alloys were received in the as-extruded condition in order to retain comparable grain size and texture. First, solid solution treatment was performed on the samples of both alloys. Subsequently, the samples were isothermally aged at 200 degrees C for 20 hours. The scanning electron microscopy was used to study the grain size and microstructure. The corrosion properties of samples were studied by potentiodynamic polarization measurements and the AE signal was concurrently recorded. Solution treated AZ80 and AZ31 samples exhibited similar behavior. The aged AZ80 sample showed lower corrosion rate. Also, a strong breakdown appeared in the later (compared to other samples) stage of the potentiodynamic test. The breakdown was found to be easily recognized by AE parameters.
Keywords:
Magnesium alloys; corrosion; acoustic emission; polarization
Available at various institutes of the ASCR
Effect of aluminum content and precipitation on the corrosion behavior and acoustic emission response of AZ31 and AZ80 magnesium alloys
In this study, we investigated the effect of aluminum content and precipitation on the corrosion behavior of the AZ31 and AZ80 magnesium alloys. The investigated alloys were received in the ...
Effect of implantation of C, Si and Cu into ZrNb nanometric multilayers
Daghbouj, N.; Karlík, M.; Lorinčík, J.; Polcar, T.; Callisti, M.; Havránek, Vladimír
2019 - English
Sputter-deposited Zr/Nb nanometric multilayer films with a periodicity (L) in the range from 6 to 167 nm were subjected to carbon, silicon and copper ion irradiation with low and high fluences at room temperature. The ion profiles, mechanical proprieties, and disordering behavior have been investigated by using a variety of experimental techniques (Secondary Ion Mass Spectrometry - SIMS, nanoindentation, X-ray diffraction - XRD, and scanning transmission electron microscopy - STEM). On the STEM bright field micrographs there is damage clearly visible on the surface side of the multilayer. Deeper, the most damaged and disordered zone, located close to the maximum ion concentration, was observed. The in-depth C and Si concentration profiles obtained from SIMS were not affected by the periodicity of the nanolayers. This is in accordance with SRIM simulations. XRD and electron diffraction analyses suggest a structural evolution in relation to L. After irradiation, Zr (0002) and Nb (110) reflexions overlap for L=6 nm. For the periodicity L > 6 nm the Zr (0002) peak is shifted to higher angles and Nb (110) peak is shifted to lower angles.
Keywords:
Zr/Nb multilayers; ion irradiation; strain; XRD; SIMS
Available at various institutes of the ASCR
Effect of implantation of C, Si and Cu into ZrNb nanometric multilayers
Sputter-deposited Zr/Nb nanometric multilayer films with a periodicity (L) in the range from 6 to 167 nm were subjected to carbon, silicon and copper ion irradiation with low and high fluences at room ...
Production and characterization of micro-size pores for ion track etching applications
Cannavó, Antonino; Havránek, Vladimír; Lavrentev, Vasyl; Torrisi, L.; Cutroneo, Mariapompea; Ceccio, Giovanni; Torrisi, Alfio; Horák, Pavel; Vacík, Jiří
2019 - English
For many years the applications of ion track etch materials have increased considerably, like charged particles detection, molecular identification with nanopores, ion track filters, magnetic studies with nanowires and so on. Over the materials generally used as track detector, the Poly-Allyl-Diglycol Carbonate (PADC), offers many advantages, like its nearly 100 % detection efficiency for charged particle, a high resistance to harsh environment, the lowest detection threshold, a high abrasion resistance and a low production costs. All of these properties have made it particularly attractive material, even if due to its brittleness, obtaining a thin film (less than 500 μm) is still a challenge. In this work, PADC foils have been exposed to a-particles emitted by a thin radioactive source of 241Am and to C ions from the Tandetron 4130 MC accelerator. The latent tracks generated in the polymer have been developed using a standard etching procedure in 6.25 NaOH solution. The dependence of the ion tracks' geometry on the ion beam energy and fluence has been evaluated combining the information obtained through a semiautomatic computer script that selects the etched ion tracks according to their diameter and mean grey value and nanometric resolution images by atomic force microscopy.
Keywords:
AFM; image analysis; PADC polymer
Available at various institutes of the ASCR
Production and characterization of micro-size pores for ion track etching applications
For many years the applications of ion track etch materials have increased considerably, like charged particles detection, molecular identification with nanopores, ion track filters, magnetic studies ...
Preparation of ppHMDSO Thin Films in Capacitively Coupled RF Glow Discharges under Dusty Plasma Conditions
Homola, V.; Buršíková, V.; Kelar, L.; Kelarová, Š.; Stupavska, M.; Peřina, Vratislav
2018 - English
The deposition of organosilicone thin films from mixture of hexamethyldisiloxane (HMDSO) and oxygen by using capacitively coupled R.F. glow discharges under dusty plasma conditions was investigated. High resolution topography and mechanical property maps of the prepared films were acquired by using atomic force microscopy techniques. The chemical bond and composition of the deposited films were analyzed by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The mechanical properties of the films were studied using quasistatic as well as dynamic nanoindentation tests and their surface free energies were evaluated by means of contact angle measuring technique using several testing liquids exhibiting various surface tensions. The thermal stability of the films was studied using thermal desorption spectroscopy. Neural network modelling was used to study the effect of plasma parameters on the hardness of ppHMDSO films
Keywords:
Hexamethyldisiloxane; mechanical properties; oxygen; PECVD
Available at various institutes of the ASCR
Preparation of ppHMDSO Thin Films in Capacitively Coupled RF Glow Discharges under Dusty Plasma Conditions
The deposition of organosilicone thin films from mixture of hexamethyldisiloxane (HMDSO) and oxygen by using capacitively coupled R.F. glow discharges under dusty plasma conditions was investigated. ...
Role of activation analysis in the preparation of reference materials
Kučera, Jan
2018 - English
The fundamentals of neutron activation analysis (NAA) and prompt gamma activation analysis (PGAA) and practices of both methods are briefly review, together with enlightening their specific role in the preparation of reference materials. The importance of homogeneity testing for the certification and use of reference materials (RMs) using NAA is appraised. Examples of the use of NAA and PGAA for the certification of element contents in environmental, biological, and material science RMs produced by world-leading institutions, such as U.S. NIST, IRMM, IAEA and by national institutions, as well, at the Nuclear Physics Institute within last almost 30 years are presented.
Keywords:
analytical methods; INAA; RNAA
Available at various institutes of the ASCR
Role of activation analysis in the preparation of reference materials
The fundamentals of neutron activation analysis (NAA) and prompt gamma activation analysis (PGAA) and practices of both methods are briefly review, together with enlightening their specific role in ...
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