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Wyszukujesz frazę "Fe" wg kryterium: Temat


Tytuł:
The influence of heat treatment on point defect concentration in Fe-Al and Fe-Al-Cr systems
Autorzy:
Kansy, J.
Hanc, A.
Giebel, D.
Powiązania:
https://bibliotekanauki.pl/articles/146336.pdf
Data publikacji:
2010
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
positron annihilation
Fe-Al
Fe-Al-Cr
point defects
Opis:
FeAl alloys of nominal Al content 28, 38 and 45 at.% and Fe28Al5Cr with minor alloying elements added to improve their application properties are studied by positron annihilation lifetime analysis. The lifetime spectra of samples FeXAl with X greater-than or equal to 38 (both quenched and cooled with furnace) are described by a single lifetime component related to the saturated positron trapping by quenched-in vacancies of concentration much higher than 100 ppm. A very strong dependence of retained vacancy concentration on the rate of cooling is shown for Fe28Al and Fe28Al5Cr alloys. After quenching, the concentration is of the order of 10.4 whereas in samples slowly cooled it is reduced to 10.5. The chromium addition to Fe28Al5Cr dismisses the vacancies concentration in comparison to the concentration in Fe28Al after the same heat treatment.
Źródło:
Nukleonika; 2010, 55, 1; 21-25
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Mössbauer and structural study of disordered alloys Fe3-xTixAl (0 < x < 1)
Autorzy:
Brząkalik, K.
Frąckowiak, J.
Powiązania:
https://bibliotekanauki.pl/articles/148880.pdf
Data publikacji:
2003
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
Fe2TiAl Heusler phase
Fe-Ti-Al system
Mössbauer spectroscopy
Opis:
A series of the disordered Fe3-xTixAl (x = 0, 0.2, 0.45, 0.55, 0.65, 0.70, 0.75, 1) alloys obtained by arc-melting were studied. Directly after melting the samples were mechanically crashed and in that form examined by the structural and Mössbauer effect methods. The alloys were strongly disordered, but it was possible to identify, apart from Fe-bcc phase, the origins of forming such phases as Fe2TiAl Heusler phase, Fe3Al with DO3 structure, FeAl and FeTi with B2 structure and non-stechiometric Fe2Ti Laves phase with hexagonal C14 structure. For Ti concentration up to x = 0.45, the disordered Fe-bcc phase dominates. For Ti concentration from x = 0.55 to x = 1, the Fe2TiAl phase coexists with FeAl phase (for x = 0.55, 0.65) and with FeTi phase (x = 0.7 and 0.75). In a sample with the nominal Fe2TiAl composition of Fe2TiAl Heusler phase, a non-stoichiometric Fe2Ti Laves phase with hexagonal C14 structure was observed.
Źródło:
Nukleonika; 2003, 48,suppl.1; 13-16
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase structure of the nanocrystalline Nd2Fe14B/alfa-Fe magnets with different grain
Autorzy:
Wnuk, I.
Wysłocki, J.
Przybył, A.
Powiązania:
https://bibliotekanauki.pl/articles/148342.pdf
Data publikacji:
2007
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
Nd2Fe14B + alfa-Fe nanocrystalline magnets
Mössbauer spectroscopy
magnetic properties
Opis:
The effect of the contents of the magnetically hard and magnetically soft phases on the magnetic properties of Nd2Fe14B + alfa-Fe nanocrystalline magnets, as produced by the method of mechanical alloying, has been established. The phase composition of specimens was determined using X-ray diffractometry and Mössbauer spectroscopy. The Mössbauer examination showed that as the powder milling times increased, the content of the Nd2Fe14B phase increased from 42.8% (after the milling time of 10 h, with a grain size of 44.8 nm) to 66.3% (after the milling time of 48 h, with a grain size of 37.3 nm) and then decreased to 40.3% after 120 h of milling. On the other hand, the content of the magnetically soft phase alfa-Fe initially decreased (from 27.7%), reaching a minimum after the milling time of 48 h (17.4%) and then increasing to 36.9% after 120 h of milling.
Źródło:
Nukleonika; 2007, 52, supl. 1; 85-88
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mössbauer study of vacuum annealed Fe100-xGax (10 less - than or equal to x less - than or equal to 35) thin films
Autorzy:
Szumiata, T.
Górka, B.
Brzózka, K.
Gawroński, M.
Gzik-Szumiata, M.
Javed, A.
Morley, N. A.
Gibbs, M. R. J.
Powiązania:
https://bibliotekanauki.pl/articles/147332.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
Fe-Ga
thin films
CEMS
MOKE
Opis:
This work reports results from comparative Mossbauer studies of as-deposited and annealed Fe100.xGax (10 less - than or equal to x less - than or equal to 35) high magnetostrictive thin films of constant thickness (50 plus or minus 2 nm). Films were grown on Si(100) substrates using a co-sputtering and evaporation chamber where Fe has been sputtered and Ga was evaporated. During growth of films, a magnetic field of 65 kA/m has been applied in the plane of the film. Annealed films have been obtained by heating in vacuum for 1 h at 350 centigrade without magnetic field. After annealing, the saturation field of the Fe-Ga films has been significantly reduced. By means of the 57Fe CEMS technique the contributions from several phases have been found: Fe-Ga A2 (bcc), traces of DO3 phase, a gallium-rich disordered phase and iron oxides (both geothite and magnetite). For the sample with x = 26.5 the heat treatment reduces the DO3 phase content whereas for the film with x = 16.4 the opposite tendency has been observed. Mossbauer results were compared with XRD and MOKE findings.
Źródło:
Nukleonika; 2013, 58, 1; 27-30
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nanocrystallization studies of rapidly quenched Fe85.4-xCoxZr6.8-yNbyB6.8Cu1 (x = 0 or 42.7, y = 0 or 1) alloys
Autorzy:
Olszewski, J.
Zbroszczyk, J.
Ciurzyńska, W.
Fukunaga, H.
Wysłocki, B.
Perduta, K.
Łukiewska, A.
Młyńczyk, A.
Lelątko, J.
Świerczek, J.
Powiązania:
https://bibliotekanauki.pl/articles/148787.pdf
Data publikacji:
2003
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
Mössbauer spectra
nanocrystalline Fe-Co alloys
Opis:
The microstructure of amorphous and nanocrystalline Fe42.7Co42.7Zr6.8-xNbxB6.8Cu1 (x = 0 or 1) alloys was investigated. We have stated that the nanocrystalline samples consist of the crystalline alfa-FeCo grains about 8 nm in diameter embedded in an amorphous matrix which is rich in cobalt. From Mössbauer spectroscopy studies we have found that the crystalline alfa-FeCo phase in the nanocrystalline samples obtained by the conventional annealing is atomically ordered. Moreover, the order degree depends on the annealing time. As for the samples partially crystallized during rapid quenching, the crystalline alfa-FeCo phase is atomically disordered.
Źródło:
Nukleonika; 2003, 48,suppl.1; 49-52
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Position of Fe ions in MgO crystalline structure
Autorzy:
Szczerba, J.
Prorok, R.
Stoch, P.
Śnieżek, E.
Jastrzębska, I.
Powiązania:
https://bibliotekanauki.pl/articles/146372.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
Mössbauer spectroscopy
MgO
Fe ions
crystal structure
Opis:
Magnesium oxide (MgO) is one of the most important raw materials in many branches of industry. Magnesium oxide is a popular refractory raw material because of its high refractoriness and high resistance to basic slags and environment. In many cases, use of MgO is limited by its properties, especially the presence of secondary phases like iron oxides. The amount and distribution of iron oxides can strongly infl uence the technological properties of MgO and depend on the manufacturing method, particularly the heat-treatment process. The aim of the study was to evaluate the infl uence of the heat-treatment process on amount and distribution of iron ions in a magnesium oxide lattice. The 57Fe Mössbauer effect measurements of fused and sintered magnesium oxide samples doped by the iron oxide were conducted. Investigation reveals in both cases the presence of Fe2+ as well as Fe3+ ions. Fe2+ ions occupy Mg2+ octahedral sites in the MgO lattice, whereas the Fe3+ ions are located in highly distorted octahedral coordination. The amount of Fe2+ varies from around 66% for fused samples to 30% for sintered samples.
Źródło:
Nukleonika; 2015, 60, 1; 143-145
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inter - and inframolecular dynamics of iron porphyrins
Autorzy:
Dziedzic-Kocurek, K.
Okła, D.
Stanek, J.
Powiązania:
https://bibliotekanauki.pl/articles/147410.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
EXAFS
Fe-porphyrins
molecular interactions
Mössbauer spectroscopy
Opis:
The temperature dependent Mössbauer spectroscopy and EXAFS analysis of the dynamical properties of selected iron-porphyrin derivatives: FeTPPCl and FePPIXCl has been presented. It has been shown that these iron-porphyrin properties may be modified by the outer ligands, but they are also strongly influenced by the intermolecular interactions, which are reduced in frozen solutions of the studied complexes.
Źródło:
Nukleonika; 2013, 58, 1; 7-11
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic interactions in frozen solutions of ironporphyrins
Autorzy:
Dziedzic-Kocurek, K.
Okła, D.
Stanek, J.
Powiązania:
https://bibliotekanauki.pl/articles/147882.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
Fe-porphyrins
intermolecular interactions
magnetic relaxation
Mössbauer spectroscopy
Opis:
The powder samples of meso-tetraphenyloporphyrin iron(III) chloride and ferriprotoporphyrin IX chloride and their frozen in solutions N,N-dimethylformamide were studied by Mössbauer spectroscopy. The variation of the outer ligands of the porphyrin rings modifies their magnetic properties but the major influence on the magnetic relaxation process exerts the intermolecular magnetic interactions, which are eliminated in dilute solutions.
Źródło:
Nukleonika; 2013, 58, 1; 83-86
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
First principles study of the isomer shift in Fe44M6Al50 (M = Ti, V, Cr, Co, Ni, Cu) alloys with B2 structure
Autorzy:
Michalecki, T.
Deniszczyk, J.
Frąckowiak, J.
Powiązania:
https://bibliotekanauki.pl/articles/147195.pdf
Data publikacji:
2004
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
iron
aluminum
isomer shift
Fe-Al compound
LMTO
Opis:
The 57Fe isomer shift for Fe44M6Al50 intermetallics with the B2 structure doped with M = Ti, V, Cr, Co, Ni and Cu additions has been calculated with the tight-binding linear muffin-tin orbital (TB-LMTO) method. The effect of variation of Wigner-Seitz (WS) spheres radii on the calculated equilibrium lattice parameter (a) and isomer shift (IS) was analyzed. The calculations have shown that the 57Fe isomer shift in Fe44M6Al50 intermetallics is directly proportional to the changes in the local 4s electronic charge at Fe atoms involved by M addtions. The screening effect of 4s electrons due to changes in (4p + 3d) electronic charge is of secondary importance. The calculated dependence of the average IS on nuclear charge (Z) of the alloying metal (M) follows qualitatively the tendency observed experimentally for the M impurities in the Fe host.
Źródło:
Nukleonika; 2004, 49,suppl.3; 3-6
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hyperfine interactions and some thermomagnetic properties of amorphous FeZr(Cr)NbBCu alloys
Autorzy:
Łukiewska, A.
Olszewski, J.
Powiązania:
https://bibliotekanauki.pl/articles/146540.pdf
Data publikacji:
2017
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
amorphous Fe-based alloys
invar effect
Mössbauer spectroscopy
Opis:
In this research, we studied the magnetic phase transition by Mössbauer spectroscopy and using vibrating sample magnetometer for amorphous Fe86–xZr7CrxNb2Cu1B4 (x = 0 or 6) alloys in the as-quenched state and after accumulative annealing in the temperature range 600–750 K. The Mössbauer investigations were carried out at room and nitrogen temperatures. The Mössbauer spectra of the investigated alloys at room temperature are characteristic of amorphous paramagnets and have a form of asymmetric doublets. However, at nitrogen temperature, the alloys behave like ferromagnetic amorphous materials. The two components are distinguished in the spectrum recorded at both room and nitrogen temperatures. The low field component in the distribution of hyperfine field induction shifts towards higher field with the annealing temperature. It is assumed that during annealing at higher temperature, due to diffusion processes, the grains of α-Fe are created in the area corresponding to this component. Both investigated alloys show the invar effect and the decrease of hyperfine field induction after annealing at 600 K for 10 min is observed. It is accompanied by the lowering of Curie temperature.
Źródło:
Nukleonika; 2017, 62, 2; 135-140
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling of EMR data for Fe2+(S=2) ions in a [2Fe-2S] cluster in the reduced ferredoxin
Autorzy:
Rudowicz, Cz.
Piwowarska, D.
Gnutek, P.
Powiązania:
https://bibliotekanauki.pl/articles/146266.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
[2Fe-2S] cluster
electron magnetic resonance (EMR)
Fe2+ ions
microscopic spin Hamiltonian (MSH)
zero field splitting (ZFS) parameters
Opis:
The modelling techniques employed in this study utilize structural data to enable correlation of EMR data – described by the spin Hamiltonian (SH) and optical spectroscopy data – described by the crystal field (CF) Hamiltonian. These techniques enable also to predict magnetic and spectroscopic properties of 3dN ions, especially 3d4 and 3d6 ions, in various systems. Specific applications are considered for [Fe2+ and Fe3+] binuclear centres in [2Fe-2S] cluster in the reduced ferredoxin and related biological molecules. The background for model calculations of the zero-field splitting (ZFS) parameters and/or crystal field parameters and the capabilities of the two major techniques used will be presented in the full paper. Here, we present preliminary results of the microscopic spin Hamiltonian (MSH) modelling for Fe2+ (3d6) ions in the reduced ferredoxin.
Źródło:
Nukleonika; 2013, 58, 3; 347-350
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Defect structure of Fe-Al and Fe-Al-X (X = Ni; Cu; Cr) metallic powders obtained by the self-decomposition method
Autorzy:
Hanc, A.
Frąckowiak, J.
Powiązania:
https://bibliotekanauki.pl/articles/147208.pdf
Data publikacji:
2004
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
iron aluminides
defects
points defects
Mössbauer spectroscopy
Fe-Al
Opis:
In the present work, the Fe-Al-X (X = Cu; Ni; Cr) metallic powders produced by the self-decomposition method of the Fe-Al doped alloys were examined by Mössbauer spectroscopy. The concentration of the Fe vacancies and the Fe atoms substituting Al (Fe-AS) was determined from the intensities of the sub-spectra in the Mössbauer analysis connected with distinct Fe environments. The results have shown that nickel and copper cause an increase of vacancy concentrations in comparison with the values found for Fe-Al metallic powders, whereas chromium decreases vacancy concentrations causing a significant increase of anti-site atoms Fe-AS concentration.
Źródło:
Nukleonika; 2004, 49,suppl.3; 7-11
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hydrogen effect on the electronic and structural properties of Nb-Fe alloys
Autorzy:
Brzeska-Michalak, B.
Ostrasz, A.
Powiązania:
https://bibliotekanauki.pl/articles/148793.pdf
Data publikacji:
2003
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
Mössbauer spectroscopy of 57Fe
iron-niobium alloys
niobium hydrides
Opis:
The influence of hydrogen on the electronic and structural properties of Nb1-yFey alloys has been studied with 57Fe Mössbauer spectroscopy and X-ray diffraction. No ability of hydrogen to creation of the ferromagnetic properties has been observed in this system. The results clearly indicate the ß-NbH0.85÷0.77 hydride formation in place of ?-Nb phase. The quadrupole splitting and the isomer shift of the ß-NbHx subspectrum have been considered in terms of interaction between the interstitials and the Mössbauer atoms within the hydride phase.
Źródło:
Nukleonika; 2003, 48,suppl.1; 53-57
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase composition investigations of the Nd-Fe alloys processed by various methods
Autorzy:
Pawlik, K.
Wysłocki, J.
Olszewski, J.
Bodak, O.
Pawlik, P.
Powiązania:
https://bibliotekanauki.pl/articles/147201.pdf
Data publikacji:
2004
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
Nd-Fe binary system
intermetallic compounds
Mössbauer spectroscopy
phase composition
Opis:
Abstract In the paper, the phase composition changes for the series of Nd10+xFe90 x (x = 0; 0.5; 1; 1.5; 2; 2.5; 3; 3.5; 4) binary alloys, produced by long time annealing and rapid solidification methods were investigated. X-ray diffractometry and Mössbauer spectroscopy were used to determine the phase composition of the alloys. These structural investigations revealed the existence of two crystalline phases in the long time annealed samples: bcc á-Fe and rhombohedral Nd2Fe17 of the Th2Zn17-type structure. Furthermore, the single phase region was observed for the Nd concentration above 12 at.%. For the rapidly solidified ribbon samples, a low volume fraction of the alfa-Fe and the crystalline phase of hexagonal symmetry were detected.
Źródło:
Nukleonika; 2004, 49,suppl.3; 27-31
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mössbauer studies of single crystal gamma-Mn-Fe
Autorzy:
Szymański, K.
Olszewski, W.
Dobrzyński, L.
Satuła, D.
Jankowska-Kisielińska, J.
Powiązania:
https://bibliotekanauki.pl/articles/147239.pdf
Data publikacji:
2004
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
gamma-Mn-Fe alloys
iron alloys
manganese alloys
Mössbauer spectroscopy
Opis:
Mössbauer measurements were performed on single crystals gamma-Mn60Fe37Cu3 in an external field of 1.3 T at room temperature. The hyperfine field distribution can be described as a vector sum of the external and internal fields. In addition, anisotropic response of magnetic moments was detected. The anisotropy, due to Fe atoms, has Fe-rich surroundings.
Źródło:
Nukleonika; 2004, 49,suppl.3; 75-78
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł

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