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Wyświetlanie 1-15 z 15
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:
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:
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:
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:
High temperature transformation of iron-bearing minerals in basalt: Mössbauer spectroscopy studies
Autorzy:
Kądziołka-Gaweł, Mariola
Wojtyniak, Marcin
Klimontko, Joanna
Powiązania:
https://bibliotekanauki.pl/articles/2086563.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Mineralogiczne
Tematy:
basalts
high temperature affects
Mössbauer spectroscopy
Fe-bearing minerals
Opis:
The high temperature decomposition of basalt from Lower Silesia (Poland) was followed by Mössbauer spectroscopy investigation. The Fe content of the sample was ~9.0 at.%. The X-ray diffraction analysis shows that augite (37%) and olivine (12%) are major Fe-bearing mineral components. The sample also contains significant amount of anorthite (22%) and nepheline (17%). The sample was heated at various temperatures between 200o C and 1100o C for three hours. Up to a temperature of 500o C changes in contribution of Fe-bearing minerals are insignificant. Heating in the temperature range from 500o C to 1100o C leads to a systematic increase in contribution of iron oxides at the cost of contribution of silicate minerals, like augite and olivine. Mössbauer spectrum obtained after heating at 1100o C showed hematite as the main iron oxide phase. The ratio of Fe3+/Fetot in the non-heated sample was equal to 0.51 and after heating at 1100o C this ratio amounted to 0.89.
Źródło:
Mineralogia; 2022, 53, 1; 10--19
1899-8291
1899-8526
Pojawia się w:
Mineralogia
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
Tytuł:
Thermodynamic properties of Au-Fe alloys studied with 57Fe Mössbauer spectroscopy
Autorzy:
Idczak, R.
Konieczny, R.
Chojcan, J.
Powiązania:
https://bibliotekanauki.pl/articles/147926.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
Mössbauer spectroscopy
Au-Fe alloys
enthalpy of solution
short-range order
Opis:
The room temperature Mossbauer spectra of 57Fe were measured for Au1.xFex alloys with x in the range 0.01 less-than or equal to x less-than or equal to 0.03. The obtained data were analysed in terms of short range order parameter (SRO) and the binding energy Eb between two iron atoms in the studied materials using the extended Hrynkiewicz-Krolas idea. The estimated negative SRO parameters and the positive binding energy suggest ordering tendencies in Au-Fe alloys at low iron concentration. The extrapolated value of Eb for x = 0 was used for the computation of enthalpy of the solution of Fe in Au. The results were compared with the corresponding data derived from calorimetric measurements, previous Mossbauer experiments and resulting from the cellular atomic model of alloys by Miedema.
Źródło:
Nukleonika; 2013, 58, 1; 93-97
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal defects in iron-based Fe-V solid solutions
Autorzy:
Chojcan, J.
Beliczyński, J.
Powiązania:
https://bibliotekanauki.pl/articles/148884.pdf
Data publikacji:
2003
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
dilute Fe-based alloys
Mössbauer spectroscopy
thermal point defects
vacancy formation
Opis:
Room temperature 57Fe Mössbauer spectra, positron annihilation lifetime data, X-ray diffraction patterns, and energy distributions of X-rays induced by an electron beam were measured for samples of the Fe0.947V0.053 solid solution quenched from different temperatures not exceeding 1250 K, into water being at about 295 K. The data were analysed in terms of concentration of unoccupied sites in the 14-site neighbourhood of the 57Fe Mössbauer probe in the specimens. It was found that the vacancy formation enthalpy amounts to 0.8 š 0.2 eV in the materials studied.
Źródło:
Nukleonika; 2003, 48,suppl.1; 17-20
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hyperfine interactions in (Cr0.9957Fe0.01)3 + xSi1 - x
Autorzy:
Satuła, D.
Szymański, K.
Olszewski, W.
Kalska-Szostko, B.
Waliszewski, J.
Rećko, K.
Powiązania:
https://bibliotekanauki.pl/articles/147344.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
A15 structure
Cr-Fe-Si alloys
Mössbauer spectroscopy
X-ray diffraction
Opis:
X-ray diffraction measurements and Mossbauer spectroscopy with external magnetic field were carried out on (Cr0.99 57Fe0.01)3+xSi-x alloys. The Mossbauer spectra for A15 type of structure can be described by superposition of single line S(1) and two doublets D(1) and D(2). The relative ratio of the S(1) and D(2) strongly depends on x. The nearest neighbours of these components have been identified. It was shown that 57Fe atoms preferentially locate in Cr positions for x less-than or equal to 0.0, while for x greater 0.0 iron atoms are distributed both in Cr and Si positions. It was shown that, in A15 structure, one Cr atom located in the 57Fe nearest neighbours (n.n.) decreases isomer shift by (0.022 plus or minus 0.002) mm/s, while one Si in n.n. increases isomer shift by (0.09 plus or minus 0.01) mm/s. The measured Mossbauer spectra of bcc Cr-Si indicate that atoms are randomly distributed and can be well described as superposition of single lines, related to various local environments of 57Fe atoms.
Źródło:
Nukleonika; 2013, 58, 1; 73-76
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ordering process in Fe-Al28Cr5 alloys studied by Mössbauer spectroscopy
Autorzy:
Hanc-Kuczkowska, A.
Kansy, J.
Deniszczyk, J.
Powiązania:
https://bibliotekanauki.pl/articles/147348.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
Fe-Al28Cr5 alloys
formation of D03 phases
Mössbauer spectroscopy
Opis:
In the paper, studies of ternary Fe-Al28Cr5 alloys directed to characterization of mechanisms of the formation of ordered intermetallic phases influencing the possibilities of their practical application are shown. Also, a role of chromium as a modifier in kinetics of the formation of ordered phases is determined. Among the research method used, Mössbauer spectroscopy for the determination of hyperfine structure parameters was adopted. These parameters, sensitive to changes in spin and charge electron densities in the nearest neighbourhood of a Mössbauer isotope nucleus, caused by specific configurations of atoms, are directly connected with the degree of ordering of a compound. Spectral analysis has been carried out using the authors' software developed based on a theoretical model relating the shape of a Mössbauer spectrum to the sample microstructure. It has been shown that Mössbauer spectroscopy enables quantitative evaluation of the degree of ordering of phases occurring in samples characterized by large graining, in the case of which it is not possible to determine the long-range order parameter by X-ray diffraction.
Źródło:
Nukleonika; 2013, 58, 1; 67-71
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A multi-analytical approach for the analysis of cation distribution in a aluminoceladonite structure
Autorzy:
Kądziołka-Gaweł, Mariola
Dulski, Mateusz
Czaja, Maria
Krzykawski, Tomasz
Szubka, Magdalena
Powiązania:
https://bibliotekanauki.pl/articles/2172615.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aluminoceladonite
ions position characterization isomorphic substitutions
Fe bearing phyllosilicates
X-ray photoelectron spectroscopy
Mössbauer spectroscopy
Raman spectroscopy
glinokrzemiany
krzemiany warstwowe
rentgenowska spektrometria fotoelektronów
XPS
spektroskopia mössabuerowska
spektroskopia Ramana
Opis:
In this paper cation arrangement in two samples of aluminoceladonite, emerald green and dark-green were studied by Mössbauer, Raman and X-ray photoelectron spectroscopies. The X-ray photoelectron spectroscopy (XPS) spectra obtained in the region of the Si2p, Al2p, Fe2p, K2p, and O1s core levels provided information, for the first time highlighting a route to identify the position of Si, Al, K, and Fe cations in a structure of layered silicates. The XPS analysis showed the presence of Al in tetrahedral and octahedral coordination while the K2p line indicated the possibility of K+ substitution by other cations in interlayer sites. Mössbauer spectroscopy provided information about crystal chemistry with respect to the local electronic and geometric environment around the Fe atom and to distortions of the polyhedra. It turned out that iron was located mostly in the cis-octahedra position wherein about 75% of iron appeared in the form of Fe3+. The most preferred cation combinations around Fe corresponded to 3Fe3+ ions and MgFe2+Fe3+/2MgFe3+. Raman spectroscopy illustrated aluminium substitution in silicon and iron positions wherein the concentration of the aluminium determined the degree of structural distortion within the layered system. These isomorphic substitutions implied a typical band arrangement in the hydroxyl region, which has not been observed in celadonites so far.
Źródło:
Acta Geologica Polonica; 2022, 72, 3; 353--368
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-15 z 15

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