Differential scanning calorimetry and Mossbauer spectroscopy of hydrogenated Pd-C, Ni-C and Fe-Ni-C alloys

ABSTRACTWe present differential scanning calorimetry (DSC) and in situ Mössbauer spectroscopy results for Metglas ribbons, to which different heat treatments were made. The Curie temperature of the amorphous phase is determined and the evolution of the magnetic field of this phase is studied as a function of temperature.

Download Full-text

MÖssbauer Study of a Tinife Shape Memory Alloy.

MRS Proceedings ◽

10.1557/proc-246-253 ◽

1991 ◽

Vol 246 ◽

Author(s):

M. Jimenez ◽

V. Marquina ◽

S. Aburto ◽

M.L. Marquina ◽

R. Gomez ◽

...

Keyword(s):

Mössbauer Spectroscopy ◽

Shape Memory ◽

Room Temperature ◽

Mossbauer Spectroscopy ◽

Density Wave ◽

Quadrupole Doublet ◽

Mössbauer Study ◽

Scanning Calorimetry ◽

Mößbauer Spectroscopy ◽

Wave Induced

AbstractMÖssbauer spectroscopy is very sensitive to structural transitions that may occur during a phase change of the type known to arise in the shape memory TiNiFe alloy. In this work we present the results of resistance vs temperature, differential scanning calorimetry (DSC) and Mössbauer spectroscopy (MS) measurements in Ti50Ni47Fe3 sample. The resistance vs temperature curve shows the usual sharp increase associated to the B2 → R transition at Tp = 245 K and then raises until a maximum is attained at ∼ 150 K. The DSC curve shows a peak maximum at the same temperature where the resistivity starts to increase. The room temperature Mössbauer spectrum consists of a single line, indicating that the iron atoms have cubic surroundings. As temperature is lowered, a small asymmetric quadrupole doublet begins to develop. The isomer shift (I.S.) and quadrupole splitting (ΔQ) values of this doublet increase with decreasing temperature until almost constant values are achieved at temperatures ∼ 100 K. We relate the changes in the Mössbauer spectra with previously proposed charge density wave induced premartensitic transition.

Download Full-text

Influence of W Addition on Phase Constitution, Microstructure and Magnetic Properties of the Nanocrystalline Pr9Fe65WxB26-x (Where: x = 2, 4, 6, 8) Alloy Ribbons

Materials ◽

10.3390/ma13102229 ◽

2020 ◽

Vol 13 (10) ◽

pp. 2229

Author(s):

Katarzyna Filipecka ◽

Piotr Pawlik ◽

Andrzej Kozdraś ◽

Waldemar Kaszuwara ◽

Jarosław Ferenc ◽

...

Keyword(s):

Magnetic Properties ◽

Mössbauer Spectroscopy ◽

Melt Spinning ◽

Mossbauer Spectroscopy ◽

Magnetic Measurements ◽

Soft Magnetic ◽

Scanning Calorimetry ◽

Phase Constitution ◽

Mößbauer Spectroscopy ◽

Microstructure And Magnetic Properties

The aim of the present work was to investigate an influence of W addition on the phase constitution, microstructure and magnetic properties of the Pr9Fe65WxB26-x (where: x = 2, 4, 6, 8) alloy ribbons. Ribbons were obtained using the melt-spinning technique under low pressure of Ar. The as-cast samples were fully amorphous and revealed soft magnetic properties. These facts were confirmed by X-ray diffractometry, Mössbauer spectroscopy and magnetic measurements. Differential scanning calorimetry and differential thermal analysis allowed us to determine the thermal stability parameters of the amorphous phase. The Kissinger plots were constructed in order to calculate the activation energies for crystallization. Heat treatment carried out at various temperatures caused changes in the phase constitution and magnetic properties of the alloys. The phase analysis has shown the presence of the hard magnetic Pr2Fe14B and paramagnetic Pr1+xFe4B4 phases. Additionally, for the x = 2 and x = 6 alloys, a crystallization of soft magnetic Fe2B and α-Fe phases was observed. The Mössbauer spectroscopy allowed us to determine the volume fractions of constituent phases formed during annealing. The microstructure of annealed ribbons was observed using transmission electron microscopy.

Download Full-text

Evaluation of the Effect of Minor Additions in the Crystallization Path of [(Fe0.5Co0.5)0.75B0.2Si0.05]100-xMx Metallic Glasses by Means of Mössbauer Spectroscopy

Metals ◽

10.3390/met11081293 ◽

2021 ◽

Vol 11 (8) ◽

pp. 1293

Author(s):

S. Leila Panahi ◽

Parthiban Ramasamy ◽

Francesc Masdeu ◽

Mihai Stoica ◽

Joan Torrens-Serra ◽

...

Keyword(s):

Mössbauer Spectroscopy ◽

Metallic Glasses ◽

Mossbauer Spectroscopy ◽

Amorphous Structure ◽

Glass Forming Ability ◽

Scanning Calorimetry ◽

Glass Forming ◽

Mößbauer Spectroscopy ◽

Mo Content ◽

Crystallization Path

Understanding the crystallization of metallic glasses is fundamental in the design of new alloys with enhanced properties and better glass-formability. The crystallization of a series of Fe-based metallic glasses of composition [(Fe0.5Co0.5)0.75B0.2Si0.05]100-xMx (M = Mo, Nb and Zr) has been studied by means of differential scanning calorimetry and transmission Mössbauer spectroscopy. This latter technique allows the following of the microstructural evolution of the studied alloys through the identification and quantification of the several Fe-containing crystalline phases and also through the changes in the amorphous structure at the initial stages of crystallization. The results show that the crystallization products are the same for all the studied compositions (α-Fe, Fe2B, (FeCo)23B6 and a paramagnetic remnant) although with different relative proportions and the crystallization of a phase without Fe in the alloys with Zr. Moreover, the addition of Zr favors the crystallization of α-Fe causing a detrimental effect on the glass forming ability, while the increase in Mo content up to 6 at% favors the crystallization of (FeCo)23B6. The different amount of α-Fe and borides is presented as a measure of the glass forming ability of this type of alloys.

Download Full-text

X-ray diffraction and Mössbauer spectroscopy studies of a mechanosynthesized Fe75B25 alloy

Nukleonika ◽

10.1515/nuka-2015-0011 ◽

2015 ◽

Vol 60 (1) ◽

pp. 43-46 ◽

Cited By ~ 1

Author(s):

Elżbieta Jartych ◽

Ludmila M. Kubalova ◽

Victoria I. Fadeeva

Keyword(s):

Mössbauer Spectroscopy ◽

Mossbauer Spectroscopy ◽

Metastable Phase ◽

High Energy ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

X Ray ◽

Mößbauer Spectroscopy ◽

Two Phases ◽

Spectroscopy Studies

Abstract In this work, the process of formation of metastable phases was investigated for the Fe75B25 composition. Mechanical synthesis was performed in a MAPF-2M high-energy planetary ball mill under an argon atmosphere. X-ray diffraction (XRD), differential scanning calorimetry (DSC), and Mössbauer spectroscopy (MS) were applied to recognize the phases. After 6 h of milling, the material consisted of two phases, that is, metastable tetragonal t-Fe2B and amorphous phases. During further thermal processing, the metastable phase was transformed into the stable Fe2B phase.

Download Full-text