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Structure, Magnetocaloric Properties, and Thermodynamic Modeling of Alloys
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Structure, Magnetocaloric Properties, and Thermodynamic Modeling of Alloys

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Metals and Alloys".

Deadline for manuscript submissions: closed (20 November 2023) | Viewed by 13615

Special Issue Editor

Prof. Piotr Gębara

E-Mail Website
Guest Editor
Department of Physics, Częstochowa University of Technology, Armii Krajowej 19 Av., 42-200 Częstochowa, Poland
Interests: X-ray diffraction; magnetocaloric effect; magnetic materials; Mössbauer spectroscopy; materials production
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The magnetocaloric effect (MCE) was discovered more than one hundred years ago. Today, it is the most energy-saving and environmentally-friendly cooling technique. New life was breathed into the MCE in 1997 after the discovery of the giant magnetocaloric effect in the Gd5Si2Ge2 alloy by Pecharsky and Gschneidner Jr. Since then, a permanent development of novel magnetocaloric materials (MCMs) has been observed. The most well-known magnetocaloric material is pure Gd and its alloy. Parallel to them, other groups have been intensively studied, including La(Fe,Si)13-type alloys, Heusler alloys, manganites, alloys based on the Laves phases and Fe or Gd-based amorphous alloys. The MCE in these alloys is the result of second- or first-order phase transition. The newest studies suggest that the ideal MCM lays on the border between first- and second-order phase transition, due to the fact that it combines a relatively high magnetic entropy change and broad temperature working range. The potential application of this kind of alloys is as an active magnetic regenerator in magnetic refrigerators or heat pumps.

This Special Issue will focus on research papers on magnetic alloys (especially magnetocaloric materials) based on materials with an amorphous, nanocrystalline or crystalline structure. We expect novelties and original results in chemical composition, production, and investigation of magnetic materials, especially with enormous magnetocaloric properties. Manuscripts concerning modeling of magnetic properties confirmed through experimental techniques will also be considered, as well as partially glass alloys, nanostructured or crystalline magnetic materials.

We invite you to submit full papers, reviews or communications to this Special Issue. In all cases, the papers must demonstrate novelty and importance to the scope.

Prof. Piotr Gębara
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Structure
  • X-ray diffraction
  • Mössbauer studies
  • Magnetocaloric properties
  • Miedema’s model
  • Thermomagnetic properties
  • Thermomagnetic effects
  • Materials production
  • Thermodynamic modeling
  • Modeling of magnetic properties
  • Theoretical approach to the MCE

Published Papers (8 papers)

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Research

12 pages, 3110 KiB  
Article
The Effect of Substitution of Mn by Pd on the Structure and Thermomagnetic Properties of the Mn1−xPdxCoGe Alloys (Where x = 0.03, 0.05, 0.07 and 0.1)
by Karolina Kutynia, Anna Przybył and Piotr Gębara
Materials 2023, 16(15), 5394; https://0-doi-org.brum.beds.ac.uk/10.3390/ma16155394 - 31 Jul 2023
Cited by 3 | Viewed by 633
Abstract
In the present paper, the influence of partial substitution of Mn by Pd on structure, thermomagnetic properties, and phase transitions in the MnCoGe alloys was investigated. The studies of phase constitution revealed an occurrence of the orthorhombic TiNiSi-type and hexagonal Ni2Ti- [...] Read more.
In the present paper, the influence of partial substitution of Mn by Pd on structure, thermomagnetic properties, and phase transitions in the MnCoGe alloys was investigated. The studies of phase constitution revealed an occurrence of the orthorhombic TiNiSi-type and hexagonal Ni2Ti- type phases. Deep analysis of the XRD pattern supported by the Rietveld analysis allowed us to notice the changes in lattice parameters and quantity of recognized phases depending on the Pd content. An increase of palladium in alloy composition at the expense of manganese induced a rise in the Curie temperature. The values of ΔSM measured for the variation of external magnetic field ~5 T equaled 8.88, 23.99, 15.63, and 11.09 for Mn0.97Pd0.03CoGe, Mn0.95Pd0.05CoGe, Mn0.93Pd0.07CoGe, and Mn0.9Pd0.1CoGe alloy, respectively. The highest magnetic entropy change ΔSM was observed for samples with Pd content x = 0.05 induced by magnetostructural transformation. The analysis of the n vs. T curves allowed confirmation of the XRD and DSC results of an occurrence of the first-order magnetostructural transition in Mn0.95Pd0.05CoGe and Mn0.93Pd0.07CoGe alloys samples. Full article
(This article belongs to the Special Issue Structure, Magnetocaloric Properties, and Thermodynamic Modeling of Alloys)
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12 pages, 3417 KiB  
Article
Influence of Nd Substitution on the Phase Constitution in (Zr,Ce)Fe10Si2 Alloys with the ThMn12 Structure
by Mieszko Kołodziej, Jean-Marc Grenèche, Sandy Auguste, Bogdan Idzikowski, Maciej Zubko, Lotfi Bessais and Zbigniew Śniadecki
Materials 2023, 16(4), 1522; https://0-doi-org.brum.beds.ac.uk/10.3390/ma16041522 - 11 Feb 2023
Viewed by 1073
Abstract
Iron-based compounds with a ThMn12-type structure have the potential to bridge the gap between ferrites and high performance Nd2Fe14B magnets. From the point of view of possible applications, the main advantage is their composition, with about 10 [...] Read more.
Iron-based compounds with a ThMn12-type structure have the potential to bridge the gap between ferrites and high performance Nd2Fe14B magnets. From the point of view of possible applications, the main advantage is their composition, with about 10 wt.% less rare earth elements in comparison with the 2:14:1 phase. On the other hand, the main issue delaying the development of Fe-rich alloys with a ThMn12-type structure is their structural stability. Therefore, various synthesis methods and stabilizing elements have been proposed to stabilize the structure. In this work, the influence of increasing Nd substitution on the phase constitution of Zr0.4−xNdxCe0.6Fe10Si2 (0 ≤ x ≤ 0.3) alloys was analyzed. X-ray diffraction and 57Fe Mössbauer spectrometry were used as the main methods to derive the stability range and destabilization routes of the 1:12 structure. For the arc-melted samples, an increase in the lattice parameters of the ThMn12-type structure was observed with the simultaneous growth of bcc-(Fe,Si) content with increasing Nd substitution. After isothermal annealing, the ThMn12-type structure (and the coexisting bcc-(Fe,Si)) were stable over the whole composition range. While the formation of a 1:12 phase was totally suppressed in the as-cast state for x = 0.3, further heat treatment resulted in the growth of about 45% of the ThMn12-type phase. The results confirmed that the stability range of ThMn12-type structure in the Nd-containing alloys was well improved by other substitutions and the heat treatment, which in turn, is also needed to homogenize the ThMn12-type phase. After further characterization of the magnetic properties and optimization of microstructure, such hard/soft magnetic composites can show their potential by exploiting the exchange spring mechanism. Full article
(This article belongs to the Special Issue Structure, Magnetocaloric Properties, and Thermodynamic Modeling of Alloys)
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21 pages, 7475 KiB  
Article
Entalpy of Mixing, Microstructure, Structural, Thermomagnetic and Mechanical Properties of Binary Gd-Pb Alloys
by Piotr Gębara, Mariusz Hasiak, Jozef Kovac and Michal Rajnak
Materials 2022, 15(20), 7213; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15207213 - 16 Oct 2022
Viewed by 1011
Abstract
The aim of the present work is to study the phase composition, microstructure and magnetocaloric effect of binary Gd100−xPbx (where x = 5, 10, 15 and 20) alloys. The XRD and SEM/EDX analysis confirmed a biphasic structure built by Gd(Pb) [...] Read more.
The aim of the present work is to study the phase composition, microstructure and magnetocaloric effect of binary Gd100−xPbx (where x = 5, 10, 15 and 20) alloys. The XRD and SEM/EDX analysis confirmed a biphasic structure built by Gd(Pb) and Gd5Pb3 phases. The analysis of M vs. T curves showed the evolution of the Curie point of recognized phases. The temperature dependences of magnetic entropy change revealed two maxima corresponding to the recognized phases. The analysis of the exponent n (ΔSMmax = C(Bmax)n) confirmed the multiphase composition of the produced alloys. The same behavior was also observed in investigations of mechanical properties. Full article
(This article belongs to the Special Issue Structure, Magnetocaloric Properties, and Thermodynamic Modeling of Alloys)
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12 pages, 5788 KiB  
Article
Some Thermomagnetic and Mechanical Properties of Amorphous Fe75Zr4Ti3Cu1B17 Ribbons
by Mariusz Hasiak and Jan Świerczek
Materials 2022, 15(1), 368; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15010368 - 04 Jan 2022
Cited by 5 | Viewed by 1483
Abstract
The microstructure, revealed by X-ray diffraction and transmission Mössbauer spectroscopy, magnetization versus temperature, external magnetizing field induction and mechanical hardness of the as-quenched Fe75Zr4Ti3Cu1B17 amorphous alloy with two refractory metals (Zr, Ti) have been [...] Read more.
The microstructure, revealed by X-ray diffraction and transmission Mössbauer spectroscopy, magnetization versus temperature, external magnetizing field induction and mechanical hardness of the as-quenched Fe75Zr4Ti3Cu1B17 amorphous alloy with two refractory metals (Zr, Ti) have been measured. The X-ray diffraction is consistent with the Mössbauer spectra and is characteristic of a single-phase amorphous ferromagnet. The Curie point of the alloy is about 455 K, and the peak value of the isothermal magnetic entropy change, derived from the magnetization versus external magnetizing field induction curves, equals 1.7 J·kg−1·K−1. The refrigerant capacity of this alloy exhibits the linear dependence on the maximum magnetizing induction (Bm) and reaches a value of 110 J·kg−1 at Bm = 2 T. The average value of the instrumental hardness (HVIT) is about 14.5 GPa and is superior to other crystalline Fe-based metallic materials measured under the same conditions. HVIT does not change drastically, and the only statistically acceptable changes are visibly proving the single-phase character of the material. Full article
(This article belongs to the Special Issue Structure, Magnetocaloric Properties, and Thermodynamic Modeling of Alloys)
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9 pages, 2202 KiB  
Article
Structure, Magnetocaloric Effect and Critical Behavior of the Fe60Co12Gd4Mo3B21 Amorphous Ribbons
by Agnieszka Łukiewska and Piotr Gębara
Materials 2022, 15(1), 34; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15010034 - 21 Dec 2021
Cited by 3 | Viewed by 1807
Abstract
The aim of the paper was to study the structure, magnetic properties and critical behavior of the Fe60Co12Gd4Mo3B21 alloy. The X-ray diffractometry and the Mössbauer spectroscopy studies confirmed amorphous structure. The analysis of temperature [...] Read more.
The aim of the paper was to study the structure, magnetic properties and critical behavior of the Fe60Co12Gd4Mo3B21 alloy. The X-ray diffractometry and the Mössbauer spectroscopy studies confirmed amorphous structure. The analysis of temperature evolution of the exponent n (ΔSM = C·(Bmax)n) and the Arrott plots showed the second order phase transition in investigated material. The analysis of critical behavior was carried out in order to reveal the critical exponents and precise TC value. The ascertained critical exponents were used to determine the theoretical value of the exponent n, which corresponded well with experimental results. Full article
(This article belongs to the Special Issue Structure, Magnetocaloric Properties, and Thermodynamic Modeling of Alloys)
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11 pages, 3036 KiB  
Article
Tuning of the Structure and Magnetocaloric Effect of Mn1−xZrxCoGe Alloys (Where x = 0.03, 0.05, 0.07, and 0.1)
by Karolina Kutynia and Piotr Gębara
Materials 2021, 14(11), 3129; https://0-doi-org.brum.beds.ac.uk/10.3390/ma14113129 - 07 Jun 2021
Cited by 3 | Viewed by 2102
Abstract
The aim of the present work is to study the influence of a partial substitution of Mn by Zr in MnCoGe alloys. The X-ray diffraction (XRD) studies revealed a coexistence of the orthorhombic TiNiSi-type and hexagonal Ni2In- type phases. The Rietveld [...] Read more.
The aim of the present work is to study the influence of a partial substitution of Mn by Zr in MnCoGe alloys. The X-ray diffraction (XRD) studies revealed a coexistence of the orthorhombic TiNiSi-type and hexagonal Ni2In- type phases. The Rietveld analysis showed that the changes in lattice constants and content of recognized phases depended on the Zr addition. The occurrence of structural transformation was detected. This transformation was confirmed by analysis of the temperature dependence of exponent n given in the relation ΔSM = C·(BMAX)n. A decrease of the Curie temperature with an increase of the Zr content in the alloy composition was detected. The magnetic entropy changes were 6.93, 13.42, 3.96, and 2.94 J/(kg K) for Mn0.97Zr0.03CoGe, Mn0.95Zr0.05CoGe, Mn0.93Zr0.07CoGe, and Mn0.9Zr0.1CoGe, respectively. A significant rise in the magnetic entropy change for samples doped by Zr (x = 0.05) was caused by structural transformation. Full article
(This article belongs to the Special Issue Structure, Magnetocaloric Properties, and Thermodynamic Modeling of Alloys)
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12 pages, 6012 KiB  
Article
Determination of Phase Transition and Critical Behavior of the As-Cast GdGeSi-(X) Type Alloys (Where X = Ni, Nd and Pr)
by Piotr Gębara and Mariusz Hasiak
Materials 2021, 14(1), 185; https://0-doi-org.brum.beds.ac.uk/10.3390/ma14010185 - 04 Jan 2021
Cited by 21 | Viewed by 2918
Abstract
The aim of the paper is to present a study of the magnetocaloric effect and the nature of phase transition in the Gd80Ge15Si5 (S1), Gd75Ge15Si5Ni5 (S2), Gd75Ge15Si [...] Read more.
The aim of the paper is to present a study of the magnetocaloric effect and the nature of phase transition in the Gd80Ge15Si5 (S1), Gd75Ge15Si5Ni5 (S2), Gd75Ge15Si5Pr5 (S3) and Gd75Ge15Si5Nd5 (S4) alloys. The magnetic entropy changes determined for studied samples, under external magnetic field ~3T, were 11.91, 12.11, 5.08 and 4.71 J/(kg K) for S1, S2, S3 and S4, respectively. The values of refrigerant capacity (under ~3T) were 164, 140, 160 and 140 J/kg for S1, S2, S3 and S4, respectively. The first order phase transition was detected for samples S1 and S2, while specimens S3 and S4 manifested the second order phase transition at the Curie point (TC). The analysis of temperature evolution of the exponent n (ΔSM = C·(Bmax)n) showed the validity of this method in detecting either the first or the second order phase transition and the structural transition. The analysis of critical behavior was carried out for samples S3 and S4. The critical exponents and precise TC values were calculated. The ascertained critical exponents were used to determine the theoretical value of the exponent n, which corresponded well with experimental result. Full article
(This article belongs to the Special Issue Structure, Magnetocaloric Properties, and Thermodynamic Modeling of Alloys)
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11 pages, 3485 KiB  
Article
Effect of Co, Ti and Cr Additions on Microstructure, Magnetic Properties and Corrosion Resistance of Magnetocaloric Gd-Ge-Si Alloys
by Mariusz Hasiak, Jacek G. Chęcmanowski, Barbara Kucharska, Amadeusz Łaszcz, Aleksandra Kolano-Burian and Jerzy Kaleta
Materials 2020, 13(24), 5758; https://0-doi-org.brum.beds.ac.uk/10.3390/ma13245758 - 17 Dec 2020
Cited by 2 | Viewed by 1606
Abstract
The paper presents studies of microstructure, magnetic and corrosion properties of the Gd58Ge20Si22, Gd56Ge20Si22Co2, Gd56Ge20Si22Ti2 and Gd56Ge20Si22 [...] Read more.
The paper presents studies of microstructure, magnetic and corrosion properties of the Gd58Ge20Si22, Gd56Ge20Si22Co2, Gd56Ge20Si22Ti2 and Gd56Ge20Si22Cr2 (at.%) alloys after isothermal heat treatment at 1450 K for 2 h. The structure investigations of the produced materials performed by X-ray diffraction show the presence of Gd5Ge2Si2-type phase in all investigated samples. DC and AC magnetic measurements confirmed that the Curie temperature depends on the chemical composition of the produced alloys. From M(T) characteristics, it was found that the lowest Curie point (TC = 268 K) was estimated for the Gd58Ge20Si22 sample, whereas the highest value of the Curie temperature (TC = 308 K) was for the Gd56Ge20Si22Cr2 alloys. Moreover, the GdGeSi alloy without alloying additions shows the highest magnetic entropy change |ΔSM| = 15.07 J⋅kg−1⋅K−1 for the maximum magnetic field of 2 T. The maximum |ΔSM| measured for the Gd56Ge20Si22 with the addition of Co, Ti or Cr for the same magnetic field was obtained in the vicinity of the Curie point and equals to 2.92, 2.73 and 2.95 J⋅kg−1⋅K−1, respectively. Electrochemical studies of the produced materials for 60 min and 55 days exposure in 3% NaCl solution show that the highest stability and corrosion resistance were exhibited the sample with added of Ti. Full article
(This article belongs to the Special Issue Structure, Magnetocaloric Properties, and Thermodynamic Modeling of Alloys)
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