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1
Content available The Prediction of Optimized Metalloid Content in Fe-Si-B-P Amorphous Alloys Using Artificial Intelligence Algorithm
Lee Min_Woo, Choi Young-Sin, Kwon Do-Hun, Cha Eun-Ji, Kang Hee-Bok, Jeong Jae-In, Lee Seok-Jae, Kim Hwi-Jun
Archives of Metallurgy and Materials
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2022
|
Vol. 67, iss. 4
1539--1542
EN
Artificial intelligence operated with machine learning was performed to optimize the amount of metalloid elements (Si, B, and P) subjected to be added to a Fe-based amorphous alloy for enhancement of soft magnetic properties. The effect of metalloid elements on magnetic properties was investigated through correlation analysis. Si and P were investigated as elements that affect saturation magnetization while B was investigated as an element that affect coercivity. The coefficient of determination R2 (coefficient of determination) obtained from regression analysis by learning with the Random Forest Algorithm (RFR) was 0.95 In particular, the R2 value measured after including phase information of the Fe-Si-B-P ribbon increased to 0.98. The optimal range of metalloid addition was predicted through correlation analysis method and machine learning.
2
Content available Reobservations of Recrystallization and its Effect on Mechanical and Magnetic Properties in a Severely Cold-Rolled Ni-Based Soft Magnetic Alloy
Mahdavi Azizeh, Mashreghi Ali Reza, Hasani Saeed, Kamali Mohammad Reza
Archives of Metallurgy and Materials
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2022
|
Vol. 67, iss. 2
703--717
EN
Despite of extensive researches for decades, there are many unclear aspects for recrystallization phenomenon in the cold rolled Ni-based alloys. Hence, different thermal cycles were conducted in order to determine microstructural evolutions and its effect on the magnetic and mechanical properties of a 90% cold-rolled thin sheet of a Ni-Fe-Cu-Mo alloy (~80 μm). The obtained results revealed that the recrystallization was started at a temperature of 550°C and was completed after 4 hours. An increase in the number of annealing twins was observed with an increase in annealing temperature, which was due to a bulging and long-range migration of grain boundaries during the discontinuous recrystallization. Ordering transformation occurred in the temperature range of 400-600°C and as a result, hardness, yield strength, and UTS were increased, while with an increase in the annealing temperature these mechanical properties were decreased. Maximum toughness was obtained by annealing at 550°C for 4 hours, while the highest elongation was obtained after annealing at 1050°C, where other mechanical properties including toughness, hardness, yield strength, and UTS were decreased due to the grain growth and secondary recrystallization. Moreover, coercivity and remanence magnetization were decreased from 4.5 Oe and 3.8 emu/g for the cold rolled sample to below 0.5 Oe and 0.15 emu/g for the sample annealed at 950°C, respectively.
3
Content available Effect of Pre-Sintering on the Diffusion Treatment of HRE for Coercivity Enhancement of a NdFeB Sintered Magnet
Lee M. W., Lee J. K., Jang T. S.
Archives of Metallurgy and Materials
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2019
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Vol. 64, iss. 2
597--601
EN
We investigated the effect of pre-sintering process on the penetration behavior of Dy in a NdFeB sintered magnet which was grain boundary diffusion treated with Cu/Al mixed Dy source. The pre-sintering of a magnet was performed at 900°C in vacuum and then the pre-sintered body was dipped in the solutions of DyH2, DyH2 + Cu, and DyH2 + Al, respectively. The dipped pre-sintered body were then fully sintered 4 hours at 1060°C followed by a subsequent annealing. The pre-sintering apparently improved the diffusivity of Dy atoms. The penetration of Dy into the magnet extended almost to 2,000 μm from the surface, about four times deeper than that of the normally sintered and diffusion treated one, when the DyH2 + Al solution was used as a Dy source. However, the resulting increase of coercivity was about 4 kOe, somewhat lower than that of the normally treated one, mostly due to excessive oxide formation that hindered to make a continuous Nd-rich grain boundary phase and a core-shell type structure.
4
Content available remote Angular and frequency behaviour of some properties of electrical steel sheets
Pluta W. A.
Przegląd Elektrotechniczny
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2017
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R. 93, nr 7
22--26
EN
Electrical steel (ES) is one of the most widely used soft magnetic material. Hence, it is used to build magnetic cores of large electrical machines and transformers. At design of these cores it is necessary to take into account anisotropy and frequency influence on magnetic properties of ES. The paper presents angular and frequency behaviour of specific total loss, remanence and coercivity of ES. The carried out analysis allow to propose a frequency model of remanence and coercivity being consistent with the three component specific total loss model.
PL
Blachy elektrotechniczne (ES) są jednym z najczęściej używanych materiałów magnetycznie miękkich. Stąd wykorzystuje się je do budowy rdzeni magnetycznych dużych maszyn elektrycznych i transformatorów. Przy projektowaniu tych rdzeni należy wziąć pod uwagę wpływ zjawiska anizotropii magnetycznej i częstotliwości na własności magnetyczne ES. W artykule przedstawiono własności kierunkowe i częstotliwościowe całkowitych strat, remanencji i natężenia koercji ES. Przeprowadzona analiza pozwala zaproponować model częstotliwościowy indukcji remanentu i natężenia koercji, zgodny z trójskładnikowym modelem jednostkowych strat mocy
5
Content available Effect Of DyMn Alloy-Powder Addition On Microstructure And Magnetic Properties Of NdFeB Sintered Magnets
Lee M.-W., Dhakal D. R., Kim T. H., Lee S. R., Kim H. J., Jang T. S.
Archives of Metallurgy and Materials
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2015
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Vol. 60, iss. 2B
1407--1409
EN
Micostructural change and corresponding effect on coercivity of a NdFeB sintered magnet mixed with small amount of DyMn powder was investigated. In the sintered magnet mixed with the DyMn alloy-powder Dy-rich shell was formed at outer layer of the main grains, while Mn was mostly concentrated at Nd-rich triple junction phase (TJP), lowering melting temperature of the Nd-rich phase that eventually improved the microstructural characteristics of the gain boundary phase. The coercivity of a magnet increased more than 3.5 kOe by the mixing of the DyMn alloy-powder.
6
Content available The modified procedures in coercivity scaling
Najgebauer M., Sokalski K., Szczygłowski J.
Archives of Electrical Engineering
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2015
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Vol. 64, nr 3
351--359
EN
The paper presents a scaling approach to the analysis of coercivity. The Widom-based procedure of coercivity scaling has been tested for non-oriented electrical steel. Due to insufficient results, the scaling procedure was improved relating to the method proposed by Van den Bossche. The modified procedure of coercivity scaling gave better results, in comparison to the original approach. The influence of particular parameters and a range of measurement data used in the estimations on the final effect of the coercivity scaling were discussed.
7
Content available Role of microstructure discontinuities in the soft magnetic composites with aluminium alloy addition
Bidulský R, Bidulská J., Actis Grande M.
Archives of Metallurgy and Materials
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2013
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Vol. 58, iss. 2
365--370
EN
The paper focuses on the effect of both the aluminium alloy addition and microstructural inhomogeneties on the magnetic behaviour of soft magnetic materials tested at low frequencies. The IIPC material (base on the commercial Somaloy 1P powder) has been blended with different amounts of commercially aluminium alloy Alumix 321 (0, 5 and 10 wt %). Specimens with a different green density were obtained by pressing at a pressure in the range from 400 to 800 MPa. Different thermal treatments (in air or nitrogen at the maximum temperature of 500ºC for 30 min) were carried out on the evaluated systems. The microstructure investigation revealed that for materials with high aluminium alloy contents, pores are located nearby or around the aluminium alloy particles. The heat treatment regime resulted in a coarse-grained structure with a small number of inclusions within the grains and at the grain boundaries. The comparison of the results indicated that the magnetic properties were considerably dependent on the microstructural inhomogeneities.
PL
Przedmiotem pracy jest wpływ dodatku stopu aluminium oraz niejednorodności mikrostruktury na właściwości magnetyczne magnetycznie miękkich materiałów badanych przy niskich częstotliwościach. Materiał IIPC (na bazie komercyjnego proszku Somaloy 1P) został zmieszany z różnymi ilościami komercyjnego stopu aluminium ALUMIX 321 (0, 5 i 10% wag.). Próbki o różnych gęstościach nasypowych prasowano stosując ciśnienie w zakresie od 400 do 800 MPa. Zastosowano różne obróbki cieplne (w powietrzu i azocie) ustalając maksymalną temperaturę 500ºC. Badania mikrostruktury pokazały, że dla materiałów o wysokiej zawartości stopu aluminium, pory sa w pobliżu lub otaczają cząstki stopu aluminium. W wyniku obróbki cieplnej tworzy się gruboziarnista struktura z minimalną liczbą wtraceń wewnątrz ziaren i na ich granicach. Porównanie wyników pokazuje, ąe właściwości magnetyczne zaleza w znacznym stopniu od niejednorodności mikrostruktury.
8
Content available A note on a fourth order discrete boundary value problem
Galewski M., Smejda J.
Opuscula Mathematica
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2012
|
Vol. 32, no. 1
115-123
EN
Using variational methods we investigate the existence of solutions and their dependence on parameters for certain fourth order difference equations.
9
Content available remote Influence of structural changes of Co78Si9B13 metallic glass on magnetic properties
Jakubczyk E., Lelątko J.
Optica Applicata
|
2009
|
Vol. 39, nr 4
859-863
EN
The primary crystallization of Co78Si9B13 metallic glass starts at 648 K and as a consequence of this the ?-Co(Si) phase with needle morphology is created. The second stage of crystallization (at 773 K) is the eutectic and as a result of this ?-Co(Si) and boron phases: (Co,Si)3B, (Co,Si)2B are formed. The crystallites of these phases have layer morphology. These characteristic morphologies in the first and second stages lead to the increase in coercivity.
10
Content available remote Magnetization reversal modeling for long ferromagnetic nanotubes
Lebecki K M
Materials Science Poland
|
2008
|
Vol. 26, No. 4
983--988
EN
The theory of infinite tube magnetization reversal, formulated by Lee and Chang, has been reconsidered. For this purpose, a standard micromagnetic simulation package OOMMF was used. To account for elongated geometry of ferromagnetic nanotubes grown nowadays, an extension module has been written allowing application of periodic boundary conditions in one dimension. The results of the modelling exhibit a basic agreement with the theory. Limitations of the approach have been described and checkpoints have been discussed necessary in finite difference simulations performed for such structures.
11
Content available remote Mechanical and magnetic properties bulk amorphous Fe59Co15Zr2Y4Me5B15 (Me=Mo or Nb) alloys
Lubas M., Zbroszczyk J., Nabiałek M., Olszewski J., Sobczyk K., Ciurzyńska W., Szota M., Brągiel P., Jasiński J. P., Świerczek J.
Archives of Metallurgy and Materials
|
2008
|
Vol. 53, iss. 3
861-866
EN
Some structural, magnetic and mechanical properties ofbulk Fe59Co15Zr2Y4Me5B15 (Me=Mo or Nb) alloys in the form of plates 0.5 mm thick obtained by a suction casting method are presented. X-ray diffraction and Mossbauer spectroscopy show that the bulk Fe59Co15Zr2Y4Me5B15 alloy is fully amorphous, whereas Fe59Co15Zr2Y4Me5B15 alloy is partially crystallized. The grains of a-FeCo crystalline phase with the volume fraction of 0.03 are embedded in the inhomogeneous amorphous matrix. The Vickers hardness of the fully amorphous Fe59Co15Zr2Y4Me5B15 alloy is the same on the surface (HVsurf) and in cross section (HVcross) of the sample and its average value eąuals to 10.4 GPa. For the partially crystallized plates of Fe59Co15Zr2Y4Me5B15 alloy the surface hardness (HVsurf=9.6 GPa) is lower than in cross section (HVcross=I0.3 GPa) of the sample. The alloys containing Nb exhibits higher wear resistance than the alloy with Mo. Both alloys are soft ferromagnets.
PL
W pracy są prezentowane badania struktury, właściwości magnetycznych i mechanicznych masywnych stopów Fe59Co15Zr2 Y4Me5B15 (Me=Mo lub Nb) w postaci płytek o grubości 0,5 mm, produkowanych metodą zasysania. Badania z wykorzystaniem dyfrakcji promieni X i spektrometrii mossbauerowskiej pokazują, że masywny stop Fe59Co15Zr2Y4Me5B15 jest w pełni amorficzny, natomiast stop Fe59Co15Zr2Y4Me5B15 jest częściowo skrystalizowany. Ziarna fazy krystalicznej FeCo są otoczone niejednorodną matrycą amorficzną i zajmują 3% objętości próbki. Twardość stopu amorficznego Fe59Co15Zr2Y4Me5B15 jest taka sama na powierzchni próbki, jak i w przekroju poprzecznym. Średnia wartość twardości dla tego stopu HV=10,4 GPa. Twardość częściowo skrystalizowanej płytki stopu Fe59Co15Zr2Y4Me5B15 na jej powierzchni jest mniejsza (HVsurf=9,60 GPa) niż w przekroju poprzecznym (HVcross=|0,3o GPa). Stop Fe59Co15Zr2Y4Me5B15 wykazuje większą odporność na ścieranie niż stop Fe59Co15Zr2Y4Me5B15. Obydwa badane stopy są ferromagnetykami magnetycznie miękkimi.
12
Content available 57Fe Mössbauer effect study of Nd-Fe-B hybrid bonded magnets
Płusa D., Olszewski J., Dośpiał J.
Nukleonika
|
2007
|
Vol. 52, supl. 1
89-92
EN
An investigation of magnetic interaction between the particles of hybrid bonded magnets based on mixtures of Nd-(Fe,Co)-B and strontium ferrite powders was carried out. An enhancement of the magnet remanence and coercivity caused by the interaction between their components was observed. From Mössbauer effect study, it results that this enhancement can be correlated with the increase of an average hyperfine field at Fe sites in Nd-(Fe,Co)-B magnets with the strontium ferrite addition.
13
Content available remote Magnetic properties of cementite (Fe3C) nanoparticle agglomerates in a carbon matrix
Lipert K., Kaźmierczak J., Pełech I., Narkiewicz U., Ślawska-Waniewska A., Lachowicz H. K.
Materials Science Poland
|
2007
|
Vol. 25, No. 2
399--404
EN
Magnetic properties of two FeC samples with different amounts of carbon have been studied. In both cases, the amount of carbon was well above the mass sufficient to transform nanocrystalline iron into iron carbide (cementite). Through the dc magnetic and transmission electron microscopy (TEM) measurements it was shown that cementite nanoparticles formed agglomerates; the size distribution of these nanoparticles was very wide, and superparamagnetic-like behaviour was not observed even at room temperature.
14
The effect of underlayers on grain orientation and magnetic properties of barium-ferrite thin film
Kim D. H., Nam I. T., Hong Y. K.
Materials Science
|
2003
|
Vol. 21, No. 1
65-72
EN
The effect of employing various sputtered underlayers in order to optimize the characteristics of Barium ferrite (BaM) thin films for magnetic recording media have been studied. BaM thin films and underlayers (Fe, Cr, Al2O3, Fe2O3, ZnFe2O4, TiO2) were prepared by rf/dc magnetron sputtering on (100) oriented bare Si substrate, and were crystallized by post-annealing. All the BaM films, except BaM/Fe/Si film, attained nearly the same perpendicular and in-plane coercivities. Perpendicular anisotropy was observed in BaM/Fe/Si film. The BaM/TiO2/Si exhibits the highest coercivity. However, regardless of the underlayer, BaM grains are randomly oriented. By adopting ZnFe2O4 as an underlayer, the interdiffusion of Si from substrate was prohibited to some degree. The microstructure of BaM in BaM/TiO2/Si was strongly dependent on both the microstructure of TiO2 underlayer and the total sputtering gas pressure. The control of an underlayer microstructure is one of the important factors to control grain size and shape of the BaM layer.
15
Content available Convergence and extensions of variational problems with non-coercive functionals
Ioffe A.
Control and Cybernetics
|
2002
|
Vol. 31, no 3
507-519
EN
The paper is a transcript of the lecture given at the European Symposium on Well-Posedness in Optimization in Warsaw. It contains a complete theory of variational problems with integrands not depending on x, including existence and relaxation theorems, a complete description of solutions and the connection between variational convergences of functionals and convergence of value functions and solutions of associated variational problems with the main emphasis on functionals that lack coercivity.
16
New processing method for the preparation of interstitially modified Sm-Fe intermetallics.
Jakubowicz J., Jurczyk M.
Inżynieria Materiałowa
|
1998
|
R. XIX, nr 4
827-831
EN
Sm2Fe17-nitrides and Sm2Fe-17-carbonitrides, which have the rhombohedral Th2Zn17 type structure have been synthesized and studied by XRD, SEM and magnetometry. A coercivity of 2.1 MA m -1 has been obtained for Sm2Fe17N-3 powder prepared by HEBM, and a simple one-step mechanical grinding of Sm2Fe17, with organic ring compounds has been used to produce an anisotropic powder. This study demonstrates that formation of an anisotropic Sm2Fe17(C,N)x powders by mechanochemical reaction between Sm2Fe17 and organic ring compounds has a significant potential for the synthesis of powders in an economic method. These materials show intrinsic coercivities, JHc up to 0.55 MA m-1 at room temperature.
17
Nanocrystalline permanent magnet materials.
Leonowicz M., Kaszuwara W., Januszewski D.
Inżynieria Materiałowa
|
1998
|
R. XIX, nr 4
797-802
EN
General characteristics of nanostructured permanent magnet materials is presented. The experimental data for Sm2Fe17N3 type magnets are shown. The materials were prepared by mechanical alloying, diffusion annealing and nitriding. The magnetic properties are discussed in the light of the processing parameters and material composition. The effect of nanostructure on the magnetic properties and Curie temperature has been proved. The influence of Co and Ga addition is also mentioned. Consolidation methods of nanocrystalline powders are proposed.
18
Magnetic anisotropy of nanocrystalline Sm-Fe-N magnets produced by heterogeneous diffusion.
Pawlik P., Wysłocki J. J., Przybył A., Kaszuwara W., Leonowicz M.
Inżynieria Materiałowa
|
1998
|
R. XIX, nr 4
823-826
EN
The Sm2Fe17Nx magnets were produced using heterogeneous diffusion and gas nitrogenation of 25% Sm-75% Fe mixture of powders. On decreasing the grain size to 0.97 micrometers the anisotropy constants K1 and K2 increase to 1.4 MJ/ cubic metres and 0.93 MJ/ cubic metres, respectively. Angular dependence of the coercivity can be understood as intermediate between the nucleation model and curling mechanism. On the basis of the domain structure observations, intrinsic magnetic properties were calculated. R
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