Effect of Y element on atomic structure, glass forming ability,and magnetic properties of FeBC alloy

The atomic structure of amorphous alloys plays a crucial role in determining both their glass-forming ability and magnetic properties. In this study, we investigate the influence of adding the Y element on the glass-forming ability and magnetic properties of Fe_(86-x)Y_xB_7C_7(x = 0, 5, 10 at.%) amorphous alloys via both experiments and ab initio molecular dynamics simulations. Furthermore, we explore the correlation between local atomic structures and properties. Our results demonstrate that an increased Y content in the alloys leads to a higher proportion of icosahedral clusters, which can potentially enhance both glass-forming ability and thermal stability. These findings have been experimentally validated. The analysis of the electron energy density and magnetic moment of the alloy reveals that the addition of Y leads to hybridization between Y-4d and Fe-3d orbitals, resulting in a reduction in ferromagnetic coupling between Fe atoms. This subsequently reduces the magnetic moment of Fe atoms as well as the total magnetic moment of the system, which is consistent with experimental results. The results could help understand the relationship between atomic structure and magnetic property,and providing valuable insights for enhancing the performance of metallic glasses in industrial applications.

Behavior of Medium-frequency Core Loss in Fe-based Nanocrystalline Soft Magnetic Alloys

The dependences of the power loss per cycle on frequency have been investigated in the ranges of 100 Hz<= f<=25000 Hz and 0.1 T< =Bm <=1.0 T for three main original magnetic states in five sorts of Fe-based nanocrystalline soft magnetic alloys. The measured and calculated results showed that the total power loss per cycle clearly exhibited a nonlinear behavior in the range below 3 kHz～5 kHz depending on both the magnetic state and the value of Dm, whereas it showed a quasi-linear behavior above this range. The total loss was decomposed into hysteresis loss, classical eddy current loss and excess loss, the obvious nonlinear behavior has been confirmed to be completely determined by the dependence of the excess loss on frequency. It has been indicated that the change rate of the excess loss per cycle with respect to frequency sharp decreases with increasing frequency in the range below about 3 kHz～5 kHz, wherease the rate of change slowly varies above this range, thus leading to the quasilinear behavior of the total loss per cycle. In this paper, some linear expressions of the total loss per cycle has been given in a wider medium-frequency segment, which can be used for roughly estimating the total loss.

General Properties of Low-frequency Power Losses in Fe-based Nanocrystalline Soft Magnetic Alloys

The dependences of the power loss per cycle on frequency f and amplitude flux density Bm have been investigated for the three main original magnetic states in five sorts of Fe-based nanocrystalline soft magnetic alloys in the ranges of 10 Hz<=f<=1000 Hz and 0.4 T<= Bm <=1.0 T. The total loss P is decomposed into the sum of the hysteresis loss Physt, the classical eddy current loss Pel and the excess loss Pexc. Physt has been found to be proportional to Bm^2 and f. The behavior of Pexc/f vs f being equivalent to P/f vs f clearly exhibits nonlinearity in the range not more than about 120 Hz, whereas the behavior of P/f vs f roughly shows linearity in the range far above 100 Hz and not more than 1000 Hz. In the range up to 1000 Hz, Physt is dominant in the original high permeability state and the state of low residual flux density, whereas Pexc in the state of high residual flux density is dominant in the wider range above about 100 Hz. The framework of the statistical theory of power loss has been used for representing the behavior of Pexc/f vs f. It has been found that the number n of the simultaneously active 'Magnetic Objects' linearly varies as n = n0 + Hexc/H0 as a function of the dynamic field Hexc in the range below about 120 Hz, whereas n approximately follows a law of the form n = n0 + (Hexc/H0)^m with 1 < m < 2 in the range far above 100 Hz and not more than 1000 Hz. The values of the field HO in principle related to the microstructure and the domain structure have been calculated for the three states.

Hot-press sintering of MA Fe-based nanocrystalline/amorphous soft magnetic powder

Microstructures and magnetic properties of Fe84Nb7B9,Fe80Ti8B 12 and Fe32Ni36（Nb/V）7Si8B17 powders and their bulk alloys prepared by mechanical alloying（MA） method and hot-press sintering were studied. The results show that: 1) After MA for 20 h,nanocrystalline bcc singl e phase supersaturated solid solution forms in Fe84-Nb7B9 and Fe8 0Ti8B12 alloys,amorphous structure forms in Fe32Ni36Nb7 Si8B17 alloy,duplex microstructure composed of nanocrystalline γ- （FeNi） supersaturated solid solution and trace content of Fe2B phase forms in Fe32Ni36-V7Si8B17 alloy. 2) The decomposition process of supersaturated solid solution phases in Fe84Nb7B9 and Fe80Ti8B 12 alloys happens at 710780 ℃,crystallization reaction in Fe （32）Ni36Nb7Si8B17 alloy happens at 530 ℃（the temperature of peak value） and residual amorphous crystallized further happens at 760 ℃ （the temperature of peak value）,phase decomposition process of supersaturated solid solution at 780 ℃ （the temperature of peak value） and crystallization reaction at 431 ℃ （the temperature of peak value） happens in Fe32Ni36V7S i8B17 alloy. 3) under 900 ℃,30 MPa,（0.5 h） hot-press sintering conditions,bulk alloys with high relative density（94.7%95.8%） can be ob tained. Except that the grain size of Fe84Nb7B9 bulk alloy is large,s uperfine grains （grain size 50200 nm） are obtained in other alloys. Exc ept that single phase microstructure is obtained in Fe80Ti8B12 bul k alloy,multi-phase microstructures are obtained in other alloys. 4) The magne tic properties of Fe80Ti8B12bulk alloy（Bs=1.74 T,Hc= 4.35 kA/m） are significantly superior to those of other bulk alloys,which is r elated to the different phases of nanocrystalline or amorphous powder formed dur ing hot-press sintering process and grain size.

Effect of the Partial Substitution of V for Nb on the Magnetic Properties of Fe-based Nanocrystalline Alloy

The variation of the magnetic properties of the nanocrystalline alloys for the partial substitution of V for Nb with crystallizing treatment temperature and time was investigated. The variation law of the magnetic properties with the annealing temperature and time is essentially the same. The magnetic properties of the Fe-based nanocrystalline alloys for the partial substitution of V for Nb reduce, and the crystallizing treatment temperature of the alloys increases. The optimum properties of Fe74Cu1Nb3Si13B9 nanocrystalline alloys crystallized at 550℃x60 min are μ0=9.2xl0^4, μm=54.8xl0^4, Hc=1.14 A/m and Bs=1.26 T. The best properties for Fe74Cu1Nb3Si13B9 alloys annealed at 560℃x60 min are μ0=8.79x10^4, μm=50.18xl0^4, Hc=1.26 A/m and Bs=1.24 T.

FRACTAL STRUCTURE OF THE CORE LOSS SPECTURM OF Fe-B-Si AMORPHOUS SOFT MAGNETIC ALLOY

The core loss spectrum P(f) of Fe-B-Si amorphous soft magnetic alloy has been studied.It is found that P(f) has the fractal structure.The effect of heat treatment on the fractal dimension Df is discussed.

Effect of particle size on the preparation and microwave absorption properties of FeSiAl magnetically soft alloy hollow microspheres

FeSiAl magnetically soft alloy hollow microspheres(MSAHMs) were prepared by self-reactive quenching technology based on Fe + Si + AI + KNO_3 reactive systems, in order to obtain absorbents with light weight, low frequency and high efficiency. Firstly, twice-balling adhesive precursor method was used to obtain FeSiAl magnetically soft alloy agglomerate powders. Then agglomerate powders with the mesh number of 150-240, 240-325 and 325-400 were sprayed through the flame field into the quenching water. At last, FeSiAl MSAHMs with coarse(average at 86.97 μm), medium(average at 52.16 μm) and fine particles(average at 31.80 μm) were got. Effect of particle size on the phases and microwave absorption properties in low frequency band was studied by XRD and vector network analyzer. The results show that,Fe_3 Si_(0.7)Al_(0.3) and Fe_3 Si_(0.5)Al_(0.5) appear in the phase components of FeSiAl MSAHMs,which is important to improve the microwave absorption properties in low frequency. In addition, the real part(ε′) and imaginary part(ε″) of complex permittivity, the real part(μ′) and imaginary part(μ″) of complex permeability of FeSiAl MSAHMs all present the trend of fine particles > medium particles > coarse particles. The microwave absorption properties in low frequency are improved with the increasing of particle size, and the absorption peak moves to lower frequency range. The properties of fine particles are the best. Their matching thickness of samples is at 5 mm, and the minimum reflectivity is-43 dB at this thickness. The absorption frequency band lower than-10 dB is 4.6-7.6 GHz with a bandwidth of 3 GHz.

Powder injection molding of Fe-Ni soft magnetic alloys

With miniaturization and complication of the shape of electronic devices in recent years,powder injection molding(PIM)seems to be a suitable process for fabricating the higher performance soft magnetic components.In this paper,high quality Fe-50Ni soft magnetic alloy was fabricated by PIM with carbonyl iron and nickel,and the effect of sintering process on its microstructure and magnetic properties were investigated.The mechanical and magnetic properties can be obviously improved by increasing the sintering temperature or using the hydrogen atmosphere instead of high vacuum,which causes by the increase of grain size and the densification.At the optimum sintering conditions,the PIM Fe-50Ni soft magnetic alloy with high properties are obtained,whose relative density,tensile strength,B_(m),H_(c),μ_(m)are 97%,465 MPa,1.52 T,16.62 A·m^(-1),42.5 mH·m^(-1),respectively.

Effect of niobium on glass-formation ability and soft magnetic properties of Gd-doping glassy alloys

The effect of niobium on glass-formation ability and soft magnetic properties were studied in Fe-Gd-B glassy alloys. The glassy alloys exhibited high glass-formation ability when the element of Nb was added. Bulk glassy rod （Fe0.87Co0.13）68.5Gd3.5Nb3B25 with a diameter up to 3 mm was produced by copper mold casting. The size of the atom might play an important role in increasing glass-formation ability. The coercive force of glassy （Fe0.87Co0.13）71.5.xGd3.sNbxB25 （x=1.2, 1.5, 2, 2.5, 3, 4） alloys decreased after the addition of niobium element and was in the range of 1.5-2.9 A/m. The permeability spectrum of （Fe0.87Co0.13）70.3Gd3.5Nb1.5B25 glassy ribbon showed that the relaxation frequency （f0） was 6.1 MHz.

Fractal Structure of the Core Loss Spectrum of Co-based Amorphous Soft Magnetic Alloy with Constant Permeability

In order to check the traditional core loss formula, the core loss spectrum P(f) of Co-based amorphous soft magnetic alloy with constant permeability has been studied. It is found that within a high frequency range from 10 kHz to 200 kHz and at Bm = 0. 1 T,the P(f) has the fractal structure P (f) = Po, and with the increasing of induced anisotropy energy Ku, the fractal dimension Dfrises, thus the total power loss at high frequency increases and the frequency characteristic of P(f) becomes worse.

Preparation and Study of the Crystallization Behavior of the Fe87Zr7B5-x Nanocristalline Soft-Magnetic Alloys

A series of materials of composition Fe87Zr7B6,Fe87Zr7B5Ag1,Fe87Zr7B5Cu1 have been prepared by the melt spinning method for different cooling speed to get completely or partly amorphous ribbons.It is proved that the crystallization process is composed of 2 steps.The first step is the precipitation of&-Fe only and the second step is the phase separation of&-Fe,Fe2Zr and Fe2B.All our own made materials have been used in the library monitoring system.Most of them showed a capability of triggling the alarm of the system.The triggling sensitivity at different positions and different sample geometry were investigated and the physical mechanisms were analyzed.

Influence of heat treatment on high frequency soft magnetic properties of Finemet amorphous alloy

In order to study high-frequency soft magnetic properties of Finemet amorphous alloy,the microstructural change and nanocrystallization under different heat treatment conditions were investigated by XRD and TEM. The crystallite size of α-Fe was calculated from the XRD pattern using the Scherrer formula,while the high frequency magnetic properties were measured at room temperature by TPS-200SA exchange tester. The results of XRD and TEM indicate that the nanocrystallization occurs at 500 ℃. When the annealing temperature increases to 560 ℃,the amorphous alloy becomes totally nanocrystallized and the crystallites distribute homogeneously,thus an excellent combination of soft magnetic properties is obtained.

Influence of electroplating conditions on magnetic properties of Fe-36wt.% Ni alloy film

A Fe-Ni soft magnetic film was prepared in sulphate solution by electroplating.The influences of the molar ratio of n[Fe^(2+)]/n[Ni^(2+)],current density,bath temperature,pH and L-ascorbic acid concentration on magnetic properties of Fe-Ni alloy film were investigated.The results show that the saturated flux density(BS)of the film increases initially and decreases after it reaches the specific value with the increase of n[Fe^(2+)]/n[Ni^(2+)]molar ratio,current density,bath temperature and pH.However,the relationship between L-ascorbic acid concentration and BS keeps linear.It is observed that the coercive force(H_(c))is enhanced with the increase of n[Fe^(2+)]/n[Ni^(2+)]molar ratio,current density and pH.By comparison,when the bath temperature increases,Hc always decreases.With the increase of L-ascorbic acid concentration,the coercive force increases initially and then decreases.

Ductile Fe-based amorphous alloys with high iron content

Fe-based amorphous alloys with high iron content of 76at%-80at%were synthesized in the Fe-Mo-Si-P-C-B alloy system by the single roller melt-spinning technique.The amorphous ribbons exhibit high Vickers microhardness and good ductility,which can be indented and bent 180°without breaking.A number of shear bands could be observed around the indents and the bending traces.Studies on the magnetic properties of the amorphous alloys show that they possess high saturation magnetizations of 1.34-1.6 T,which increases with the increase of iron content.The core losses of these Fe-based amorphous alloys at various magnetic inductions were tested and found to be significantly dependent on their components.The Fe-Mo-Si-P-C-B amorphous alloys with excellent mechanical properties and soft magnetic properties have promising potential in functional applications.

Reduction of High-Frequency Core Loss of a Fe_(77.2)Si_(11)B_(8.5)Cu_(0.8)Nb_(2.5)Soft Magnetic Nanocrystalline Alloy by Minor Alloying

Enhancing saturation magnetic flux density(Bs)while reducing high-frequency core loss in Finemet-type nanocrystalline alloys is of great significance in achieving the miniaturization,high-frequency,and energy-saving of modern power electronic devices.In this work,we first designed a high-Bs Fe_(77.2)Si_(11)B_(8.5)Cu_(0.8)Nb_(2.5)alloy by appropriately reducing the non-magnetic elements in typical Finemet nanocrystalline alloys,and subsequently alloyed 2 at%Co,Al,and Mo,respectively.The effects of alloying elements on structure and static and high-frequency magnetic properties were studied.The results reveal that,alloying Al or Mo reduces the averageα-Fe grain size(Dα-Fe)in the nanocrystalline alloys,while Co exhibits a slight influence.The added Al or Mo results in decreases in both the Bs and coercivity(Hc)of the nanocrystalline alloys,whereas Co increases the Bs without changing Hc,and meanwhile,all alloying elements show minimal effects on effective permeability(μe).Furthermore,the addition of Co,Al,or Mo lowers the core loss(Pcv)at 0.2 T/100 kHz of the based nanocrystalline alloy with reductions of 10.9%,29.6%,and 26.8%,respectively.A Fe_(75.2)Si_(11)B_(8.5)Cu_(0.8)Nb_(2.5)Al_(2)nanocrystalline alloy exhibits outstanding soft magnetic properties with Bs,Hc,μe at 10 kHz and 100 kHz,and Pcv at 0.2 T/100 kHz of 1.34 T,0.8 A/m,27,400,18,000,and 350 kW/m3,respectively.The reduction in Pcv is primarily attributed to the decreased eddy current losses,originating from the increased electrical resistivity by elements alloying.

Effect of Fe Substitution on Magnetic Properties and Radar Wave Absorption of the Y_(2)Co_(17) Rare Earth Soft Magnetic Alloy

The rapid development of information technology leads a demand for high frequency soft magnetic materials with ex-ceptional radar wave absorption properties.A new magnetic material with superior radar wave absorption is explored in this paper.we explored the preparation of Y_(2)Co_(17)-xFex(x=0.0,1.0,2.0,3.0)alloy powders using yttrium oxide as a raw material by a low-cost and short preparation cycle reduction-diffusion process.The crystal structure,intrinsic magnetic properties,high frequency magnetism and radar wave absorption of Y_(2)Co_(17)-xFex(x=0.0,1.0,2.0,3.0)were investigated.These compounds have a perfect magnetic repair of Y_(2)Co_(17) and enable the improvement of the overall magnetic properties of Y_(2)Co_(17)-xFex(x=0.0,1.0,2.0,3.0)compounds.The Y_(2)Co_(17)-xFex/Polyurethane(PU)(x=0.0,1.0,2.0,3.0)absorbers were divided in detail using the zero-reflection mechanism.The results show that all Y_(2)Co_(17)-xFex/PU(x=0.0,1.0,2.0,3.0)absorbers have excellent absorption performance(reflection loss RL is less than-85 dB);in addition,Y_(2)Co_(15)Fe_(2)/PU absorbers and Y_(2)Co_(14)Fe_(3)/PU absorbers are superior candidates for S-band materials.In particular,the perfectly matched frequency fp of the modulated Y_(2)Co_(14)Fe_(3)/PU absorber is shifted to the L-band(1–2 GHz)where early warning radars are located.The Y_(2)Co_(14)Fe_(3)/PU absorber has an effective absorption bandwidth of 300 MHz(1.5–1.8 GHz)at a thickness of 5.230 mm.It can also absorb the full L-band at-4 dB,which has rarely been reported.

Thermal Stability and Magnetic Properties of (Fe,Co)-Zr-Nd-B Amorphous Alloys

A new type of Fe-based amorphous alloy containing rare earth element was prepared by melt spinning technique. The glass-forming ability (GFA),thermal stability and magnetic properties were investigated in the composition range of Fe_(70)Co_8Zr_(7- x )Nd_ x B_(15) ( x =0% to 6%,atom fraction). They exhibit the glass transition and supercooled liquid region before crystallization. The width of supercooled liquid region obtained for the series of Fe_(70)Co_8Zr_(7- x )Nd_ x B_(15) exceeds (40 K,) among which the maximum width for Fe_(70)Co_8Zr_5Nd_2B_(15) amorphous alloy reaches 61 K. Another main attraction is that the selected Fe-based amorphous alloys have good soft magnetic properties. The saturation magnetization ( J _s) is in the range of 1.10 to 1.37 T,and coercive force ( H _c) in the range of 2.28 to 8.15 A·m (-1) for Fe_(70)Co_8Zr_(7- x )Nd_ x B_(15) amorphous alloys. It is found that the saturation magnetization ( J _s) increases with the increment of the relative content of the Nd for the Fe_(70)Co_8Zr_(7- x )Nd_ x B_(15) alloys. The H _c values for the glasses with Nd content of 1%,2% and 3% are below 3 A·m (-1). The research indicates that Fe_(70)Co_8Zr_5Nd_2B_(15) amorphous alloy has good high GFA and good soft magnetic properties,of which the width of supercooled liquid region,J _s,and H _c are 61 K,1.25 T and 2.28 A·m (-1),respectively.

Excellent soft magnetic properties realized in FeCoN thin films

FeCoN soft magnetic thin films are prepared by using the reactive direct-current magnetron sputtering technique. It is found that the addition of N2 can reduce the coercivity of the FeCoN film, and excellent soft magnetic properties can be obtained when the ratio of N2 flow to total gas flow is 10%. The influences of texture, grain size, and stress on the magnetic properties and the high-frequency behaviors of the films are also discussed.

Role of compositional changes on thermal,magnetic,and mechanical properties of Fe-P-C-based amorphous alloys

This work aimed to tune the comprehensive properties of Fe-P-C-based amorphous system through investigating the role of microalloying process on the crystallization behavior,glass forming ability(GFA),soft magnetic features,and mechanical properties.Considering minor addition of elements into the system,it was found that the simultaneous microalloying of Ni and Co leads to the highest GFA,which was due to the optimization of compositional heterogeneity and creation of near-eutectic composition.Moreover,the FeCoNiCuPC amorphous alloy exhibited the best anelastic/viscoplastic behavior under the nanoindentation test,which was owing to the intensified structural fluctuations in the system.However,the improved plasticity by the extra Cu addition comes at the expense of magnetic properties,so that the saturation magnetization of this alloying system is significantly decreased compared to the FeCoPC amorphous alloy with the highest soft magnetic properties.In total,the results indicated that a combination of added elemental constitutes,i.e.,Fe69Co5Ni5Cu1P13C7 composition,provides an optimized state for the comprehensive properties in the alloying system.

Dependence of Structure and Magnetic Properties on Annealing Temperature in Fe(72.5)Cu1Nb2V2Si(13.5)B9 Alloy

The magnetic properties of Fe_(72.5)Cu_1Nb_2V_2Si_(13.5)B_9 alloy are investigated from an amorphous to a nanocrystalline and complete crystalline state. The sample annealed at 550℃ for 0.5 h shows a homogeneous nanocrystalline structure and presents excellent soft magnetic properties. When the specimens were annealed at a temperature above 600℃, the magnetic properties are obviously deteriorated because the grain size grows up, exceeding the exchange length.