Effects of Alloying Elements on the Thermal Stability and Corrosion Resistance of an Fe-based Metallic Glass with Low Glass Transition Temperature

The effects of alloying elements on the thermal stability, glass-forming ability (GFA), corrosion resistance, and magnetic and mechanical properties of a soft magnetic Fe₇₅P₁₀C₁₀B₅ metallic glass with a low glass transition temperature (T _g) of 723 K (450°C) were investigated. The addition of Mo, Ni, and Co significantly increased the stabilization of supercooled liquid, GFA, and corrosion resistance in the H₂SO₄ solution. The maximum critical diameter (d _c) of 4 mm for glass formation was obtained for the Fe₅₅Co₁₀Ni₅Mo₅P₁₀C₁₀B₅ alloy, which shows the largest supercooled liquid region (ΔT _x ) of 89 K (89 °C). The substitution of Cr for Mo further enhanced the corrosion resistance of the Fe₅₅Co₁₀Ni₅Mo₅P₁₀C₁₀B₅, while the ΔT _x and d _c decreased. The (Fe, Ni, Co)₇₀(Mo, Cr)₅P₁₀C₁₀B₅ bulk metallic glasses showed low T _g of 711 K to 735 K (438 °C to 462 °C), wide ΔT _x of 67 K to 89 K, high saturation magnetization of 0.79 to 0.93 T, low coercive force of 2.36 to 6.61 A m^?1, high compressive yield strength of 3271 to 3370 MPa, and plastic strain of 0.8 to 2.3 pct. In addition, the mechanism for enhancing stability of supercooled liquid was discussed in terms of the precipitated phases during crystallization.     

Influence of partial substitution of cerium for lanthanum on magnetocaloric properties of La_(1–x)Ce_xFe_(11.44)Si_(1.56) and their hydrides

The structure and magnetocaloric properties of La1–xCexFe11.44Si1.56 and their hydrides La1–xCexFe11.44Si1.56Hy（x=0, 0.1, 0.2, 0.3, 0.4） were investigated.The samples crystallized mainly in the cubic Na Zn13-type structure with a small amount of α-Fe phase as impurity.The lattice constants and Curie temperature presented the same change tendency with increasing of Ce content.For the hydrides, the influence of Ce content on lattice constants was weakened and the values of H concentration y were approximate to be 1.56.The La1–xCexFe11.44Si1.56 compounds exhibited large values of isothermal entropy change –ΔSm around the Curie temperature TC under a low magnetic field change of 1.5 T.The value of –ΔSm increased and then decreased with increasing Ce content, reached the maximum, 26.07 J/kg·K for x=0.3.TC increased up to the vicinity of room temperature by hydrogen absorption for the Ce substituted compounds, but TC only slightly decreased with increasing Ce content.The first-order metamagnetic transition was still kept in the hydrides and the maximum values of –ΔSm were lower than those of the La1–xCexFe11.44Si1.56 compounds, but still remained large values, about 10.5 J/kg K under a magnetic field change of 1.5 T.The values of –ΔSm were nearly independent of the Ce content and did not increase with increasing x for the hydrides.The La1–xCexFe11.44Si1.56Hy（x=0–0.4） hydrides exhibited large magnetic entropy changes, small hysteresis loss and effective refrigerant capacity covered the room temperature range from 305 to 317 K.These hydrides are very useful for the magnetic refrigeration applications near room temperature under low magnetic field change.     

Influence of Melt-Spinning Parameters on the Structure and Soft Magnetic Properties of (Fe0.65Co0.35)88Zr7B4Cu1 Alloy

Melt-spun ribbons of (Fe_0.65Co_0.35)₈₈Zr₇B₄Cu₁ alloy have been prepared at different wheel speeds, namely, 47, 39, 34, and 17 m/s, and subsequently annealed at 773 K (500 °C) under controlled atmosphere. Structural and soft magnetic properties have been evaluated using X-ray diffraction, differential scanning calorimetry, transmission electron microscopy, and vibrating sample magnetometer. The structure of as-spun ribbons changes from fully amorphous to partially amorphous/nanocrystalline to fully nanocrystalline (bcc α-Fe(Co) + Fe₂Zr) on decreasing the wheel speed. Annealing of amorphous ribbons leads to the precipitation of nanocrystalline bcc α-Fe(Co) phase. The Curie temperature (T _c ) of the amorphous phase is found to increase with decreasing wheel speed possibly due to the effect of exchange field penetration of nanocrystals present in the amorphous matrix. The saturation magnetization (4πM _s ) of as-spun ribbons having partially nanocrystalline bcc α-Fe(Co) phase is high as compared to the ribbons with completely amorphous phase, and it remains almost the same even after annealing. The lowest coercivity has been achieved in the ribbons that are fully amorphous, and the coercivity was found to increase with decreasing wheel speed.     

Nanocrystalline films of soft magnetic iron-based alloys

The physicochemical and structural aspects of designing soft magnetic alloys Fe-MX (where M is a Group III–V metal of the periodic table and X = C, N, O) in the form of nanocrystalline films precipitation-hardened by refractory interstitial phases are discussed and developed. The results of studying the structure and magnetic properties of Fe₇₈Zr₁₀N₁₂ films are reported. The films in the amorphous state are produced by reactive magnetron sputtering. Upon annealing at 300–600°C, the amorphous films crystallize to form mainly a bcc α-Fe-based phase and the fcc ZrN phase. The grain size of the bcc phase is shown to increase from ～3 nm to ～30 nm as the annealing temperature increases; the grain size of the fcc phase does not exceed 2–3 nm. Films annealed at 400°C exhibit a record level of magnetic properties: H _c = 5–6 A/m and B _s = 1.7–1.8 T. The experimental results obtained confirm the validity of our scientific approach.     

Crystal structure and hard magnetic properties of TbCu_7-type Sm_(0.98)Fe_(9.02–x)Ga_x nitrides

The compound Sm0.98Fe9.02–xGaxNδ(x=0, 0.25, 0.5, 0.75, 1) were prepared by melt-spun method and subsequent annealing and nitriding. The Rietveld analysis showed that the lattice expansion played an important role in improving the Curie temperature. An obvious development of the Curie temperature was obtained with the increased Ga content from x=0–1(ΔTc=90 oC). The optimum coercivity of nitrides was obtained at x=0.25 with the value Hcj=652 kA/m(8.15 kOe) after annealing, which corresponded to a reasonable distribution of grain sizes of both TbCu7-type SmFe9Nδ and α-Fe. However, an excess of Ga doping might lead to an abnormal growth of α-Fe, which in turn deteriorated the magnetic properties. It was concluded that a moderate Ga content was very effective in raising the coercivity and Curie temperament in the TbCu7-type Sm-Fe-N.     

Preparation of Fe-, Co-, and Ni-Based amorphous alloy powders by high-pressure gas atomization and their structural relaxation behavior

By using newly constructed high-pressure gas atomization equipment, the effect of atomizing gas (Ar, N₂, or He) on the formation tendency of amorphous alloy powders and their Curie temperature(T _c ), structural relaxation, glass transition(T _g ), and crystallization(T _x ) was examined for Fe-P-C, Fe-Si-B, Fe-Cr-Mo-P-C, Co-Si-B, Ni-Si-B, Ni-Pd-P, and Cu-Zr alloys with easy glass-forming capacity. Amorphous powders are formed in all the alloy systems and the critical diameter for the formation of amorphous powders is 25 to 44 μm for Ar and 44 to 100 μm for He. The average particle size is considerably smaller for He than for Ar and N₂, probably because of large kinematic viscosity of He. No appreciable differences inT _c ,T _g , andT _x of Fe₇₇P₁₃C₁₀ amorphous powders with the kind of atomizing gas are seen and these values are the same as those of the amorphous ribbon with 20 μm thickness. However, He-atomized Fe₇₇P₁₃C₁₀ powders exhibit a lower onset temperature of relaxation and larger heats of relaxation and crystallization as compared with the Ar- and N₂-atomized powders, and the values of the He-atomized powders are comparable to those of the ribbon sample, indicating that He-gas atomization has a higher cooling capacity and results in the formation of a more disordered amorphous structure. This difference agrees with the tendency estimated under the assumption that heat removal from atomized droplets occurs by Newtonian cooling caused only by the convective heat transfer. Accordingly, the greater heat removal capacity of He gas is concluded to be a dominant factor for the formation of amorphous alloy powders with a more unrelaxed atomic configurations.     

Crystallization of an Fe-Ni base amorphous alloy

The crystallization of an amorphous Fe-Ni base alloy was studied in a dynamic heating mode from room temperature to 700°C and during isothermal annealing at 400°C. Differential scanning calorimetry, X-ray diffraction, transmission electron microscopy, and hardness measurement were used to characterize the crystallization process under two heating conditions. In the dynamic heating condition, structural relaxation or atomic regrouping was thought to occur belowT _c. AboveT _c, crystallization occurred spontaneously and four crystalline phases were formed. The number of phases and the relative amount of these phases varied with the heating temperature. At a higher temperature, recrystallization occurred which resulted in grain growth. The final matrix phase was observed to coexist with other phases after crystallization. In the isothermal heating condition, it was found that the transformation of the alloy from amorphous state to crystalline state was through the nucleation and growth process. The first crystallization steps were via the formation of metastable phases. The final matrix phase than nucleated from the existing metastable phases. Hardness measurements in both heating conditions indicated that the alloy attained its peak hardness immediately after complete crystallization.     

Devitrification of Fe-Based Amorphous Metal SAM 1651: A Structural and Compositional Study

The effect of heat treatment on the chemistry and structure of an Fe-based bulk metallic glass (BMG) Fe₄₈Cr₁₅Mo₁₄C₁₅B₆Y₂ (SAM 1651) was examined experimentally. Chemical segregation was found in the as-received material, with islands 10 to 200 nm in diameter enriched in Y, Mo, and C and depleted in Fe and Cr, with respect to the surrounding matrix. Heat treatment in the range of 600 °C to 800 °C caused partial devitrification of the BMG with the formation of nanocrystalline (Fe, Cr)₂₃C₆ and (Fe, Cr)₇C₃ carbides in a matrix of the remaining amorphous phase. The devitrification process followed a primary crystallization route. Amorphous particle-free zones (PFZs) in the devitrified material were found, corresponding to the Y-Mo–rich islands in the fully amorphous SAM 1651. The formation of Cr-rich carbide during devitrification caused the formation of nanometer-sized Cr-depleted zones surrounding the carbide particles, which is detrimental to the corrosion performance of the alloy after thermal exposure.     

Table-like magnetocaloric effect and large refrigerant capacity of composite magnetic refrigerants based on LaFe11.6Si1.4Hy alloys

Composite magnetic refrigerants were prepared by physical mixing LaFe_(11.6)Si_(1.4)H_y alloys with different Curie temperatures(Tc). The phase structures of these LaFe_(11.6)Si_(1.4)H_y alloys were analyzed by X-ray diffraction(XRD) and the magnetocaloric effect(MCE) and refrigerant capacity(RC) of these composite magnetic refrigerants were investigated by experiment and calculation in this paper. The magnetocaloric effect(MCE) and refrigerant capacity(RC) of these composite magnetic refrigerants were investigated by experiment and calculation in this paper. The results indicate the experimental magnetic entropy change(-△S_M)-Tcurve corresponds reasonably with the(-△S_M)-Tcurve calculated by the linear combination of(-△S_M)-T curves of the single material. An optimal mixing ratio can make the composite magnetic refrigerant possess a table-like(-△S_M)-Tcurve which is beneficial to magnetic Ericsson cycle. When three LaFe_(11.6)Si_(1.4)H_y alloys with different T_c are mixed, the full width at half maximum(△T_(FWHM)) of(-△S_M)-T curves is about 48.7 K and the RC is about 177.76 J/kg under a magnetic field change of 2 T. The composite magnetic refrigerants based on LaFe_(11.6)Si_(1.4)H_y alloys can be promising candidates for near room temperature magnetic refrigeration and the work will be helpful to develop novel composite magnetic refrigerants with table-like MCE and large RC.     

The microstructure and magnetization reversal behavior of melt-spun (Nd1−xCex)-Fe-B ribbons

In this study,the alloy ingots with nominal compositions of(Nd_(1-x)Ce_x)_(31)Fe_(bal)Co_(0.2)Ga_(0.1)B(x=0, 0.1 wt%,0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%) were prepared and then melt-spun to form nanocrystalline ribbons at the wheel speed of 20 m/s. XRD results show that all melt-spun ribbons exhibit the tetragonal structure(Nd,Ce)_2 Fe_(14)B phase with the space group P42/mmm. The Curie temperature and lattice constant decrease with the increase of Ce content. The Curie temperature decreases gradually from 306 to 247 ℃with the increase of Ce content. Those results indicate that Ce element has been incorporated into Nd_2 Fe_(14)B main crystalline phase and formed(Ce,Nd)-Fe-B hard magnetic phase. It is also found that the remanence ratio(M_r/M_s) decreases from 0.693 to 0.663 and the coercivity(H_c) decreases from 18.7 to14.2 kOe with the increase of Ce content. However, a relatively high coercivity of 18.3 kOe for(Nd_(1-x)Ce_x)_(31)Fe_(bal)Co_(0.2)Ga_(0.1)B(x = 0.2) melt-spun ribbon is achieved. The coercivity is sensitive to microstructure. The AFM patterns show the sample(x = 0.2) has the most uniform and finest microstructure. The magnetization reversal behavior(δM plots) is discussed in detail. The positive δM value is observed in every sample, which confirms the existence of exchange coupling interaction. Evidently, theδM maximum value reaches 0.9 in the sample(x = 0.2). It is indicated that the intergranular exchange coupling effect is the strongest, which is consistent with coercivity enhancing.     

Thermodynamic study of bulk metallic glass: Zr41.2Ti13.8Cu12.5Ni10.0Be22.5

Recently, multicomponent glass forming alloys have been found which exhibit extraordinary glass forming ability and cooling rates of less than 100 K/s are sufficient to suppress nucleation of crystalline compounds and consequently form a bulk metallic glass (BMG). The thermophysical properties of liquid metals and alloys in the undercooled state is become great interest of research in recent years. Due to the high thermal stability of undercooled melts of BMG glass formers the experimental data of the thermophysical properties of bulk metallic melts are available in the undercooled region. It is interesting to study the thermodynamics of such materials. The aim of the present work to discuss the thermodynamic behavior of BMG by estimating the Gibb’s free energy difference ΔG, enthalpy difference ΔH and entropy difference ΔS between the undercooled liquid and corresponding equilibrium solid phases. The study is made by estimating ΔG, ΔH and ΔS for BMG: Zr_41.2Ti_13.8Cu_12.5Ni_10.0Be_22.5 in the entire temperature range T _m (melting temperature) to T _g (glass transition temperature).     

Effect of Dy-substitution on structural and magnetic properties of MnZn ferrite nanoparticles

This paper describes the structural and magnetic properties of Dy-substituted Mn-Zn ferrite nanoparticles. Mn-Zn-Dy ferrite nanoparticles of the composition Mn_(0.5)Zn_(0.5)Dy_xFe_(2-x)O_4(x=0.05, 0.1,0.15 and 0.2) were synthesized by a facile chemical co-precipitation method. The samples were characterized through X-ray diffraction(XRD), transmission electron microscopy(TEM), Fourier transform infrared spectroscopy(FTIR), vibrating sample magnetometer(VSM) and Curie temperature. The XRD patterns confirm the synthesis of single crystalline phase of Mn-Zn-Dy ferrite nanoparticles. Lattice parameter increases with increase in Dy-substitution which confirms the replacement of Fe~(3+) ions by Dy~(3+) ions.Crystallite size is of the order of 6-8 nm for all these samples. The particle sizes observed from TEM analysis are in good agreement with the XRD values. The magnetic measurements show superparamagnetic nature of the samples. The saturation magnetization decreases with increase in Dyconcentration and can be correlated to modifications in the A-B exchange interactions as a result of the structural modifications due to Dy-substitution. The Curie temperature for Mn_(0.5)Zn_(0.5)Fe_2 O_4 nanoparticles is 124 ℃ and decreases up to 84 ℃ with the increase in the Dy-concentration. The decrease in Curie temperature can be attributed to the weakening of the superexchange interaction between A-site and B-site as a result of Dy-substitution. The low value of Curie temperature and higher value of thermomagnetic coefficient k_T shown by these samples makes them suitable for the preparation of temperature sensitive ferrofluid for heat transfer applications.     

Magnetocaloric effect in ErNi_2 melt-spun ribbons

ErNi2 ribbons were produced by rapid solidification using the melt spinning technique.Their structural,magnetic and magnetocaloric properties in the as-solidified state were studied by X-ray diffraction,scanning electron microscopy,magnetization and specific heat measurements.Samples are single phase with the MgCu_2-type crystal structure,a Curie temperature T_C of 6.8 K and a saturation magnetization at2 K and 5 T of 124.0 A·m~2/kg.For a magnetic field change μ_0△H of 5 T(2 T) ribbons show a maximum magnetic entropy change |△S_M~(peak)| of 24.1(16.9) J/(kg·K),and an adiabatic temperature change △T_(ad)~(max) of8.1(4.4) K;this is similar to the previously reported literature for bulk alloys that were processed through conventional melting techniques followed by prolonged thermal annealing.In addition,the samples also show slightly wider △S_M(T) curves with respect to bulk alloys leading to a larger refrigerant capacity.     

Magnetic and magnetocaloric properties in GdZn2 synthesized by ball milling

In this study, we prepared GdZn₂ by mechanical alloying method and measured its magnetization to reveal the magnetic and magnetocaloric properties. For a milling time (MT) ≥ 10 and 20 h, the GdZn₂ phase was confirmed by X-ray diffraction measurements. For MT = 40 and 60 h, amorphous like patterns are observed. For MT = 10 and 20 h, magnetization (M) as a function of temperature below 80 K shows ferromagnetic-like increase. The observed values of M are 4.5 μ_B at 5 K for MT = 10 and 20 h, which is smaller than that of the theoretical expected value of 7 μ_B. For MT = 40 and 60 h, the long-range ferromagnetic order collapses because there is no spontaneous magnetization. The value of ΔT, where ΔT is the full width at half maximum of the magnetic entropy change (ΔS_m (T)), increases significantly for MT ≤ 20 h because of the gradual release of magnetic entropy by the milling effect. Since M decreases with increasing MT, the maximum values of |ΔS_m|, the relative cooling power, and the refrigerant capacity also decreases.     

Influence of Heat Treatment Parameters on Properties of NdRFeMCoB Sintered Magnets

Influence of multi-step heat treatments on magnetic properties and structure of three magnet types NdRFeMCoB: high-energy (B_t < 1, 3 T) (A); high-coercive (_iH_c < 2000 kA/m) (B) and thermally stable (α_b> |0, 02| %/K in the temperature interval 293–373K) (C) was investigated. Significant affect of condition of Nd₂Fe₁₄B phase on high-coercive condition development is shown. High values of _iH_c in magnets of NdRFeMCoB type can be provided by creating of elasto-stressed condition of Nd₂Fe₁₄B phase and minimal stresses values near boundary phases during heat treatments. The highest results on _iH_c are achieved after multi-step heat treatments. The temperature of the last step of heat treatment for optimal chemical compositions of the alloys (in dependence on the ratio of such elements as Al, Cu, Ga, Pr, Co) is in the interval of 725–905K (preferably, 775–825K). The value of _iH_c of magnet (B) Nd_13,2Tb_1,8Fe_baiCo₅Mo_3,8Al_0,9B₉(at. %) after heat treatment {1175–1075K (4–12 ks) - hardening + 625–725K (3,6–36 ks) + 810K (3, 6 ks) - hardening} was 2600 kA/m. It was possible to attain the following properties for the magnets (C) (Nd_0.22Pr_0.44Tb_0.20Ho_0.10Gd_0.04)₁₅(Fe_0.73Co_0.27)_baiAl_0.99Cu_0.1Ga_0.1B_8.5(at. %) after optimal thermal treatment (1175K (3,6–7,2 ks) with slow (12–16 ks) cooling to 675K and subsequent endurance at T=775K for 3,6 ks - hardening}: B_r= 1,0 T, _iH_c = 1560 kA/m, BH_max= 192 kJ/m³, α_b> |0, 015| %/K in the temperature interval 293–373K.     

The effect of metallic elements on the crystallization behavior of amorphous Fe-Si-B alloys

The crystallization behavior of amorphous Fe_84-X Si₆B₁₀M_X (M=Nb, Zr, V, or Cu) alloys was examined using differential scanning calorimetry (DSC) and transmission electron microscopy (TEM) with the aim of clarifying the effect of additional M elements. The compositional dependence of the first crystallization temperatureT _x1 increased in the order of Zr > Nb > V; however, the addition of 1 at. pct Cu caused a decrease inT _x1. Such an effect of the M elements on the thermal stability of an amorphous phase was interpreted in terms of the difference in the atomic size. These alloys were composed of a mixed structure ofα-Fe and amorphous phases after aging for 3.6 ks in the first exothermic temperature range. The addition of more than 3 at. pct Nb or Zr significantly affected the morphology and grain size of theα-Fe phase. However, their particles possessed dendritic morphology with a grain size of 0.1 to 0.3 μm, when the Nb or Zr content was less than 2 at. pct. Further addition of these elements brought about the formation of sphericalα-Fe particles. The average grain size, for instance, was as small as 20 nm in the aged alloy containing 6 at. pct Nb, which shows that a remarkable grain refinement occurs with increasing Nb content.     

Effect of High-Pressure Torsion Deformation and Subsequent Annealing on Structure and Magnetic Properties of Overquenched Melt-Spun Nd9Fe85B6 Alloy

The influence of a high-pressure torsion deformation (HPTD) and subsequent annealing on the magnetic properties and phase transformations in the melt-spun Nd₉Fe₈₅B₆ alloy has been investigated. Because of the low density of nucleation centers and formation of the metastable NdFe₇ and Nd₂Fe₂₃B₃ phases, the crystallization of the nearly amorphous ribbons leads to the non-uniform and coarse Nd₂Fe₁₄B grains resulting in the lower values of the coercivity H_c and remanence B_r. The HPTD prior to annealing creates numerous α-Fe nanograins, which apparently serve as nucleation sites for Nd₂Fe₁₄B. In the ribbons subjected HPTD and annealed at 600 °C, the α-Fe and Nd₂Fe₁₄B grains are uniform and fine (13 and 22 nm, respectively) leading to the increase of H_c by 23% and the increase of B_r by 16%. Thus, HPTD is a powerful tool for improvement of the magnetic hysteresis properties in the overquenched Nd₉Fe₈₅B₆.     

Structural,magnetic and electrical characterization of the La0.7Ca0.3Co1–xMnxO3（x=0,0.7 and 1） compounds prepared by a simple method

Structural, magnetic and electrical properties of the La0.7Ca0.3Co1–xMnxO3（x=0, 0.7 and 1） samples prepared by a simple method were systematically studied and it was found that the crystal structure was transformed from rhombohedral for La0.7Ca0.3CoO3（LCCO） and La0.7Ca0.3Co0.3Mn0.7O3（LCCMO） samples to orthorhombic for La0.7Ca0.3MnO3（LCMO） sample. The AC magnetic susceptibility measurements showed that LCCO sample underwent a transition from paramagnetic（PM） to ferromagnetic（FM） phase at Curie temperature, TC~155 K and below Curie temperature, the glassy ferromagnetism nature was observed. In LCCMO sample,clear evidence of spin glass（SG） state was observed at low temperature. PM-FM phase transition at about TC~260 K and long range FM order at low temperatures were observed in LCMO sample. Both the LCCO and LCCMO samples exhibited insulating behavior in the whole range of measuring temperature whereas the LCMO sample underwent a clear metal-insulator（MI） transition at about TMI~263 K, corresponding to Curie temperature. Metallic region of ρ（T） curve of the LCMO sample was fitted to the model of electron-electron and electron-magnon scattering. The charge carrier transport behavior in all the samples was compared based on polaronic models.     

Influence of gadolinium and dysprosium substitution on magnetic properties and magnetocaloric effect of Fe78−xRExSi4Nb5B12Cu1 amorphous alloys

Amorphous Fe_78−xRE_xSi₄Nb₅B₁₂Cu₁ (RE = Gd, Dy) ribbons with different RE contents were prepared by melt spinning to investigate the effect of heavy rare earth (Gd, Dy) substitution on the hyperfine structure, magnetic properties and magnetocaloric effect. The Curie temperature of RE substituted alloys, hyperfine field and magnetic moments of Fe atoms initially increase up to 1 at% RE content and then decrease monotonously for increasing RE content up to 10 at%. The dependence of magnetic entropy change (–ΔS_M) and refrigeration capacity (RC) of the alloys on RE contents displays the same tendency. The RC_AREA values of the alloys substituted with 1 at% Gd and Dy are similar to those of recently reported Fe-based metallic glasses with enhanced RC values compared with those of Gd₅Ge_1.9Si₂Fe_0.1. Enhanced –ΔS_M and RC values, negligible coercive force and hysteresis commonly make these Fe_78−xRE_xSi₄Nb₅B₁₂Cu₁ amorphous alloys as low-cost candidates for high-temperature magnetic refrigeration.