Phase transition in metallic glasses Fe66Co12Si9B13 and Fe66Ni12Si9b13

Phase transitions were analysed during annealing of amorphous metallic glasses Fe₆₆Co₁₂Si₉B₁₃ and Fe₆₆Ni₁₂Si₉B₁₃. They were measured by means of X-ray diffraction, electrical and Hall resistivity methods. Forming crystalline phases were identified. Those for metallic glasses with cobalt are α-Fe, Fe₃B and Co₂B while those with nickel are α-Fe, Fe₂B, Ni₂B.     

Investigation of X-ray diffraction and positron life times in Fe78Si9B13 alloys of amorphous and crystalline structures before and after hydriding

Measurements of mean positron life-times and X-ray diffraction were carried out in unhydrided alloys Fe₇₈Si₉B₁₃ of amorphous and crystalline structures, and after hydriding them. The process of hydriding was carried out at a pressure of 55.773 × 10⁵ N/m². during 168 h. The crystalline samples were obtained after annealing the amorphous alloy Fe₇₈Si₉B₁₃ at 673, 773 and 873 K, respectively. The results obtained after the hydriding process suggest thatan additional electron energy band is formed due to introducing hydrogen inside the samples. The annealing process shows that there exists a nonmonotonic relation between the concentration of free electrons and the degree of order to the structure.     

Thermal neutron irradiation of Fe−Si−B glasses

Effect of thermal neutron irradiation of metallic glasses Fe₇₈Si₉B₁₃ and Fe₇₈Si₈B₁₄ has been studied using Mossbauer spectroscopy. The surfaces of the two specimens are found to behave very differently under irradiation. The difference may be attributed to the presence of a thin oxide layer at the surface of as-prepared Fe₇₈Si₉B₁₃.     

Vickers Microhardness and Hyperfine Magnetic Field Variations of Heat Treated Amorphous Fe78Si9B13 Alloy Ribbons

Amorphous Fe₇₈Si₉B₁₃ alloy ribbons were heat treated between 296 and 763 K, using heating rates between 1 and 4.5 K/min. Whereas one ribbon partially crystallized at T _x = 722 K, the other one partially crystallized at T _x = 763 K. The partially crystallized ribbon at 722 K, heat treated using a triangular form for the heating and cooling rates, was substantially less fragile than the partially crystallized at 763 K where a tooth saw form for the heating and cooling rates was used. Vickers microhardness and hyperfine magnetic field values behaved almost concomitantly between 296 and 673 K. The Mössbauer spectral line widths of the heat-treated ribbons decreased continuously from 296 to 500 K, suggesting stress relief in this temperature range where the Vickers microhardness did not increase. At 523 K the line width decreased further but the microhardness increased substantially. After 523 K the line width behave in an oscillating form as well as the microhardness, indicating other structural changes in addition to the stress relief. Finally, positron lifetime data showed that both inner part and surface of Fe₇₈Si₉B₁₃ alloy ribbons were affected distinctly. Variations on the surface may be the cause of some of the high Vickers microhardness values measured in the amorphous state.     

Diffusion of Au and Cu in amorphous Fe80B20 and Fe82B18 alloys

Diffusion rates (D) of Au in two amorphous alloys, Fe₈₀B₂₀ and Fe₈₂B₁₈, and of Cu in amorphous Fe₈₂B₁₈ alloy were measured in the temperature range 546–645 K by using the technique of Rutherford backscattering spectrometry (RBS) and Auger electron spectroscopy (AES), respectively. The diffusion of Au was found to be 3 to 6 times faster in Fe₈₀B₂₀ than in Fe₈₂B₁₈, though both the alloys had almost similar crystallization temperatures. The observed differences in the diffusion rates corroborate the fact that Fe₈₀B₂₀ has a more open structure than Fe₈₂B₁₈ as revealed from the reported values of the metal packing fractions of these two alloys. Also, the diffusivities of smaller sized Cu atoms (radius: 0.128 nm) were found to be higher by more than an order of magnitude than those of larger sized Au atoms (radius: 0.146 nm), suggesting a dependence ofD on the size of the diffusing species.     

Fe78B13Si9、(Fe0.99Mo0.01)78B13Si9非晶合金的激波晶化实验研究

 研究了Fe₇₈B₁₃Si₉、(Fe_0.99Mo_0.01)₇₈B₁₃Si₉非晶合金的激波晶化行为。激波是由氢-氧爆炸产生的。实验结果表明：激波能使非晶合金在微秒时间内晶化,晶化主相为α-Fe基固溶体,次晶化相为Fe₃Si,且观察到α-Fe基因溶体晶格常数变小。用DTA分析进一步证实：激波晶化是比较完全的,晶化相相当稳定。     

High-magnetic-field magnetization and magnetoresistance of some amorphous ferromagnets

Measurements of isothermal magnetization and magnetoresistance at T = 4.0-4.2 K and 15 ? H ? 132 kG on the amorphous ferromagnets Fe₈₀B₂₀, Fe₇₈Mo₂B₂₀, Fe₄₀Ni₄₀P₁₄B₆, and Fe₃₂Ni₃₆Cr₁₄P₁₂B₆ indicate a relatively large H-induced increase (3.6%) in the high-magnetic-field magnetization of the latter alloy, and marked differences in the magnitude and sign of the high-field magnetoresistance of the four alloys. The results are qualitatively interpreted in terms of internal effective field distributions which include a small fraction of atomic spins in negative field sites.     

铁基非晶的低频脉冲磁场处理效应

对非晶合金Fe₇₈ Si₉ B₁₃进行了低频脉冲磁场处理，用穆斯堡尔谱学、透射电 镜等方法观察处理试样的微观结构变化.研究发现，当脉冲频率20—25Hz,磁场16—32kA/m,作用时间≤2min，合金发生了纳米晶化，纳米相岐睩e(Si)晶粒尺寸为10nm. 而且，在低频脉冲磁场处理过程中，非晶试样的温升≤20℃. 关键词： 非晶态合金 脉冲磁场处理 纳米晶化     

Fe基非晶态合金的低温电阻研究

本文报道Fe_100-xB_x,Fe_87-xSi_xB₁₃,(Fe_1-xCo_x)₇₈Si_9.5B_12.5,(Fe_1-xM_x)_80-84B_16-20(M=Zr,V,Nb,Ta,Cr,Mo,W,Mn)非晶态合金的 关键词：     

Amorphous FexCo78-xSi9B13 alloys in radio frequency fields

The “rf collapse” effect is used to determine the quadrupole splitting distributions in ferromagnetic amorphous Fe_xCo_78-xSi₉B₁₃ alloys. The rf field induces crystallization of amorphous alloys which, for x<60 at.%, suppress the rf collapse.     

Mössbauer Effect Study of Corroded Amorphous Alloy Fe78B13Si9

Mössbauer effect and Scanning Electron Microscopy were used to investigate the effect of immersing the amorphous alloy Fe₇₈B₁₃Si₉ in 3% NaCl solution over different periods and different pH. The results indicated that the average angle of orientation of the magnetic moments had increased with increasing time of immersion and decrease in pH value. The corrosion product was found to be lepidocrocite (γ-FeOOH).     

Nanocrystallization process and ferromagnetic properties of amorphous (Fe0.99Mo0.01)78Si9B13 ribbons

The nanocrystallization process of soft ferromagnetic (Fe_0.99Mo_0.01)₇₈Si₉B₁₃ ribbons has been studied in detail. Microstructural and ferromagnetic properties are examined by transmission electron microscopy (TEM), X-ray diffraction (XRD), Mössbauer spectroscopy (MS), differential scanning calorimetry (DSC) and magnetization measurements. The Curie and crystallization temperatures are determined to be T_C=665 K and T_x=750 K, respectively. The T_x value is in well agreement with DSC measurement results. XRD patterns had shown two metastable phases (Fe₂₃B₆, Fe₃B) which were formed under in situ nanocrystallization process. These metastable phases embedded in the amorphous matrix have a significant effect on magnetic ordering. The ultimate nanocrystalline (NC) phases of α-Fe(Mo, Si) and Fe₂B at optimum annealing temperature had been observed respectively. It is notable that the magnetization of the amorphous phase decreases more rapidly with increasing temperature than those of NC ferromagnetism, which suggest the presence of the distribution of exchange interaction in the amorphous phase or high metalloid contents.     

Electrical resistivity of amorphous metallic glasses Fe80B80 and Fe78Mo2B20 between 78 and 1000 K

Electrical resistivity (ρ) of amorphous Fe₈₀B₂₀ and Fe₇₈Mo₂B₂₀ have been studied as a function of temperature (T) between 78 and 1000 K. The ρ vs T curves, obtained with specified warming and cooling rates, show that such curves are sensitive probes of the crystallization process. Within the experimental error, no anomalies in the ρ behavior can be seen at the Curie temperature of each amorphous alloy.     

静高压下非晶(Fe0.99,Mo0.01)78Si9B13合金晶化过程的热力学研究

 在600~930 K，常压到7 GPa的范围内，对非晶(Fe_0.99,Mo_0.01)₇₈Si₉B₁₃合金等温等压退火30 min。实验表明：其晶化产物α-Fe(Mo, Si)、Fe₃B和Fe₂B相的析出与所加压力密切相关。压力使非晶(Fe_0.99,Mo_0.01)₇₈Si₉B₁₃合金的晶化温度和亚稳Fe₃B相的析出温度下降，在一定的压力和温度下，亚稳Fe₃B相将向稳定Fe₂B相转变，其转变温度随压力而变化。还对非晶(Fe_0.99,Mo_0.01)₇₈Si₉B₁₃合金的晶化和亚稳Fe₃B到稳定Fe₂B转变的热力学机制进行了讨论，并给出Fe₃B向Fe₂B的相转变方程。     

Modification of Properties of Fe28Ni50Si9B13 Metallic Glass During Heat Treatment

The crystallization process of the metallic glass Fe₂₈Ni₅₀Si₉B₁₃ was investigated by DSC, Hall effect, electrical resistivity, and X-ray diffraction methods. It proceeds in two stages. Ni phase is formed at the temperature of 723 K and Ni₃B phase at 773 K. The phase creation is accompanied by an abrupt decrease of the Hall and electrical resistivities and the spontaneous Hall coefficient.     

Temperature dependence of the hall effect in amorphous Ni-Si-B alloys between 1.5 and 290 K: Evidence for magnetic ordering near a resistance minimum

The Hall effect in the metallic glasses Ni₇₆Si₁₂B₁₂, Ni₇₈Si₈B₁₄ and Ni₈₀Si₁₀B₁₀ has been measured as a function of temperature (1.5 ≤ T ≤ 290 K) and magnetic field (B ^<_～ 1.2 Tesla). At room temperature the Hall resistivity ρ_H is negative and depends linearly on the magnetic field for all three compositions. With decreasing temperature Ni₈₀Si₁₀B₁₀ exhibits a negative spontaneous Hall coefficient and a transition to ferromagnetism at about 110 K. In case of Ni₇₆Si₁₂B₁₂ and Ni₇₈Si₈B₁₄ an anomalous part contributes below ～ 40 K and ρ_H changes from negative to positive sign at about 9 K. For these two alloys we find that the initial slope of the ρ_H(B) curves follows a Curie-Weiss law with Tθ ≈ 0 K and the anomalous contribution of the Hall resistivity can be described by a Brillouin function for superparamagnetism.     

Magnetostriction characteristics of the iron rich Fe-B-Si metallic glasses

Linear longitudinal and transverse magnetostriction and forced volume magnetostriction curves versus magnetic field for some as-quenched iron-rich amorphous alloys are presented. For the Fe₇₈Si₈B₁₄, Fe₇₈Si₉B₁₃ and Fe₇₉Si₁₂B₉ alloys the linear saturation magnetostriction was equal to 37·6×10^–6, 28·9×10^–8 and 34×10^–6, respectively.This work was in part financially supported by the Warsaw Technical University Institute of Material Science and Technology within the framework of the Project CPBR 2·4.     

Effect of transition metal additions on the resistivity of Fe83B17 amorphous alloys

Alloying effects of transition metals on Fe₈₃B₁₇ amorphous alloy were investigated. The resistivity versus temperature curves of Fe₈₃T₃B₁₇ between 4.2–300 K depend on the magnetic behaviour of the transition elements, while below 4.2 K show universal behaviour as it was suggested recently.     

Investigation of the magnetic characteristic of amorphous Fe40Ni40B20 and Fe6Co70Ni13Si7B4 foils by a magnetooptical method

Magnetic parameters, the local anisotropy field H_k, the effective field h related to the correlation radius, and the coercive force H_c, are determined for free and contact surfaces by investigating the magnetization curves of amorphous Fe₄₀Ni₄₀B₂₀ and Fe₆Co₇₀Ni₁₃Si₇B₄ foils by a highly-sensitive method of measuring the magnetooptical phase.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 49–52, November, 1989.     

Effect of 3d transition metal substitution on microstructure and microwave absorption properties of FeSiB nanocrystalline flakes

Effect of 3d transition metal substitution (Co and Ni) is studied on microstructure and absorption properties of FeSiB flakes in GHz. Fe_78−xM_xSi₉B₁₃ (M=Co or Ni, x=0, 5, 10 and 15) nanocrystalline flakes with nanocrystal/amorphous two-phase structure were prepared by ball milling. Substitution decreases the nanocrystal size and affects microwave behavior both compositionally and structurally according to the substitution mechanism. Compositional influence is contributing to the change of intrinsic magnetization parameters; structural influence works on exchange coupling. Absorption band of Fe₇₈Si₉B₁₃ flakes shifts towards lower frequency by the substitution, and Fe₆₃Co₁₅Si₉B₁₃ absorber shows promising absorption at C-band.