Apparent Activation Energy Of Crystallization Research Articles

Revealing the effect of annealing at Tg on the crystal growth in Au49Ag5.5Pd2.3Cu26.9Si16.3 metallic glass via nanocalorimetry

In this study, Au49Ag5.5Pd2.3Cu26.9Si16.3 metallic glass is annealed at Tg and its impact on crystal growth is demonstrated with nanocalorimetry. With annealing following the rapid quenching, an amorphous phase free of nuclei, a relaxed amorphous phase, an amorphous phase with nuclei, and an amorphous phase with crystals are sequentially produced. With the reheating at rates ranging from 100 to 50,000 K/s, these four stages are quantitatively distinguished. Additionally, crystal growth behaviors of these four stages are demonstrated by the Kissinger and Mauro-Yue-Ellison-Gupta-Allan model. For the quenched and relaxed amorphous phases, the apparent crystallization activation energy (Ea) decreases with increasing heating rate, with a noticeable upward deviation at ultrahigh heating rates. When nuclei and crystals form in the amorphous phase, Ea keeps decreasing with the heating rate. As the annealing time increases, the maximum growth rate (umax) exhibits a monotonic increase while the temperature corresponding to umax displays a maximum.

Effect of high copper content in Cux(As2Se3)100-x glass on properties relevant for engineering of thermally induced processes

ABSTRACT Kinetic analysis of thermally induced processes was carried out in Cux(As2Se3)100-x glass with high copper content, x = 20 and 25 at.%. Non-isothermal differential scanning calorimetry at different heating rates was used to analyze the glass-transition and crystallization processes. It was shown that the glass-transition temperature increases with the increase in the copper content and that the examined glasses during the glass transition process do not show large configurational changes in the structure. Apparent activation energy of crystallization was determined using Kissinger method. In the composition with 25 at.% of copper the crystallization of three structural units was detected: CuAsSe2, Cu3AsSe4 and Cu2Se. Analysis of the crystallization mechanism and determination of parameters that depend on the morphology of nucleation and growth showed that volume nucleation and three-dimensional growth occur with a constant number of nucleation centers. Isoconversional analysis showed that the activation energy does not change significantly during the crystallization process.

Effect of hyperfine structure on crystallization, microstructure and magnetic properties of amorphous Nd9Fe85B6 alloy

Crystallization of amorphous alloy is a commonly used method to fabricate nanocomposite permanent magnets. However, the effect of the hyperfine structures of amorphous alloy on microstructure evolution and magnetic properties of the obtained nanocomposites is far from understood. Here, amorphous Nd9Fe85B6 alloys with different hyperfine structures, i.e., different short-range orders (Rs = 0.80–0.91 nm), were prepared via melt spinning. The effects of the hyperfine structure on crystallization behavior, microstructure, and magnetic properties of the material upon thermal annealing were investigated in depth. Crystallization kinetics calculations show that a larger Rs leads to a smaller apparent crystallization activation energy, which leads to higher volume fractions of α-Fe and Nd2Fe14B. At the same time, a crystallizaition process dependent stage crystallization activation energy of Nd2Fe14B has been obtained, which is low at nucleation stage and increases with crystallization process, i.e. easy for nucleation but hard for growth, which leads to a smaller grain size of Nd2Fe14B. As a result, optimized magnetic properties were obtained in the sample with Rs = 0.91 nm.

Nanocrystallization of Cu46Zr33.5Hf13.5Al7 Metallic Glass

The recently discovered Cu46Zr33.5Hf13.5Al7 (at.%) bulk metallic glass (BMG) presents the highest glass-forming ability (GFA) among all known copper-based alloys, with a record-breaking critical casting thickness (or diameter) of 28.5 mm. At present, much remains to be explored about this new BMG that holds exceptional promise for engineering applications. Here, we report our study on the crystallization behavior of this new BMG, using isochronal and isothermal differential scanning calorimetry (DSC), X-ray diffraction (XRD), and transmission electron microscopy (TEM). With the calorimetric data, we determine the apparent activation energy of crystallization, the Avrami exponent, and the lower branch of the isothermal time–temperature–transformation (TTT) diagram. With XRD and TEM, we identify primary and secondary crystal phases utilizing samples crystallized to different degrees within the calorimeter. We also estimate the number density, nucleation rate, and growth rate of the primary crystals through TEM image analysis. Our results reveal that the crystallization in this BMG has a high activation energy of ≈360 kJ/mole and that the primary crystallization of this BMG produces a high number density (≈1021 m−3 at 475 °C) of slowly growing (growth rate < 0.5 nm/s at 475 °C) Cu10(Zr,Hf)7 nanocrystals dispersed in the glassy matrix, while the second crystallization event further produces a new phase, Cu(Zr,Hf)2. The results help us to understand the GFA and thermal stability of this new BMG and provide important guidance for its future engineering applications, including its usage as a precursor to glass–crystal composite or bulk nanocrystalline structures.

Dynamic crystallization kinetics and morphology of carbonaceous nanofillers-reinforced poly (lactic acid) foams

Carbon black (CB), multi-walled carbon nanotubes (CNT), and graphene oxide (GO)-reinforced poly (lactic acid) (PLA) foams were prepared. Morphological studies indicated that incorporating nanoparticles into foamed PLA (F-PLA) changed the sphericity degree, diameter, and homogeneity of cells. Among all samples, foamed PLA containing 0.25 phr GO exhibited the highest void content (+46%) compared to foamed neat PLA, while its cell density diminished by 21%. In contrast, despite a lower improvement in void content (+18%), foamed PLA containing 0.25 phr CNT experienced a +3% enhancement in cell density compared to foamed neat PLA. Also, the nanoparticles were well dispersed in un-foamed PLA without any obvious aggregation. The crystallization kinetics of foams were studied using DSC. The results revealed that PLA foams reinforced with 0.25 phr CNT and GO had a significant effect on crystallization promotion. The crystallization kinetics of foamed samples were studied using different models such as Jeziorny, Avrami, Ozawa, Kissinger, and Doyle-Ozawa. The results demonstrated that adding nanofillers did not affect the crystallization mechanism of foamed PLA. Also, incorporating up to 0.5 phr CNT and GO decreased the apparent crystallization activation energy compared to neat F-PLA. An almost similar trend was observed for the local crystallization activation energy.

Influence of partial substitution of Ti for Al on microstructure, thermal stability and corrosion resistance of novel quaternary Ni33.3Y33.3Al33.4-xTix medium entropy metallic glasses

In this present study, the influence of partial substitution of Ti for Al on microstructure, thermal stability and corrosion resistance of novel quaternary low-density Ni33.3Y33.3Al33.4-xTix (x = 3∼21 at.%) medium entropy metallic glass ribbons (ME-MG ribbons) was investigated. According to the rule of atomic radius similarity, by gradually replacing Al by Ti, we have synthesized a series of multi-component glassy alloy ribbons via using a single roller melt-spinning technique and also have examined their phase structure, thermal characteristics, microhardness and anti-corrosion properties. Besides, the phase composition of some representative annealed ribbon samples and the crystallization activation energy of these melt-spun ME-MG ribbons have been also determined and studied in detail. Results show that all of the rapidly solidified alloy ribbons can maintain completely amorphous nature. However, the thermal stability of ME-MG ribbons becomes reduced with the increasing Ti content. The maximum crystallization onset temperature at the heating rate of 20 K/min is around 706.65 K for Ni33.3Y33.3Al30.4Ti3 alloy ribbons. The maximum apparent activation energy of crystallization by means of thermodynamic analysis can be up to ∼803 kJ/mol for Ni33.3Y33.3Al21.4Ti12 alloy ribbons. The average microhardness value of these metallic ribbons can reach 455 HV0.1 or more when Ti content is less than 15 at.%, which is approximately 1.5 times the hardness of the Al-based amorphous alloy ribbons. The microstructural characterization of each ME-MG ribbon surface in as-received state and after a period of 45-hour and 75-hour corrosion immersion in 0.6 M NaCl solution was applied by scanning electron microscopy as well. Substituting moderately Al with Ti can effectively improve the anti-corrosion ability; the most positive pitting corrosion potential and the smallest corrosion current density are approximately -0.145 VSCE and 0.045 μA/cm2 for Ni33.3Y33.3Al24.4Ti9 and Ni33.3Y33.3Al27.4Ti6 ME-MG ribbons, respectively. Thus, it can be deduced that these new-fashioned ME-MG ribbons possess the superior anti-corrosion property, higher microhardness and acceptable thermal stability simultaneously, which may open momentous possibilities for the development and practical application of high-performance metal materials.

Effect of Co addition on the microstructure, thermal stability and anti-corrosion properties of AlNiZrYCox high-entropy metallic glass ribbons

In this current research, the effect of Co addition on the microstructure and anti-corrosion properties of equiatomic AlNiZrY high-entropy metallic glass (abbreviated to HE-MG) ribbons were investigated. Also, the thermal stability and crystallization activation energy of these HE-MG ribbons have been studied. Ribbons of composition (Al1/4Ni1/4Zr1/4Y1/4)100-xCox (x= 0, 5, 8, 12) were synthesized via arc-melting method and melt-spinning technique. By increasing the content of Co, we found that the melt-spun equiatomic AlNiZrY and Co-containing AlNiZrY HE-MG ribbons could still remain amorphous state. The thermal stability of ribbons were conducted by means of a differential scanning calorimeter (DSC), which suggested that the thermal stability of four kinds of HE-MG ribbons is higher than common Al-Ni-based amorphous alloys. The maximum apparent activation energy of crystallization through thermodynamic analysis at different heating rates can reach ∼630 kJ/mol for (Al1/4Ni1/4Zr1/4Y1/4)92Co8 HE-MG ribbons. The microstructure characterization of each HE-MG ribbon before and after one-day corrosion immersion was done by scanning electron microscopy (SEM). In order to evaluate the microhardness and corrosion resistance of the as-received HE-MG ribbons with and without the addition of Co, the microhardness measurements and the electrochemical corrosion tests in 3.5 wt.% NaCl solution were carried out. The results revealed that the average microhardness value of HE-MG ribbons are all above 470 HV0.1, regardless of whether the ribbons immersed in corrosive media for one-day immersion or not. The corrosion current density of (Al1/4Ni1/4Zr1/4Y1/4)88Co12 HE-MG ribbons is around 0.46 μA/cm2, which possesses the sterling anti-corrosion property and opens vital possibilities for the development of high-performance metal coatings under the condition of harsh marine environment.

Non-isothermal crystallization kinetics of a Fe–Cr–Mo–B–C amorphous powder

Fe–Cr–Mo–B–C amorphous powders are usually used in thermal spraying, spark plasma sintering or 3D printing to prepare coatings or large-sized bulk amorphous alloys. However, their non-isothermal crystallization kinetics is far from being investigated in detail because of their relatively complicated crystallization behavior. In this work, the phase evolution, crystallization kinetics and crystallization mechanism of Fe–Cr–Mo–B–C (Cr: 25–27 wt%, Mo: 16–18 wt%, B: 2–2.2 wt%, C: 2–2.5 wt%) amorphous powder during non-isothermal crystallization are analyzed by X-ray diffraction, scanning electron microscope and differential scanning calorimetry together with Ozawa method and local Avrami exponent. The peak temperature of the first precipitated phase is less sensitive to the heating rate. In the non-isothermal crystallization process upon constant-rate heating to elevated temperatures the phase sequence is: α-Fe, M23(C, B)6, M7C3 and FeMo2B2 (M = Fe, Cr, Mo). The apparent activation energy of crystallization of the amorphous powders obtained using Kissinger’s method is between 385 and 557 kJ/mol, which is higher than that of most iron-based amorphous alloys reported so far, indicating a relatively high stability against crystallization. a-Fe and FeMo2B2 have a similar transformation mechanism: the early phase transition is completed by diffusion controlled growth with an increasing nucleation rate; as the crystallized volume fraction increases, the nucleation rate decreases, and nucleation does not occur even in the later stage of crystallization. The crystallization mechanism of M23(C, B)6 and M7C3 is similar: when the crystallized volume fraction α is higher than 0.1, only crystal growth occurs. This might be due to the fact that the large number of interfaces formed between the early precipitated phase and the amorphous matrix promote nucleation, rendering nucleation complete at the stage when the crystallized volume fraction α is less than 0.1. Therefore, the first and fourth crystallization events are diffusion controlled, the second and third crystallization events are primarily governed by grain growth.

Effect of Mo content on glass forming ability and crystallization behavior of Fe-based alloy prepared by atmospheric plasma spraying

Abstract The preparation of Fe-based amorphous alloys has the problems of high cost due to the use of high purity raw materials and low production efficiency of copper mould suction casting. Herein, Fe75.5-xCr4Si3.5P9.5B7.5Mox(x = 0,1,3,5,7) alloys with a thickness of 100–300 μm were prepared by atmospheric plasma spraying method using industrial raw materials and commercial pure materials as starting materials. The effects of Mo contents on the glass forming ability and crystallization behavior were analyzed. Microstructure and crystallization behavior of as-prepared alloys were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and differential scanning calorimeter (DSC). The plasma spraying prepared Fe75.5-xCr4Si3.5P9.5B7.5Mox with 0 and 5 at% of Mo exhibited fully amorphous alloy features. When Mo content was 5 at%, the crystallization temperature of amorphous alloy increased and the crystallization process changed from one step (amorphous → α-Fe(Si) + Fe3B + Fe2P) to two steps (amorphous → α-Fe(Mo, Si) → α-Fe(Mo, Si) + Fe3B + Fe2P), in which the apparent activation energy of crystallization increased from 475 kJ mol−1 to 542 kJ mol−1 and 546 kJ mol−1. It could be concluded that the enhanced glass forming ability and thermal stability are attributed to the suppression of heterogeneous nucleation by addition optimum amount of Mo. It would provide a basis for the practical application of Fe-based amorphous alloys.

New Ti-based bulk metallic glasses with exceptional glass forming ability

New Ti-based bulk metallic glasses (BMGs) of Ti32.8+XZr30.2−XNi5.3Cu9Be22.7 (3 ≤ |X| ≤ 15, at.%) with large size were prepared. The results reveal that the forming of primary icosahedral quasicrystal phase (I-phase) and the enthalpy of the primary crystallization (ΔH1) were closely related to the glass forming abilities (GFAs). The crystallization product of the metallic glass alloys at primary crystallization state is a metastable I-phase. It is demonstrated that apparent activation energy for crystallization obtained by fitting the Kissinger equation at Tx temperature increases with the increase of Ti concentration, while GFAs deteriorate. The ΔH1 of metallic glasses declines with the increase of Ti concentration. The Ti32.8+XZr30.2−XNi5.3Cu9Be22.7 possess high similar compressive fracture strength of about 1800 MPa, which is one of the best options as structural materials on account of high specific strength and low cost.

Crystallization kinetics study of melt-spun Zr66.7Ni33.3 amorphous alloy by electrical resistivity measurements

In this paper, the electronic transport properties of as-spun Zr66.7Ni33.3 alloys were studied in detail by a combination of electrical resistivity and absolute thermoelectric power measurements over a temperature range from 25 up to 400 °C. Moreover, the isochronal and isothermal crystallization kinetics of Zr66.7Ni33.3 glassy alloy has been investigated based on the electrical resistivity measurements. The comparative study of the crystallization kinetics of these binary amorphous alloys was carried out, for the first time to our knowledge, using an accurate method for electrical resistivity measurements. In the isochronal heating process, the apparent activation energy for crystallization was determined to be, respectively, 371.4 kJ mol−1 and 382.2 kJ mol−1, by means of Kissinger and Ozawa methods. The Johnson–Mehl–Avrami model was used to describe the isothermal transformation kinetics, and the local Avrami exponent has been determined in the range from 2.97 to 3.23 with an average value of 3.1, implying a mainly diffusion-controlled three-dimensional growth with an increasing nucleation rate. Based on an Arrhenius relationship, the local activation energy was analyzed, which yields an average value Ex = 376.2 kJ mol−1.

Quantifying the effect of particle size on the crystallization of 45S5 bioactive glass

The crystallization behavior of 45S5 bioactive glass powders with two different particle sizes (<5 µm, BG5 and <32 µm. BG32) was investigated under non-isothermal conditions. The Ozawa and Augis-Bennett methods provided an Avrami coefficient close to 1 for both glass types, which suggests that surface crystallization was predominant during heat treatment. The Kissinger equation was used to determine the apparent activation energies for crystallization (Ec) that were found to be 250 ± 3 and 311 ± 9 kJ/mol for BG5 and BG32, respectively. The activation energies for viscous flow have also been assessed and were found higher than Ec (284 ± 8 and 338 ± 9 kJ/mol) for both particle sizes. It was noted that the process of crystallization for 45S5 glass could not be properly described by the Johnson-Mehl-Avrami (JMA) model and it appeared more complex than a simple nucleation-growth mechanism.

The crystallization behavior of Dy3 +/Tb3 + doped aluminoborosilicate glasses

The crystallization behavior and microstructure of a series of Dy3+/Tb3+ doped aluminoborosilicate (ABS) magneto-optical glass was investigated using differential scanning calorimetry (DSC), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The apparent crystallization activation energy (Eg) and the kinetic properties at the corresponding glass transition temperature (Tg) were studied as a function of Dy3+/Tb3+ concentration. The results showed that the glass matrix precipitated Al3Tb(BO3)4 and TbBO3 crystals when subjected to heat treatment at 852.8 and 902.6°C, respectively. The crystallization activation energy of these two crystalline phases (Al3Tb(BO3)4 and TbBO3) was Ep1=993.3kJ/mol and Ep2=544.97kJ/mol, respectively. The average crystallization index was 0.5 and 0.8, respectively. By applying the Kissinger equation to the parameterized crystallization behavior, the calculated phase transition activation energy was determined to be 420.18kJ/mol. The parameterized crystallization behavior of this particular ABS magneto-optical glass can be used to avoid the deterioration of magneto-optical properties due to the crystallization of glass matrix.

Non-isothermal crystallization kinetics of the heavy-group lanthanide dititanates

The systematic investigation of crystallization kinetics of heavy-group lanthanide dititanate pyrochlores, HL2Ti2O7 (HL=Lu, Tm, Er, Ho, Y, Dy, and Tb) is presented. Materials are prepared by the Pechini-type polymerized complex route, and their thermal properties were studied by differential thermal analysis under non-isothermal conditions. For this group, the crystallization temperature became larger with increasing the ionic radius of lanthanides, from 1066 K for Lu2Ti2O7 to 1125 K for Tb2Ti2O7. The linear dependence of crystallization temperature on radius of heavy lanthanide ions is found to follows Tc[K]=168.86+920.89×rion[Å] semi-empirical equation. Apparent activation energies of crystallization were obtained from calculations based on the Arrhenius equation, isoconversional method and Pérez-Maqueda method, and are ∼805 kJ mol−1 calculated by three different methods. The crystallization kinetics followed the so-called Avrami–Erofeev (A3) model, as confirmed using several criteria, namely, the Málek, master plot, and Pérez-Maqueda methods. The crystallization mechanism of all lanthanide dititanate pyrochlores is found to be the same, and the crystallization process involves a constant rate of nucleation and two-dimensional growth of nuclei.

Non-isothermal crystallization kinetics of Y2Ti2O7

The crystallization kinetics of Y2Ti2O7 powders prepared by a Pechini-type polymerized complex route was studied using differential thermal analysis under non-isothermal conditions. Apparent activation energies of crystallization of 816 and 804kJmol−1 were obtained from calculations based on the Arrhenius equation and isoconversional analysis, respectively. The crystallization kinetics followed the so-called A3 model, as confirmed using several criteria, namely, the Málek, master plot, and Pérez-Maqueda methods. The measurement results and calculated crystallization parameters (n=3, m=2) showed that the crystallization process includes a constant rate of nucleation and two-dimensional growth of nuclei, and excluded the possibility of surface crystallization.

The rheological properties of biodiesel derived from cottonseed oil

ABSTRACTThe low-temperature rheological properties of a biopetroleum and petroleum diesel were investigated. Differential scanning calorimetry (DSC) was employed to study their crystallization, and the Kissinger method was used to calculate the apparent activation energy of crystallization. The results show that the biopetroleum changes from Newtonian fluid to non-Newtonian fluid with the drop of temperature, and the transition temperature is close to the cold filter plugging point (CFPP) of the biopetroleum. The low-temperature rheological properties of the biopetroleum are as similar as petroleum diesel. A commercial low-temperature flow improver ethylene-vinyl acetate (T1804) had a good filterability depression effect on the biopetroleum.

Kinetics of Fe3+mineral crystallization from ferrihydrite in the presence of Si at alkaline conditions and implications for nuclear waste disposal

Fe 3+ minerals are ubiquitous in diverse near-surface environments, where they exert important controls on trace species transport. In alkaline environments such as the glass-steel interface in geological high-level radioactive waste disposal sites that use cement for plugging and grouting, Fe minerals are closely associated with Si that may affect their crystallization behavior as well as their capacities to regulate hazardous element cycling. While it is well known that Si retards Fe mineral crystallization, there is currently an overall lack of quantitative information on the rates of crystallization of stable Fe minerals in the presence of Si at alkaline conditions. Crystallization of Fe 3+ minerals goethite and hematite from ferrihydrite co-precipitated with different amounts of Si was studied at pH 10 and at temperatures ranging from 50 to 80 °C using powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). Mineral abundances evaluated from Rietveld refinement of XRD data show that the proportion of goethite in the final assemblage decreases relative to hematite with increasing Si. TEM observation of goethite and hematite crystals formed in the presence of Si show significant morphological differences compared to those formed in the absence of Si. Rate constants for crystallization derived from fitting of time-dependent changes in mineral abundances with the Avrami equation show a decreasing trend with increasing Si for both goethite and hematite. Apparent activation energies for crystallization for both minerals increase with increasing Si, with that of goethite increasing more drastically compared to hematite, indicating the inhibitive effect of Si on the crystallization of both minerals. The overall inhibition of crystallization may be explained in terms of the effects of Si on the surface properties of the ferrihydrite precursor. The rate constants and apparent activation energies reported in this study may be useful in estimating the crystallization behavior and timescales of Fe minerals in both natural and engineered environments. This information may eventually be helpful in predicting the fate of hazardous elements in such environments.

Crystallization kinetics of a high-zirconium-based glassy alloy: A DSC study

The non-isothermal and isothermal crystallization kinetics of Zr72.5Al10Fe17.5 glassy alloy was investigated using differential scanning calorimeter (DSC). Under non-isothermal heating condition, the primary phase in the initial crystallization is Zr6Al2Fe phase and the final crystallized products consist of Zr6Al2Fe, Zr2Fe and a-Zr phases. The apparent activation energy for crystallization estimated using the Kissinger method is 342.1 ± 8.1 kJ/mol. The local activation energy decreased with the increase in the crystallization volume fraction during nonisothermal crystallization. Under isothermal heating condition, the average Avrami exponent of about 2.76 implies a mainly diffusion-controlled three-dimensional growth with an increasing nucleation rate. The local activation energy for isothermal crystallization shows a different variation trend from that for nonisothermal crystallization, indicating different nucleation-and-growth mechanisms for the two crystallizaiton conditions.

Influence of Ni addition on nanocrystallization kinetics of FeCo-based amorphous alloys

The effects of Ni addition on the crystallization temperature, apparent crystallization activation energy, nucleation and growth mechanism of melt-spun (Fe0.5Co0.5)73.5−xNixSi13.5B9Nb3Cu (x=0,2,4,5,8,10,15,20) alloys were investigated in this study. X-ray diffractometer (XRD) was used to analyze the microstructure, and differential scanning calorimeter (DSC) and the Johnson–Mehl–Avrami (JMA) model were applied to analyze and compare the results of the crystallization processes. The experimental results showed that the best thermal stability of samples and the maximum value of apparent activation energy were gained at 4at.% addition of Ni. With increasing the Ni addition, thermal stability of residual amorphous matrix and resistance to secondary crystallization gradually decreased. During the secondary crystallization process, nucleation process continued until the end of crystallization, and there are interaction effects among the thermal stability of the residual amorphous phase, resistance to crystallization and variation in nucleation rate.

Effect of Fe Content on Crystallization Behaviors and Magnetic Properties of Amorphous Alloys Fex(SiB)96-xP3Cu1

Crystallization behavior and soft magnetic properties of amorphous alloys Fex(Si B)96-xP3Cu1(x=75, 78, 80, 83 and 85, atomic fraction, %) were investigated. It was found that the apparent activation energy for crystallization decreased with the increasing Fe content of the Fex(Si B)96- xP3Cu1 alloys. The phases precipitated after properly complete crystallization treatment were the same for all the alloys with varying Fe content. The annealed Fex(Si B)96- xP3Cu1(x=80, 83 and 85) alloys exhibited a uniform nanostructure with grain size smaller than 20 nm, while the grain sizes of the alloys with x=75 and 78 ranged from 5 nm to 50 nm. The saturation magnetization enhanced nonlinearly as the Fe content increased from 75 to 85. The nanocrystalline alloy Fe85Si3B8P3Cu1 exhibited excellent soft magnetic properties with a coercivity of 12 A·m-1and a saturation magnetization of 1.87 T. The core loss values of nanocrystalline alloys Fe85Si3B8P3Cu1 and Fe83Si4B9P3Cu1were still less than 1.0 W·kg- 1even if the saturation magnetic induction intensity was up to 1.7 T, which were superior to that of the commercial Fe78Si9B13 alloy and nonorientated silicon steel.