Patent Description:
Compared with traditional soft magnetic materials (such as ferrite, silicon steel and the like), amorphous-nanocrystalline soft magnetic alloys are a new type of soft magnetic materials having excellent soft magnetic properties (lower coercivity, higher permeability, etc.) and higher saturation flux density Bs. Power electronic components, such as transformers, motors, instrument transformers, filter inductors, inverters and wireless charging modules, that are made of amorphous-nanocrystalline alloys as core materials have the advantages of smaller size, higher efficiency, higher precision, higher quality and the like as compared with similar components made of traditional soft magnetic materials. Thus, they have been widely used in the fields of automobiles, variable frequency electrical appliances, power systems, new energy power generation, communication and electronic equipment, wireless charging and the like, and have played an important role in the development of various power electronic devices toward miniaturization, energy saving and high precision in daily life and industrial production.

With the rapid development of technology and economy, the demand for power electronic components in various fields is constantly increasing. In addition to the continuous development toward miniaturization, energy saving and high precision, the operating frequency of the power electronic components is also rapidly increasing. For example, in the emerging field of wireless charging in recent years, Qi Wireless Charging Standard based on the principle of electromagnetic induction has been widely used in smart phones, Bluetooth headsets, smart watches and other consumer electronic products, and its electromagnetic wave frequency of wireless power transmission is <NUM>-<NUM>, that is, the working frequency of soft magnetic materials therein is <NUM>-<NUM>. The PMA Standard, which is also based on the principle of electromagnetic induction, has an electromagnetic wave frequency of up to <NUM>-<NUM> and a transmission power greater than that of the Qi Standard, and thus, has wide application prospects in future. In high-end applications in the field of high-frequency filter inductors, such as common-mode inductors for high-end automobiles, the working frequency has now reached <NUM> or above, and there is a trend and demand for rapid development toward higher frequency band. With the popularization and application of <NUM> technology, the development of electronic components toward higher frequency band is an inevitable trend.

The development of power electronic components toward miniaturization, energy saving, high frequency and high precision requires the soft magnetic materials therein to have higher saturation flux density Bs, higher high-frequency permeability µ, lower coercivity Hc and lower loss value. Among the commonly used soft magnetic materials, silicon steel has the highest saturation flux density (<NUM> T or above), but has higher coercivity Hc and loss and lower permeability, and thus, is only suitable for low-frequency applications (<NUM> or below), such as distribution transformers, conventional motors, etc. Ferrite has higher high-frequency permeability, but its saturation flux density is too low, generally less than <NUM> T, which hinders the development of devices toward miniaturization and high power. Commercial amorphous soft magnetic alloy ribbons have higher saturation flux density (-<NUM> T), but have lower high-frequency permeability and higher high-frequency loss, and thus, are mainly used in the applications of <NUM> or below. Commercial FINEMET series of nanocrystalline soft magnetic alloy ribbons, which are currently soft magnetic materials having obvious advantages at the frequency band of <NUM> or above, have saturation flux density of -<NUM> T, higher high-frequency permeability and lower high-frequency loss. However, with the development of the power electronic components toward further miniaturization, high power and high frequency, the disadvantages of the commercial FINEMET series of nanocrystalline alloy ribbons have gradually emerged: (<NUM>) the saturation flux density is lower, which is not conducive to the further miniaturization or high power of devices; and (<NUM>) the permeability at the frequency band of <NUM> or above is not high enough, which hinders the development toward further high frequency of components.

In the prior art, using vacuum transverse magnetic field heat treatment and ribbon thinning, the high-frequency permeability of the FINEMET series of nanocrystalline alloy ribbons can be increased to some extent. However, since the basic alloy composition and the microstructure of the material are not improved, the use of vacuum magnetic field heat treatment and ribbon thinning has limited effects on improving high-frequency permeability: using the combination of transverse magnetic field heat treatment and ribbon thinning, the effective permeability, at <NUM>, of a nanocrystalline ribbon with a thickness of <NUM> can be generally increased to <NUM> or above, and the effective permeability at <NUM> can be increased to <NUM>. However, based on the existing ribbon preparation technique, <NUM> is already the lowest thickness limit of mass-produced ribbons, and the yield is very low, which seriously hinders the development of electronic components toward high frequency and miniaturization.

However, at present, there are many studies on novel nanocrystalline alloys with higher permeability at the frequency band of <NUM> or below, but few studies on novel nanocrystalline alloys with higher permeability, lower loss and higher saturation flux density at the frequency band of <NUM> or above.

The invention patent <CIT>. in Japan discloses an Fe-M-Si-B-Cu nanocrystalline alloy. The permeability at <NUM> of this series of nanocrystalline alloy ribbons reaches <NUM> or above, but the permeability at <NUM> is less than <NUM>. <CIT> discloses an iron-based sub-nanometer alloy with excellent manufacturability and a preparation method thereof.

Chinese patent <CIT> discloses a Fe-Si-B-Nb-V-Cu-Co nanocrystalline alloy with high permeability at high frequency. The effective permeability at the frequency of <NUM> of this series of nanocrystalline alloy ribbons can reach <NUM> or above without vacuum transverse magnetic field annealing, and the effective permeability at the frequency of <NUM> can reach <NUM>. However, the Fe content of nanocrystalline alloys of this series is low, and the atomic percent is only <NUM>%-<NUM>%. Although the value of saturation flux density is not given in the specification of the patent, according to the technical experience in the field of nanocrystalline alloys that the saturation flux density is positively correlated with the Fe content, most ingredients in the alloys of this series have a saturation flux density lower than that of a commercial FINEMET alloy (with a Fe content of about <NUM> at%), that is, lower than <NUM> T, which is not conductive to miniaturization of electronic components.

Thus, there is a serious lack of novel soft magnetic materials having higher permeability, lower loss and higher saturation flux density at high frequency, especially at the frequency band of <NUM> or above, which are currently required by power electronic components, thereby hindering the development of the power electronic components toward high frequency and miniaturization.

In view of the problems in the prior art, through an innovative amorphous alloy ingredient and microstructure design scheme, the invention provides a Fe-based amorphous alloy containing subnanometer-scale ordered clusters and a preparation method thereof. After the amorphous alloy is heat-treated, the formed nanocrystalline alloy has an effective permeability of <NUM> or above and a saturation flux density of <NUM> T or above at the frequency of <NUM>. Besides, wide ribbons can be prepared from industrial raw materials using industrialized ribbon making equipment, thereby meeting the demand of power electronic components for novel soft magnetic materials having higher high-frequency permeability, lower loss and higher saturation flux density at present.

In order to solve the technical problems above, the invention adopts the following technical solutions:.

The invention provides a Fe-based amorphous alloy containing subnanometer-scale ordered clusters. The composition expression of the Fe-based amorphous alloy is FeaSibBc(CudXe)MfM'g, where X is at least one of Ti, Zr and Hf, M is at least one of V, Ta and Nb, and M' is at least one of Co, Ni, C, P, Ge, Cr, Mn, W, Zn, Sn, Sb and Mo; where a, b, c, d, e, f and g respectively represent the atomic percent (percentage of the number of atoms) of the corresponding element, and satisfy: <NUM>≤a≤<NUM>, <NUM>≤b≤<NUM>, <NUM>≤c≤<NUM>, <NUM>≤d≤<NUM>, <NUM>≤e≤<NUM>, <NUM>≤f≤<NUM>, <NUM>≤g≤<NUM>, <NUM>≤e/d≤<NUM> and a+b+c+d+e+f+g=<NUM>. The Fe-based amorphous alloy is a composite composed of an amorphous alloy matrix with atoms arranged completely disorderedly and ordered atom clusters with a size of <NUM>-<NUM> homogeneously dispersed in the matrix.

Further, the above ordered atom clusters in the above Fe-based amorphous alloy in the invention are Cu-X body-centered cubic clusters formed by Cu atoms and X atoms.

Further, the above Fe-based amorphous alloy of the invention may be ribbon-like, powder-like or wire-like in shape.

The above design of the Fe-based amorphous alloy containing subnanometer-scale ordered clusters in the invention is realized through the following ideas:
According to the magnetic theory of soft magnetic materials, the permeability µ of the nanocrystalline alloy is ∝ <NUM>/D<NUM>, where D is the grain diameter. As can be seen, reducing the average grain diameter of the alloy is an important means to improve the permeability. At present, the commercial FINEMET nanocrystalline alloy has an internal grain size of about <NUM>-<NUM>. Therefore, the key of the invention is to design a solution for preparing a nanocrystalline alloy with smaller grain size.

A nanocrystalline soft magnetic alloy is generally prepared by heat-treating an amorphous alloy, which precipitates α-Fe grains with diameters ranging from ten to tens of nanometers. The amorphous alloy is a homogeneous disordered system, and there are no heterogeneous nucleation sites for grain precipitation. Therefore, it is very difficult to prepare a nanocrystalline alloy with homogeneous grain size distribution by crystallization of amorphous alloy. Moreover, the smaller the grain size of the alloy, the more difficult it is to prepare. As shown by massive research and development work on novel high-performance nanocrystalline alloys, the novel nanocrystalline alloys are prone to problems such as heterogeneous structure and formation of coarse α-Fe grains in the preparation and heat treatment process, leading to the degradation of soft magnetic properties and the increase of loss.

The inventors provide a method for reducing the size of subsequent precipitated grains by increasing the heterogeneity of the amorphous alloy: subnanometer-scale ordered atom clusters are introduced into the amorphous alloy such that the amorphous alloy is prepared into a composite composed of an amorphous alloy matrix with atoms arranged completely disorderedly and subnanometer-scale ordered atom clusters homogeneously dispersed in the matrix. In the subsequent heat treatment process of the amorphous alloy, these homogeneously distributed ordered atom clusters provide nucleation sites for the precipitation of α-Fe crystals from the amorphous alloy matrix, and can prevent the formed α-Fe grains from further growth and prevent formation of the coarse grains.

The enthalpy of mixing between Cu and Fe, B, V, Cr, Mn, Co, Ni, Zn, Ga, Nb, Mo, Sn, Sb, Ta, W and other elements in a binary mixture is positive or <NUM>. That is, when the Cu atoms are mixed with the atoms of the aforementioned various elements, the Cu atoms have a weak bonding force with these elements, and cannot easily form atom pairs having a strong bonding force with the atoms of these elements. However, the inventors find that the enthalpy of mixing between Cu and Ti, Zr and Hf (collectively referred to as X in the invention) is negative, and Cu-X atom pairs with a strong bonding force can be formed. Moreover, by carefully adjusting the contents of Cu and X and the ratio of Cu to X in the Fe-based amorphous alloy and using an appropriate preparation method of the amorphous alloy, Cu-X body-centered cubic clusters with a size of <NUM>-<NUM> can be formed in Fe-based amorphous alloy.

It should be noted that the lattice structure of the Cu-X body-centered cubic clusters is the same as that of the α-Fe grains in the nanocrystalline alloy, and the lattice constant is similar to that of the α-Fe (for example, the lattice constant of the CuZr clusters is <NUM>, and the lattice constant of the pure α-Fe is <NUM>). Thus, in the subsequent heat treatment process of the amorphous alloy, the Cu-X clusters serve as the nucleation sites for the precipitation of the α-Fe grains in the amorphous alloy, so that the α-Fe grains are homogeneously distributed. On the other hand, these Cu-X clusters also serve as barriers and pinning points to prevent the α-Fe grains from further growth in the heat treatment process, thereby avoiding the formation of coarse grains. Therefore, the heat-treated nanocrystalline alloy has homogeneous and small grain size, and has better soft magnetic properties and higher permeability than the nanocrystalline alloy developed before.

The design of the amorphous alloy ingredients above will be further described below:
In the alloy ingredients, Fe is an essential magnetic element, and is the key to ensuring a high saturation flux density. However, a too high Fe content will reduce the amorphous forming ability of the alloy, which enables the amorphous alloy to precipitate coarse grains in the preparation process, thereby causing the degradation of the soft magnetic properties. The atomic percent of Fe determined in the invention is <NUM>-<NUM>, preferably <NUM>-<NUM>.

B is an element conducive to the formation of the amorphous alloy. When its content is too low, it is not easy to form a complete amorphous solid. When its content is too high, it will reduce the saturation flux density of the alloy and result in a reduction in the amorphous forming ability. The atomic percent of B is <NUM>-<NUM>, preferably <NUM>-<NUM>.

Si element can improve the fluidity of the alloy and increase the disorder degree of the arrangement of atoms in the alloy, thereby improving the amorphous forming ability and forming ability of the alloy and reducing the difficulty of material preparation.

The effect of adding Cu and X to the alloy at the same time at a certain ratio, as described above, is to form subnanometer-scale Cu-X ordered atom clusters homogeneously distributed in the amorphous alloy, so that the grains of the nanocrystalline alloy obtained by heat treatment are homogeneously distributed and further refined, which is the key of the invention. However, the excessive addition may easily cause the formation of coarse Cu-X grains in the amorphous alloy, which affects the soft magnetic properties. When the adding amount is too small, the clusters formed are small in number and low in density, and thus cannot play the role of refining nanocrystalline grains. The contents of Cu and X are respectively controlled to <NUM>≤d≤<NUM> and <NUM>≤e≤<NUM>, and <NUM>≤e/d≤<NUM>, preferably <NUM>≤d≤<NUM> and <NUM>≤e≤<NUM>. It is creative in the invention that Cu and X are first prepared into an alloy ingot which is subsequently added to a liquid alloy. The prepared amorphous alloy ribbon contains a large number of Cu-X ordered atom clusters, so the nanocrystalline grain size is smaller and more controllable in heat treatment process, and the permeability at high frequency is higher.

Large atoms of V, Ta and Nb etc. can form strong interatomic bonding with atoms of host elements Fe, Si and B etc. Due to the difficulty of diffusion of large atoms, proper addition can improve the thermal stability of the alloy, inhibit the growth of nanocrystalline grains and improve the amorphous forming ability. The atomic percent of such elements is <NUM>-<NUM>, preferably <NUM>-<NUM>.

In addition, Fe in the alloy of the invention can be partially substituted by at least one element selected from Co, Ni, C, P, Ge, Cr, Mn, W, Zn, Sn, Sb and Mo, which plays a role of improving the amorphous forming ability of the alloy. Considering that the saturation flux density will decrease after Fe is substituted by such elements, the atomic percent of this substitution is controlled within <NUM>.

In order to prepare the above amorphous alloy containing Cu-X ordered atom clusters, a Cu-X intermediate alloy is smelted firstly according to the contents of Cu and X in the amorphous alloy, then the Cu-X intermediate alloy is added to a liquid master alloy in which the remaining ingredients are homogeneously smelted before preparing an amorphous alloy ribbon, powder or wire. After the Cu-X intermediate alloy is completely molten into the liquid master alloy, holding for a long time or at high temperature is not allowed. This is because there is a large negative enthalpy of mixing between X and host elements such as Fe, Si and B in the alloy, and atom pairs with a strong bonding force can be formed, thereby affecting the formation of the Cu-X ordered clusters.

Accordingly, the invention further provides a preparation method of the above Fe-based amorphous alloy containing subnanometer-scale ordered clusters. The preparation method includes the following steps:.

The above raw materials of the invention are most ideally pure metals or alloys, or the purity is not less than <NUM> wt%.

In the invention, the amorphous alloy ribbon can be prepared from the liquid alloy by single roll melt spinning. The amorphous alloy powder can be prepared from the liquid alloy by atomization. The amorphous alloy wire can be prepared from the liquid alloy by melt drawing or other methods.

The invention further provides a nanocrystalline alloy derivative obtained after heat-treating the above Fe-based amorphous alloy containing subnanometer-scale ordered clusters. Specifically, the above Fe-based amorphous alloy containing subnanometer-scale ordered clusters is heat-treated to obtain the nanocrystalline alloy derivative with excellent soft magnetic properties. The composition expression of the nanocrystalline alloy derivative is FeaSibBc(CudXe)MfM'g, where X is at least one of Ti, Zr and Hf, M is at least one of V, Ta and Nb, and M' is at least one of Co, Ni, C, P, Ge, Cr, Mn, W, Zn, Sn, Sb and Mo; where a, b, c, d, e, f and g respectively represent the atomic percent (percentage of the number of atoms) of the corresponding element, and satisfy: <NUM>≤a≤<NUM>, <NUM>≤b≤<NUM>, <NUM>≤c≤<NUM>, <NUM>≤d≤<NUM>, <NUM>≤e≤<NUM>, <NUM>≤f≤<NUM>, <NUM>≤g≤<NUM>, <NUM>≤e/d≤<NUM> and a+b+c+d+e+f+g=<NUM>. The nanocrystalline alloy derivative is a composite composed of an amorphous alloy matrix and grains with a size of <NUM>-<NUM> homogeneously dispersed in the matrix.

Further, according to the nanocrystalline alloy derivative, the grains are α-Fe grains, and the size of the α-Fe grains is preferably <NUM>-<NUM>.

Further, according to the nanocrystalline alloy derivative, the nanocrystalline alloy derivative may be ribbon-like, powder-like or wire-like in shape.

Further, according to the nanocrystalline alloy derivative, a preparation method of the nanocrystalline alloy derivative includes: heat-treating the above Fe-based amorphous alloy containing subnanometer-scale ordered clusters in a heat treatment furnace as defined in claim <NUM> such that the amorphous alloy precipitates nanocrystalline grains with a size of <NUM>-<NUM> around the ordered atom clusters, thereby forming the nanocrystalline alloy.

Further, according to the nanocrystalline alloy derivative, the ribbon-like material of the nanocrystalline alloy derivative has ultrahigh permeability at high frequency: the permeability at the frequency of <NUM> is <NUM> or above, and the saturation flux density is <NUM> T or above.

The advantages and beneficial effects of the invention mainly include:.

The invention will be further described in detail below with reference to the accompanying drawing and specific embodiments. It should be noted that the following embodiments are intended to facilitate the understanding of the invention and do not limit the invention in any way.

In this embodiment, the composition expression of the Fe-based amorphous alloy containing subnanometer-scale ordered clusters is Fe<NUM>Si<NUM>B<NUM>Nb<NUM>Cu<NUM>Zr<NUM>.

The preparation and heat treatment method and steps of the Fe-based amorphous alloy were described as follows:.

The amorphous alloy ribbon, and the nanocrystalline ribbon and the magnetic core obtained after heat treatment described above were tested as follows:.

The saturation flux density Bs, the effective permeability µ at <NUM> (@<NUM>) and the internal grain size D of the nanocrystalline alloy prepared after magnetic field heat treatment in step (<NUM>) in this embodiment are listed in Table <NUM>.

The specific ingredients of each alloy, that is, the composition expression, are shown in Table <NUM>.

The preparation and heat treatment methods and steps of the amorphous alloy ribbons of this series of embodiments were basically the same as in Embodiment <NUM>. Except that the raw materials and proportioning thereof, the smelting temperature of the alloy, the remelting temperature, the ribbon spraying temperature and the heat treatment process parameters were different from those in Embodiment <NUM> due to different alloy ingredients, other methods and process parameters were the same as those in Embodiment <NUM>. In the embodiments, an amorphous alloy ribbon with a thickness of <NUM> was prepared, and roll-cut and wound into a circular magnetic core having an inner diameter of <NUM>, an outer diameter of <NUM> and a height of <NUM>, the circular magnetic core was subjected to vacuum heat treatment and transverse magnetic field heat treatment, and a <NUM> T transverse magnetic field was applied during the magnetic field heat treatment.

The amorphous alloy ribbons, and the nanocrystalline alloy ribbons and the magnetic cores obtained after heat treatment in the embodiments were tested as in Embodiment <NUM>, and the saturation flux density Bs, the effective permeability µ at <NUM> (@<NUM>) and the internal grain size D are listed in Table <NUM>. As for Embodiment <NUM> and Embodiment <NUM>, the XRD pattern of the amorphous alloy ribbon is shown in <FIG>, the XRD pattern of the nanocrystalline alloy ribbon prepared after heat treatment is shown in <FIG>, the typical variation curve of the permeability, at the frequency of <NUM>-<NUM>, of the nanocrystalline magnetic core prepared after magnetic field heat treatment is shown in <FIG>, and the magnetic hysteresis loop of the nanocrystalline ribbon is shown in <FIG>. Other test results of the other embodiments are not shown one by one.

It can be seen from data in Table <NUM> that in the nanocrystalline alloys of all above embodiments, the grain size is basically within the range of <NUM>-<NUM>, the permeability at the frequency of <NUM> reaches <NUM> or above, and the saturation flux density reaches <NUM> T or above.

The alloy in this comparative embodiment is a FINEMET nanocrystalline alloy currently industrially produced and applied, and its composition is Fe<NUM>Si<NUM>B<NUM>Nb<NUM>Cu<NUM>.

The wide ribbon having a thickness of <NUM> and a width of <NUM> of Comparative Embodiment <NUM> was wound by a magnetic core winder into a circular magnetic core having an inner diameter of <NUM>, an outer diameter of <NUM> and a height of <NUM>. Then the circular magnetic core was heat-treated as follows: The magnetic core was placed in a vacuum heat treatment furnace. The vacuum heat treatment furnace was vacuumized and heated by energization. The magnetic core was heated to <NUM>-<NUM> at a heating rate of <NUM>/min, subjected to multi-stage heat treatment at <NUM>-<NUM> for <NUM>-<NUM>, and then cooled to room temperature. Then, the nanocrystalline magnetic core after vacuum heat treatment was placed in a vacuum magnetic field heat treatment furnace. The heat treatment furnace was vacuumized and heated by energization to <NUM>-<NUM> at a heating rate of <NUM>/min. A <NUM> T transverse magnetic field (along a ribbon width direction) was externally applied in the furnace. The nanocrystalline magnetic core was held for <NUM>-<NUM>, then cooled to room temperature and discharged.

The amorphous alloy ribbon, and the nanocrystalline alloy ribbon and the magnetic core obtained after heat treatment in Comparative Embodiment <NUM> were tested as in Embodiment <NUM>. The high-resolution transmission electron microscopy picture of the amorphous ribbon shows that in the amorphous alloy ribbon of this comparative embodiment, the atoms are arranged completely disorderedly, and there are no ordered atom clusters. The saturation flux density, the effective permeability at <NUM> and the internal grain size of the nanocrystalline magnetic core and ribbon obtained after magnetic field heat treatment are listed in Table <NUM>. The typical variation curve of the permeability, at <NUM>-<NUM>, of the nanocrystalline magnetic core is shown in <FIG>, and the magnetic hysteresis loop of the nanocrystalline ribbon is shown in <FIG>.

As can be seen from the comparison of data in Table <NUM>, <FIG>, the saturation flux density and the permeability of the nanocrystalline alloy ribbons of the embodiments of the invention are significantly higher than those of Comparative Embodiment <NUM>, and the internal grain size of the nanocrystalline alloys of the embodiments of the invention is smaller than that of Comparative Embodiment <NUM>, which should be the main reason why the permeability of the alloy of the invention is higher than that of Comparative Embodiment <NUM>.

The composition expression of the alloy of this comparative embodiment is Fe<NUM>Si<NUM>B<NUM>Nb<NUM>Cu<NUM>Mo<NUM>.

The preparation and heat treatment method and steps of the Fe-based amorphous alloy ribbon were as follows:.

The amorphous alloy ribbon, and the nanocrystalline alloy ribbon and the magnetic core obtained after heat treatment in Comparative Embodiment <NUM> were tested as in Embodiment <NUM>. The high-resolution transmission electron microscopy picture of the amorphous ribbon shows that in the amorphous alloy ribbon of this comparative embodiment, the atoms are arranged completely disorderedly, and there are no ordered atom clusters. The saturation flux density, the effective permeability at <NUM> and the internal grain size of the nanocrystalline magnetic core and ribbon obtained after magnetic field heat treatment are listed in Table <NUM>. The typical variation curve of the permeability, at <NUM>-<NUM>, of the nanocrystalline magnetic core is shown in <FIG>.

As can be seen from the comparison of data in Table <NUM> and <FIG>, compared with Comparative Embodiment <NUM>, the internal grain size of the nanocrystalline alloys of the embodiments of the invention is smaller, and the permeability at each frequency is significantly higher than that of the alloy of Comparative Embodiment <NUM>.

The alloy of this comparative embodiment has the same composition expression as Embodiment <NUM>: Fe<NUM>Si<NUM>B<NUM>Nb<NUM>Cu<NUM>Zr<NUM>. The difference from Embodiment <NUM> is that: during the preparation process of the amorphous alloy ribbon, the ribbon preparation method as described in Comparative Embodiment <NUM> was used instead of the use of the Cu-Zr intermediate alloy.

The preparation and heat treatment method and steps of the Fe-based amorphous alloy ribbon were described as follows:.

The amorphous alloy ribbon, and the nanocrystalline alloy ribbon and the magnetic core obtained after heat treatment in Comparative Embodiment <NUM> were tested as in Embodiment <NUM>. The high-resolution transmission electron microscopy picture of the amorphous alloy ribbon shows that in the amorphous alloy of this comparative embodiment, the atoms are basically arranged completely disorderedly, and there are few ordered atom clusters. The saturation flux density, the effective permeability at <NUM> and the internal grain size of the nanocrystalline magnetic core and ribbon of this comparative embodiment are listed in Table <NUM>.

As can be seen from the table, the saturation flux density of the nanocrystalline alloy of this comparative embodiment is the same as that of Embodiment <NUM>. However, since there are few subnanometer-scale ordered clusters in the amorphous alloy, the size of the grains precipitating from the nanocrystalline alloy is obviously larger than that of Embodiment <NUM>, so that the permeability is also greatly lower than that of the nanocrystalline alloy of the Embodiment <NUM>.

The alloy of this comparative embodiment has the same composition expression as Embodiment <NUM>: Fe<NUM>Si<NUM>B<NUM>Nb<NUM>Cu<NUM>Zr<NUM>. The difference from Embodiment <NUM> is that: during the preparation process of the amorphous alloy ribbon, the ribbon preparation method as described in Comparative Embodiment <NUM> and Comparative Embodiment <NUM> was used instead of the use of the Cu-Zr intermediate alloy.

The preparation and heat treatment steps of the amorphous alloy ribbon and the magnetic core in this comparative embodiment will not be repeated here. Except that the raw material proportioning, the smelting temperature of the master alloy, the remelting temperature, the ribbon spraying temperature and the heat treatment process parameters were different from those in Comparative Embodiment <NUM> due to different alloy ingredients, the other methods and process parameters were the same as those in Comparative Embodiment <NUM>.

The amorphous alloy ribbon, and the nanocrystalline alloy ribbon and the magnetic core obtained after heat treatment in Comparative Embodiment <NUM> were tested as in Embodiment <NUM>. The high-resolution transmission electron microscopy picture of the amorphous alloy ribbon shows that in the amorphous alloy of this comparative embodiment, the atoms are basically arranged completely disorderedly, and there are few ordered atom clusters. The saturation flux density, the effective permeability at <NUM> and the internal grain size of the nanocrystalline magnetic core and ribbon of this comparative embodiment are listed in Table <NUM>. The typical variation curve of the permeability, at <NUM>-<NUM>, of the nanocrystalline magnetic core is shown in <FIG>.

As can be seen from data in Table <NUM> and <FIG>, this comparative embodiment is similar to Comparative Embodiment <NUM>: The saturation flux density of the nanocrystalline alloy is the same as that of Embodiment <NUM>. However, since there are few subnanometer-scale ordered clusters in the amorphous alloy, the size of the nanocrystalline grains precipitating from the nanocrystalline alloy is obviously larger than that of Embodiment <NUM>, so that the permeability is also greatly lower than that of the nanocrystalline alloy of the Embodiment <NUM>.

Claim 1:
A Fe-based amorphous alloy containing subnanometer-scale ordered clusters, wherein the composition expression of the Fe-based amorphous alloy is FeaSibBc(CudXe)MfM'g, and X is at least one of Ti, Zr and Hf, M is at least one of V, Ta and Nb, and M' at least one of Co, Ni, C, P, Ge, Cr, Mn, W, Zn, Sn, Sb and Mo; a, b, c, d, e, f and g respectively represent the atomic percent (percentage of the number of atoms) of the corresponding element, and satisfy: <NUM>≤a≤<NUM>, <NUM>≤b≤<NUM>, <NUM>≤c≤<NUM>, <NUM>≤d≤<NUM>, <NUM>≤e≤<NUM>, <NUM>≤f≤<NUM>, <NUM>≤g≤<NUM>, <NUM>≤e/d≤<NUM> and a+b+c+d+e+f+g=<NUM>; the Fe-based amorphous alloy is a composite material composed of an amorphous alloy matrix with atoms arranged in complete disorder and ordered atomic clusters having the size ranging from <NUM> to <NUM> uniformly dispersed and distributed in the matrix; the ordered atom clusters in the Fe-based amorphous alloy are Cu-X body-centered cubic clusters formed by Cu atoms and X atoms; the Fe-based amorphous alloy is made by first smelting the Fe-Si-B-M-M' master alloy and the Cu-X intermediate alloy, then re-melting the master alloy, and adding the intermediate alloy into the completely molten master alloy, and after the intermediate alloy is completely molten, made by a material preparation apparatus.