阅读说明：本技术 一种纳米晶合金及其制备方法 (Nanocrystalline alloy and preparation method thereof ) 是由 贺爱娜 杨富尧 张博峻 董亚强 黎嘉威 马光 冯砚厅 陈新 韩钰 高洁 刘洋 于 2020-11-12 设计创作，主要内容包括：本发明涉及软磁合金材料技术领域,公开了一种纳米晶合金及其制备方法,将FeCuSiBNbMoDy带材在交变磁场慢速升温至T_1,去除交变磁场保温t_1；快速升温至T_2,保温t_2；恒定磁场下快速降温至T_3,保温t_3；慢速降温至T_4,保温t_4后快速降温至室温,得到纳米晶合金。通过Fe、Cu、Nb、Si、B、Mo、Dy元素间的协同作用,有效促进无序相的析出,提高形核率,降低有效各向异性常数,通过制备工艺的调控最终获得损耗低且对服役温度不敏感的纳米晶软磁合金。可应用于高频变压器、共模电感、无线充电、滤波器等器件中可保证产品性能的稳定和安全可靠。(The invention relates to the technical field of soft magnetic alloy materials, and discloses a nanocrystalline alloy and a preparation method thereof 1 Removing the alternating magnetic field to keep the temperature t 1 (ii) a Quickly heating to T 2 Keeping temperature t 2 (ii) a Quickly cooling to T under constant magnetic field 3 Keeping temperature t 3 (ii) a Slowly cooling to T 4 Keeping temperature t 4 And then rapidly cooling to room temperature to obtain the nanocrystalline alloy. Through the synergistic effect among Fe, Cu, Nb, Si, B, Mo and Dy elements, the precipitation of disordered phases is effectively promoted, the nucleation rate is improved, the effective anisotropy constant is reduced, and the nanocrystalline magnetically soft alloy which is low in loss and insensitive to service temperature is finally obtained through the regulation and control of the preparation process. The method can be applied to devices such as high-frequency transformers, common-mode inductors, wireless charging and filters, and can ensure the stability, safety and reliability of product performance.)

1. The preparation method of the nanocrystalline alloy is characterized in that the alternating magnetic field of a FeCuSiBNbMoDy strip is slowly heated to T₁Removing the alternating magnetic field to keep the temperature t₁(ii) a Quickly heating to T₂Thermal insulation t₂(ii) a Quickly cooling to T under constant magnetic field₃Thermal insulation t₃(ii) a Slowly cooling to T₄Thermal insulation t₄And then rapidly cooling to room temperature to obtain the nanocrystalline alloy.

2. The method for preparing a nanocrystalline alloy according to claim 1, wherein T is T₁At 350-430 ℃ t₁Is above 0.1 min;

the T is₂At 480-620 ℃ and t₂Is 1 s-60 min;

the T is₃At 380-420 ℃ t₃Is 1 s-60 min;

the T is₄At 260-340 ℃ t₄Is above 0.1 min.

3. The method of claim 1, wherein the FeCuSiBNbMoDy strip has the formula Fe_aCu_bSi_cB_dNb_eMo_fDy_gWherein a, b, c, d, e, f and g are atomic percentages, a + b + c + d + e + f + g is 100, a is 72-80, b is 0.1-1.5, c is 5-15, d is 4-10, e is 0.5-1.5, f is 0.1-1, and g is 0.1-1.

4. The method for producing a nanocrystalline alloy according to claim 1, wherein the temperature change rate of the rapid temperature increase or rapid temperature decrease is 300 ℃/min or more.

5. The method for preparing a nanocrystalline alloy according to claim 1, wherein the temperature change rate of the slow temperature rise or the slow temperature fall is 0.01-3 ℃/min.

6. The method for preparing a nanocrystalline alloy according to claim 1, wherein the amplitude of the alternating magnetic field is 0.1-10T, and the frequency is 0.1 Hz-1 MHz.

7. The method for producing a nanocrystalline alloy according to claim 1, wherein the constant magnetic field is a transverse static magnetic field and/or a longitudinal static magnetic field, or a rotating static magnetic field, and the magnitude of the magnetic field is 0.1 to 10T.

8. The method of producing a nanocrystalline alloy according to claim 1 or 3, wherein Nb in the FeCuSiBNbMoDy strip is replaced by any one of Zr, Ta, Hf, W, Al, Cr, Co, Ni, Mn, Ga, Mg, Na, K; dy is replaced by other rare earth elements.

9. The nanocrystalline alloy prepared according to any one of claims 1 to 8, wherein the nanocrystalline alloy maintains a change rate of 15% or less at a high frequency loss of-60 ℃ to 250 ℃.

10. The nanocrystalline alloy of claim 9, wherein the nanocrystalline alloy maintains a rate of change of 10% or less at a high frequency loss of-150 ℃ to 250 ℃.

Technical Field

The invention relates to the technical field of soft magnetic alloy materials, in particular to a nanocrystalline alloy insensitive to service temperature and a preparation method thereof.

Background

With the emergence of energy crisis and the development of science and technology, energy conservation, consumption reduction, low carbon and environmental protection are all important in the world, and the development of electronic devices towards low energy consumption of miniaturization, high efficiency and high frequency is required. Compared with the traditional soft magnetic materials such as traditional soft magnetic ferrite, silicon steel, permalloy and the like, the nanocrystalline soft magnetic alloy has the following advantages:

1) energy conservation in manufacturing: by adopting the rapid solidification technology, the strip can be formed in a very short time (<10 s).

2) The eddy current loss is low: the belt is thin, the thickness is 18-20 microns, and the high-frequency eddy current loss is low.

3) High magnetic permeability and low coercive force: the nanocrystalline soft magnetic alloy has an amorphous phase and a nanocrystalline phase double-phase coupling structure, and the ferromagnetic exchange coupling effect of the amorphous phase and the nanocrystalline phase promotes the improvement of the soft magnetic property.

4) The composite soft magnetic property is good, and the alloy has high magnetic induction intensity and low cost of the iron-based amorphous alloy and high magnetic permeability, low loss and low magnetostriction coefficient of the cobalt-based amorphous alloy.

Therefore, the nanocrystalline soft magnetic alloy is known as a novel double-green energy-saving strategic new material in the 21 st century, the Finemet alloy is industrialized, replaces permalloy, soft magnetic ferrite and cobalt-based amorphous alloy, and is widely applied to the fields of high-frequency power electronics and electronic information such as high-frequency transformers, common-mode inductors, wireless charging and filters. Many studies have been made on iron-based amorphous nanocrystalline magnetically soft alloys, for example, CN104934179A discloses an iron-based nanocrystalline magnetically soft alloy with strong amorphous forming ability and a preparation method thereof, the expression of the alloy is Fe_xSi_aB_bP_cNb_dCu_eIn the expression, x, a, b, c, d and e respectively represent the atom percentage content of each corresponding component, and the following conditions are satisfied: a is more than or equal to 0.5 and less than or equal to 12, b is more than or equal to 0.5 and less than or equal to 15, c is more than or equal to 0.5 and less than or equal to 12, d is more than or equal to 0.1 and less than or equal to 3, e is more than or equal to 0.1 and less than or equal to 3, x is more than or equal to 70 and less than or equal to 85, and x + a +100 percent. The soft magnetic alloy can be used for preparing the iron-based amorphous alloy with the critical dimension of 3.5mm by adopting a common copper mold casting method, and after annealing, the saturation magnetic induction intensity is more than 1.5T, and the coercive force value is below 1A/m.

CN102412045A discloses an iron-based nanocrystalline magnetically soft alloy, which is characterized in that the composition of the alloy is expressed by a chemical formula of Fe_gSi_aP_bC_cCu_dMn_eAl_fWherein a, b, c, d, e, f and g are atomic percentages, a is 8.5-12, b is 4-7, c is 1-3, d is 0.5-1.5, e is 0.25-0.5, f is 0.75-1.5, and g is 100-a-b-c-d-e-f. The iron-based nanocrystalline soft magnetic alloy does not contain precious Co, Zr, Nb, B and other elements, is low in cost, has excellent soft magnetic performance that Bs can reach 1.71T at most and Hc can reach 0.9A/m at least under the condition of the optimal crystallization annealing process, is more suitable for mass production, and can replace the existing silicon steel sheet and iron-based amorphous nanocrystalline soft magnetic alloy to be applied to the fields of power electronic transformers, mutual inductors and the like.

However, the variation of heat dissipation and performance of components with temperature rise is one of the most critical aspects in electronic design. The heat generated by the component is generated by the heat source caused by the external environment or the loss of the capacity of the component. The nanocrystalline soft magnetic material is one of key core materials of devices such as a high-frequency transformer, a common-mode inductor, wireless charging and a filter, and the final product performance of the devices such as the inductor, the transformer, the filter and the wireless charging can be seriously influenced or even disabled if the soft magnetic performance of the nanocrystalline soft magnetic material is changed violently along with the service temperature.

Therefore, the method is particularly important for developing the nanocrystalline soft magnetic material which has low loss and is insensitive to service temperature.

Disclosure of Invention

The invention aims to solve the problem of temperature sensitivity of a nanocrystalline soft magnetic material in the prior art, and optimizes alloy performance by selecting alloy elements, and regulating and controlling grain precipitation and free volume release of heat treatment parameters such as magnetic field, speed, temperature, time and the like, so as to obtain the nanocrystalline alloy material which is low in loss and insensitive to service temperature.

In order to achieve the purpose, the invention adopts the technical scheme that:

a process for preparing nm-class crystal alloy includes such steps as heating FeCuSiBNbMoDy band in alternative magnetic field to T₁Removing the alternating magnetic field to keep the temperature t₁(ii) a Quickly heating to T₂Keeping temperature t₂(ii) a Quickly cooling to T under constant magnetic field₃Keeping temperature t₃(ii) a Slowly cooling to T₄Keeping temperature t₄And then rapidly cooling to room temperature to obtain the nanocrystalline alloy insensitive to service temperature. Wherein T is₁、T₂、T₃、T₄Is temperature, t₁、t₂、t₃、t₄Is time.

Preferably, the first and second electrodes are formed of a metal,

the T is₁At 350-430 ℃ t₁Is above 0.1 min;

the T is₂At 480-620 ℃ and t₂Is 1 s-60 min;

the T is₃At 380-420 ℃ t₃Is 1 s-60 min;

the T is₄At 260-340 ℃ t₄Is above 0.1 min.

In the selection of alloy elements, Fe is one of ferromagnetic elements Fe, Co and Ni with wide sources and low cost, and the production cost can be greatly reduced by selecting Fe compared with Co and Ni; cu can promote nucleation and improve the nucleation rate of the nanocrystalline, Si and B can promote the formation of disordered phases, and large atoms Nb and Mo can refine the nanocrystalline grains and reduce the effective magnetic anisotropy constant of the nanocrystalline alloy. Mo also has the advantages of oxidation resistance, improvement of preparation manufacturability, further improvement of formation of disordered phases, inhibition of crystallization by Dy and improvement of formation of disordered phases. According to the invention, through the synergistic effect among Fe, Cu, Nb, Si, B, Mo and Dy elements, the preparation process is improved, the precipitation of disordered phases is effectively promoted, the nucleation rate is increased, and the effective anisotropy constant is reduced.

In the preparation process, the temperature is increased to the cluster nucleation temperature at an ultra-slow speed under the alternating magnetic field, the diffusion and aggregation of atoms are promoted under the repeated alternating excitation and enough time relaxation, the agglomeration rate of the Cu element is greatly improved, and the heat is preserved for a period of time to ensure the full and uniform agglomeration; rapidly heating to a first crystallization temperature to promote the simultaneous precipitation of dense nanocrystalline nucleation sites, and on the basis, maintaining the temperature to ensure that the dense nucleation sites grow simultaneously to obtain uniform and extremely small crystal grains; rapidly cooling to a temperature slightly lower than the first crystallization starting temperature under a constant magnetic field, releasing the micro stress generated by crystallization so as to reduce the magneto-elastic anisotropy, and slowly cooling to a temperature near the amorphous Curie temperature point for a period of time so as to reduce the quasi-staggered dipole;

by combining the mutual synergistic effect of the alloy and the parameters, the nanocrystalline soft magnetic alloy with low loss and insensitivity to service temperature can be obtained.

Further preferably, said T₁At 380-420 ℃ t₁Is more than 20 min;

the T is₂At 520-600 ℃ t₂20-30 min;

the T is₃At 390-410 ℃ and t₃Is 1 s-1 min;

the T is₄At 280-330 ℃ and t₄Is more than 15 min.

Applying an alternating magnetic field to T from room temperature₁Can promote the separation of Cu element and Fe element to enrich Cu element, and keep temperature t₁The Cu element can be enriched to form clusters, the nucleation rate of the nanocrystalline is improved, the crystal grains are refined, and further the loss is reduced and the service temperature insensitivity is improved.

At T₂Thermal insulation t₂And crystal grains with high density, fineness, uniform dispersion and nano structure can be separated out, and low high-frequency loss and good temperature stability can be obtained.

Fast to T under constant magnetic field₃Thermal insulation t₃The micro stress generated by crystallization can be released to further reduce the magneto-elastic anisotropy, thereby further improving the high-frequency loss and improving the temperature stability.

Slowly cooling to T under constant magnetic field₄Temperature t is kept close to the amorphous Curie temperature₄The quasi-dislocation dipole can be reduced, the induced anisotropy can be obtained, the high-frequency loss is further reduced, and the temperature stability is improved.

Preferably, theThe expression of the FeCuSiBNbMoDy strip is Fe_aCu_bSi_cB_dNb_eMo_fDy_gWherein a, b, c, d, e, f and g are atomic percentages, a + b + c + d + e + f + g is 100, a is 72-80, b is 0.1-1.5, c is 5-15, d is 4-10, e is 0.5-1.5, f is 0.1-1, and g is 0.1-1.

The temperature change rate of the rapid temperature rise or rapid temperature decrease is more than 300 ℃/min.

The temperature change rate of the slow temperature rise or slow temperature fall is 0.01-3 ℃/min. T is₁The smaller the temperature rise speed is, the enough time relaxation can be ensured to lead the Cu element and the Fe element to diffuse, separate and agglomerate.

T₁To T₂The higher the temperature rise speed is, the more easily the nanocrystalline crystal grains are nucleated and grow up simultaneously; t is₂To T₃The higher the cooling speed is, the more favorable the micro stress generated by crystallization is released, and the magnetic elastic anisotropy is further reduced; t is₃To T₄The smaller the cooling rate is, the more favorable the reduction of the quasi-dislocation dipole and the acquisition of the induced anisotropy are.

The four kinds of mutual synergistic action are favorable for improving the nucleation rate of fine grains, reducing the magnetocrystalline anisotropy constant, inducing induced anisotropy and improving the high-frequency characteristic and the temperature stability.

The amplitude of the alternating magnetic field is 0.1-10T, and the frequency is 0.1 Hz-1 MHz. The larger the amplitude of the alternating magnetic field is, the more favorable the reduction of nucleation potential barrier and the promotion of nucleation are. The higher the frequency, the faster the element diffusion, and the more favorable the separation of the Cu element and the Fe element to form the Cu cluster. The interaction of the two is beneficial to improving the number density of the Cu cluster, further improving the crystallization degree, reducing the grain size, and reducing the high-frequency loss and the stable sensitivity.

The constant magnetic field is a transverse static magnetic field and/or a longitudinal static magnetic field or a rotary static magnetic field, and the size of the magnetic field is 0.1-10T.

Nb in the FeCuSiBNbMoDy strip is replaced by any one of Zr, Ta, Hf, W, Al, Cr, Co, Ni, Mn, Ga, Mg, Na and K; dy is replaced by other rare earth elements Gd, La, Ce, Pr, Nd, Tb, Dy and Ho.

The invention also provides the nanocrystalline alloy prepared by the preparation method, and the loss of the nanocrystalline alloy keeps the change rate below 15% at minus 60-250 ℃.

Preferably, the loss of the nanocrystalline alloy maintains a change rate of 10% or less at-150 ℃ to 250 ℃.

The nanocrystalline alloy prepared by the method can be applied to elements of electronic devices, can ensure the stability of product performance, has low loss, and is particularly suitable for being applied in working environments with harsh temperature conditions.

Compared with the prior art, the invention has the following beneficial effects:

(1) the nanocrystalline magnetically soft alloy obtained by the method has ultralow high-frequency loss, and the loss is not more than 500kW/m under the magnetic field with the amplitude of 0.2T and the frequency of 150kHz³And has wide application prospect in the high-frequency field.

(2) The loss of the nanocrystalline soft magnetic alloy is insensitive to the service temperature, the change rate is kept below 10% at-60-250 ℃, and the nanocrystalline soft magnetic alloy is applied to devices such as a high-frequency transformer, a common-mode inductor, wireless charging, a filter and the like, can ensure the stability, safety and reliability of the performance of products, and is particularly suitable for the working environment with harsh conditions.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Those skilled in the art should understand that they can make modifications and equivalents without departing from the spirit and scope of the present invention, and all such modifications and equivalents are intended to be included within the scope of the present invention.

Example 1

(1) Obtaining Fe by smelting₇₇Cu₁Si₁₀B₉Nb₁Mo₁Dy₁An alloy strip, which is placed in a heat treatment furnace;

(2) slowly raising the temperature to 350 ℃ at a temperature raising rate of 0.01 ℃/min under the conditions that the amplitude of the alternating magnetic field is 0.1T and the frequency is 0.1 Hz; removing the alternating magnetic field and keeping the temperature for 0.1 min;

(3) rapidly heating to 480 ℃ at the heating rate of 300 ℃/min, and keeping the temperature for 1 s;

(4) increasing a transverse static magnetic field with the amplitude of 0.1T, rapidly cooling to 380 ℃ at the speed of 300 ℃/min, and preserving heat for 1 s;

(5) and slowly reducing the temperature to 260 ℃ at the speed of 0.01 ℃/min under a transverse static magnetic field, preserving the temperature for 0.1min, and quickly reducing the temperature to room temperature at the speed of 300 ℃/min to obtain the nanocrystalline alloy.

Example 2

(1) Obtaining Fe by smelting_76.5Cu₁Si_12.5B₈Nb₁Mo_0.5Dy_0.5An alloy strip, which is placed in a heat treatment furnace;

(2) slowly raising the temperature to 400 ℃ at a temperature raising rate of 0.5 ℃/min under the conditions that the amplitude of the alternating magnetic field is 0.5T and the frequency is 100 Hz; removing the alternating magnetic field and preserving heat for 10 hours;

(3) then rapidly heating to 590 ℃ at the heating rate of 800 ℃/min, and preserving the heat for 30 min;

(4) increasing a longitudinal static magnetic field with the amplitude of 0.3T, rapidly cooling to 400 ℃ at the speed of 800 ℃/min, and preserving heat for 60 min;

(5) and then slowly reducing the temperature to 320 ℃ at the speed of 1 ℃/min, preserving the temperature for 100min, and quickly reducing the temperature to room temperature at the speed of 800 ℃/min to obtain the nanocrystalline alloy.

Example 3

(1) Obtaining Fe by smelting_75.9Cu₁Si₁₃B₈Nb_1.5Mo_0.5Dy_0.1An alloy strip, which is placed in a heat treatment furnace;

(2) slowly raising the temperature to 430 ℃ at a temperature raising rate of 3 ℃/min under the conditions that the amplitude of the alternating magnetic field is 10T and the frequency is 1 MHz; removing the alternating magnetic field and preserving heat for 120 h;

(3) rapidly heating to 620 ℃ at the heating rate of 1000 ℃/min, and keeping the temperature for 60 min;

(4) increasing transverse and longitudinal static magnetic field with amplitude of 10T, rapidly cooling to 420 deg.C at 1000 deg.C/min, and maintaining for 60 min;

(5) and under the condition of transverse and longitudinal static magnetic fields, slowly reducing the temperature to 340 ℃ at the speed of 3 ℃/min, preserving the temperature for 120h, and quickly reducing the temperature to room temperature at the speed of 1000 ℃/min to obtain the nanocrystalline alloy.

Comparative example 1

According to the process of example 1, only in the preparation process, the alternating magnetic field and the transverse static magnetic field are not increased, and the nanocrystalline alloy is obtained.

Comparative example 2

According to the process of example 2, only in the preparation process, the alternating magnetic field and the longitudinal static magnetic field are not increased, and the nanocrystalline alloy is obtained.

Comparative example 3

According to the process of example 3, only in the preparation process, an alternating magnetic field and a transverse and longitudinal static magnetic field are not added, and the nanocrystalline alloy is obtained.

The nanocrystalline alloys prepared in examples 1-3 and comparative examples 1-3 were tested for room temperature loss at 0.1T and 150kHz by an AC B-H instrument. As can be seen from the results of the loss test,

the room temperature loss of the nanocrystalline soft magnetic alloy prepared in example 1 at 0.1T and 150kHz is 580kW/m³The room temperature loss of the nano-crystalline soft magnetic alloy prepared in comparative example 1 at 0.1T and 150kHz was 870kW/m³；

The room temperature loss of the nanocrystalline alloy prepared in example 2 at 0.1T and 150kHz was 420kW/m³Comparative example 2 the prepared nanocrystalline alloy had a room temperature loss of 840kW/m at 0.1T and 150kHz³；

The room temperature loss of the nanocrystalline alloy prepared in example 3 at 0.1T and 150kHz was 380kW/m³Comparative example 3 the prepared nanocrystalline alloy had a room temperature loss of 780kW/m at 0.1T and 150kHz³. This fully demonstrates the rationality and effectiveness of heat treatment regulation of the alloys of the present invention.

The nanocrystalline alloy prepared by the test example and the comparative example is tested for loss under the amplitude of 0.1T and the frequency of 150kHz within the service temperature range of-60 ℃ to 250 ℃ by adding liquid nitrogen and raising the temperature in situ; and comparing the loss at room temperature with the loss at room temperature to obtain the change rate of the loss at room temperature, wherein the specific numerical values are shown in table 1.

TABLE 1 rate of change of loss for nanocrystalline alloys prepared in examples and comparative examples

As can be seen from the table, the alloy prepared in example 1 has a loss variation rate of 14.5% at maximum in the service temperature range of-60 ℃ to 250 ℃ compared with the loss at room temperature, and the loss variation rate of comparative example 1 is as high as 21.8%. The loss change rate of the alloy prepared in the embodiment 2 is 13 percent at most in the service temperature range of-60-250 ℃, while the loss change rate of the alloy prepared in the comparative example 2 is 28.6 percent; the loss change rate of the alloy prepared in the embodiment 3 is 9.5 percent at most in the service temperature range of-60-250 ℃, and the loss change rate of the alloy prepared in the embodiment 3 is 31.3 percent.

The main difference between the preparation processes of the nanocrystalline alloys of examples 1-3, namely, the room temperature losses at 0.1T and 150kHz and the change rate of the comparative room temperature loss are summarized in Table 2, and it can be seen from the table that the high frequency loss and the loss change rate at 0.1T and 150kHz are all reduced in examples 1-3, but the amplitude and the frequency of the alternating magnetic field are continuously increased in the step (2) of the preparation of the nanocrystalline alloys of examples 1-3, the amplitude of the static magnetic field is also increased in the step (4), and the larger the amplitude of the alternating magnetic field is, the more favorable the nucleation barrier is reduced, and the nucleation is promoted. The higher the frequency, the faster the element diffusion, and the more favorable the separation of the Cu element and the Fe element to form the Cu cluster. The interaction of the two is beneficial to improving the number density of the Cu cluster, further improving the crystallization degree, reducing the grain size, and reducing the high-frequency loss and the stable sensitivity. And the adjustment of the heating rate or the cooling rate among the temperatures, the selection of alloy element components and the comprehensive synergistic effect improve the nucleation rate of fine grains, reduce the magnetocrystalline anisotropy constant, induce induced anisotropy and improve the high-frequency characteristic and the temperature stability.

TABLE 2 summary of the main differences and performance results of the preparation processes of examples 1-3