Soft magnetic amorphous alloy capable of reducing high-frequency loss and preparation method

Abstract

The invention belongs to the technical field of soft magnetic material preparation, and particularly relates to a soft magnetic amorphous alloy capable of reducing high-frequency loss and a preparation method. The preparation method comprises the following steps: preparing an amorphous alloy sample, preparing the amorphous alloy sample into a magnetic core, and annealing; wherein the annealing temperature Toa is more than or equal to To + 10 DEG C and less than or equal to Tx1-50 DEG C; to is the annealing temperature corresponding to the minimum coercive force of the amorphous alloy sample; tx1 is the temperature at which the first crystallization peak of the amorphous alloy sample begins to crystallize. According to the preparation method, annealing is conducted under the condition that the annealing temperature Toa is larger than or equal to To + 10 DEG C and smaller than or equal to Tx1-50 DEG C through the ordering process in the amorphous alloy relaxation process, local ordering of the amorphous alloy can be promoted through the temperature interval, a high-number-density reverse domain nucleus is generated in the magnetization process, the magnetic domain structure of the amorphous alloy is refined, and the magnetic domain structure of the amorphous alloy is improved. The residual loss caused by local eddy current due to domain wall displacement in the high-frequency magnetization process is reduced, and the high-frequency loss of the amorphous alloy is greatly reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of soft magnetic material preparation, and in particular relates to a soft magnetic amorphous alloy capable of reducing high-frequency loss and a preparation method thereof. Background Art

[0002] Due to its unique disordered atomic structure, amorphous alloys exhibit high resistivity, low coercivity and excellent soft magnetic properties, and have important applications in power electronic devices (such as transformers and inductors). However, amorphous alloys are prone to introduce residual stress during the preparation and processing process, resulting in magnetoelastic coupling effects, which significantly deteriorate the soft magnetic properties of amorphous alloys, such as increasing coercivity and increasing losses. In order to eliminate stress and optimize soft magnetic properties, the annealing process has become a core link in the post-processing of amorphous alloys. At present, most soft magnetic amorphous alloy products are mainly used in lower frequency bands (50-1000Hz), such as power frequency transformers related to power distribution. The existing annealing process usually aims to reduce the coercivity (Hc), release stress through atomic diffusion, reduce the pinning effect of magnetic domain walls, thereby reducing the coercivity and suppressing low-frequency band losses, but has limited effect on improving high-frequency band losses.

[0003] As power electronic equipment develops towards high frequency and miniaturization, high-frequency loss has become a key bottleneck restricting the application of amorphous alloys. Losses at high frequencies mainly include hysteresis loss, eddy current loss and residual loss. Eddy current loss and residual loss are dominant. Among them, eddy current loss is mainly related to the resistivity and thickness of the material, and residual loss comes from the micro-eddy currents generated by the moving domain walls. Existing methods to reduce high-frequency losses generally include reducing the thickness of the prepared soft magnetic amorphous alloy strip, or using a coating process to increase the surface resistivity to reduce eddy current loss, or reducing losses by refining the magnetic domains through laser scoring. However, these improvement methods require high equipment and process costs and are difficult to apply on a large scale. Improving the high-frequency performance of soft magnetic amorphous alloys without adding other process conditions remains a huge problem. Summary of the Invention

[0004] In order to solve the above problems, the present invention provides a soft magnetic amorphous alloy with reduced high-frequency loss and a preparation method thereof.

[0005] To this end, the present invention provides the following technical solutions.

[0006] The present invention provides a method for preparing a soft magnetic amorphous alloy with reduced high-frequency loss, comprising:

[0007] Prepare an amorphous alloy sample, make it into a magnetic core, and anneal it; wherein the annealing temperature T oa Satisfaction: T o +10℃≤T oa ≤T x1 -50℃;

[0008] To is the annealing temperature corresponding to the minimum coercivity of the amorphous alloy sample;

[0009] T x1 It is the temperature at which the first crystallization peak of the amorphous alloy sample begins to crystallize.

[0010] The amorphous alloy sample can be in the form of strips, powders, etc. When the annealing temperature T corresponding to the minimum coercive force of the amorphous alloy sample is tested, o The temperature T at which the first crystallization peak of the amorphous alloy sample begins to crystallize x1 There is no special requirement for the shape of the amorphous alloy sample. The test sample can be prepared according to the requirements of the art. For example, the amorphous alloy sample can be made into a strip, a ring or a U-shaped sample.

[0011] In the present invention, when preparing a soft magnetic amorphous alloy with reduced high-frequency loss, the annealing temperature T is adjusted. oa Satisfaction: T o +10℃≤T oa ≤T x1 At -50°C, the amorphous alloy forms a large number of locally ordered regions, significantly refining the magnetic domains and thus reducing high-frequency losses. If the annealing temperature is too high, problems such as crystallization will occur, resulting in increased high-frequency losses. If the annealing temperature is too low, high-frequency losses cannot be reduced.

[0012] As an optional embodiment, the annealing temperature T oa Satisfaction: T o +30℃≤T oa ≤T x1 -55°C. Exemplarily, the annealing temperature T oa Any value that satisfies this range, such as T oa =T x1 -80℃ and T oa ≥T o +30℃、T oa =T x1 -85℃ and T oa ≥T o +30℃、T oa =T x1 -90℃ and T oa ≥T o +30℃、T oa =T o +40℃ and T oa ≤T x1 -55℃、T oa =T o +50℃ and T oa ≤T x1 -55℃、T oa =T o +55℃ and T oa≤T x1 -55℃, etc. This annealing temperature can further reduce high-frequency loss.

[0013] As an optional embodiment, the annealing time is 30-120 min. Exemplarily, the annealing time is any value such as 30 min, 50 min, 70 min, 90 min, 100 min, and 120 min.

[0014] As an optional embodiment, the preparation method of the present invention is applicable to all existing soft magnetic amorphous alloys. Here, the soft magnetic amorphous alloy is described as an example; the soft magnetic amorphous alloy is an iron-based soft magnetic amorphous alloy;

[0015] Preferably, the iron-based soft magnetic amorphous alloy has a structural formula of Fe a B b Si c C d P e ; Among them, 77≤a≤84; 7≤b≤14; 2≤c≤14; 0≤d≤4; 0≤e≤2; Fe is iron, B is boron, Si is silicon, C is carbon, and P is phosphorus. When the value is 0, it means that the corresponding element is not contained.

[0016] Preferably, the iron-based soft magnetic amorphous alloy comprises Fe 78 Si9B 13 or Fe 80.2 B 11 C 4.0 Si 3.9 P 0.9 .

[0017] The subscripts in the structural formula represent the atomic percentage of each atom in the structural formula, and the unit is at.%. Only the atomic percentage numbers are retained in the structural formula, and the sum of the subscript numbers is 100. 78 Si9B 13 For example, Fe in Fe 78 Si9B 13 The atomic percentage is 78%, and only the number 78 is retained in the structural formula.

[0018] As an optional embodiment, the T o The test method includes the use of a DC magnetic property measurement method. Specifically, the coercivity of the soft magnetic amorphous alloy is tested at different annealing temperatures, and based on the annealing temperature-coercivity curve, the annealing temperature corresponding to the minimum coercivity is determined, that is, the annealing temperature T corresponding to the minimum coercivity of the amorphous alloy sample is determined. o When testing the coercivity, the test was performed according to the procedures known in the art.

[0019] As an optional embodiment, the T x1 . Test and obtain the T according to the known operating steps in this field x1 .

[0020] As an optional embodiment, the high frequency has a frequency of 1-500 kHz. Exemplarily, the high frequency has a frequency of 1 kHz, 10 kHz, 40 kHz, 80 kHz, 100 kHz, 150 kHz, 200 kHz, 250 kHz, 300 kHz, 350 kHz, 400 kHz, 450 kHz, 500 kHz, etc.

[0021] The present invention provides a soft magnetic amorphous alloy prepared by the above preparation method.

[0022] As an optional embodiment, the structural ordering parameter θ of the soft magnetic amorphous alloy is ≥4%; and θ satisfies the following relationship:

[0023]

[0024] The half-height width is obtained by X-ray diffraction testing.

[0025] Among them, the quenched sample refers to the sample that has not been heat treated; the annealed sample refers to the soft magnetic amorphous alloy obtained after annealing at a given temperature; the diffraction peak is the broad and flat peak that appears in the X-ray diffraction pattern of the soft magnetic amorphous alloy.

[0026] The structural ordering parameter θ of the soft magnetic amorphous alloy of the present invention is ≥4%, indicating that the alloy has a large number of locally ordered regions, which can refine the magnetic domain and reduce high-frequency loss.

[0027] The preparation method of the soft magnetic amorphous alloy provided by the present invention comprises: preparing the soft magnetic amorphous alloy according to the composition of the alloy, smelting 3-5 times, spinning the strip to obtain an amorphous alloy strip, making a magnetic core, and annealing. During the annealing, it is only necessary to control the annealing temperature T oa Satisfaction: T o +10℃≤T oa ≤T x1 -50℃, there is no special requirement for the annealing temperature rise and fall procedure, for example, the core can be placed directly at a temperature that meets T oa The annealing furnace required can be used for annealing directly, or the temperature can be raised to T by furnace heating or step heating. oa The preparation method of the present invention can make the structure order parameter θ≥4%, the magnetic domain of the prepared amorphous alloy is small, and the high-frequency loss is significantly reduced.

[0028] The technical solution of the present invention has the following advantages:

[0029] 1. The present invention provides a method for preparing a soft magnetic amorphous alloy with reduced high-frequency loss, which comprises preparing an amorphous alloy sample, making it into a magnetic core, and annealing it; wherein the annealing temperature T oa Satisfaction: T o +10℃≤T oa ≤T x1 -50℃; T o is the annealing temperature corresponding to the minimum coercivity of the amorphous alloy sample; T x1 The preparation method utilizes the ordering process during the relaxation of amorphous alloys to obtain the first crystallization peak of the amorphous alloy sample at the annealing temperature T oa Satisfaction: T o +10℃≤T oa ≤T x1 Annealing is performed at -50°C. This temperature range can promote the local ordering of amorphous alloys, generate high-density reverse domain nuclei during the magnetization process, refine the magnetic domain structure of the amorphous alloy, reduce the residual loss caused by local eddy currents caused by domain wall displacement during high-frequency magnetization, and significantly reduce the high-frequency loss of amorphous alloys. oa Satisfaction: T o +10℃≤T oa ≤T x1 The annealing temperature is -50°C, which is higher than the annealing temperature for minimum coercivity and lower than the crystallization temperature. Significant structural ordering occurs before crystallization, forming a large number of locally ordered regions. This can significantly refine the magnetic domains, thereby reducing high-frequency losses, optimizing device performance, and simplifying the process. When the annealing temperature is too high or too low, high-frequency losses will increase significantly.

[0030] The conventional thinking in the prior art is to reduce coercive force and increase resistance to achieve reduced high-frequency losses. However, high-frequency losses include hysteresis loss, eddy current loss, and residual loss. These three losses increase with increasing frequency, but the rate of increase of eddy current loss and residual loss is higher than that of hysteresis loss. The inventors have found that annealing at a specific annealing temperature can increase the local order of soft magnetic amorphous alloys, and refining the magnetic domains can reduce eddy current loss and residual loss, especially significantly reducing residual loss, thereby significantly reducing high-frequency losses. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1This invention is T o and T x1 Schematic diagram of how to obtain ;

[0033] Figure 2 Schematic diagram of a method for obtaining the half-height width of the amorphous diffraction peak of the quenched sample and the annealed sample in Example 1 of the present invention;

[0034] Figure 3 3 is a comparison diagram of magnetic domains of Example 1 of the present invention and Comparative Example 1. DETAILED DESCRIPTION

[0035] The following examples are provided for a better understanding of the present invention and are not intended to limit the best mode of implementation. They do not limit the content and scope of protection of the present invention. Any product identical or similar to the present invention obtained by anyone under the guidance of the present invention or by combining the features of the present invention with other prior arts shall fall within the scope of protection of the present invention.

[0036] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in this field can be used. If the manufacturer of the reagents or instruments is not specified, they are all commercially available conventional reagents.

[0037] Example 1

[0038] This embodiment provides a soft magnetic amorphous alloy (Fe 78 Si9B 13 ) comprising the following steps:

[0039] (1) The ingredients were prepared according to the composition of the soft magnetic amorphous alloy and repeatedly smelted three times in a vacuum induction melting furnace to make a master alloy ingot; then the ingot was placed in an induction furnace for melting, and the strip was prepared by a copper wheel single roller stripping method. The alloy thin strip sample was prepared by rapid cooling and solidification using a copper roller, with a thickness of about 23 μm.

[0040] (2) Take some alloy thin strip samples and heat them at a heating rate of 5°C / min using a differential scanning calorimeter (DSC) until they are completely crystallized. Determine the crystallization temperature T at which the first crystallization peak of the sample begins. x1 The coercivity of the samples at different annealing temperatures was tested and the coercivity-annealing temperature curve was obtained. The annealing temperature T corresponding to the lowest coercivity was o is 380℃. x1 and T o See the test diagram for Figure 1 The temperature range for optimizing high-frequency performance is 390℃-452℃.

[0041] (3) The thin strip sample obtained in step (1) is wound into a ring-shaped magnetic core (inner diameter 20 mm, outer diameter 31.5 mm), and a constant tension of about 0.5 N is applied (the purpose of applying tension is to ensure the uniformity of the ring). After the annealing furnace reaches the set value of 440°C, the ring-shaped magnetic core is placed in the annealing furnace and annealed in a vacuum atmosphere for 90 minutes. After the annealing is completed, the annealing is cooled to 200°C in the furnace and then air-cooled to obtain a soft magnetic amorphous alloy core.

[0042] (4) A soft magnetic AC test device was used to test the core loss at different frequencies and working magnetic induction intensities. The test conditions and core loss are shown in Table 1.

[0043] Example 2

[0044] This embodiment provides a soft magnetic amorphous alloy (Fe 78 Si9B 13 The preparation method of the present invention is basically the same as that of Example 1, except that the annealing temperature in step (3) is 420° C. The test parameters and core loss are shown in Table 1.

[0045] Example 3

[0046] This embodiment provides a soft magnetic amorphous alloy (Fe 80.2 B 11 C 4.0 Si 3.9 P 0.9 ) comprising the following steps:

[0047] (1) The ingredients were prepared according to the composition of the soft magnetic amorphous alloy and repeatedly smelted three times in a vacuum induction melting furnace to make a master alloy ingot; then the ingot was placed in an induction furnace for melting, and the strip was prepared by a copper wheel single roller stripping method. The alloy thin strip sample was prepared by rapid cooling and solidification using a copper roller, with a thickness of about 23 μm.

[0048] (2) Take some alloy thin strip samples and heat them at a heating rate of 5°C / min using a differential scanning calorimeter (DSC) until they are completely crystallized. Determine the crystallization temperature T at which the first crystallization peak of the sample begins. x1 The coercivity of the samples at different annealing temperatures was tested. The annealing temperature T corresponding to the lowest coercivity was o The temperature range for achieving optimal high-frequency performance is 310°C-382°C.

[0049] (3) The amorphous strip obtained in step (1) is wound into a toroidal magnetic core (inner diameter 20 mm, outer diameter 29.5 mm), and a constant tension of about 0.5 N is applied. After the annealing furnace reaches the set value of 375°C, the toroidal magnetic core is placed in the annealing furnace for transverse magnetic annealing. The annealing time is 60 minutes, and then water quenching is performed to obtain a soft magnetic amorphous alloy core.

[0050] (4) A soft magnetic AC test device was used to test the core loss at different frequencies and working magnetic induction intensities. The test parameters and core loss are shown in Table 1.

[0051] Example 4

[0052] This embodiment provides a soft magnetic amorphous alloy (Fe 80.2 B 11 C 4.0 Si 3.9 P 0.9 The preparation method of the ferrite core is substantially the same as that of Example 3, except that the annealing temperature in step (3) is 360° C. The test parameters and core loss are shown in Table 1.

[0053] Comparative Example 1

[0054] This comparative example provides a soft magnetic amorphous alloy (Fe 78 Si9B 13 ) is prepared in the same manner as in Example 1, except that o Annealing is performed at 380°C, that is, the annealing temperature in step (3) is 380°C.

[0055] Comparative Example 2

[0056] This comparative example provides a soft magnetic amorphous alloy (Fe 78 Si9B 13 ) is basically the same as that in Example 1, except that the annealing temperature in step (3) is 460°C.

[0057] Comparative Example 3

[0058] This comparative example provides a soft magnetic amorphous alloy (Fe 80.2 B 11 C 4.0 Si 3.9 P 0.9 ) is prepared in the same manner as in Example 3, except that o Annealing is performed at 300°C, that is, the annealing temperature in step (3) is 300°C.

[0059] Test Case

[0060] This test example provides performance tests of various embodiments and comparative examples, as follows:

[0061] Structural ordering parameter θ: The structure of the soft magnetic amorphous alloy is characterized by an X-ray diffractometer. The percentage decrease in the half height of the amorphous diffraction peak relative to the quenched sample is calculated according to the following formula:

[0062]

[0063] Among them, the quenched sample refers to the strip prepared after spinning, and the quenched sample is not heat treated; the annealed sample refers to the soft magnetic amorphous alloy obtained by using the embodiment or comparative annealing method; the diffraction peak is the broad and flat peak that appears in the X-ray diffraction pattern of the soft magnetic amorphous alloy. Figure 2 It is the half-height width of the diffraction peak of the quenched sample of the soft magnetic amorphous alloy in Example 1 (the strip obtained in step 1) and the annealed sample.

[0064] A soft magnetic AC test device is used to test the core loss at different frequencies and different maximum magnetic induction intensities. Among them, Ps@(1T,5kHz): core loss at a maximum magnetic induction intensity of 1T and a frequency of 5kHz; Ps@(1T,10kHz): core loss at a maximum magnetic induction intensity of 1T and a frequency of 10kHz; Ps@(0.2T,100kHz): core loss at a maximum magnetic induction intensity of 0.2T and a frequency of 100kHz.

[0065] The test results are shown in Table 1.

[0066] Table 1 Test results of various embodiments and comparative examples

[0067]

[0068] Note: “ / ” indicates exceeding the test range of the device.

[0069] From the above results, the annealing temperature T oa Satisfaction: T o +10℃≤T oa ≤T x1 -50℃, which helps to reduce high-frequency loss. The soft magnetic amorphous alloy obtained by the annealing method of the present invention has a higher degree of order, which is beneficial to reduce the high-frequency loss of 1-500kH. When the annealing temperature is lower than T o At +10°C, the high-frequency loss reduction effect is poor. When the annealing temperature is too high, the soft magnetic amorphous alloy undergoes significant crystallization, the coercivity increases sharply, and the hysteresis loss increases significantly, resulting in increased loss. In severe cases, it will exceed the detection limit and the loss cannot be measured.

[0070] Figure 3 This is a comparison of the magnetic domains of the soft magnetic amorphous alloys prepared in Example 1 and Comparative Example 1, obtained using magneto-optical Kerr microscopy. As can be seen from the figure, the soft magnetic amorphous alloy obtained by the annealing method of the present invention significantly refines the magnetic domain structure, which helps reduce residual losses.

[0071] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A method for preparing a soft magnetic amorphous alloy with reduced high-frequency loss, characterized in that: include: Prepare an amorphous alloy sample, make it into a magnetic core, and anneal it; wherein the annealing temperature T oa Satisfaction: T o +10℃≤T oa ≤T x1 -50℃; T o is the annealing temperature corresponding to the minimum coercivity of the amorphous alloy sample; T x1 It is the temperature at which the first crystallization peak of the amorphous alloy sample begins to crystallize.

2. The preparation method according to claim 1, characterized in that The annealing temperature T oa Satisfaction: T o +30℃≤T oa ≤T x1 -55℃.

3. The preparation method according to claim 1, characterized in that The annealing time is 30-120 min.

4. The preparation method according to any one of claims 1 to 3, characterized in that The soft magnetic amorphous alloy is an iron-based soft magnetic amorphous alloy; Preferably, the iron-based soft magnetic amorphous alloy has a structural formula of Fe a B b Si c C d P e ; Among them, 77≤a≤84; 7≤b≤14; 2≤c≤14; 0≤d≤4; 0≤e≤2; Preferably, the iron-based soft magnetic amorphous alloy comprises Fe 78 Si9B 13 or Fe 80.2 B 11 C 4.0 Si 3.9 P 0.9 .

5. The preparation method according to any one of claims 1 to 4, characterized in that The T o The test method includes the use of DC magnetic performance measurement method.

6. The preparation method according to any one of claims 1 to 5, characterized in that The T was tested by differential scanning calorimetry. x1 .

7. The preparation method according to any one of claims 1 to 6, characterized in that The frequency of the high frequency is 1-500 kHz.

8. The soft magnetic amorphous alloy prepared by the preparation method according to any one of claims 1 to 7.

9. The soft magnetic amorphous alloy according to claim 8, characterized in that: The structural ordering parameter θ of the soft magnetic amorphous alloy is ≥4%; θ satisfies the following relationship: The half-height width is obtained by X-ray diffraction testing.

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