Preparation method of nitrogen-containing iron-based soft magnetic amorphous / nanocrystalline alloy and application thereof

Abstract

The application belongs to the technical field of alloy smelting and amorphous alloy, and particularly relates to a preparation method of nitrogen-containing iron-based soft magnetic amorphous / nanocrystalline alloy and application thereof. a Si b B c C d N e The application adopts a new preparation idea to obtain secondary raw materials with stable nitrogen content by chemical nitriding treatment of high-purity iron metal, smelts the secondary raw materials into nitrogen-containing alloy ingots by proportioning with amorphous forming elements, and then obtains completely amorphous Fe a Si b B c C d N e iron-based soft magnetic amorphous alloy by rapid quenching technology. Finally, the nitrogen-containing iron-based soft magnetic amorphous alloy with completely amorphous state is heat treated to be crystallized into amorphous / nanocrystalline alloy. The application omits the subsequent nitriding step in the preparation process of amorphous alloy, and to some extent, overcomes the problems of difficult nitrogen doping of the previous iron-based amorphous alloy and nitrogen existing only on the surface of the strip, and has the advantages of simplicity, high efficiency, low cost and the like, thereby providing a new reference and guidance for the nitrogen doping approach of amorphous alloy.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of alloy smelting and amorphous alloy, and particularly relates to a preparation method of nitrogen-containing iron-based soft magnetic amorphous / nanocrystalline alloy and application thereof. BACKGROUND

[0002] Amorphous alloy, also known as metallic glass, is a kind of solid alloy with atom disorder arrangement formed under the condition of rapid cooling, and the atoms in the alloy cannot form ordered structure by diffusion. Compared with crystalline alloy, the spatial arrangement of atoms in amorphous alloy has the characteristics of long-range disorder and short-range order. Due to this unique disordered structure, amorphous alloy has no defects such as dislocation and grain boundary which are common in traditional alloy structure. Macroscopically, the structure of amorphous alloy is uniform, showing isotropic properties. From the perspective of thermodynamics, amorphous alloy is metastable, and its free energy is higher than that of crystalline alloy. This also makes amorphous alloy have unique physical properties, such as exciting magnetic performance.

[0003] In recent years, it is a common method to regulate the magnetic properties of Fe-based amorphous alloy by doping trace elements. Among them, the doping of metal elements is easier to operate than that of non-metal elements. The soft magnetic properties mainly refer to the optimization of saturation magnetic induction (Bs) and coercivity (Hc). For the Bs of Fe-based amorphous alloy, the Bs is positively correlated with the mass fraction of iron within a certain range. Therefore, the Bs of Fe-based amorphous alloy generally decreases after doping metal elements, resulting in the decrease of soft magnetic properties. Although Co element can effectively improve the Bs of Fe-based amorphous alloy, the high price of Co element limits the large-scale commercial application of such alloys. Non-metal elements are another key factor for Fe-based amorphous alloy to maintain high saturation magnetic induction. The addition of non-metal elements can keep the mass fraction of iron at a high level, so as to make the alloy have a high Bs value. The existing research on non-metal element doping mainly focuses on the addition and replacement of Si, B, P and C elements. In addition to Si and B elements as essential elements of Fe-based amorphous alloy, the influence of P and C elements on the soft magnetic properties of Fe-based amorphous alloy has also been widely studied. However, the influence of N element doping on the soft magnetic properties of Fe-based amorphous alloy is less studied. One of the main reasons is that N element cannot be effectively doped in the alloy ingot. For example, Chinese invention patent CN 109440058 A discloses a nitrogen-containing Fe-based amorphous nanocrystalline soft magnetic alloy and a preparation method thereof. The plasma nitriding method is used to carry out low-temperature low-pressure or low-temperature normal-pressure nitriding on the Fe-based amorphous alloy, and the nitriding temperature is required to be 100-400℃, and the nitriding time is 10-60min. However, plasma nitriding is a surface treatment process. By using this method to directly nitride the surface of the Fe-based amorphous alloy, the distribution of nitrogen is mainly concentrated on the surface of the alloy, and the distribution is uneven. Patent CN 109440023 B also discloses a high magnetic coupling Fe-based amorphous nanocrystalline alloy and a preparation method thereof. The method uses nitride as a raw material for alloying to prepare a nitrogen-containing Fe-based amorphous nanocrystalline alloy. However, the melting point of nitride is high, and the density is low. In the process of arc melting, after other raw materials are melted, the nitride is easily suspended on the surface of the molten liquid due to its low density, so that the nitrogen element that really melts into the alloy ingot cannot be effectively controlled.

[0004] For amorphous alloy, negative mixing enthalpy is beneficial to improve the amorphous forming ability. Since the mixing enthalpy of N element with other metal elements is negative and the value is low, only a small amount of N element needs to be added to change the amorphous forming ability of Fe-based amorphous alloy. However, the existing nitriding methods all have their own defects and cannot effectively control the stable doping of N element. Among them, the nitrogen in the nitriding treatment of finished amorphous strip exists only on the surface of the strip, and the nitriding method using nitride for smelting is not ideal due to the low density and high melting point of nitride. Therefore, further research is needed in the field of smelting to prepare amorphous alloy containing nitrogen element.

[0005] In summary, it is necessary to develop a new nitrogen doping method to change various nitrogenation defects caused by traditional nitrogenation methods, such as improving the uncontrollable content of nitrogen elements. SUMMARY

[0006] In order to overcome the shortcomings of the prior art, the present application provides a preparation method of nitrogen-containing iron-based soft magnetic amorphous / nanocrystalline alloy, which uses a pre-prepared nitrogen-containing raw material to prepare a nitrogen-containing iron-based soft magnetic amorphous alloy, overcoming the problem of difficulty in nitrogen doping of iron-based amorphous alloy and nitrogen existing only on the surface of the strip, providing a new doping idea for nitrogen doping of iron-based amorphous alloy and greatly expanding the way of doping non-metallic elements in iron-based amorphous alloy.

[0007] In order to achieve the above purpose, the technical scheme adopted by the present application is:

[0008] The present application provides a preparation method of nitrogen-containing iron-based soft magnetic amorphous / nanocrystalline alloy, the general formula of the nitrogen-containing iron-based soft magnetic amorphous alloy is: a Si b B c C d N e The atomic ratio of each component in the general formula is: a = 75%-85%, b = 0%-10%, c = 5%-15%, d = 0-2%, e = 0.05-0.5%; wherein a+b+c+d+e = 100%;

[0009] The preparation method of the nitrogen-containing iron-based soft magnetic amorphous / nanocrystalline alloy comprises the following steps:

[0010] S1, high-purity iron metal is subjected to plasma nitriding treatment to obtain a nitrogen-containing iron sheet as a secondary raw material, and then the secondary raw material is alloyed with amorphous forming elements selected from at least one of B, Si and C to smelt an alloy ingot according to the chemical formula of the alloy;

[0011] S2, crushing the alloy ingot of step S1 and using a strip casting device to perform strip casting to prepare an amorphous alloy strip by using rapid quenching technology;

[0012] S3, under vacuum or protective atmosphere, the amorphous alloy strip of step S2 is subjected to heat treatment to obtain a nitrogen-containing iron-based amorphous nanocrystalline soft magnetic alloy.

[0013] The plasma nitriding method is adopted in the application, in the process, nitrogen ions obtain electrons on the surface of the metal material, are reduced into nitrogen atoms and penetrate into the surface of the steel part and gradually diffuse inward to form a nitriding layer, i.e. nitriding treatment. Meanwhile, in the process of ion bombardment, sputtering occurs on the surface to obtain cleaning, the oxide layer and oxidation products covering the surface of the material can be automatically removed, and the nitrogen element exists in the material in the form of atoms. After the treatment, the nitrogen element exists in the raw material in the form of nitrogen atoms. The method for preparing the nitrogen-containing iron-based soft magnetic amorphous alloy from the pre-prepared nitrogen-containing raw material can overcome the problems of difficult nitrogen doping of the iron-based amorphous alloy and nitrogen existing only on the surface of the strip, provide a new doping idea for nitrogen doping of the iron-based amorphous / nanocrystalline alloy and greatly expand the way of doping non-metallic elements of the iron-based amorphous / nanocrystalline alloy.

[0014] Preferably, the high-purity iron metal is in the form of high-purity iron flakes or high-purity iron powder, and the purity is above 99.9%.

[0015] Preferably, the smelting is vacuum arc smelting or induction smelting, and inert gas or nitrogen gas is filled as a protective gas in the smelting process.

[0016] Preferably, the spinning equipment is a single-roller rapid-cooling spinning machine, and the linear speed of the spinning copper roller is 45-60 m / s.

[0017] Preferably, the heat treatment is a stress relief annealing treatment, and the annealing temperature is selected according to the DSC thermal analysis result. The stress relief annealing is generally selected between 100℃ below the first crystallization temperature (i.e. the temperature at which alpha-Fe starts to precipitate) and the first crystallization temperature, and the time is 10 min-1 h. The stress relief annealing refers to the annealing before the temperature at which alpha-Fe nanoparticles are precipitated, and the alloy after the annealing treatment is still in an amorphous structure.

[0018] More preferably, the annealing temperature is 300-510℃, and the time is 10 min-1 h.

[0019] Preferably, B is derived from boron or boron iron.

[0020] The application further provides a nitrogen-containing iron-based soft magnetic amorphous / nanocrystalline alloy prepared by the preparation method.

[0021] The nitrogen-containing iron-based soft magnetic amorphous / nanocrystalline alloy prepared by the method has not only a relatively high Bs, but also a proper amount of doped nitrogen element, which can further reduce the coercivity of the amorphous alloy, and has an excellent industrial application prospect.

[0022] Compared with the prior art, the application has the following beneficial effects:

[0023] The application discloses a preparation method of nitrogen-containing iron-based soft magnetic amorphous / nanocrystalline alloy. a Si b B c C d N e The atom proportion of each component in the amorphous alloy is as follows: a=75% to 85%, b=0% to 10%, c=5% to 15%, d=0 to 2%, and e=0.05% to 0.5%, and a+b+c+d+e=100%. Finally, the obtained iron-based soft magnetic amorphous alloy containing nitrogen elements in a complete amorphous state is subjected to heat treatment to be crystallized into an amorphous / nanocrystalline alloy. The nitrogen-containing iron-based soft magnetic amorphous alloy is prepared by using a pre-prepared nitrogen-containing raw material. The appropriate N content can not only improve the amorphous forming ability of the iron-based amorphous / nanocrystalline alloy, but also has a certain influence on the coercivity of the amorphous alloy, and can effectively reduce the coercivity of the amorphous alloy. Meanwhile, the subsequent nitriding step is omitted in the preparation process of the amorphous alloy, which to some extent overcomes the problems of difficulty in doping nitrogen in the iron-based amorphous alloy and nitrogen existing only on the surface of the strip in the past, and has the advantages of simplicity, high efficiency and low cost, thereby providing a new reference and guidance for the nitrogen doping approach of the amorphous alloy. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 XRD pattern of the surface of the thin iron sheet after the nitriding chemical surface treatment;

[0025] Figure 2 X-ray diffraction pattern of the quenched iron-based amorphous strip;

[0026] Figure 3 X-ray diffraction patterns of example 1 (a), example 2 (b) and comparative example 1 (c) after annealing;

[0027] Figure 4 Hysteresis curve of the quenched iron-based amorphous alloy;

[0028] Figure 5 Curve of the change of the coercivity of the iron-based amorphous / nanocrystalline alloy with the heat treatment temperature. DETAILED DESCRIPTION

[0029] The specific embodiments of the application are further described below. It should be noted that the description of the embodiments is used to help understand the application, but does not constitute a limitation on the application. In addition, the technical features involved in each embodiment of the application described below can be combined with each other as long as there is no conflict.

[0030] The experimental methods in the following examples are all conventional methods, and the experimental materials used in the following examples are all commercially available unless otherwise specified.

[0031] The present application provides a nitrogen-containing iron-based amorphous / nanocrystalline soft magnetic alloy, which has a general formula of Fe a Si b B c C d N e , wherein the atomic proportions of the components in the general formula are: a = 75% to 85%, b = 0% to 10%, c = 5% to 15%, d = 0 to 2%, and e = 0.05 to 0.5%; and wherein a + b + c + d + e = 100%.

[0032] The preparation method of the nitrogen-containing iron-based amorphous alloy comprises the following steps:

[0033] (1) Nitriding high-purity metallic iron (in the form of thin sheets, powders, etc.) to obtain nitrogen-containing secondary raw materials. Then, the nitrogen-containing secondary raw materials are melted with amorphous-forming elements (B, Si, C) to obtain alloy ingots; the B source includes boron or boron iron, and the C source is graphite.

[0034] (2) Breaking the alloy ingots obtained by melting and using a single-roll tape caster to prepare amorphous alloy tapes.

[0035] (3) Under vacuum or in a protective atmosphere, the amorphous tapes obtained are subjected to heat treatment to obtain nitrogen-containing iron-based amorphous / nanocrystalline soft magnetic alloys.

[0036] All raw materials of the present application do not have special requirements and restrictions on their sources, and can be purchased on the market or prepared according to conventional methods familiar to those skilled in the art of melting.

[0037] All pure metal raw materials of the present application use conventional purity in the field, and the purity is more than 99.9%.

[0038] The preparation of the nitrogen-containing secondary raw materials required by the present application does not have special requirements for nitriding technology, and the actual nitriding time and other requirements are prepared according to the actual nitrogen content.

[0039] The present application does not have special restrictions on the melting conditions, and the melting conditions familiar to those skilled in the art can be used, and those skilled in the art can adjust them according to the actual production conditions, product requirements and quality requirements.

[0040] The way of the spinning is not particularly limited in the present application, and a spinning way for preparing amorphous alloy known to those skilled in the art can be adopted. Those skilled in the art can select and adjust according to actual production conditions, product requirements and quality requirements. The spinning is preferably single-roll rapid cooling spinning in the present application. The spinning equipment is preferably a single-roll rapid cooling spinning machine.

[0041] The amorphous alloy ribbon obtained in the above step is subjected to heat treatment under vacuum or a protective atmosphere, and then iron-based amorphous nanocrystalline soft magnetic alloy is obtained.

[0042] The concept of the heat treatment is not particularly limited in the present application, and a heat treatment for amorphous alloy known to those skilled in the art can be adopted. Those skilled in the art can select and adjust according to actual production conditions, product requirements and quality requirements. The heat treatment is preferably stress relief annealing in the present application.

[0043] The temperature of the heat treatment is not particularly limited in the present application, and a heat treatment temperature for amorphous alloy known to those skilled in the art can be adopted. Those skilled in the art can select and adjust according to actual production conditions, product requirements and quality requirements. The temperature range of the heat treatment is preferably 300-510°C in the present application.

[0044] In order to further clearly present the nitrogen-containing iron-based amorphous / nanocrystalline alloy and the preparation method thereof of the present application, detailed descriptions are given in the form of examples and comparative examples as follows.

[0045] Example 1: Preparation of Fe 82.45 Si2B 15 C 0.5 N 0.05 Amorphous alloy ribbon

[0046] (1) Preparation of nitrogen-containing secondary raw material (nitrogen-containing iron sheet): high-purity thin iron sheet (>99.9wt%) is cut into a square sheet of 100mm×100mm, and then the front and back surfaces of the iron sheet are subjected to plasma nitriding treatment to obtain a nitrogen-containing iron sheet as a secondary raw material. The plasma nitriding treatment is as follows: first, the prepared iron sheet is placed in a nitriding furnace, cooling water is passed, a vacuum pump is turned on to vacuumize, and the gas pressure in the furnace body is lower than 5Pa. Then, 99.99% high-purity ammonia gas is introduced into the furnace body, the rectifier output voltage is adjusted, the glow is started, and the temperature is raised to 200°C. At the same time, the flowmeter and vacuum valve are adjusted so that the flow rate of ammonia gas is 0.4m 3 / h, and the gas pressure is maintained at about 500Pa at 200°C for 0.5h. Then, the same nitriding operation is performed on the other surface of the pure iron sheet. The nitrogen content of the prepared nitrogen-containing iron sheet is determined by an oxygen-nitrogen analyzer, and the nitrogen content is 0.34wt%. Figure 1The XRD result of the surface of the obtained secondary raw material of the nitrogen-containing iron sheet shows that it mainly exists in the form of FexN (x=2 or 3).

[0047] (2) According to the alloy chemical formula Fe 82.45 Si2B 15 C 0.5 N 0.05 The weighed ingredients are put into a vacuum arc melting furnace, the furnace body is vacuumed to 5*10 -3 -2 Pa, then argon or nitrogen is filled as a protective gas, when the gas pressure in the furnace is lower than 0.01 Mpa of the atmospheric pressure, the gas filling valve is closed. At the same time, the temperature of the electric arc melting is reached to 3000℃ or above 3000℃, the raw materials are heated and melted, after the raw materials are completely melted, the melting is continuously carried out for 2 minutes, then it is cooled to solidification, after being quickly turned over, the melting is repeated for 3 times, and the alloy ingot with uniform composition is obtained.

[0048] (3) The alloy ingot obtained by melting is crushed into small alloy pieces, after being cleaned, it is put into a quartz tube with an open lower end, then it is placed in an induction coil of a tape casting device (single roller rapid cooling tape casting machine), after being vacuumed, high-purity argon with a purity of 99.99% is filled as a protective gas, the current is adjusted to melt the alloy, and then the alloy in a molten state is sprayed to the surface of a copper roller with a rotating speed of 55 m / s and a cooling system by using a gas pressure difference, the cooling rate reaches 10 5 -10 6 K / s, and the amorphous tape thin strip with a width of about 1 mm and a thickness of about 21 μm is prepared. The structure of the alloy tape is detected by an X-ray diffractometer, and the X-ray diffraction analysis result of the obtained amorphous thin strip is shown in Figure 2 . As shown in Figure 2 , the completely amorphous strip has a widened diffraction peak at about 45°, and no obvious sharp crystallization peak is found in other ranges, which indicates that the quenched structure of the sample obtained in Example 2 is amorphous.

[0049] (4) The prepared amorphous alloy tape sample is tested by an oxygen-nitrogen analyzer, and the result shows that the nitrogen content of the tape is 0.0175 wt%, and the theoretical nitrogen content is 0.0145 wt%.

[0050] (5) The amorphous alloy thin strip is put into a heat treatment furnace for annealing treatment, argon is filled for protection during the heat treatment process, the furnace is heated to 300℃, and is kept for 30 min, then is heated to 350℃, 380℃, 410℃ and 430℃ respectively, and is kept for 10 min, wherein the heating rate of the furnace is 5℃ / min, then the furnace is cooled to room temperature, and the thin strip is taken out, and the iron-based amorphous nanocrystalline alloy is obtained. The XRD result corresponding to each temperature after treatment is shown in Figure 3(a) It can be seen that obvious crystallization peaks appear after 410℃, which indicates that nanocrystals gradually precipitate to form amorphous / nanocrystalline dual-phase structure above 410℃.

[0051] The saturation magnetic induction (Bs) and coercivity (Hc) of the annealed thin strips were tested by magnetic detection equipment (vibrating sample magnetometer VSM and soft magnetic DC tester).

[0052] Figure 4 Fig. 2 is a hysteresis loop diagram of the Fe-based amorphous alloy, Figure 5 Fig. 3 is a curve of the coercivity of the Fe-based amorphous nanocrystalline alloy changing with the heat treatment temperature. It can be seen that the prepared Fe 82.45 Si2B 15 C 0.5 N 0.05 The Bs value of the amorphous state is 1.71T, and the Hc value is 7.9A / m. At the same time, with the increase of the heat treatment temperature, the coercivity reaches the minimum of 2.1A / m at 380℃.

[0053] Example 2: Preparation of Fe 82.4 Si2B 15 C 0.5 N 0.1 amorphous alloy strip

[0054] (1) Preparation of nitrogen-containing secondary raw material (nitrogen-containing iron sheet): high-purity thin iron sheet (>99.9wt%) is cut into 100mm×100mm square sheet, and then the front and back surfaces of the iron sheet are subjected to plasma nitriding treatment (the specific treatment is the same as that of Example 1) to obtain a nitrogen-containing iron sheet as a secondary raw material. The nitrogen content of the prepared nitrogen-containing iron sheet is determined by an oxygen-nitrogen analyzer, and the nitrogen content is 0.34wt%. Figure 1 The XRD results of the surface of the obtained nitrogen-containing iron sheet as a secondary raw material can be carded to show that it mainly exists in the form of FexN (x=2 or 3).

[0055] (2) According to the chemical formula Fe 82.4 Si2B 15 C 0.5 N 0.1 The weighed ingredients (nitrogen-containing iron sheet, Si, Fe-B alloy, C) are put into a vacuum arc melting furnace, the furnace body is vacuumed to 5×10 -3 After that, argon or nitrogen is filled as a protective gas, and when the gas pressure in the furnace is lower than 0.01Mpa of atmospheric pressure, the gas filling valve is closed. At the same time, the temperature of the electric arc melting is raised to 3000℃ or above 3000℃, the raw materials are heated and melted, and after the raw materials are completely melted, the melting is continued for 3 minutes, and then it is cooled to solidification. After quickly turning it over, the melting is repeated for 3 times to obtain an alloy ingot with uniform composition.

[0056] (3) The alloy ingot obtained by smelting is broken into small pieces of alloy, which are cleaned and then loaded into a quartz tube with an open lower end, and then placed in an induction coil of a spinning belt device (single-roll rapid-cooling spinning belt machine). After vacuumizing, high-purity argon gas with a purity of 99.99% is filled as a protective gas. The current is adjusted to melt the alloy. The alloy in a molten state is sprayed onto the surface of a copper roller with a rotating speed of 55 m / s and a cooling system by using a gas pressure difference. The cooling rate is 105-106 K / s. An amorphous ribbon with a width of about 1 mm and a thickness of about 14 μm is prepared. The structure of the alloy ribbon is detected by an X-ray diffractometer. The X-ray diffraction analysis result of the obtained amorphous ribbon is shown in Figure 2 (b) from which it can be seen that the amorphous ribbon has a broadened diffraction peak at about 45°, and no obvious sharp crystallization peak in other ranges, indicating that the quenched structure of the sample obtained in Example 3 is amorphous. Figure 2

[0057] (4) The prepared amorphous alloy ribbon is tested by an oxygen-nitrogen analyzer. The result shows that the nitrogen content of the ribbon is 0.0256 wt%, and the theoretical nitrogen content is 0.029 wt%.

[0058] (5) The amorphous alloy ribbon is placed in a heat treatment furnace for annealing treatment. Argon gas is filled for protection during the heat treatment process. The furnace is heated to 300 °C, and held for 30 min. Then, the furnace is heated to 350 °C, 380 °C, 410 °C and 430 °C, respectively, and held for 10 min. The heating rate of the furnace is 5 °C / min. Then, the furnace is cooled to room temperature. The ribbon is taken out, and an iron-based amorphous nanocrystalline alloy is obtained. The XRD results corresponding to each temperature treatment are shown in Figure 3 (b) from which it can be seen that the amorphous ribbon has a broadened diffraction peak at about 45°, and no obvious sharp crystallization peak in other ranges, indicating that the quenched structure of the sample obtained in Example 3 is amorphous.

[0059] The saturation magnetic induction (Bs) and coercivity (Hc) performance of the ribbon after annealing are tested by a magnetic detection device (vibrating sample magnetometer VSM and soft magnetic DC tester).

[0060] Figure 4 is the hysteresis loop diagram of the iron-based amorphous alloy, Figure 5 is the curve of the coercivity of the iron-based amorphous nanocrystalline alloy changing with the heat treatment temperature. It can be seen that the prepared Fe 82.4 Si2B 15 C 0.5 N 0.1 The Bs value of the amorphous state is 1.70 T, and the Hc value is 11.7 A / m. At the same time, with the increase of the heat treatment temperature, the coercivity reaches the minimum of 2.7 A / m at 380 °C.

[0061] Comparative Example 1: Fe 82.5 Si2B​15 C 0.5 Amorphous alloy ribbon

[0062] (1) According to the alloy formula Fe 82.5 Si2B 15 C 0.5 The weighed ingredients are put into a vacuum arc melting furnace, the furnace is vacuumed to 5*10 -3 After that, argon or nitrogen is filled as a protective gas, when the gas pressure in the furnace is lower than 0.01 Mpa of atmospheric pressure, the gas filling valve is closed. At the same time, the temperature of the arc melting is reached to 3000℃ or above 3000℃, the raw materials are heated and melted, after the raw materials are completely melted, the melting is continued for 3 minutes, then it is cooled to solidification, and it is quickly turned over and repeated for 3 times of melting, so that the alloy ingot with uniform composition is obtained.

[0063] (2) The alloy ingot obtained by melting is crushed into small alloy pieces, which are cleaned and put into a quartz tube with an open lower end, and then placed in an induction coil of a ribbon drawing device (single roller rapid cooling ribbon drawing machine). After vacuumizing, high-purity argon with a purity of 99.99% is filled as a protective gas, the current is adjusted to melt the alloy, and then the alloy in a molten state is sprayed onto the surface of a copper roller with a rotating speed of 55 m / s and a cooling system by using the pressure difference, so that the amorphous ribbon with a width of about 1 mm and a thickness of about 13 μm is prepared. The structure of the alloy ribbon is detected by an X-ray diffractometer, and the X-ray diffraction analysis result of the obtained amorphous ribbon is shown in Figure 2 As shown in Figure 2 , the completely amorphous ribbon has a broadened diffraction peak at about 45°, and no obvious sharp crystallization peak in other ranges, which indicates that the quenched structure of the sample obtained in Example 1 is amorphous.

[0064] (3) The prepared amorphous alloy ribbon sample is tested by an oxygen and nitrogen analyzer, and the result shows that the nitrogen content of the ribbon is 0.0098 wt%, and the theoretical nitrogen content is 0 wt%.

[0065] (4) The amorphous alloy ribbon is put into a heat treatment furnace for annealing treatment, argon is filled as a protective gas during the heat treatment process, the furnace is heated to 300℃, and kept for 30 min, then heated to 350℃, 380℃, 410℃ and 430℃ respectively, and kept for 10 min, wherein the heating rate of the furnace is 5℃ / min, then the furnace is cooled to room temperature, and the ribbon is taken out, so that the iron-based amorphous nanocrystalline alloy is obtained. The XRD results corresponding to each temperature treatment are shown in Figure 3 (c), and after 410℃, obvious crystallization peaks appear, which indicates that above 410℃, nanocrystals are gradually precipitated to form an amorphous / nanocrystalline dual-phase structure.

[0066] The magnetic detection equipment (vibrating sample magnetometer VSM and soft magnetic DC tester) is used for respectively testing the saturation magnetic induction intensity (Bs) and coercive force (Hc) of the thin strip after annealing.

[0067] Figure 4 The hysteresis loop diagram of the iron-based amorphous alloy, Figure 5 The coercive force of the iron-based amorphous nanocrystalline alloy changes with the heat treatment temperature. It can be seen that the prepared Fe 82.5 Si2B 15 C 0.5 The Bs value of the amorphous state is 1.72T, and the Hc value is 13.3A / m. At the same time, with the increase of the heat treatment, the coercive force reaches the minimum at 380 DEG C, which is 3.3A / m.

[0068] It can be seen that the preparation technology of the nitrogen element doped iron-based amorphous / nanocrystalline alloy provided by the present application is feasible, and the quenched state Bs value of the product is higher than 1.65T. Not only the high Bs (Chen Guojun, Niu Yongji, Peng Weifeng, et al. Research progress of high saturation magnetic flux density Fe-based amorphous soft magnetic alloy [J]. Magnetic materials and devices, 2011, 42 (5): 6. DOI:10.3969 / j.issn.1001-3830.2011.05.002.) is maintained, but also the nitrogen element doping can further reduce the coercive force of the amorphous alloy, which has excellent industrial application prospect.

[0069] The preparation method of the nitrogen-containing iron-based soft magnetic amorphous nanocrystalline soft magnetic alloy and the application thereof are described in detail above, and the principles and implementation modes of the present application are described by applying specific examples. The above description of the embodiments is only used to help understand the method and core idea of the present application, including the best mode, and also enables any person skilled in the art to practice the present application, including manufacturing and using any device or system, and implementing any combined method. It should be pointed out that, for those skilled in the art, various changes, modifications, replacements and variations of the embodiments can be made without departing from the principles and spirits of the present application, and still fall within the protection scope of the present application.

Claims

1. A method of producing a nitrogen-containing iron-based soft magnetic amorphous / nanocrystalline alloy, characterized by, The general formula of the nitrogen-containing iron-based soft magnetic amorphous / nanocrystalline alloy is Fe a Si b B c C d N e The atomic proportions of the components in the general formula are as follows: a=75%-85%, b=0%-10%, c=5%-15%, d=0-2%, and e=0.05-0.5%; wherein a+b+c+d+e=100%. The preparation method of the nitrogen-containing iron-based soft magnetic amorphous / nanocrystalline alloy comprises the following steps: S1, high-purity iron metal is subjected to plasma nitriding treatment to obtain nitrogen-containing iron sheet as secondary raw material, which is then blended with amorphous forming elements selected from at least one of B, Si and C according to the alloy chemical formula to smelt into alloy ingot; S2, the alloy ingot of step S1 is crushed and then subjected to tape casting by using a tape casting device to obtain amorphous alloy strip by using rapid quenching technology; S3, the amorphous alloy strip of step S2 is subjected to heat treatment under vacuum or protective atmosphere to obtain nitrogen-containing iron-based amorphous nanocrystalline soft magnetic alloy.

2. The method of claim 1, wherein the nitrogen-containing iron-based soft magnetic amorphous / nanocrystalline alloy is prepared by a method comprising: preparing a molten alloy by melting a mixture of Fe, Si, Al, C, B, and N; and rapidly quenching the molten alloy to form an amorphous alloy. The high-purity iron metal is in the form of high-purity iron sheet or high-purity iron powder, and the purity is above 99.9%.

3. The method of claim 1, wherein the nitrogen-containing iron-based soft magnetic amorphous / nanocrystalline alloy is prepared by a method comprising: preparing a molten alloy by melting a mixture of Fe, Si, Al, C, B, and N; and rapidly quenching the molten alloy to form an amorphous alloy. The smelting is vacuum arc smelting or induction smelting, and inert gas or nitrogen gas is filled as protective gas during the smelting process.

4. The method of claim 1, wherein the nitrogen-containing iron-based soft magnetic amorphous / nanocrystalline alloy is prepared by a method comprising: preparing a molten alloy by melting a mixture of Fe, Si, Al, C, B, and N; and rapidly quenching the molten alloy to form an amorphous alloy. The tape casting device is a single-roll rapid quenching tape casting machine, and the linear speed of the tape casting copper roll is 45-60 m / s.

5. The method of claim 1, wherein the nitrogen-containing iron-based soft magnetic amorphous / nanocrystalline alloy is prepared by a method comprising: preparing a melt of an iron-based alloy containing nitrogen; and rapidly quenching the melt to form an amorphous alloy ribbon. The heat treatment is stress relief annealing treatment, the annealing temperature is between 100℃ below the first crystallization temperature and the first crystallization temperature, and the time is 10 min-1 h.

6. The method of claim 5, wherein the nitrogen-containing iron-based soft magnetic amorphous / nanocrystalline alloy is prepared by a method comprising: First, the temperature is raised to 300℃, and then the temperature is kept for 30 min, and then the temperature is raised to 350-600℃, and then the temperature is kept for 10 min-1 h.

7. The method of claim 5, wherein the nitrogen-containing iron-based soft magnetic amorphous / nanocrystalline alloy is prepared by a method comprising: preparing a melt of an alloy comprising iron, boron, carbon, silicon, and nitrogen; and rapidly quenching the melt to form an amorphous alloy ribbon. B is derived from boron or boron iron.

8. The nitrogen-containing iron-based soft magnetic amorphous / nanocrystalline alloy prepared by the preparation method of any one of claims 1-7.

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