CN109440023B - A high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy and its preparation method - Google Patents

Abstract

The invention discloses a high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy and a preparation method thereof. The method comprises: (1) melting a nitrogen-containing raw material to obtain a nitrogen-coupled iron-based alloy ingot; (2) obtaining After the nitrogen-coupled iron-based alloy ingot is crushed and remelted, a completely amorphous nitrogen-coupled iron-based amorphous alloy is prepared by rapid quenching preparation technology; (3) the obtained completely amorphous nitrogen-coupled iron-based amorphous alloy is The crystal alloy is sequentially subjected to two-stage annealing and tempering to obtain a high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy. The first-stage annealing temperature of the two-stage annealing is 20-50°C lower than the first crystallization start temperature, The temperature of the second stage of annealing is between the first crystallization start temperature and the second crystallization start temperature. The above method improves the saturation magnetic induction intensity of the iron-based amorphous nanocrystalline alloy, and also improves the service performance of the iron-based amorphous nanocrystalline soft magnetic alloy in complex and severe environments.

Description

A high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy and its preparation method

technical field

The invention relates to the field of magnetoelectric functional materials, in particular to a high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy and a preparation method thereof.

Background technique

With the development of the electronic power industry, it is urgent to develop an alloy material with high saturation magnetic induction. Iron-based amorphous nanocrystalline alloys have the advantages of low coercivity, high effective magnetic permeability, low iron loss, low cost, and simple production process, and have received extensive attention in recent years.

The patent specification whose notification number is CN 101796207 B discloses a thin strip of amorphous alloy with excellent machinability, and the saturation magnetic induction of the Fe _balance Cu _0.98 Nb _3.1 Si _13.4 B _9.3 amorphous alloy strip provided in Example 1 It is 1.24T.

The patent specification with the publication number CN 106917042 A discloses a high-frequency high-magnetic induction intensity iron-based nanocrystalline soft magnetic alloy and its preparation method. Melting is carried out under the protection of an inert atmosphere. The melting temperature is 1300-1800 ° C. Cool for 20 minutes to obtain master alloy ingots. After the master alloy ingots are crushed, continuous amorphous alloys are prepared by single-roll quenching method, and finally heat treated at 500-600°C for 1-90 minutes and then cooled to obtain high-frequency high-magnetic induction intensity iron-based nanocrystalline soft magnets. Alloy, the saturation magnetic induction is 1.30~1.55T.

However, there are still many challenges in the development and application of iron-based amorphous nanocrystalline alloys, such as:

(1) The brittleness of amorphous alloys. Iron-based amorphous alloys, especially nanocrystalline alloys, have the problems of low ductility and high brittleness. It is necessary to study the factors affecting their ductility in depth, and explore ways to improve ductility to ensure safe use.

(2) The saturation magnetic induction is still low, and the comprehensive magnetic properties still need to be further improved. It is necessary to further study new processes or alloys with better manufacturability, so that the alloys have high saturation magnetic induction, low coercive force and high magnetic permeability, that is, iron-based amorphous alloys or amorphous nano-alloys with excellent comprehensive properties. crystal alloy.

(3) Lack of efficient amorphous alloy processing technology. Due to high hardness and brittleness, amorphous alloy/nanocrystalline alloy is difficult to process and the processing efficiency is not high. It is necessary to study the factors affecting the processing performance of amorphous/nanocrystalline alloys in depth, and explore technical methods to improve processing efficiency and ensure processing quality.

(4) Develop soft magnetic amorphous/nanocrystalline alloy systems that meet different needs. Different industrial products have very different requirements on the magnetic properties of amorphous alloys. It is necessary to develop a variety of soft magnetic amorphous nanocrystalline alloy systems that meet the needs of different products for different application fields and products.

In addition, with the increase of the saturation magnetic induction of Fe-based amorphous and nanocrystalline alloys, the ability to form amorphous will gradually decrease, which is not conducive to obtaining wide and thick amorphous and nanocrystalline ribbon alloys. Moreover, iron-based amorphous nanocrystalline alloys, especially iron-based amorphous nanocrystalline alloys with high saturation magnetic induction, have poor corrosion resistance in harsh environments such as high temperature and humidity, resulting in poor service stability.

Therefore, how to improve the saturation magnetic induction of the system while ensuring the corrosion resistance and amorphous formation ability of iron-based amorphous nanocrystalline alloys is of great significance.

The introduction of nitrogen is beneficial to improve the ability of amorphous formation, can change the spin interaction between alloy atoms, effectively improve the saturation magnetic induction of the system, and can also regulate the phase precipitation behavior of the alloy and the ions in the corrosive medium. species and ionic behavior. For example, adding an appropriate amount of nitrogen to steel can greatly improve the corrosion resistance and mechanical properties of steel.

The method of introducing nitrogen into the master alloy is called nitriding. A common nitriding method is to melt the master alloy in a nitrogen-containing atmosphere. This method usually requires long-term high-temperature treatment. On the one hand, it is affected by the solubility of nitrogen in the master alloy, and on the other hand, it often needs to be carried out under high pressure. Therefore, the nitrogen content of the product after nitriding is often low, and this method is difficult to operate. big. If the above nitriding method is applied to iron-based amorphous materials, it is easy to cause the iron-based amorphous materials to transform into crystalline structures during the nitriding process, and amorphous products cannot be obtained. In addition, the above nitriding method can only distribute nitrogen on the surface of the iron-based amorphous material, and the distribution of nitrogen is uneven.

Therefore, in addition to the problems of low efficiency and inability to obtain a completely amorphous structure in research in this field, there are also problems such as uneven distribution of nitrogen, enrichment on the surface of the material caused by the traditional nitriding method, and the material becomes brittle and difficult to process after nitriding. question. There is an urgent need in the field for a method for obtaining a nitrogen-coupled iron-based amorphous nanocrystalline alloy with high toughness and uniform nitrogen distribution.

Contents of the invention

Aiming at the deficiencies in this field, the present invention provides a method for preparing a high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy, which is prepared by using nitrogen-containing raw materials, which not only greatly improves the performance of the iron-based amorphous nanocrystalline alloy. The saturation magnetic induction intensity is high, and the subsequent nitriding step is omitted, which overcomes the difficulty in doping iron-based amorphous alloys with nitrogen and the uneven distribution of nitrogen elements in the past. It is simple and efficient, low in cost, controllable in product quality and suitable for large-scale production. And so on, it is instructive to improve the saturation magnetic induction of the material.

A method for preparing a high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy, comprising:

(1) Fe, amorphous forming elements, elemental and/or compounds of large atomic size elements and nanocrystalline nucleating elements, and nitrides are smelted as raw materials to obtain nitrogen-coupled iron-based alloy ingots, and the amorphous forming elements At least one selected from Al, B, P, C or Si, large atomic size elements selected from at least one of IV B, V B or VI B group elements, nanocrystalline nucleation elements selected from Cu, Ag or Zn at least one of

(2) After crushing and remelting the obtained nitrogen-coupled iron-based alloy ingot, a completely amorphous nitrogen-coupled iron-based amorphous alloy is prepared by rapid quenching preparation technology;

(3) The obtained completely amorphous nitrogen-coupled iron-based amorphous alloy is sequentially subjected to two-stage annealing and tempering to obtain a high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy, the first stage of the two-stage annealing The annealing temperature is 20-50° C. lower than the first crystallization start temperature, and the second annealing temperature is between the first crystallization start temperature and the second crystallization start temperature.

In step (1), preferably, the large atomic size element is selected from at least one of Zr, Cr, Nb, Mo, W or Hf.

Preferably, the nanocrystal nucleation element is Cu.

Preferably, the nitride has a low melting point, and the nitrogen element is not easy to decompose and overflow, specifically, it can be one or more of FexN, ZrN, CrN, NbN, AlN and MoN, where _x =2～4, In order to achieve the regulation of nitrogen content. More preferably, the nitride is FexN, where _x =2-4.

Using nitride as the raw material for smelting can ensure that nitrogen exists in the form of nitride in the obtained nitrogen-coupled iron-based alloy ingot alloy. Compared with the nitriding of traditional iron and steel materials, the nitrogen in the nitrogen-coupled iron-based alloy ingot alloy obtained by the method is more stable in the form of nitrogen, and is not easily decomposed into nitrogen gas overflow.

The smelting can be induction smelting or arc smelting. In order to ensure that the master alloy ingot is not polluted and does not have a large composition loss ratio, the cavity is kept clean during smelting, and the smelting is carried out under a protective atmosphere.

Preferably, the smelting is carried out in a rare gas atmosphere or a nitrogen atmosphere.

Preferably, the melting temperature is 1300-1800° C., and the holding time after melting the raw materials is 15-45 minutes.

The smelting process needs to reach a certain holding temperature and a certain holding time to ensure uniform composition. If the temperature is too low or the holding time is short, it will lead to incomplete melting of nitrides and uneven distribution of nitrides and nitrogen, which will lead to serious heterogeneity in the subsequent preparation of amorphous alloys by single-roll quick quenching or gas atomization. If the temperature is too high or the holding time is too long, the nitrogen element will overflow in the form of nitrogen gas, and the nitrogen content in the product cannot be guaranteed, so the effect of nitrogen doping is not obvious.

Nitrogen-coupled iron-based amorphous alloys with incomplete amorphous state or uneven composition distribution cannot obtain size-controllable and uniform nanocrystals by further annealing, which greatly reduces the obtained high magnetic induction nitrogen-coupled iron-based amorphous nanocrystals. properties of the alloy. On the other hand, due to the partial crystallization of nitrogen-coupled iron-based amorphous alloys with incomplete amorphous state or uneven composition distribution, the toughness is greatly reduced, which greatly limits the further development of nitrogen-coupled iron-based amorphous alloys. processing production.

The smelting can make the components of the alloy evenly distributed through a long time of heat preservation, thus avoiding the occurrence of heterogeneous nucleation in the subsequent rapid quenching and annealing processes, and then resulting in partial crystallization. At the same time, due to the large atomic size difference and negative mixing enthalpy between nitrogen atoms and other constituent elements, the long-range diffusion of atoms is suppressed and crystallization is avoided. During the annealing process, lower-energy nitrogen-centered atomic clusters are formed, and these clusters need to cross a higher energy barrier to evolve, so the thermal stability of nitrogen-coupled alloys is effectively improved.

In step (2), the rapid quenching preparation technology may be a single-roll quenching method or a gas atomization method.

The single-roll quick quenching method is to spray the molten alloy on the surface of the high-speed rotating cooling roll. When spraying, a dynamic balance molten pool is formed on the roll surface, and the molten alloy is rapidly solidified to form continuous amorphous or microcrystalline strips. Completely amorphous nitrogen-coupled iron-based amorphous alloy strips can be prepared by single-roll rapid quenching.

The gas atomization method is a method in which a fast-moving fluid impacts or otherwise breaks a metal or alloy liquid into fine droplets, which are then condensed into solid powder. The gas atomization method can prepare completely amorphous nitrogen-coupled iron-based amorphous alloy powder.

Both the single-roll quick quenching method and the gas atomization method need to be evacuated first, so that the air pressure in the single-roll quick quenching device or the gas atomization device is not greater than 0.02Pa, and then filled with rare gas or nitrogen to make the single roll The gas pressure in the quick quenching device or the gas atomization device is 0.09-0.04MPa lower than the standard atmospheric pressure.

Preferably, in order to avoid crystallization or oxidation of the strip, the line speed of the copper roll in the single-roll quick quenching method is 20-40 m/s.

The remelting is carried out in a rare gas atmosphere or a nitrogen atmosphere.

The crushed nitrogen-coupled iron-based alloy ingot can be placed in a quartz tube for remelting, single-roll rapid quenching to prepare strips or gas atomization to make powder. A good completely amorphous strip or powder can be obtained by controlling the remelting heating time, the size of the nozzle at the lower end of the quartz tube, the distance from the quartz tube to the copper roller, the air pressure difference inside and outside the quartz tube, and the rotational speed of the copper roller.

The remelting can be carried out by heating and remelting in the quartz tube through an induction coil, the air pressure difference inside and outside the quartz tube is 200-300Pa, and at the same time, the nozzle width at the lower end of the quartz tube is controlled to be 0.4-0.8mm, thereby controlling the single-roll quick quenching to obtain The thickness of the strip is 22-28 μm, and the particle size of the powder obtained by controlled gas atomization is 75-100 μm.

In step (3), the two-stage annealing is used to control the crystallization behavior of the completely amorphous nitrogen-coupled iron-based amorphous alloy, and to control the nanocrystals in the obtained high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy. The crystallite size can be precipitated to help improve corrosion resistance and saturation magnetic induction, thereby effectively improving the saturation magnetic induction of high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloys, and improving the high magnetic induction nitrogen-coupled iron-based The service performance of amorphous nanocrystalline alloys in complex and harsh environments has greatly broadened the application range of high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloys.

The two-stage annealing and tempering are carried out under the protection of a rare gas atmosphere and a nitrogen atmosphere, so as to avoid oxidation or surface crystallization of the completely amorphous nitrogen-coupled iron-based amorphous alloy during the annealing and tempering process.

If there is no protective condition of rare gas atmosphere and nitrogen atmosphere, the second-stage annealing and tempering can be carried out under high vacuum, and the vacuum degree should not be greater than 1.0×10 ^-2 Pa.

The first crystallization start temperature refers to the temperature at which α-Fe starts to precipitate during the heat treatment, which is generally 480-530°C.

The first crystallization end temperature refers to the temperature at which α-Fe is completely precipitated, which is generally 590-610°C.

The second crystallization start temperature refers to the temperature at which other phases other than α-Fe that may adversely affect the magnetic properties start to precipitate, which is often different in alloy systems containing different impurities.

The temperature of the second stage of annealing should be within the interval between the first crystallization start temperature and the second crystallization start temperature, so as to precipitate α-Fe as much as possible and avoid the precipitation of magnetic deterioration phases.

The purpose of the first-stage annealing is to precipitate Fe ₃ N and Fe ₄ N nanoparticles. Preferably, the temperature of the first-stage annealing, which can be regarded as the nitride precipitation temperature, is 460-510° C. and the time is 10-20 minutes.

The purpose of the second-stage annealing is to precipitate α-Fe nano-grains, which can be regarded as a quenching treatment. Preferably, the temperature of the second-stage annealing is 530-750° C. and the time is 10-60 minutes.

After the second stage of annealing, water quenching can be used to rapidly reduce the temperature of the alloy before tempering.

The tempering is to regulate the precipitation behavior of nitrides, and promote the transformation of some Fe ₃ N, Fe ₄ N and disordered α′-martensitic phase iron-based compounds into ordered α”-Fe ₁₆ N ₂ , thereby The saturation magnetic induction of the iron-based amorphous nanocrystalline alloy is improved. Preferably, the tempering temperature is 150-250° C. and the time is 60-120 minutes.

The present invention further provides a completely amorphous nitrogen-coupled iron-based amorphous alloy prepared according to the method for preparing the high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy.

The completely amorphous nitrogen-coupled iron-based amorphous alloy is an intermediate product in the preparation process of the nitrogen-containing iron-based nanocrystalline soft magnetic alloy, with a high nitrogen content of 500-1100ppm, and can withstand the maximum bending angle Not less than 180°, with excellent bending toughness, which is conducive to further nanocrystallization treatment and mechanical winding process.

In a preferred example, the composition of the completely amorphous nitrogen-coupled iron-based amorphous alloy includes Fe _80-91 M _{3- 10} B _3-10 N _0-0.5 , M is Nb, Mo, Zr, Hf One or both of , Al and V. The atoms of nitrogen-coupled iron-based amorphous alloys in this composition form have a large negative mixing enthalpy and a large difference in atomic size. The precursors of amorphous nanocrystalline alloys have higher amorphous stability.

The present invention also provides a high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy prepared according to the preparation method of the high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy.

The high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy has a nanocrystalline grain size of 10-15nm, a high saturation magnetic induction of 1.37-1.84T, good corrosion resistance, and a low corrosion rate. Under the condition of 0.5M NaCl solution, the corrosion rate is not more than 0.12mm/a.

The high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy can be one of the following compositions:

Fe _73-84 Si _3-16 B _8-12 M _2.4-3 Cu _0.6-3 N _0-0.5 、

Fe _80-91 M _3-10 B _3-10 Cu _0-3 N _0-0.5 、

Fe _33-66 Co _20-52 M _2-7 B _3-10 Cu _0.6-3 N _0-0.5 、

Fe _75-81 Si _9-14 B _3-9 Cu _0.6-1.3 (Nb _x M _y )N _0-0.5 、

Fe _80-91 M _3-10 B _3-10 N _0-0.5 ,

Wherein, M is one or two of Nb, Mo, Zr, Hf, Al, Cr, Ta and V, and 1.2≤x+y≤2.5.

Preferably, the composition of the high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy includes Fe _80-91 M _3-10 B _{3- 10} N _0-0.5 , M is Nb, Mo, Zr, Hf, Al and One or both of V. Fe _80-91 M _3-10 B _3-10 , as one of the classic components of Nanoperm nano soft magnetic materials, has a high saturation magnetic induction of about 1.63T, and can obtain 1.71-1.84T after doping with nitride Saturation magnetic induction.

Compared with the prior art, the present invention has main advantages including:

(1) The purpose of nitrogen coupling is effectively achieved, and iron-based amorphous nanocrystalline alloys with high nitrogen content can be obtained, and the nitrogen content is controllable.

(2) Overcome the problem of iron-based amorphous crystallization in the process of nitrogen doping, solve the problem of poor toughness and difficult processing of iron-based amorphous alloys after nitrogen doping, simple and efficient, low cost, controllable product quality, suitable for large-scale Production.

(3) The intermediate product is a completely amorphous nitrogen-coupled iron-based amorphous alloy, which can withstand a maximum bending angle of not less than 180°, has excellent bending toughness, and has a high nitrogen content of 500-1100ppm.

(4) The nanocrystalline grain size of the prepared high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy is 10-15nm, the saturation magnetic induction is high, 1.37-1.84T, the corrosion resistance is good, and the corrosion rate is low. Under the condition that the corrosion medium is 0.5M NaCl solution, the corrosion rate is not greater than 0.12mm/a.

In summary, the present invention improves the saturation magnetic induction of the iron-based amorphous nanocrystalline alloy, and at the same time improves the service performance of the iron-based amorphous nanocrystalline soft magnetic alloy in complex and harsh environments, and can cater to the greatest extent The "miniaturization, high efficiency, lightweight and green" required by current electronic power devices has greatly broadened the application range of iron-based amorphous nanocrystalline soft magnetic alloys, and has great application prospects and research significance.

Description of drawings

Figure 1 shows the nitrogen-coupled iron-based amorphous alloy strip prepared in Example 1, the high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy strip prepared in Example 2, and the nitrogen-free iron-based alloy strip prepared in Comparative Example 1. The X-ray diffraction (XRD) pattern of the nitrogen-free iron-based amorphous nanocrystalline alloy strip prepared by amorphous alloy strip and comparative example 2;

Fig. 2 is the transmission electron microscope photo of the high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy strip prepared in embodiment 2;

Fig. 3 is the comparison diagram of the room temperature hysteresis loop of the high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy strip prepared in Example 2 and the nitrogen-free iron-based amorphous nanocrystalline alloy strip prepared in Comparative Example 2;

4 is a comparison diagram of the polarization curves of the high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy strip prepared in Example 2 and the nitrogen-free iron-based amorphous nanocrystalline alloy strip prepared in Comparative Example 2.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. For the experimental methods without specific conditions indicated in the following examples, the conventional conditions or the conditions suggested by the manufacturer are usually followed.

Example 1

Nitrogen-coupled iron-based amorphous alloy strips were prepared, and the chemical formula was (Fe ₉₀ Zr ₇ B ₃ ) _99.75 N _0.25 .

(1) Elemental Fe, Zr, B, and ZrN are uniformly mixed according to the above stoichiometric ratio, and a nitrogen-coupled iron-based alloy ingot with uniform composition is prepared by using an electric arc melting furnace. First evacuate until the air pressure is lower than 2.0×10 ^-2 Pa, then fill in argon until the air pressure is 0.05 MPa for multiple smelting, and cool the molten alloy ingot for 30 minutes after smelting to obtain a nitrogen-coupled iron-based alloy ingot with uniform composition.

(2) The obtained nitrogen-coupled iron-based alloy ingot is ground with a grinding wheel to remove surface impurities, crushed and remelted, and packed into a quartz tube with a nozzle at the bottom. The width of the nozzle is 0.8mm, and the gas pressure in the furnace chamber is adjusted to be low. At the standard atmospheric pressure of 0.09MPa, the pressure difference between the inside and outside of the quartz tube is adjusted to 300Pa, and the strip is thrown at a linear speed of 40m/s in a single-roll quenching device protected by a nitrogen atmosphere to obtain a nitrogen-coupled iron-based amorphous alloy strip. The nitrogen content It is 900ppm, the surface is smooth, and the thickness is 23μm.

As shown in FIG. 1 , the obtained (Fe ₉₀ Zr ₇ B ₃ ) _99.75 N _0.25 nitrogen-coupled iron-based amorphous alloy strip is completely amorphous.

The obtained completely amorphous nitrogen-coupled iron-based amorphous alloy strip has excellent bending toughness and can be folded in half by 180°.

The obtained completely amorphous nitrogen-containing iron-based amorphous alloy strip is further wound to form an iron core product, and the manufactured iron core product has the characteristics of uniform nitrogen distribution.

Example 2

The nitrogen-coupled iron-based amorphous alloy strip prepared in Example 1 was subjected to high vacuum heat treatment to obtain a high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy strip, the chemical formula is (Fe ₉₀ Zr ₇ B ₃ ) _99.75 N _0.25 .

Place the obtained completely amorphous nitrogen-coupled iron-based amorphous alloy strip in a quartz tube, evacuate to 5.0×10 ^-3 Pa, place the quartz tube in a heat treatment furnace, and heat up at a rate of about 2°C/s Raise the rate to 510°C, heat it for 15 minutes, then raise the temperature to 630°C, hold it for 1 hour, then quickly take out the quartz tube and place it in water to quench to room temperature, and then perform high vacuum tempering at 200°C for 90 minutes to obtain a high magnetic induction nitrogen coupling Iron-based amorphous nanocrystalline alloy ribbon.

The nitrogen content of the obtained high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy strip is 890ppm, the saturation magnetic induction is 1.73T, and the corrosion rate is 0.12mm/a under the condition that the corrosion medium is 0.5M NaCl solution, with Excellent saturation magnetic induction and corrosion resistance.

The XRD pattern of the obtained high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy strip is shown in Figure 1, and the transmission electron microscope photo is shown in Figure 2. The grain size of the nanocrystals is about 13nm, and a small amount _of Fe3 is precipitated N and ZrN.

Example 3

A high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy ribbon was prepared, with a chemical formula of Fe _76.5 Si _12.7 B ₈ Cu ₁ (Nb _0.75 Mo _0.75 )N _0.3 .

(1) Mix elemental Fe, Si, B, Cu, Nb, Mo, and NbN uniformly according to the above stoichiometric ratio, put them into an alumina crucible in an induction melting furnace, and evacuate until the air pressure is lower than 2.0×10 ^-2 Pa, and then filled with argon to a pressure of 0.05MPa for smelting, heat preservation for 25 minutes after melting, and then pour the molten alloy ingot into a copper mold to cool for 30 minutes to obtain a nitrogen-coupled iron-based alloy ingot with uniform composition.

(2) The obtained nitrogen-coupled iron-based alloy ingot is ground with a grinding wheel to remove surface impurities, crushed and remelted, and then packed into a quartz tube with a nozzle at the bottom. The width of the nozzle is 0.8mm, and the furnace chamber pressure is adjusted to be lower than The standard atmospheric pressure is 0.09MPa, the pressure difference between the inside and outside of the quartz tube is adjusted to 300Pa, and the strip is thrown at a linear speed of 40m/s in a single-roll quenching device protected by a nitrogen atmosphere to obtain a completely amorphous nitrogen-coupled iron-based amorphous alloy strip. The material has a nitrogen content of 760ppm and a smooth surface.

(3) Place the obtained completely amorphous nitrogen-coupled iron-based amorphous alloy strip in a quartz tube, evacuate to 5.0×10 ^-3 Pa, and place the quartz tube in a heat treatment furnace at about 2°C/ The heating rate of s was raised to 490°C, kept for 15 minutes, then raised to 560°C, kept for 10 minutes, then the quartz tube was quickly taken out and quenched in water to room temperature, and finally tempered in high vacuum at 200°C for 1 hour to obtain high magnetic sensitivity nitrogen Coupling iron-based amorphous and nanocrystalline alloy ribbons.

The saturation magnetic induction of the obtained high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy strip is as high as 1.63T.

The patent specification with the publication number CN 106917042 A discloses a nitrogen-free iron-based amorphous nanocrystalline alloy strip with a chemical formula of Fe _76.5 Si _12.7 B ₈ Cu ₁ (Nb _0.75 Mo _0.75 ), and a saturation magnetic induction of 1.50T.

The patent specification with the notification number CN 101796207 B discloses an amorphous alloy ribbon with a chemical molecular formula of Fe _balance Cu _0.98 Nb _3.1 Si _13.4 B _9.3 and a saturation magnetic induction of 1.24T.

Compared with the technical solutions disclosed in the above two patent specifications, the high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy strip of this embodiment has a higher saturation magnetic induction.

Example 4

A high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy ribbon was prepared, with a chemical formula of Fe ₇₆ Si _11.75 B _8.5 P _0.5 Nb _1.4 V _0.1 Mo _0.5 Cu ₁ N _0.25 .

(1) Put the raw materials Fe, Si, B, Fe ₃ P, Nb, FeV, Mo, Cu and NbN with a purity greater than 99.8% into the alumina crucible in the induction melting furnace cleaned up according to the above stoichiometric ratio, and pump Vacuum until the air pressure is lower than 0.02Pa, then fill it with argon until the air pressure is 0.05MPa for melting, the melting temperature is 1300°C, keep warm for 20 minutes after melting, then pour the molten alloy ingot into a copper mold and cool for 20 minutes to obtain nitrogen with uniform composition Coupled iron-based alloy ingot;

(2) Pack the obtained nitrogen-coupled iron-based alloy ingot into a quartz tube with a nozzle width of 0.8 mm after crushing, adjust the gas pressure in the furnace chamber to be 0.09 MPa lower than the standard atmospheric pressure, and adjust the pressure difference between the inside and outside of the quartz tube The temperature is 300Pa, and the single-roll quick quenching method is used to throw the strip at a speed of 40m/s in a nitrogen atmosphere to produce a continuous and completely amorphous nitrogen-coupled iron-based amorphous alloy strip;

(3) Place the obtained nitrogen-coupled iron-based amorphous alloy strip in a quartz tube, evacuate until the air pressure is not greater than 5.0×10 ^-3 Pa, place the quartz tube in a heat treatment furnace, and heat it at about 3°C/min. The heating rate was increased to 480°C, kept at 10min, then raised to 560°C, kept at 10min, then quickly took out the quartz tube and quenched it in water to room temperature, and finally carried out high vacuum tempering at 150°C for 90min to obtain high magnetic sensitivity nitrogen Coupling iron-based amorphous and nanocrystalline alloy ribbons.

The saturation magnetic induction of the obtained high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy ribbon is as high as 1.57T.

Example 5

Prepare high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy powder, the chemical formula is (Fe ₇₈ Nb ₈ B ₁₃ Cu ₁ ) _99.63 N _0.37 .

(1) Elemental Fe, Nb, B, Cu, and NbN are uniformly mixed according to the above stoichiometric ratio, and a nitrogen-coupled iron-based alloy ingot with uniform composition is prepared by using an electric arc melting furnace. First evacuate until the air pressure is lower than 2.0×10 ^-2 Pa, and then fill it with argon until the air pressure is 0.05MPa to carry out repeated melting until it is uniform. After melting, the molten alloy ingot is cooled for 30 minutes to obtain a nitrogen-coupled iron-based alloy casting with uniform composition. ingot.

(2) The obtained nitrogen-coupled iron-based alloy ingot was ground with a grinding wheel to remove surface impurities, and gas atomized to obtain completely amorphous nitrogen-coupled iron-based amorphous alloy powder with a particle size of 75-100 μm and a nitrogen content of 960 ppm.

(3) Put the obtained nitrogen-coupled iron-based amorphous alloy powder into a quartz tube, raise the temperature to 480°C at a rate of about 3°C/min, heat it for 10 minutes, then raise the temperature to 550°C, hold it for 30 minutes, and heat it for the second stage annealing Ensure that the vacuum degree in the quartz tube is not higher than 5.0×10 ^-3 Pa, then take out the quartz tube and quickly cool it to room temperature in water, and then perform high vacuum tempering at 150°C for 90 minutes to obtain a high magnetic induction nitrogen-coupled iron-based Amorphous nanocrystalline alloy powder.

The high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline magnetic powder core prepared by using the obtained high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy powder has the characteristics of uniform nitrogen distribution, and the nitrogen content is 960ppm.

Comparative example 1

Compared with Example 1, the only difference is that ZrN is not added to the raw material, and other conditions are the same, and a nitrogen-free iron-based amorphous alloy strip with a chemical molecular formula of Fe ₉₀ Zr ₇ B ₃ is obtained.

Comparative example 2

Using the iron-based amorphous alloy strip of Comparative Example 1, the same two-stage annealing and tempering treatment as in Example 2 were carried out to obtain a nitrogen-free iron-based amorphous nanocrystalline alloy strip.

The soft magnetic properties of the high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy strip prepared in Example 2 and the nitrogen-free iron-based amorphous nanocrystalline alloy strip prepared in Comparative Example 2 were tested by a vibrating sample magnetometer. As shown in Figure 3, the saturation magnetic induction of the nitrogen-free iron-based amorphous nanocrystalline alloy strip prepared in Comparative Example 2 is 1.63T, and the high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy strip prepared in Example 2 The saturation magnetic induction of the material is 1.73T.

The high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy strip prepared in Example 2 and the nitrogen-free iron-based amorphous nanocrystalline alloy strip prepared in Comparative Example 2 were tested with an electrochemical workstation. The chemical curve is used to characterize the corrosion resistance.

As shown in Figure 4, compared with the nitrogen-free iron-based amorphous nanocrystalline alloy strip prepared in Comparative Example 2, the high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy strip prepared in Example 2 has a smaller Corrosion current, corrected corrosion potential.

Under the condition that the corrosion medium is 0.5M NaCl solution, the corrosion rate of the nitrogen-free iron-based amorphous nanocrystalline alloy strip prepared in Comparative Example 2 is 0.3mm/a, and the high magnetic induction nitrogen-coupled iron prepared in Example 2 The corrosion rate of the base amorphous nanocrystalline alloy strip is significantly reduced, and is 0.12mm/a, indicating that the corrosion resistance of the high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy strip prepared in Example 2 is far better than that of the Example 2: Nitrogen-free Fe-based amorphous nanocrystalline alloy ribbon prepared in Example 2.

This is because the precipitation phase behavior of the nanocrystal crystallization is controlled after the iron-based amorphous nanocrystal system is doped with nitrogen by nitride. As shown in Figures 2B and 2C, the high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy strip prepared in Example 2 obtained the precipitation of Fe ₃ N phase and ZrN phase. Therefore, the high magnetic induction prepared in Example 2 Nitrogen-sensitive coupled iron-based amorphous nanocrystalline alloy strips have smaller corrosion current and more positive corrosion potential.

Comparative example 3

The nitrogen-coupled iron-based amorphous alloy strip material of Example 1 was used, and conventional annealing treatment was adopted. First, place the obtained completely amorphous nitrogen-coupled iron-based amorphous alloy strip in a quartz tube, vacuumize to 5.0×10 ^-3 Pa, and then place the quartz tube in a heat treatment furnace at about 2°C/s The heating rate was raised to 630°C and kept for 1 hour. Finally, the quartz tube was quickly taken out and quenched in water to room temperature, and then tempered at 200°C for 90 minutes to obtain nitrogen-coupled iron-based amorphous nanocrystalline alloy strips. The nitrogen content is 890ppm, and the saturation magnetic induction is 1.68T.

Comparative example 4

Adopt the nitrogen-coupled iron-based amorphous alloy strip material of embodiment 1, adopt the two-stage annealing treatment identical with embodiment 2, but do not carry out tempering treatment, obtain nitrogen-coupled iron-based amorphous nanocrystalline alloy strip material, nitrogen content is 890ppm, the saturation magnetic induction is 1.67T.

In addition, it should be understood that after reading the above description of the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Claims (6)

1. A method for preparing a high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy, comprising: (1) Melting Fe, amorphous-forming elements, elements and/or compounds of large atomic size elements and nanocrystalline nucleating elements, and nitrides as raw materials to obtain nitrogen-coupled iron-based alloy ingots, the amorphous-forming elements At least one selected from Al, B, P, C or Si, large atomic size elements selected from at least one of IV B, V B or VI B group elements, nanocrystalline nucleation elements selected from Cu, Ag or Zn at least one of (2) After the obtained nitrogen-coupled iron-based alloy ingot is crushed and remelted, a completely amorphous nitrogen-coupled iron-based amorphous alloy is prepared by rapid quenching preparation technology; (3) The obtained completely amorphous nitrogen-coupled iron-based amorphous alloy is sequentially subjected to two-stage annealing and tempering to obtain a high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy. The first stage of the two-stage annealing The annealing temperature is 20-50°C lower than the first crystallization start temperature, and the second annealing temperature is between the first crystallization start temperature and the second crystallization start temperature; The first crystallization start temperature refers to the temperature at which α-Fe starts to be precipitated during the heat treatment process, which is 480-530°C; The second crystallization start temperature refers to the temperature at which other phases other than α-Fe that may have adverse effects on magnetic properties start to precipitate. 2. the preparation method of high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy according to claim 1, is characterized in that, described nitride _is Fe in N, ZrN, CrN, NbN, AlN and MoN One or more, where x = 2~4. 3. the preparation method of high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy according to claim 1, is characterized in that, described large atomic size element is selected from among Zr, Cr, Nb, Mo, W or Hf at least one of . 4. The method for preparing high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy according to claim 1, characterized in that, the rapid quenching preparation technology is a single-roll rapid quenching method or a gas atomization method. 5. The preparation method of high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy according to claim 1, characterized in that, the temperature of the first stage annealing is 460~510°C, and the time is 10~20 min , the temperature of the second stage annealing is 530~750 ℃, and the time is 10~60 min. 6. The method for preparing the high magnetic induction nitrogen-coupled iron-based amorphous nanocrystalline alloy according to claim 1, characterized in that the tempering temperature is 150-250 °C and the time is 60-120 min.