An iron-based nanocrystalline ultra-thin ribbon and its preparation method

Abstract

The present invention relates to the technical field of iron-based nanocrystalline strips, and specifically to an iron-based nanocrystalline ultra-thin strip and a preparation method thereof, comprising: adding raw materials in proportion to a smelting furnace for melting, skimming off slag to obtain a molten alloy; forming the molten alloy into an amorphous strip by a single-roller strip-spinning method; subjecting the amorphous strip to a constant tension bending annealing treatment to obtain a nanocrystalline strip; and subjecting the nanocrystalline strip to a plasma nitriding treatment to obtain an iron-based nanocrystalline ultra-thin strip. During the annealing process, the present invention applies tension, i.e., longitudinal tensile stress, to the amorphous strip, heating and raising the temperature to allow the grains to nucleate and grow. After the force is removed, longitudinal compressive stress is applied to the strip in the longitudinal direction, which helps the grains in the alloy matrix compete with each other and tend to align in the transverse direction, making it easier for magnetic domains to form in the transverse direction of the strip. Furthermore, the strip is continuously bent during annealing to further refine the grains, thereby improving the magnetization performance of the iron-based nanocrystalline ultra-thin strip.

Description

Technical Field

[0001] The present invention relates to the technical field of iron-based nanocrystalline strips, in particular to an iron-based nanocrystalline ultra-thin strip and a preparation method thereof. Background Art

[0002] Using an amorphous alloy as a precursor, an appropriate annealing process yields an iron-based nanocrystalline alloy with uniformly precipitated α-Fe particles with a diameter of 10-20 nm on an amorphous matrix. Compared to traditional soft magnetic materials such as silicon steel and electrical pure iron, these alloys possess superior soft magnetic properties, helping to meet the demands for miniaturization, efficiency, and lightweighting in power electronic components. However, iron-based nanocrystalline soft magnetic alloys, especially those with high saturation magnetic induction, exhibit poor service stability in harsh operating environments.

[0003] Current annealing processes typically involve placing an amorphous alloy ribbon in an annealing furnace and heating it under an inert atmosphere to reduce grain size and improve the magnetic properties of the resulting nanocrystalline alloy ribbon. However, this annealing process struggles to achieve uniform grain refinement, resulting in a limited degree of nanocrystallization of the alloy matrix, which compromises the magnetic properties of the resulting iron-based nanocrystalline ultrathin ribbon. Therefore, an iron-based nanocrystalline ultrathin ribbon and its preparation method are proposed. Summary of the Invention

[0004] To address the deficiencies of the prior art, the present invention provides an iron-based nanocrystalline ultra-thin ribbon and a preparation method thereof. Through constant tension bending annealing treatment and plasma nitriding treatment, the iron-based nanocrystalline ultra-thin ribbon has good corrosion resistance and magnetic properties.

[0005] To achieve the above objectives, the present invention provides the following technical solution: an iron-based nanocrystalline ultra-thin strip, comprising the following raw materials, calculated in atomic percentage: Cu 0.5-1.5%, Si 12.0-13.5%, Co 0.5-1.0%, B 5.5-7.5%, Zr 3.5-4.5%, Nb 0.5-1.5%, Y 0.5-1.0%, and the balance being Fe.

[0006] Preferably, the raw materials used are selected from pure iron (Fe content > 99.9%), pure silicon (Si content > 99.6%), pure copper (Cu content > 99.9%), ferroniobium (Nb content 65.5%, Si content 2.2%, total Nb-Si-Fe content > 99.5%), ferroboron (B content 19.6%, total B-Fe content > 99.5%), yttrium iron (Y content 68.4%, total Y-Fe content > 99.5%), ferrozirconium (Zr content 45.5%, Si content 32.4%, total Zr-Si-Fe content > 99.5%) and pure cobalt (Co content > 99.9%).

[0007] The present invention also provides a method for preparing an iron-based nanocrystalline ultra-thin ribbon, comprising the following steps:

[0008] (1) adding raw materials in proportion to a smelting furnace for melting, and skimming off the slag to obtain alloy liquid;

[0009] (2) The alloy liquid is made into amorphous strips by a single-roller strip spinning method;

[0010] (3) subjecting the amorphous strip to a constant tension bending annealing treatment to obtain a nanocrystalline strip;

[0011] (4) Plasma nitriding treatment is performed on the nanocrystalline strip to obtain an iron-based nanocrystalline ultra-thin strip.

[0012] Preferably, in step (2), in the single-roller strip-spinning method, the spray pressure is controlled to be 0.5-0.8 MPa, the distance between the nozzle and the copper roller is adjusted to be 0.5-1 mm, and the linear speed of the copper roller is 35-40 m / s.

[0013] Preferably, in step (2), the thickness of the amorphous strip is 25-35 μm.

[0014] Preferably, in step (3), the constant tension bending annealing treatment is specifically as follows: the amorphous strip passes through the pressure roller on one side, enters the annealing furnace through the left positioning roller, is bent by multiple sets of adjustment rollers, exits the annealing furnace through the right positioning roller, and passes through the pressure roller on the other side.

[0015] Preferably, in the annealing furnace, the amorphous strip is heated to 400-450°C in the first heating section, and its residence time in the first heating section is 40-60 minutes; the amorphous strip is heated to 550-600°C in the second heating section, and its residence time in the second heating section is 80-100 minutes.

[0016] Preferably, the amorphous strip between the pressing rollers on both sides is subjected to a horizontal pulling force of 5.5-6.5N.

[0017] Preferably, the bending angle of the amorphous strip formed in the adjusting roller is 40-60°.

[0018] Preferably, in step (4), the plasma nitriding treatment is specifically as follows: placing the nanocrystalline strip into a plasma nitriding furnace, with the furnace cover as the anode and the nanocrystalline strip as the cathode, and introducing ammonia into the furnace; controlling the ammonia pressure to be 1-5 Pa, the cathode voltage to be 0.6-0.7 kV, the conduction current to be 10-15 A, the nitriding temperature to be 200-230 ° C, and the nitriding time to be 40-55 min.

[0019] The present invention provides an iron-based nanocrystalline ultra-thin ribbon and a preparation method thereof, which has the following beneficial effects compared with the prior art:

[0020] The present invention applies tension, i.e., longitudinal tensile stress, to the amorphous strip during annealing, and heats the strip to allow the grains to undergo nucleation and growth. After the force is removed, this is equivalent to applying longitudinal compressive stress in the longitudinal direction of the strip, which helps the grains in the alloy matrix compete with each other and tend to be arranged in the transverse direction, making it easier for magnetic domains to form in the transverse direction of the strip. Furthermore, the strip is continuously bent during annealing, which helps further refine the grains and reduce the pinning potential energy of the magnetic domains. This improves the magnetization performance of the iron-based nanocrystalline ultra-thin strip.

[0021] The present invention performs plasma nitriding treatment on nanocrystalline ribbons. The introduction of nitrides can greatly improve the corrosion resistance of the iron-based nanocrystalline ultra-thin ribbons, while the nitrides will affect the magnetic properties. However, during the plasma nitriding treatment, nitrogen atoms enter the iron lattice, causing the iron lattice to be distorted, thereby increasing the local average magnetic moment. When zirconium atoms in a non-collinear structure aggregate, they suppress their low spin state number by reducing the nearest neighbor Fe-Fe pairs with antiferromagnetic coupling characteristics, thereby increasing the initial value of the local iron atomic magnetic moment, thereby offsetting the magnetic dilution effect, and ultimately making the iron-based nanocrystalline ultra-thin ribbons have good corrosion resistance and magnetic properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0023] Figure 1 This is a schematic diagram of the constant tension bending annealing process of the present invention;

[0024] Figure 2 This is a schematic diagram of the constant tension annealing process of the present invention;

[0025] Figure 3 This is the corrosion morphology of the iron-based nanocrystalline ultra-thin strip of the present invention. DETAILED DESCRIPTION

[0026] The following examples illustrate the implementation methods of the present application in detail, so that the implementation process of how the present application applies technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0027] Example 1

[0028] A method for preparing an iron-based nanocrystalline ultrathin ribbon comprises the following steps:

[0029] (1) In terms of atomic percentage, Fe 72.5 Si 13.5 B 7.5 Zr 3.5 Co 0.5 Nb 1.5 Cu0.5 Y 0.5 Pure iron, pure silicon, pure copper, ferroniobium, ferroboron, yttrium iron, ferrozirconium and pure cobalt are added into a smelting furnace for melting, and the alloy liquid is obtained after skimming off the slag.

[0030] (2) The alloy liquid is made into amorphous strips with a thickness of 25 μm by a single-roller strip spinning method;

[0031] In the single-roller stripping method, the spray pressure is controlled to be 0.5 MPa, the distance between the nozzle and the copper roller is adjusted to be 0.5 mm, and the linear speed of the copper roller is 35 m / s.

[0032] (3) The amorphous strip is subjected to constant tension bending annealing treatment, that is, the amorphous strip is passed through the pressure roller on one side, enters the annealing furnace through the left positioning roller, is bent by multiple sets of adjustment rollers with a bending angle of 40°, exits the annealing furnace through the right positioning roller, and passes through the pressure roller on the other side; during this period, the amorphous strip is heated to 450°C in the first heating section, and its residence time in the first heating section is 40 minutes; the amorphous strip is heated to 550°C in the second heating section, and its residence time in the second heating section is 100 minutes; the amorphous strip between the pressure rollers on both sides is controlled to be subjected to a horizontal tension of 5.5N; and a nanocrystalline strip is obtained.

[0033] (4) Plasma nitriding treatment is performed on the nanocrystalline strip, i.e., the nanocrystalline strip is placed in a plasma nitriding furnace, the furnace cover is used as the anode, the nanocrystalline strip is used as the cathode, and ammonia gas is introduced into the furnace; the ammonia pressure is controlled to be 1 Pa, the cathode voltage is 0.7 kV, the conduction current is 10 A, the nitriding temperature is 230 ° C, and the nitriding time is 40 min; an iron-based nanocrystalline ultra-thin strip is obtained.

[0034] Example 2

[0035] A method for preparing an iron-based nanocrystalline ultrathin ribbon comprises the following steps:

[0036] (1) In terms of atomic percentage, Fe 74 Si 12 B 5.5 Zr 4.5 Co1Nb 0.5 Cu 1.5 Y1 ratio, pure iron, pure silicon, pure copper, ferroniobium, ferroboron, yttrium iron, ferrozirconium and pure cobalt are added into the smelting furnace for melting, and the alloy liquid is obtained after skimming off the slag.

[0037] (2) The alloy liquid is made into amorphous strips with a thickness of 35 μm by a single-roller strip spinning method;

[0038] In the single-roller stripping method, the spray pressure is controlled to be 0.8 MPa, the distance between the nozzle and the copper roller is adjusted to be 1 mm, and the linear speed of the copper roller is 40 m / s.

[0039] (3) The amorphous strip is subjected to constant tension bending annealing treatment, that is, the amorphous strip is passed through the pressure roller on one side, enters the annealing furnace through the left positioning roller, is bent by multiple sets of adjustment rollers with a bending angle of 60°, exits the annealing furnace through the right positioning roller, and passes through the pressure roller on the other side; during this period, the amorphous strip is heated to 450°C in the first heating section, and its residence time in the first heating section is 60 minutes; the amorphous strip is heated to 600°C in the second heating section, and its residence time in the second heating section is 80 minutes; the amorphous strip between the pressure rollers on both sides is controlled to be subjected to a horizontal tension of 6.5N; and a nanocrystalline strip is obtained.

[0040] (4) Plasma nitriding treatment was performed on the nanocrystalline strips, i.e., the nanocrystalline strips were placed in a plasma nitriding furnace, with the furnace cover as the anode and the nanocrystalline strips as the cathode, and ammonia gas was introduced into the furnace; the ammonia pressure was controlled to be 5 Pa, the cathode voltage was 0.6 kV, the conduction current was 15 A, the nitriding temperature was 200 ° C, and the nitriding time was 55 min; and an iron-based nanocrystalline ultra-thin strip was obtained.

[0041] Example 3

[0042] A method for preparing an iron-based nanocrystalline ultrathin ribbon comprises the following steps:

[0043] (1) In terms of atomic percentage, Fe 77 Si 12 B 5.5 Zr 3.5 Co 0.5 Nb 0.5 Cu 0.5 Y 0.5 Pure iron, pure silicon, pure copper, ferroniobium, ferroboron, yttrium iron, ferrozirconium and pure cobalt are added into a smelting furnace for melting, and the alloy liquid is obtained after skimming off the slag.

[0044] (2) The alloy liquid is made into amorphous strips with a thickness of 30 μm by a single-roller strip spinning method;

[0045] In the single-roller strip-spinning method, the spray pressure is controlled to be 0.6 MPa, the distance between the nozzle and the copper roller is adjusted to be 0.7 mm, and the linear speed of the copper roller is 38 m / s.

[0046] (3) The amorphous strip is subjected to constant tension bending annealing treatment, that is, the amorphous strip is passed through the pressure roller on one side, enters the annealing furnace through the left positioning roller, is bent by multiple sets of adjustment rollers with a bending angle of 45°, exits the annealing furnace through the right positioning roller, and passes through the pressure roller on the other side; during this period, the amorphous strip is heated to 400°C in the first heating section, and its residence time in the first heating section is 60 minutes; the amorphous strip is heated to 600°C in the second heating section, and its residence time in the second heating section is 80 minutes; the amorphous strip between the pressure rollers on both sides is controlled to be subjected to a horizontal tension of 6.0N; and a nanocrystalline strip is obtained.

[0047] (4) Plasma nitriding treatment was performed on the nanocrystalline strip, i.e., the nanocrystalline strip was placed in a plasma nitriding furnace, with the furnace cover as the anode and the nanocrystalline strip as the cathode, and ammonia gas was introduced into the furnace; the ammonia pressure was controlled to be 2 Pa, the cathode voltage was 0.6 kV, the conduction current was 12 A, the nitriding temperature was 230 ° C, and the nitriding time was 45 min; and an iron-based nanocrystalline ultra-thin strip was obtained.

[0048] Example 4

[0049] A method for preparing an iron-based nanocrystalline ultrathin ribbon comprises the following steps:

[0050] (1) In terms of atomic percentage, Fe 73.5 Si 12.5 B 6.5 Zr4Co1Nb1Cu1Y 0.5 Pure iron, pure silicon, pure copper, ferroniobium, ferroboron, yttrium iron, ferrozirconium and pure cobalt are added into a smelting furnace for melting, and the alloy liquid is obtained after skimming off the slag.

[0051] (2) The alloy liquid is made into amorphous strips with a thickness of 30 μm by a single-roller strip spinning method;

[0052] In the single-roller stripping method, the spray pressure is controlled to 0.7 MPa, the distance between the nozzle and the copper roller is adjusted to 0.8 mm, and the linear speed of the copper roller is 35 m / s.

[0053] (3) The amorphous strip is subjected to constant tension bending annealing treatment, that is, the amorphous strip is passed through the pressure roller on one side, enters the annealing furnace through the left positioning roller, is bent by multiple sets of adjustment rollers with a bending angle of 50°, exits the annealing furnace through the right positioning roller, and passes through the pressure roller on the other side; during this period, the amorphous strip is heated to 420°C in the first heating section, and its residence time in the first heating section is 50 minutes; the amorphous strip is heated to 580°C in the second heating section, and its residence time in the second heating section is 90 minutes; the amorphous strip between the pressure rollers on both sides is controlled to be subjected to a horizontal tension of 6.0N; and a nanocrystalline strip is obtained.

[0054] (4) Plasma nitriding treatment is performed on the nanocrystalline strip, that is, the nanocrystalline strip is placed in a plasma nitriding furnace, the furnace cover is used as the anode, the nanocrystalline strip is used as the cathode, and ammonia is introduced into the furnace; the ammonia pressure is controlled to be 3.5 Pa, the cathode voltage is 0.6 kV, the conduction current is 12 A, the nitriding temperature is 220 ° C, and the nitriding time is 50 min; an iron-based nanocrystalline ultra-thin strip is obtained.

[0055] Comparative Example 1

[0056] A method for preparing an iron-based nanocrystalline ultrathin ribbon is basically the same as that of Example 4, except that the nanocrystalline ribbon is not subjected to plasma nitriding treatment, and the obtained nanocrystalline ribbon is regarded as an iron-based nanocrystalline ultrathin ribbon.

[0057] Comparative Example 2

[0058] A method for preparing an iron-based nanocrystalline ultrathin ribbon comprises the following steps:

[0059] (1) In terms of atomic percentage, Fe 77.5 Si 12.5 B 6.5 Co1Nb1Cu1Y 0.5 Pure iron, pure silicon, pure copper, ferroniobium, ferroboron, yttrium iron and pure cobalt are added into a smelting furnace for melting in a certain ratio, and the alloy liquid is obtained after skimming off the slag.

[0060] Steps (2) to (4) are the same as the corresponding steps in Example 4 to obtain an iron-based nanocrystalline ultrathin strip.

[0061] Comparative Example 3

[0062] A method for preparing an iron-based nanocrystalline ultrathin ribbon comprises the following steps:

[0063] (1) In terms of atomic percentage, Fe 73.5 Si 12.5 B 6.5 Zr4Co1Nb1Cu1Y 0.5 Pure iron, pure silicon, pure copper, ferroniobium, ferroboron, yttrium iron, ferrozirconium and pure cobalt are added into a smelting furnace for melting, and the alloy liquid is obtained after skimming off the slag.

[0064] (2) The alloy liquid is made into amorphous strips with a thickness of 30 μm by a single-roller strip spinning method;

[0065] In the single-roller stripping method, the spray pressure is controlled to 0.7 MPa, the distance between the nozzle and the copper roller is adjusted to 0.8 mm, and the linear speed of the copper roller is 35 m / s.

[0066] (3) Annealing the amorphous strip, i.e., passing the amorphous strip through an annealing furnace; during this process, the amorphous strip is heated to 420°C in a first heating section, and its residence time in the first heating section is 50 minutes; the amorphous strip is heated to 580°C in a second heating section, and its residence time in the second heating section is 90 minutes; and a nanocrystalline strip is obtained.

[0067] (4) Plasma nitriding treatment is performed on the nanocrystalline strip, that is, the nanocrystalline strip is placed in a plasma nitriding furnace, the furnace cover is used as the anode, the nanocrystalline strip is used as the cathode, and ammonia is introduced into the furnace; the ammonia pressure is controlled to be 3.5 Pa, the cathode voltage is 0.6 kV, the conduction current is 12 A, the nitriding temperature is 220 ° C, and the nitriding time is 50 min; an iron-based nanocrystalline ultra-thin strip is obtained.

[0068] Comparative Example 4

[0069] A method for preparing an iron-based nanocrystalline ultrathin ribbon comprises the following steps:

[0070] (1) In terms of atomic percentage, Fe 73.5 Si 12.5 B 6.5 Zr4Co1Nb1Cu1Y 0.5 Pure iron, pure silicon, pure copper, ferroniobium, ferroboron, yttrium iron, ferrozirconium and pure cobalt are added into a smelting furnace for melting, and the alloy liquid is obtained after skimming off the slag.

[0071] (2) The alloy liquid is made into amorphous strips with a thickness of 30 μm by a single-roller strip spinning method;

[0072] In the single-roller stripping method, the spray pressure is controlled to 0.7 MPa, the distance between the nozzle and the copper roller is adjusted to 0.8 mm, and the linear speed of the copper roller is 35 m / s.

[0073] (3) The amorphous strip is subjected to constant tension annealing treatment, i.e. the amorphous strip is passed through the pressure roller on one side, enters the annealing furnace through the left positioning roller, exits the annealing furnace through the right positioning roller, and passes through the pressure roller on the other side; during this period, the amorphous strip is heated to 420°C in the first heating section, and its residence time in the first heating section is 50 minutes; the amorphous strip is heated to 580°C in the second heating section, and its residence time in the second heating section is 90 minutes; the amorphous strip between the pressure rollers on both sides is controlled to be subjected to a horizontal tension of 6.0N; and a nanocrystalline strip is obtained.

[0074] (4) Plasma nitriding treatment is performed on the nanocrystalline strip, that is, the nanocrystalline strip is placed in a plasma nitriding furnace, the furnace cover is used as the anode, the nanocrystalline strip is used as the cathode, and ammonia is introduced into the furnace; the ammonia pressure is controlled to be 3.5 Pa, the cathode voltage is 0.6 kV, the conduction current is 12 A, the nitriding temperature is 220 ° C, and the nitriding time is 50 min; an iron-based nanocrystalline ultra-thin strip is obtained.

[0075] Quality Inspection

[0076] 1. Saturation magnetic induction intensity: The saturation magnetic induction intensity of the iron-based nanocrystalline ultrathin ribbon samples of Example 4 and Comparative Examples 1-4 was measured using a vibrating sample magnetometer (VSM) at room temperature. The specific test results are shown in Table 1.

[0077] 2. Coercivity: The coercivity of the iron-based nanocrystalline ultra-thin ribbon samples of Example 4 and Comparative Examples 1-4 was measured at room temperature using a soft magnetic DC magnetic property measurement system. The specific test results are shown in Table 1.

[0078] Table 1 Saturation magnetic induction and coercive force

[0079]

[0080]

[0081] 3. Magnetic Permeability: The inductance of the iron-based nanocrystalline ultra-thin ribbon samples of Example 4 and Comparative Examples 1-4 was measured using a 429A impedance analyzer, and the magnetic permeability was calculated. The specific test results are shown in Table 2.

[0082] 4. Corrosion resistance: The iron-based nanocrystalline ultra-thin ribbon samples of Example 4 and Comparative Examples 1-4 were immersed in a 0.5 mol / L sodium chloride solution for 24 hours and then taken out for observation. Figure 3 and as shown in Table 2.

[0083] Table 2 Magnetic permeability and corrosion resistance

[0084] type Magnetic permeability at 10kHz Corrosion conditions Example 4 <![CDATA[1.82×10 4 ]]> Almost no corrosion products Comparative Example 1 <![CDATA[1.75×10 4 ]]> Large accumulation of corrosion products Comparative Example 2 <![CDATA[1.73×10 4 ]]> A few scattered accumulations of corrosion products Comparative Example 3 <![CDATA[1.44×10 4 ]]> / Comparative Example 4 <![CDATA[1.61×10 4 ]]> /

[0085] From the above table and combined Figure 3 It can be seen that:

[0086] (1) Compared with Example 4, the magnetic properties of the samples in Comparative Examples 1 and 2 did not decrease significantly, but their corrosion resistance deviated significantly, indicating that plasma nitriding treatment / zirconium doping has little effect on the magnetic properties, but can significantly improve the corrosion resistance of the samples.

[0087] (2) Compared with Example 4, the sample in Comparative Example 3 was not subjected to constant tension bending treatment, resulting in a significant decrease in its magnetic properties.

[0088] (3) Compared with Example 4, the sample in Comparative Example 4 was subjected to constant tension treatment but not to bending treatment, resulting in a decrease in its magnetic properties.

[0089] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. An iron-based nanocrystalline ultra-thin ribbon, characterized in that: The composition comprises the following raw materials in atomic percentage: Cu 0.5-1.5%, Si 12.0-13.5%, Co 0.5-1.0%, B 5.5-7.5%, Zr 3.5-4.5%, Nb 0.5-1.5%, Y 0.5-1.0%, and the balance is Fe; The method for preparing the iron-based nanocrystalline ultra-thin ribbon comprises the following steps: (1) Add the raw materials in proportion to the smelting furnace for melting, and skim off the slag to obtain the alloy liquid; (2) The alloy liquid is made into amorphous strips by a single-roller strip spinning method; (3) subjecting the amorphous strip to constant tension bending annealing to obtain nanocrystalline strips; (4) Plasma nitriding treatment is performed on the nanocrystalline strip to obtain an iron-based nanocrystalline ultra-thin strip; In step (3), the constant tension bending annealing treatment is specifically as follows: the amorphous strip passes through the pressure roller on one side, enters the annealing furnace through the left positioning roller, is bent by multiple sets of adjustment rollers, exits the annealing furnace through the right positioning roller, and passes through the pressure roller on the other side; The bending angle formed by the amorphous strip in the adjusting roller is 40-60 degrees.

2. The iron-based nanocrystalline ultra-thin ribbon according to claim 1, characterized in that The raw materials used are selected from pure iron, pure silicon, pure copper, ferroniobium, ferroboron, ferroydtrium, ferrozirconium and pure cobalt.

3. The iron-based nanocrystalline ultra-thin ribbon according to claim 1, characterized in that In step (2), in the single-roller strip-spinning method, the spray pressure is controlled to be 0.5-0.8 MPa, the distance between the nozzle and the copper roller is adjusted to be 0.5-1 mm, and the linear speed of the copper roller is 35-40 m / s.

4. The iron-based nanocrystalline ultra-thin ribbon according to claim 1, characterized in that: In step (2), the thickness of the amorphous strip is 25-35 μm.

5. The iron-based nanocrystalline ultra-thin ribbon according to claim 1, characterized in that In the annealing furnace, the amorphous strip is heated to 400-450°C in the first heating section, and its residence time in the first heating section is 40-60 minutes; the amorphous strip is heated to 550-600°C in the second heating section, and its residence time in the second heating section is 80-100 minutes.

6. The iron-based nanocrystalline ultra-thin ribbon according to claim 1, characterized in that: The amorphous strip between the pressing rollers on both sides is subjected to a horizontal pulling force of 5.5-6.5N.

7. The iron-based nanocrystalline ultra-thin ribbon according to claim 1, characterized in that: In step (4), the plasma nitriding treatment is specifically as follows: placing the nanocrystalline strip into a plasma nitriding furnace, using the furnace cover as the anode and the nanocrystalline strip as the cathode, and introducing ammonia into the furnace; controlling the ammonia pressure to be 1-5 Pa, the cathode voltage to be 0.6-0.7 kV, the conduction current to be 10-15 A, the nitriding temperature to be 200-230 ° C, and the nitriding time to be 40-55 min.

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