Method for manufacturing nanocrystalline alloy strips, and nanocrystalline alloy strips

Abstract

Provided is a thin nanocrystal alloy band production method with which it is possible to obtain, in a highly productive manner, a thin nanocrystal alloy band having excellent magnetic characteristics and isotropy. A method for producing a thin nanocrystal alloy band represented by a composition formula (Fe1-xAx)aSibBcCudMe, where A represents at least one of Ni and Co, M represents at least one selected from Nb, Mo, V, Zr, Hf, and W, and, 80.0≤a≤87.0, 0≤b≤9.0, 12.0≤c≤16.0, 0≤d≤1.5, 0≤e≤1.5, and 0≤x≤0.1 are satisfied in terms of atom%, the method comprising transporting a thin amorphous alloy band while pressing the thin amorphous alloy band against a heating body so as to be heat the same, wherein the heating body is heated to a heating temperature Ta of Tx1+80°C to Tx1+160°C when Tx1°C represents a bcc-Fe crystallization onset temperature as measured when the temperature increase rate of the thin amorphous alloy band is set to 20 K / min.

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a nanocrystalline alloy ribbon having a nanocrystalline structure and to the nanocrystalline alloy ribbon.

Background Art

[0002] Nanocrystalline alloy ribbons having a nanocrystalline structure exhibit excellent magnetic properties and are used in transformers, electronic components, motors, etc. Those transformers, electronic components, motors, etc. are required to be miniaturized and have higher efficiency. Therefore, further improvement in the properties of the nanocrystalline alloy used for the magnetic cores used in those components (transformers, electronic components, motors, etc.) is required. The properties required for the nanocrystalline alloy include a high saturation magnetic flux density and a low core loss (iron loss). Among those components, with the increase in the operating frequency due to the high frequency of semiconductors and the like, efforts are being made to increase the operating frequency to achieve miniaturization, and Fe-based amorphous alloys and Fe-based nanocrystalline alloys with low core loss have attracted attention. In order to commercially popularize them, a soft magnetic alloy excellent in price, productivity, and heat treatability is required.

[0003] It has been found that Fe-based nanocrystalline alloy ribbons can achieve both a high saturation magnetic flux density and a low coercive force and iron loss by heat treatment at a very high heating rate. As heat treatment methods for realizing a high heating rate, methods such as bringing a ribbon into contact with a heated plate or sandwiching a ribbon with a heated plate are known.

[0004] In Patent Document 1, in the composition formula FeB a Cu b M’ c where M’ is at least one element selected from Nb, Mo, Ta, W, Ni, and Co, having a composition satisfying 10≦a≦16, 0<b≦2, and 0≦c≦8, and heating an alloy having an amorphous phase at a heating rate of 10°C / second or more, and holding it for 0 to 80 seconds at a temperature not lower than the crystallization start temperature and lower than the formation start temperature of the Fe-B compound, a method for manufacturing a soft magnetic material that achieves both a high saturation magnetization and a low coercive force is described.

[0005] ​ In Patent Document 2, a nanocrystalline alloy ribbon represented by the compositional formula Fe 100-a-b-c-d B a Si b Cu c M d where a, b, c, and d are all atomic percentages, satisfying 0 < a, 0 < b, 0 < c, 0 ≤ d, and 78 ≤ 100 - a - b - c - d, and M represents at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W. The amorphous alloy ribbon is continuously run in a state where a tensile force F is applied, and a part of the amorphous alloy ribbon that is continuously run in a state where the tensile force F is applied is brought into contact with a heat transfer medium maintained at a temperature of 450°C or higher, so that the temperature of the amorphous alloy ribbon is raised to a reaching temperature of 450°C or higher at a heating rate such that the average heating rate in the temperature range from 350°C to 450°C is 10°C / second or more is described.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] According to the method described in Patent Document 1, a method of sandwiching a thin strip with a heated plate is disclosed. According to this method, isotropic and good characteristics can be obtained, and the generation of wrinkles and streaks can be suppressed. However, it takes time for a series of heat treatment operations of inserting the thin strip, sandwiching it with a heating body, and taking it out. And since the amount that can be processed at one time is limited, it is not suitable as a method for heat-treating a large amount of thin strips during mass production. In addition, since the soft magnetic material described in Patent Document 1 does not contain Si, a SiO2 film that contributes to the corrosion resistance of the soft magnetic material is not formed on the material surface. Therefore, it is difficult to prevent rust and the like.

[0008] According to the method described in Patent Document 2, a method is disclosed in which a thin strip is brought into contact with a heated plate. Since heat treatment can be performed while the thin strip is being transported, mass production is possible. In addition, good magnetic properties can be obtained. However, although tension is applied to the thin strip to ensure uniform contact with the heated plate, ingenuity is required to keep the moving thin strip in uniform contact with the heated plate. Furthermore, since only one side of the thin strip is in contact with the heated plate during transport, and the opposite side of the surface in contact with the heated plate is not restrained, there is a risk that the occurrence of wrinkles or streaks due to crystallization upon contact with the heated plate, or partial lifting of the thin strip, may not be suppressed.

[0009] Furthermore, nanocrystalline alloy strips are manufactured by injecting molten alloy, adjusted to a predetermined alloy composition, onto a rotating cooling roll, rapidly cooling and solidifying it to produce alloy strips, and then heat-treating the alloy strips. Nanocrystalline alloy strips are thin, have a predetermined width, and are manufactured as long strips. According to this manufacturing method, anisotropy is easily introduced in the casting direction (longitudinal direction), and even after heat treatment, the magnetic properties tend to differ between the longitudinal direction of the long strip and the width direction perpendicular to the longitudinal direction.

[0010] For example, nanocrystalline alloy strips used in motors and other applications are required to have as isotropic properties as possible. However, as mentioned above, it has been difficult to obtain nanocrystalline alloy strips that possess excellent magnetic properties (high saturation magnetic flux density, low iron loss) and are isotropic using a highly productive method.

[0011] The object of this disclosure is to provide a method for producing nanocrystalline alloy thin strips that have excellent magnetic properties and isotropy, that have wrinkles or streaks suppressed and achieve a high packing density, and that can produce them in a highly productive manner. Furthermore, the objective is to provide nanocrystalline alloy thin strips obtained by this method that possess excellent magnetic properties and isotropy, as well as nanocrystalline alloy thin strips that suppress wrinkles or streaks and achieve a high packing density. [Means for solving the problem]

[0012] This disclosure comprises the following configuration. <1> In a method for producing a nanocrystalline alloy strip having a structure in which crystal grains with an average particle size of 30 nm or less are present in the amorphous phase, the amorphous alloy strip is heated by bringing it into contact with a heating element. The aforementioned nanocrystalline alloy thin strip has the compositional formula (Fe 1-x A x ) a Si b B c Cu d M e Represented as follows, where A is at least one of Ni and Co, and M is at least one selected from Nb, Mo, V, Zr, Hf, and W, with atomic percent values ​​of 80.0 ≤ a ≤ 87.0, 0 ≤ b ≤ 9.0, 12.0 ≤ c ≤ 16.0, 0 ≤ d ≤ 1.5, 0 ≤ e ≤ 1.5, and 0 ≤ x ≤ 0.1. When the amorphous alloy strip is heated by bringing it into contact with the heating element, the amorphous alloy strip is transported, and a strip-holding member contacts the opposite side of the amorphous alloy strip from the side that contacts the heating element, so that the amorphous alloy strip is heated while sandwiched between the heating element and the strip-holding member. A method for manufacturing a nanocrystalline alloy thin strip, wherein, when the bccFe crystallization start temperature measured at a heating rate of 20 K / min of the amorphous alloy thin strip is defined as Tx1°C, the heating element is heated to a heating temperature Ta between Tx1 + 80°C and Tx1 + 160°C. <2> The thin band retaining member is a flexible member. <1> A method for producing a nanocrystalline alloy thin strip as described above. <3> When the amorphous alloy strip is heated by bringing it into contact with the heating element, the heating rate of the amorphous alloy strip is 50°C / second to 4000°C / second. <1> or <2> A method for producing a nanocrystalline alloy thin strip as described above. <4> When the amorphous alloy strip is heated by bringing it into contact with the heating element, the transport speed of the amorphous alloy strip is 1 m / min or more. <1> from <3> A method for producing a nanocrystalline alloy thin strip as described in any one of the items. <5> When the amorphous alloy strip is heated by bringing it into contact with the heating element, the contact time between the amorphous alloy strip and the heating element is 0.1 seconds to 30 seconds. <1> from <4> A method for producing a nanocrystalline alloy thin strip as described in any one of the items. <6> When the FeB deposition start temperature, measured at a heating rate of 20 K / min for the amorphous alloy strip, is defined as Tx2°C, the maximum temperature of the amorphous alloy strip heated in contact with the heating element is controlled to be Tx2 + 160°C or less. <1> from <5> A method for producing a nanocrystalline alloy thin strip as described in any one of the items. <7> In the above compositional formula, 82.0≦a≦86.5, 0.01≦b≦3.0, 13.0≦c≦15.0, 0.01≦d≦1.5, and 0≦e≦1.5. <1> from <6> A method for producing a nanocrystalline alloy thin strip as described in any one of the items. <8> The amorphous alloy strip is heated while being pressed against the heating element or the strip-holding member, and the pressure applied to the amorphous alloy strip against the heating element is 0.03 MPa or higher. <1> from <7> A method for producing a nanocrystalline alloy thin strip as described in any one of the items. <9> The wrinkle height on the surface of the nanocrystalline alloy thin strip is 0.15 mm or less, and the packing density is 84.0% or more. <1> from <8> A method for producing a nanocrystalline alloy thin strip as described in any one of the items. <10> The nanocrystalline alloy thin strip has a saturation magnetic flux density Bs of 1.75T or higher. <1> from <9> A method for producing a nanocrystalline alloy thin strip as described in any one of the items. <11> The magnetic flux density B80 when a magnetic field of 80 A / m is applied in the longitudinal direction of the nanocrystalline alloy thin band. L And, when a magnetic field of 80 A / m is applied in the width direction perpendicular to the longitudinal direction, the magnetic flux density B80 W The ratio of (B80 L / B80 W ) is 0.80~1.20 and B80 L B80 WBoth are 1.0T or more. <1> from <10> A method for producing a nanocrystalline alloy thin strip as described in any one of the items. <12> The aforementioned nanocrystalline alloy thin strip has a coercivity Hc of 25 A / m or less, an iron loss (1 T, 1 kHz) of 15 W / kg or less, and a saturation magnetostriction of 20 ppm or less. <1> from <11> A method for producing a nanocrystalline alloy thin strip as described in any one of the items. <13> The amorphous alloy strip has a thickness of 20 μm or more and a width of 10 mm or more. <1> from <12> A method for producing a nanocrystalline alloy thin strip as described in any one of the items. <14> In a nanocrystalline alloy thin strip having a structure in which crystal grains with an average particle size of 30 nm or less are present in the amorphous phase, Composition formula (Fe 1-x A x ) a Si b B c Cu d M e Represented as follows, where A is at least one of Ni and Co, and M is at least one selected from Nb, Mo, V, Zr, Hf, and W, with atomic percent values ​​of 80.0 ≤ a ≤ 87.0, 0 ≤ b ≤ 9.0, 12.0 ≤ c ≤ 16.0, 0 ≤ d ≤ 1.5, 0 ≤ e ≤ 1.5, and 0 ≤ x ≤ 0.1. The saturation magnetic flux density Bs is 1.75T or higher. Magnetic flux density B80 when a magnetic field of 80 A / m is applied in the longitudinal direction of a nanocrystalline alloy thin band. L And, when a magnetic field of 80 A / m is applied in the width direction perpendicular to the longitudinal direction, the magnetic flux density B80 W The ratio of (B80 L / B80 W ) is 0.80~1.20 and B80 L B80 W Both are nanocrystalline alloy thin strips with a thickness of 1.0T or higher. <15> In the above compositional formula, 82.0≦a≦86.5, 0.01≦b≦3.0, 13.0≦c≦15.0, 0.01≦d≦1.5, and 0≦e≦1.5. <14> The nanocrystalline alloy thin strip described above. <16> The wrinkle height on the surface of the nanocrystalline alloy thin strip is 0.15 mm or less, and the packing density is 84.0% or more. <14> or <15> The nanocrystalline alloy thin strip described above. <17> The coercivity Hc is 25 A / m or less, the iron loss (1 T, 1 kHz) is 15 W / kg or less, and the saturation magnetostriction is 20 ppm or less. <14> from <16> A nanocrystalline alloy thin strip as described in any one of the items. <18> The thickness is 20 μm or more, and the width is 10 mm or more. <14> from <17> A nanocrystalline alloy thin strip as described in any one of the items. [Effects of the Invention]

[0013] According to this disclosure, it is possible to provide a method for producing nanocrystalline alloy thin strips that have excellent magnetic properties and isotropy, as well as nanocrystalline alloy thin strips that have suppressed wrinkles or streaks and achieve a high packing density, in a highly productive manner. Furthermore, this method can provide nanocrystalline alloy thin strips that possess excellent magnetic properties and isotropy, as well as nanocrystalline alloy thin strips that suppress wrinkles or streaks and achieve a high packing density. [Brief explanation of the drawing]

[0014] [Figure 1] This is a conceptual diagram showing one embodiment of the heat treatment method disclosed herein. [Figure 2] This is a conceptual diagram showing another embodiment of the heat treatment method of the present disclosure. [Figure 3] This is a conceptual diagram showing another embodiment of the heat treatment method of the present disclosure. [Figure 4] This is a laser microscope image evaluating the wrinkle height of the amorphous alloy strip of sample No. 4 in this disclosure before heat treatment. [Figure 5] This is a laser microscope image evaluating the wrinkle height of sample No. 8 in this disclosure. [Figure 6] This is a laser microscope image showing the evaluation of the wrinkle height of sample No. 9 in this disclosure. [Figure 7] This is a laser microscope image evaluating the wrinkle height of sample No. 4 in this disclosure. [Figure 8] This is an example of a temperature profile during heat treatment as disclosed herein. [Modes for carrying out the invention]

[0015] The embodiments of this disclosure will be described in detail below. This disclosure is not limited to the embodiments described below and may be implemented with appropriate modifications within the scope of the purposes of this disclosure.

[0016] In this disclosure, numerical ranges indicated using "~" represent ranges that include the numbers before and after "~" as the lower and upper limits, respectively. In numerical ranges described in stages in this disclosure, the upper or lower limit stated in one numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Furthermore, in numerical ranges described in this disclosure, the upper or lower limit stated in one numerical range may be replaced with the values ​​shown in the examples. In this disclosure, a combination of two or more preferred embodiments is a more preferred embodiment.

[0017] The nanocrystalline alloy thin strip disclosed herein has the compositional formula (Fe 1-x A x ) a Si b B c Cu d M e Represented as , where A is at least one of Ni and Co, and M is at least one selected from Nb, Mo, V, Zr, Hf, and W, with atomic % values ​​of 80.0 ≤ a ≤ 87.0, 0 ≤ b ≤ 9.0, 12.0 ≤ c ≤ 16.0, 0 ≤ d ≤ 1.5, 0 ≤ e ≤ 1.5, and 0 ≤ x ≤ 0.1.

[0018] The composition of the nanocrystalline alloy strips of this disclosure will be described in detail below. The atomic percentage of Fe (iron) is between 80.0% and 87.0%. A high saturation magnetic flux density can be obtained by setting the Fe content to 80.0% or more. Preferably, it is 81% or more, more preferably 82.0% or more, even more preferably 82.5% or more, even more preferably 83% or more, even more preferably 83.5% or more, and even more preferably 84% or more. Furthermore, since amorphous formation becomes difficult if the Fe content exceeds 87.0%, the Fe content should be 87.0% or less. Preferably, it should be 86.5% or less, and even more preferably 86% or less.

[0019] Furthermore, some of the Fe may be substituted with at least one of the elements Ni and Co. (Fe 1-x A x When x is set to ), A is at least one of Ni and Co, and x is 0.1 or less. Substituting a portion of Fe with element A is optional, and x can be 0. Substituting a small amount of Ni has the effect of suppressing grain size growth and reducing coercivity. However, the effect becomes less when x exceeds 0.1 and the saturation magnetic flux density is significantly reduced. Preferably x is 0.05 or less, and more preferably 0.03 or less. Substituting Fe with Co has the effect of increasing the saturation magnetic flux density, but it is very expensive and increases coercivity and iron loss, so it is good to have x 0.1 or less, preferably 0.05 or less, and more preferably 0.03 or less.

[0020] When some of the Fe is replaced with at least one of the elements Ni and Co, (Fe 1-x A x ) a The value of 'a' represented by the above-mentioned Fe range of 80.0% to 87.0% (80.0 ≤ a ≤ 87.0). Preferably it is 81% or more, more preferably 82.0% or more, more preferably 82.5% or more, more preferably 83% or more, more preferably 83.5% or more, and more preferably 84% or more. Also preferably it is 86.5% or less, and more preferably 86% or less.

[0021] The atomic percentage of silicon (Si) is between 0% and 9.0%. The Si content can be 0%. The inclusion of Si allows for the formation of an SiO2 oxide film several tens of nanometers thick on the alloy surface. This improves the corrosion resistance of the nanocrystalline alloy strip. To achieve this improved corrosion resistance, it is preferable to include 0.01% or more Si. More preferably, it should be 0.15% or more, and even better, 1.0% or more. If the Si content exceeds 9.0%, it becomes difficult to obtain a high saturation magnetic flux density, and it also becomes difficult to increase the thickness of the alloy strip. For this reason, the Si content should be 9.0% or less. Preferably, it should be 5.0% or less, preferably 4% or less, more preferably 3.0% or less, and even more preferably 2% or less.

[0022] The amount of boron (B) is between 12.0% and 16.0% in atomic percent. Since amorphous formation becomes difficult if the B content is less than 12.0%, the B content should be 12.0% or more. Preferably, it should be 12.5% ​​or more, more preferably 13.0% or more, and even more preferably 13.5% or more. If the B content exceeds 16.0%, the difference between the bccFe(αFe) crystallization start temperature and the FeB precipitation start temperature decreases, narrowing the temperature range in which heat treatment is possible. A narrower temperature range in which heat treatment is possible can easily affect productivity. Therefore, the B content should be 16.0% or less. Preferably, it should be 15.0% or less, more preferably 14.5% or less, and even more preferably 14.4% or less.

[0023] The amount of copper (Cu) is between 0% and 1.5% in atomic percent. The Cu content can be 0%, but including Cu makes it easier to obtain a uniform, fine nanocrystalline structure. In particular, including Cu is preferable to reduce iron loss. For this reason, the Cu content is preferably 0.01% or more. More preferably 0.05% or more, and even more preferably 0.1% or more. It may also be 0.2% or more, or 0.4% or more, or 0.5% or more. If the Cu content exceeds 1.5%, the material becomes brittle, making it difficult to increase the thickness of the soft magnetic alloy strip. For this reason, the Cu content should be 1.5% or less. Preferably, it should be 1.0% or less, and more preferably 0.9% or less. It may also be 0.85% or less, or 0.7% or less, or 0.6% or less.

[0024] The M element is at least one selected from Nb, Mo, V, Zr, Hf, and W, and its atomic percentage is between 0% and 1.5%. The amount of element M may be 0%, but including element M can shift the precipitation start temperature of the FeB compound, which significantly degrades soft magnetism, to a higher temperature. This widens the difference between the bccFe(αFe) crystallization start temperature and the FeB precipitation start temperature, which has the effect of expanding the range of optimal heat treatment temperatures and relaxing the heat treatment conditions. Preferably, it is 0.1% or more, and more preferably 0.15% or more. Since element M is expensive, its price increases. Therefore, a lower content is preferable. Accordingly, the content of element M should be 1.5% or less. Preferably, it should be 1.0% or less, and more preferably 0.9% or less. It may also be 0.8% or less, or 0.7% or less, or 0.6% or less. Furthermore, the amount of element M is preferably less than 0.4%, more preferably 0.3% or less, and even more preferably 0.25% or less.

[0025] The nanocrystalline alloy strips of this disclosure may contain carbon (C). The amount of C is preferably 1% by mass or less. The inclusion of C is expected to improve the fluidity of the molten metal (reducing its viscosity), improve adhesion to the cooling roll, and contribute to surface smoothing of the alloy strip. Furthermore, C tends to segregate on the surface of the alloy strip, and when it diffuses to the surface during heat treatment, it is expected to promote structural relaxation and improve the angularity of the DC BH curve. When C is included, it is preferably 0.03% by mass or more.

[0026] Furthermore, the nanocrystalline alloy strips of this disclosure may contain impurities other than the elements mentioned above. Examples of impurities include sulfur (S), oxygen (O), nitrogen (N), Cr, manganese (Mn), phosphorus (P), titanium (Ti), and aluminum (Al). For example, the S content is preferably 200 ppm by mass or less, the O content is preferably 5000 ppm by mass or less, the N content is preferably 1000 ppm by mass or less, the Ti content is preferably 1000 ppm by mass or less, and the Al content is preferably 1000 ppm by mass or less. The total content of these impurities is preferably 0.5% by mass or less. Furthermore, elements corresponding to impurities may be added as long as they are within the above range.

[0027] The method for manufacturing the nanocrystalline alloy thin strip described herein will now be explained. The nanocrystalline alloy strip of this disclosure can be obtained by ejecting a molten alloy having the above-described alloy composition onto a rotating cooling roll, rapidly cooling and solidifying it on the cooling roll to obtain an alloy strip, and then heat-treating the alloy strip. The alloy strip obtained by rapidly cooling and solidifying the molten alloy has an amorphous alloy structure and is an amorphous alloy strip. By heat-treating this amorphous alloy strip, a nanocrystalline alloy strip can be obtained. The amorphous alloy strip obtained by rapidly cooling and solidifying the molten alloy may contain a crystalline phase consisting of fine crystals.

[0028] A molten alloy can be produced by mixing various elemental sources (pure iron, ferroboron, ferrosilicon, etc.) that make up the desired alloy composition, heating them in an induction furnace, and melting them above their melting point. A thin alloy strip can be obtained by ejecting molten alloy from a slit-shaped nozzle of a predetermined shape onto a rotating cooling roll, and rapidly cooling and solidifying the molten alloy on the cooling roll. In this case, the cooling roll can have an outer diameter of 350 to 1000 mm, a width of 100 to 400 mm, and a rotational speed of 20 to 35 m / sec. This cooling roll is equipped with an internal cooling mechanism (such as water cooling) to suppress the temperature rise of the outer circumference. Furthermore, it is preferable that the outer periphery of the cooling roll is made of a Cu alloy with a thermal conductivity of 120 W / (m·K) or higher. By making the thermal conductivity of the outer periphery 120 W / (m·K) or higher, the cooling rate when the molten alloy is cast into an alloy strip can be increased. This suppresses the embrittlement of the alloy strip, enables the thickness of the alloy strip, and suppresses surface crystallization during casting, thereby suppressing grain coarsening during heat treatment and reducing iron loss.

[0029] Furthermore, the thermal conductivity of the outer periphery of the cooling roll is preferably 150 W / (m·K) or higher, and more preferably 180 W / (m·K) or higher. In particular, when the thickness of the nanocrystalline alloy strip is 30 μm or more, it is preferable that the thermal conductivity of the outer periphery be 150 W / (m·K) or higher. The outer circumference of the cooling roll is the part that comes into contact with the molten alloy, and its thickness should be approximately 5 to 15 mm. The inner part should be made of a structural material that maintains the roll structure.

[0030] A nanocrystalline alloy strip is obtained by heat-treating an amorphous alloy strip produced by the rapid cooling method described above. The method for producing a nanocrystalline alloy strip according to this disclosure is characterized by its heat treatment method.

[0031] The heat treatment method of the present disclosure is a method of heating an amorphous alloy strip by bringing it into contact with a heating element. When heating an amorphous alloy strip by bringing it into contact with a heating element, the amorphous alloy strip is transported, and a strip-holding member contacts the opposite side of the amorphous alloy strip that is in contact with the heating element, so that the amorphous alloy strip is heated while sandwiched between the heating element and the strip-holding member. When the crystallization start temperature of bccFe measured at a heating rate of 20 K / min for an amorphous alloy thin strip is defined as Tx1°C, the heating temperature Ta of the heating element is set to a temperature between Tx1 + 80°C and Tx1 + 160°C. It is preferable that the heating rate of the amorphous alloy strip be set to 50°C / sec to 4000°C / sec. Furthermore, it is preferable that the transport speed of the amorphous alloy strip be 1 m / min or more.

[0032] In this disclosure, a flexible member may be pressed against the opposite side of the amorphous alloy strip from the side in contact with the heating element to press the amorphous alloy strip against the heating element. As the flexible component, a metal component is preferable. Furthermore, the thin strip retaining member may be a belt or a roll.

[0033] An example of a heat treatment method described herein is explained. Figure 1 is a conceptual diagram showing one embodiment of the heat treatment method of this disclosure. The heat treatment method shown in Figure 1 comprises a heating roller 2 which serves as a heating element, a thin strip retaining metal belt 3 (thin strip retaining member), and rollers 4 and 5 which support the thin strip retaining metal belt 3.

[0034] The heating roller 2 and the thin strip holding metal belt 3 (thin strip holding member) are positioned to be in contact with each other, and the amorphous alloy thin strip 1 is heated while sandwiched between the heating roller 2 (heating body) and the thin strip holding metal belt 3.

[0035] At this time, the amorphous alloy strip 1 is pressed against the heating element (heating roller 2) by the strip-holding metal belt 3 (strand-holding member). Alternatively, the strip-holding metal belt 3 (strand-holding member) may be pressing the amorphous alloy strip 1 against the heating element (heating roller 2), or the heating element (heating roller 2) may be pressing the amorphous alloy strip 1 against the strip-holding metal belt 3 (strand-holding member). Hereafter, the explanation will assume that the amorphous alloy strip 1 is pressed against the heating element (heating roller 2) by the strip-holding metal belt 3 (strand-holding member).

[0036] In Figure 1, the arrows indicate the movement of each part, and the heating rollers 2, 4, and 5 are structured to rotate. As a result, the amorphous alloy thin strip 1 (hereinafter also referred to as thin strip 1) is heated while being transported and pressed against the heating roller 2. It is preferable to use heating rollers 4 and 5 that can also be heated. This makes it preferable to heat the thin strip holding metal belt 3. When rollers 4 and 5 are heating rollers, it is preferable to set the temperature of the thin strip holding metal belt 3 (the temperature when it is in contact with the thin strip 1) to be the same as or slightly lower than the heating temperature of the thin strip 1. The temperature of rollers 4 and 5 should be set to a temperature that is appropriate for the temperature of the thin strip holding metal belt 3. For example, it is also desirable to set the temperature of rollers 4 and 5 about 50°C higher than the temperature of the heating element. The temperatures of the thin strip holding metal belt 3 and rollers 4 and 5 can be selected to be suitable for the heat treatment of the thin strip 1.

[0037] The thin metal belt 3 is an example of a flexible member, and from the viewpoint of flexibility and strength, a metal member is preferred for the flexible member. For example, it is more preferable to use a material with excellent heat resistance, such as heat-resistant stainless steel or nickel-based superalloy. According to the heat treatment method described above, a flexible member (thin strip retaining metal belt 3) is pressed against the opposite side of the amorphous alloy thin strip 1 from the side that contacts the heating element, thereby pressing the amorphous alloy thin strip 1 against the heating element (heating roller 2). Preferably, the amorphous alloy thin strip 1 is in close contact with the heating roller 2 by the thin strip retaining metal belt 3, and the amorphous alloy thin strip 1, the thin strip retaining metal belt 3, and the heating roller 2 move as a single unit.

[0038] Here, the heating roller 2 is a heating element (heating element of this disclosure) for heating the amorphous alloy thin strip by directly contacting it. The amorphous alloy thin strip 1 is heated by contacting a part of the outer surface (a part of the circumferential region) of the cylindrical heating roller 2. The heating roller 2 may be provided with a driving force for transporting the amorphous alloy thin strip. The rollers for driving the thin strip holding metal belt 3 may be both rollers 4 and 5, or just one of them. The roller 5 may be provided with a driving force, and roller 4 may be mechanically subordinate to it. By doing so, complex control such as electrically synchronized operation of rollers 4 and 5 can be avoided, and furthermore, there is no need to correct for synchronization misalignment due to the difference in thermal expansion between rollers 4 and 5.

[0039] The heating roller 2 is an example of a heating element having a convex surface for heating an amorphous alloy strip by contact with it. The "convex surface" refers to a raised surface on the amorphous alloy strip side, and can be any shape that allows the amorphous alloy strip to follow and ensure sufficient contact, such as the curved side surface of a cylindrical (cylindrical) shape as shown in the roller in Figure 1, or a curved surface that is part of a component, such as the curved surface of a semi-circular member.

[0040] Figure 2 is a conceptual diagram showing another embodiment of the heat treatment method of the present disclosure. The heat treatment method shown in Figure 2 includes a heating roller 2, which serves as the heating element, and thin strip pressing rollers 6, 7, and 8, which act as thin strip pressing members to press the amorphous alloy thin strip 1 against the heating roller 2. The thin strip 1 is passed between the heating roller 2 (heating element) and the thin strip pressing rollers 6, 7, and 8, and heated while being pressed against the heating element (heating roller 2). The arrows indicate the movement of each part, and the heating roller 2 and the thin strip pressing rollers 6, 7, and 8 are structured to rotate. As a result, the amorphous alloy thin strip 1 is heated while being transported and pressed against the heating roller 2. It is preferable to use heating rollers that can also heat the thin strip pressing rollers 6, 7, and 8.

[0041] Figure 3 is a conceptual diagram showing another embodiment of the heat treatment method of this disclosure. The heat treatment method shown in Figure 3 uses a semicircular heating element 32 instead of the heating roller 2 in Figure 1, and includes a thin strip pressing metal belt 33 and rollers 34 and 35 that support the thin strip pressing metal belt 33 as means for pressing the amorphous alloy thin strip 1 against the heating element 32. The thin strip 1 is passed between the heating element 32 and the thin strip pressing metal belt 33 (thin strip pressing member), and the thin strip 1 is heated while being pressed against the heating element 32. The arrows indicate the movement of each part, and the rollers 34 and 35 are structured to rotate. As a result, the amorphous alloy thin strip 1 is heated while being conveyed and pressed against the heating element 32. It is preferable to use heating rollers that can also heat the rollers 34 and 35. As a result, it is preferable to heat the thin strip pressing metal belt 33.

[0042] As shown in Figures 1, 2, and 3, when heating an amorphous alloy strip by bringing it into contact with a heating element, the amorphous alloy strip can be heated while being transported, with the strip sandwiched between the heating element and the strip-holding member. In this case, it is preferable to set the heating rate of the amorphous alloy strip to 50°C / sec to 4000°C / sec. When obtaining a nanocrystalline alloy strip by heat treatment, the heating rate required to achieve a fine nanocrystalline structure varies depending on the composition, but a faster heating rate is required for compositions with low Cu, low M content, and high Fe content that can obtain a high saturation magnetic flux density. In the case of the composition of this disclosure, the lower limit of the heating rate is 50°C / sec, and the upper limit can be determined by the equipment capacity of the heat treatment apparatus, the temperature of the heating element and the strip pressing member, the contact state between the heating element and the strip and the strip, etc., but is substantially around 4000°C / sec. Preferably it is 500°C / sec or higher.

[0043] The heating element preferably has a width wider than the width of the amorphous alloy strip. This ensures that when the amorphous alloy strip is pressed against the heating element, the entire width of the strip is in close contact with the heating element. Furthermore, when the amorphous alloy strip is pressed against the heating element and heated, the distance from contact to separation from the heating element is preferably 50 mm or more along the length of the heating element surface. More preferably, this distance from contact to separation from the heating element is 150 mm or more along the length of the heating element surface. The transport speed for amorphous alloy strips is preferably 1 m / min or more. In mass production, increasing the transport speed increases the production volume, so a transport speed of 10 m / min or more is more preferable. The contact time between the amorphous alloy strip and the heated object is preferably 0.1 to 30 seconds. The lower limit of the contact time is more preferably 0.2 seconds, the upper limit is more preferably 10 seconds, even more preferably 5 seconds, and most preferably 2 seconds. To improve mass productivity, when increasing speed and stabilization, it is preferable to set the contact time to 0.2 to 2 seconds.

[0044] When heat-treating amorphous alloy strips, the maximum temperature reached by the strip may exceed the heating element temperature due to self-heating associated with crystallization. If the temperature of the amorphous alloy strip becomes too high, the desired magnetic properties cannot be obtained. Therefore, when the FeB precipitation start temperature measured at a heating rate of 20 K / min is defined as Tx2°C, it is preferable to control the strip temperature so that it is Tx2 + 160°C or lower. The heating temperature Ta, transport speed, etc., are set to enable this control. If the temperature exceeds Tx2 + 160°C, FeB will precipitate, and the magnetic properties will deteriorate significantly.

[0045] According to the heat treatment method of this disclosure, by pressing an amorphous alloy strip against a heating element, contact between the heating element and the strip is improved, heat transfer is enhanced, and the heating rate is increased. In addition, more of the heat generated by crystallization can be dissipated by the heating element and the pressing belt or roll, thereby suppressing the maximum temperature of the strip (suppressing the temperature rise due to self-heating). Furthermore, pressing with a belt or roll can suppress wrinkles or streaks that tend to occur during crystallization. As a result, heat treatment at higher temperatures becomes possible, enabling a faster heating rate and heat treatment with a shorter contact time. Therefore, productivity can be improved, a uniform nanocrystalline structure can be obtained, and a nanocrystalline alloy strip with a higher saturation magnetic flux density and superior magnetic properties can be obtained.

[0046] [Heating rate and maximum temperature of amorphous alloy strips during heat treatment] The heating rate and maximum temperature of amorphous alloy strips during heat treatment were confirmed using the following method. The surface temperature of the amorphous alloy thin strip was measured using a radiation thermometer FLHX-TNE0090 manufactured by Japan Sensor Co., Ltd. Since this radiation thermometer can only perform fixed-point measurements, the temperature measurement of the amorphous alloy thin strip during heat treatment was performed without transporting the strip. As shown in Figure 3, the thin strip retaining metal belt 33 was not driven, the thin strip 1 was placed between the thin strip retaining metal belt 33 and the heating element 32, and tension was applied to the thin strip retaining metal belt 33 to press the thin strip 1 against the heating element 32. The strip was then held in place for a predetermined time, and its temperature was measured. This allowed for confirmation of the temperature change of the thin strip after it was pressed against the heating element. Figure 8 shows an example of a measured temperature profile. The X-axis represents time (seconds), and the Y-axis represents the measured temperature of the thin strip. The measurement was taken by pressing the thin strip against a heating element heated to a set temperature (520°C) using the method described above. The contact time in Figure 8 is the time the thin strip was pressed against the heating element. According to this measurement method, the temperature of the thin strip rises to about 400°C before contact with the heating element. Therefore, the heating rate was calculated as the temperature change from the moment of contact with the heating plate until the set temperature (520°C) was reached, divided by time, as shown in Figure 8. The maximum temperature of the thin strip was defined as the maximum temperature of the peak that appeared after the thin strip came into contact with the heating element. The temperature of the thin strip was measured by drilling a measurement hole in the thin strip holding metal belt 33.

[0047] The pressure applied to press the amorphous alloy strip against the heated body is preferably 0.03 MPa or higher. More preferably 0.04 MPa or higher, and even more preferably 0.05 MPa or higher. To further improve contact between the amorphous alloy strip and the heating element, it is also effective to give the heating element curvature. Preferably, the radius of curvature of the heating element is 25 mm or more. To increase the heating rate when heating amorphous alloy strips, it is effective to heat the pressing belt or roll to the same temperature as the heating element and heat the strip from both sides. In Figures 1, 2, and 3, heated rolls are used as rolls 4, 5, 6, 7, 8, 34, and 35. To suppress the heat generation during bccFe crystallization of the strip, it is also effective to set the temperature of the belt or roll lower than the heating plate temperature (Ta°C).

[0048] According to this disclosure, it is possible to obtain nanocrystalline alloy thin strips that have excellent magnetic properties and isotropy, as well as nanocrystalline alloy thin strips that suppress wrinkles or streaks and achieve a high packing density.

[0049] The nanocrystalline alloy thin strip of this disclosure preferably has a saturation magnetic flux density Bs of 1.75T or higher, and more preferably 1.80T or higher. Furthermore, the nanocrystalline alloy thin strip of this disclosure has a magnetic flux density B80 when a magnetic field of 80 A / m is applied in the longitudinal direction of the nanocrystalline alloy thin strip. LAnd, when a magnetic field of 80 A / m is applied in the width direction perpendicular to the longitudinal direction, the magnetic flux density B80 W The ratio of (B80 L / B80 W ) is 0.80~1.20 and B80 L B80 W It is preferable that both be 1.0T or higher. (B80 L / B80 W ) is more preferably 0.90 to 1.10.

[0050] The nanocrystalline alloy strip of this disclosure preferably has a packing density of 84.0% or more. The packing density is preferably 86% or more, and more preferably 88% or more. The space factor can be measured using the following method in accordance with JIS C 2534:2017. Twenty thin strips, each cut to a length of 120 mm, are stacked and placed on a flat sample stage. A flat anvil with a diameter of 16 mm is placed on the stacked strips under a pressure of 50 kPa, and the height is measured at 10 mm intervals in the width direction. The maximum height at that time is defined as hmax (μm), and the packing fraction LF is calculated using the following formula: LF (%) = weight of sample (g) / density (g / cm³). 3 ) / hmax(μm) / sample length (240cm) / thin band width (cm) × 10000 At this time, density (g / cm³) 3 This value represents the density of the alloy strip after heat treatment. This density is 7.5 g / cm³. 3 It can be done this way.

[0051] When an amorphous alloy strip is heated in contact with a heating element to transform it into a nanocrystalline alloy strip, variations in the contact between the amorphous alloy strip and the heating element can lead to localized differences in the heating rate and temperature of the amorphous alloy strip, resulting in differences in the progression of crystallization. This causes localized strain, leading to the problem of the alloy strip lifting away from the heating element. In the lifted areas, self-heating due to crystallization is less able to escape to the heating element, causing the alloy strip temperature to rise rapidly, reaching the FeB deposition temperature and making it prone to wrinkles or streaks. As a result, the packing density decreases, and the wrinkled or streaked areas become very brittle, leading to handling problems such as cracking during transport and stacking, as well as deterioration of magnetic properties.

[0052] According to this disclosure, by pressing the amorphous alloy strip against the heating element using a strip-holding member that contacts the opposite side of the amorphous alloy strip that contacts the heating element, the amorphous alloy strip can be heated uniformly, and the pressing action suppresses the lifting of the alloy strip, thereby suppressing the occurrence of wrinkles or streaks. Furthermore, it also has the effect of correcting wrinkles and other defects caused by cooling variations that occur during the casting of amorphous alloy strips. As a result, according to this disclosure, wrinkles and streaks are suppressed, and a nanocrystalline alloy strip with good flatness can be obtained. The nanocrystalline alloy strips of this disclosure preferably have a wrinkle or streak height of 0.15 mm or less. More preferably, they have a wrinkle or streak height of 0.10 mm or less. In this disclosure, the wrinkle or streak height is also referred to as "wrinkle height." The wrinkle height can be evaluated by the method described in the following examples.

[0053] The nanocrystalline alloy thin strip of the present disclosure preferably has a coercivity Hc of 25 A / m or less, preferably 15 A / m or less, an iron loss (1 T, 1 kHz) of 15 W / kg or less, preferably 10 W / kg or less, and a saturation magnetostriction of 20 ppm or less, preferably 15 ppm.

[0054] The nanocrystalline alloy strip of this disclosure preferably has a thickness of 20 μm or more, more preferably 25 μm or more, and even more preferably 30 μm or more. It preferably has a width of 10 mm or more, more preferably 100 mm or more, and even more preferably 200 mm or more. Furthermore, since good magnetic properties become difficult to obtain as the thickness of the nanocrystalline alloy strip of this disclosure increases, it is preferable to have a thickness of 50 μm or less. More preferably, it is 40 μm or less. Also, since stable production becomes difficult if the width of the nanocrystalline alloy strip of this disclosure becomes too wide, it is preferable to have a width of 500 mm or less. More preferably, it is 400 mm or less.

[0055] The nanocrystalline alloy thin strips disclosed herein can be used to form magnetic cores for use in transformers, electronic components, motors, and the like, thereby obtaining magnetic cores with excellent properties. When constructing a magnetic core, it can be done by cutting alloy strips into a predetermined shape and stacking them, winding alloy strips, or stacking and bending alloy strips. Furthermore, by combining the magnetic core and windings of this disclosure to construct components such as transformers, electronic components, and motors, components with excellent properties can be obtained. In this case, the magnetic core of this disclosure may be combined with a magnetic core made of other magnetic materials.

[0056] [Example 1] Elemental sources were mixed to achieve the compositions shown in Table 1, heated to 1300°C to produce molten alloy, and this molten alloy was ejected onto a cooling roll with an outer diameter of 400 mm and a width of 200 mm, rotating at a peripheral speed of 30 m / s. The molten alloy was then rapidly cooled and solidified on the cooling roll to produce an amorphous alloy strip. The outer periphery of the cooling roll is made of a Cu alloy with a thermal conductivity of 150 W / (m·K), and it is equipped with a cooling mechanism inside for temperature control of the outer periphery. The resulting amorphous alloy strip had a width of 50 mm and a thickness of 30 μm. For each amorphous alloy thin strip, measurements were taken using a Rigaku differential scanning calorimeter DSC8231 at a heating rate of 20 K / min to determine the crystallization start temperature (Tx1°C) for bccFe(αFe) and the FeB precipitation start temperature (Tx2°C). The results are shown in Table 1.

[0057] Using amorphous alloy strips of each material shown in Table 1, nanocrystalline alloy strips were fabricated by heat treatment under varying heat treatment conditions. The conditions and evaluation results are shown in Tables 2 and 3. Blank spaces in the tables indicate that measurements were not taken.

[0058] For each sample (nanocrystalline alloy thin strip), iron loss, saturation magnetic flux density Bs, magnetic flux density B80, coercivity Hc, saturation magnetostriction, grain size, volume fraction, wrinkle height, and packing fraction were measured. The details of each measurement are as follows.

[0059] [Iron loss] A heat-treated single-plate sample was measured using a Toei Kogyo AC magnetic field measuring device TWM18SR under conditions of magnetic flux density 1T and frequency 1kHz.

[0060] [Saturated magnetic flux density Bs] A magnetic field of 8000 A / m is applied to a heat-treated single-plate sample using a DC magnetization characteristic tester manufactured by Metron Giken, and the maximum magnetic flux density at that time is measured and defined as Bs. Since the nanocrystalline alloy thin strip of this disclosure has a relatively easy-to-saturate property, it is saturated when a magnetic field of 8000 A / m is applied, and B 8000 Since the saturation magnetic flux density Bs is approximately the same value, the saturation magnetic flux density Bs is set to B 8000 It is represented as follows.

[0061] [Magnetic flux density B80] Using a DC magnetization characteristic testing device manufactured by Metron Giken, a magnetic field of 80 A / m was applied to the longitudinal direction (casting direction) and the width direction perpendicular to the longitudinal direction of a nanocrystalline alloy thin strip, and the maximum magnetic flux density at that time was measured as B80. L B80 W And the ratio B80 L / B80 W The coefficient was calculated, and the isotropy was evaluated.

[0062] [Coercive force Hc] Using a DC magnetization characteristic testing device manufactured by Metron Giken, a magnetic field of 8000 A / m was applied to the longitudinal direction (casting direction) of a nanocrystalline alloy thin strip. The magnetic field was then gradually weakened, and the magnetic field at which the magnetic flux density became 0 T was defined as the coercivity.

[0063] [Saturated magnetostriction] A strain gauge manufactured by Kyowa Electric Industry was attached to a sample, and a magnetic field of 5 kOe was applied using an electromagnet. The electromagnet was rotated 360°, changing the direction of the magnetic field applied to the sample by 360°. The maximum change in the elongation and contraction of the sample was measured from the change in the electrical resistance of the strain gauge. Saturation magnetostriction was defined as 2 / 3 × maximum change.

[0064] [Particle size] Particle size refers to the average particle size of a nanocrystal. The average grain size of the nanocrystals was determined using Scherrer's equation, employing the full width at half maximum (FMAX) of the diffraction peak from the (110) plane in the X-ray diffraction pattern obtained from X-ray diffraction experiments. The FMAX of the (110) peak was determined by peak decomposition using a pseudo-Voigt function for the diffraction pattern. If the average grain size is D, the FMAX is W, the diffraction angle is θ, Scherrer's constant is K, and the X-ray wavelength is λ, then D can be determined from Scherrer's equation (Equation 1) given below. In this case, we assumed an X-ray wavelength λ = 0.154050 nm and a Scherrer constant K = 0.891.

[0065]

number

[0066] [Volume ratio] The volume fraction is the volume fraction of the nanocrystals, and the non-nanocrystal portion is the amorphous portion. This volume fraction is determined by the ratio of the integrated intensity of the nanocrystal to the integrated intensity of (crystal + amorphous). The integrated intensities of the peaks shown by the nanocrystal and the halo patterns shown by the amorphous material are obtained by peak decomposition using a pseudo-Voigt function for the X-ray diffraction pattern. If Ic is the sum of the integrated intensities of all the peaks shown by the nanocrystal and Ia is the sum of the integrated intensities of all the halo patterns shown by the amorphous material, then the volume fraction V can be obtained from the following equation (Equation 2).

[0067]

number

[0068] [Wrinkle height] Wrinkle height refers to the height of wrinkles or streaks formed on the surface of the thin strip. The height of the surface of each sample (nanocrystalline alloy thin strip) was measured using a Keyence VR3200 laser microscope while sandwiched between glass plates, and the difference between the maximum and minimum values ​​was calculated as the wrinkle height. The reason for sandwiching the samples between glass plates is that the thin strips are very thin, and if only the thin strip is placed on the measurement stage, the strip may partially lift due to waviness, affecting the height. The purpose of this was to minimize these effects. The observation field of view of the laser microscope was approximately 18 mm × 25 mm, and measurements were taken at three locations for each sample, with the largest value being taken as the wrinkle height. Glass plates measuring 70 mm × 70 mm and 3 mm thick were used. Figure 4 shows the evaluation results of the amorphous alloy strip of sample No. 4 before heat treatment. Due to the uneven surface of the strip, the wrinkle height was 0.073 mm even before heat treatment. Figure 5 shows the measurement results of a nanocrystalline alloy strip (No. 8) that was heat-treated at 510°C without restraint, using the amorphous alloy strip of sample No. 4 before heat treatment. It can be seen that the wrinkles formed during heat treatment were raised, and the difference between the maximum and minimum values ​​(wrinkle height) was 0.156 mm. The packing density of No. 8 was 83.5%. Figure 6 shows the measurement results of a nanocrystalline alloy strip (No. 9) that was heat-treated at 515°C without restraint, using the amorphous alloy strip of sample No. 4 before heat treatment. Wrinkles were formed almost entirely over the surface, and the difference between the maximum and minimum values ​​(wrinkle height) was 0.381 mm. The packing density of No. 9 was 78.0%. Figure 7 shows the measurement results for sample No. 4, which was heat-treated at a pressing pressure of 0.115 MPa and a heating element temperature of 530°C. There were no wrinkles, and the wrinkle height was 0.052 mm, which was better than that of the amorphous alloy strip. By pressing the strip during heat treatment, wrinkles or streaks can be suppressed, and heat treatment can be performed at a higher temperature than without pressing. Furthermore, the packing density was a good 89.3%. Furthermore, in Example No. 1, a wrinkle height of 0.072 mm was obtained and the space utilization ratio was 89.0%, in Example No. 5, a wrinkle height of 0.043 mm was obtained and the space utilization ratio was 89.2%, and in Example No. 6, a wrinkle height of 0.087 mm was obtained and the space utilization ratio was 89.0%. Furthermore, in embodiment No. 7, the wrinkle height was high at 0.220 mm. In No. 7, the pressing pressure by the thin strip pressing member was low at 0.029 MPa, which is thought to be the reason for the high wrinkle height.

[0069] [Table 1]

[0070] [Table 2]

[0071] [Table 3]

[0072] According to the embodiments of this disclosure, Bs is 1.75T or higher, and B80 L B80 W All of them are 1.0T or higher, and the ratio B80 L / B80 W Materials with coercivity in the range of 0.80 to 1.20 were obtained. Furthermore, they exhibited excellent magnetic properties, with low coercivity (Hc) and iron loss. Thus, nanocrystalline alloy thin strips with excellent magnetic properties and isotropy were obtained. In addition, the wrinkle height was low, and wrinkles or streaks were suppressed, resulting in nanocrystalline alloy thin strips with a high packing density. Moreover, the average particle size of the nanocrystals was 30 nm or less, and nanocrystalline alloy thin strips with a nanocrystal volume fraction of 30% or more were obtained. Samples No. 14, 15, and 16 were heat-treated without pressing the thin strips against the heating element, resulting in a B80 rating. L / B80 W The result was that the coercivity Hc was high, as it did not fall within the range of 0.80 to 1.20. Samples No. 8 and No. 9 were heat-treated without pressing the thin strips against the heating element, resulting in large wrinkle heights and low packing density. Sample No. 19 has a maximum thin band temperature exceeding Tx2 + 160°C, high (poor) coercivity Hc and iron loss, and low B80. L / B80 W It was greater than 1.2.

Claims

1. In a method for producing a nanocrystalline alloy strip having a structure in which crystal grains with an average particle size of 30 nm or less are present in the amorphous phase, the amorphous alloy strip is heated by bringing it into contact with a heating element. The nanocrystalline alloy thin strip is represented by the compositional formula (Fe1-xAx)aSibBcCudMe, where A is at least one of Ni and Co, and M is at least one selected from Nb, Mo, V, Zr, Hf, and W, with atomic percent values ​​of 80.0 ≤ a ≤ 87.0, 0 ≤ b ≤ 9.0, 12.0 ≤ c ≤ 16.0, 0 ≤ d ≤ 1.5, 0 ≤ e ≤ 1.5, and 0 ≤ x ≤ 0.

1. When the amorphous alloy strip is heated by bringing it into contact with the heating element, the amorphous alloy strip is transported, and a strip-holding member contacts the opposite side of the amorphous alloy strip from the side that contacts the heating element, so that the amorphous alloy strip is heated while sandwiched between the heating element and the strip-holding member. A method for manufacturing a nanocrystalline alloy thin strip, wherein, when the bccFe crystallization start temperature measured at a heating rate of 20 K / min of the amorphous alloy thin strip is defined as Tx1°C, the heating element is heated to a heating temperature Ta of Tx1 + 80°C or higher and Tx1 + 160°C or lower.

2. The method for manufacturing a nanocrystalline alloy thin strip according to claim 1, wherein the thin strip holding member is a flexible member.

3. A method for producing a nanocrystalline alloy strip according to claim 1 or claim 2, wherein when the amorphous alloy strip is heated by bringing it into contact with the heating element, the heating rate of the amorphous alloy strip is 50°C / second to 4000°C / second.

4. A method for producing a nanocrystalline alloy strip according to claim 1 or claim 2, wherein when the amorphous alloy strip is heated by bringing it into contact with the heating element, the transport speed of the amorphous alloy strip is 1 m / min or more.

5. A method for producing a nanocrystalline alloy strip according to claim 1 or claim 2, wherein when the amorphous alloy strip is heated by bringing it into contact with the heating element, the contact time between the amorphous alloy strip and the heating element is 0.1 seconds to 30 seconds.

6. A method for producing a nanocrystalline alloy strip according to claim 1 or 2, wherein, when the FeB deposition start temperature measured at a heating rate of 20 K / min for the amorphous alloy strip is Tx2°C, the maximum temperature of the amorphous alloy strip heated in contact with the heating element is controlled to be Tx2 + 160°C or less.

7. A method for producing a nanocrystalline alloy thin strip according to claim 1 or claim 2, wherein in the composition formula, 82.0 ≤ a ≤ 86.5, 0.01 ≤ b ≤ 3.0, 13.0 ≤ c ≤ 15.0, 0.01 ≤ d ≤ 1.5, and 0 ≤ e ≤ 1.

5.

8. The method for manufacturing a nanocrystalline alloy strip according to claim 1 or 2, wherein the amorphous alloy strip is heated while being pressed against the heating element or the strip-holding member, and the pressure applied to the amorphous alloy strip is 0.03 MPa or more.

9. A method for manufacturing a nanocrystalline alloy thin strip according to claim 1 or claim 2, wherein the wrinkle height on the surface of the nanocrystalline alloy thin strip is 0.15 mm or less and the packing density is 84.0% or more.

10. The method for manufacturing a nanocrystalline alloy thin band according to claim 1 or claim 2, wherein the nanocrystalline alloy thin band has a saturation magnetic flux density Bs of 1.75 T or more.

11. A method for manufacturing a nanocrystalline alloy thin strip according to claim 1 or claim 2, wherein the ratio (B80L / B80W) of the magnetic flux density B80L when a magnetic field of 80 A / m is applied in the longitudinal direction of the nanocrystalline alloy thin strip to the magnetic flux density B80W when a magnetic field of 80 A / m is applied in the width direction perpendicular to the longitudinal direction is 0.80 to 1.20, and both B80L and B80W are 1.0T or higher.

12. The method for manufacturing a nanocrystalline alloy thin band according to claim 1 or claim 2, wherein the nanocrystalline alloy thin band has a coercivity Hc of 25 A / m or less, an iron loss (1 T, 1 kHz) of 15 W / kg or less, and a saturation magnetostriction of 20 ppm or less.

13. The method for producing a nanocrystalline alloy thin strip according to claim 1 or claim 2, wherein the amorphous alloy thin strip has a thickness of 20 μm or more and a width of 10 mm or more.

14. In a nanocrystalline alloy thin strip having a structure in which crystalline grains with an average particle size of 30 nm or less are present in the amorphous phase, It is represented by the empirical formula (Fe1-xAx)aSibBcCudMe, where A is at least one of Ni and Co, and M is at least one selected from Nb, Mo, V, Zr, Hf, and W, with atomic percent values ​​of 80.0 ≤ a ≤ 87.0, 0 ≤ b ≤ 9.0, 12.0 ≤ c ≤ 16.0, 0 ≤ d ≤ 1.5, 0 ≤ e ≤ 1.5, and 0 ≤ x ≤ 0.

1. The saturation magnetic flux density Bs is 1.75 T or higher. A nanocrystalline alloy thin strip in which the ratio (B80L / B80W) of the magnetic flux density B80L when a magnetic field of 80 A / m is applied in the longitudinal direction of the nanocrystalline alloy thin strip to the magnetic flux density B80W when a magnetic field of 80 A / m is applied in the width direction perpendicular to the longitudinal direction is 0.80 to 1.20, and both B80L and B80W are 1.0T or greater.

15. The nanocrystalline alloy thin strip according to claim 14, wherein in the composition formula, 82.0 ≤ a ≤ 86.5, 0.01 ≤ b ≤ 3.0, 13.0 ≤ c ≤ 15.0, 0.01 ≤ d ≤ 1.5, and 0 ≤ e ≤ 1.

5.

16. The nanocrystalline alloy thin strip according to claim 14 or claim 15, wherein the wrinkle height on the surface of the nanocrystalline alloy thin strip is 0.15 mm or less and the packing density is 84.0% or more.

17. A nanocrystalline alloy thin strip according to claim 14 or claim 15, wherein the coercivity Hc is 25 A / m or less, the iron loss (1 T, 1 kHz) is 15 W / kg or less, and the saturation magnetostriction is 20 ppm or less.

18. A nanocrystalline alloy strip according to claim 14 or claim 15, having a thickness of 20 μm or more and a width of 10 mm or more.

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