JPH0260753B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for heat treating an amorphous magnetic alloy. More specifically, the present invention relates to a heat treatment method that can efficiently and in large quantities produce thin plates of amorphous magnetic alloys with isotropic induced magnetic anisotropy, high magnetic permeability, and low magnetic loss. Conventionally, as high permeability alloy materials with crystal structure, Fe-Si alloy, Fe-Ni alloy, Fe-Al alloy,
Fe-Si-Al alloys are known and are used in many fields depending on their characteristics. However, these crystalline magnetic alloys still have property and usage drawbacks. Among these, sendust, which is an Fe-Si-Al alloy, is an alloy containing about 10% Si and has a high magnetic permeability, but it has the disadvantage that it cannot be plastically worked. Therefore, its use is limited to special applications where its high hardness is utilized, such as magnetic head elements for VTRs, and is only used after special processing. Also, the frequency characteristics of magnetic permeability are not satisfactory. Further, permalloy alloys are used as iron cores for various types of weak electrical appliances, but they have the disadvantage that their manufacturing method requires a very large number of steps and is expensive. Furthermore, its saturation magnetic flux density is low, limiting its use. Under these circumstances, there is a desire to develop magnetic alloy materials that have excellent properties and are free from drawbacks in use. Among these, amorphous magnetic alloys have recently attracted much attention and are being actively researched. Metals usually exist as crystals in ^which atoms are arranged in an ordered ^state in the solid state.
When solidified by cooling at a high rate of sec, an amorphous alloy with an atomic arrangement similar to that in the molten state is obtained even in the solid state. Even by X-ray diffraction or electron beam diffraction, this amorphous alloy does not show a diffraction image showing a crystalline structure, and has an atomic arrangement that does not have long-range regularity, which is structurally different from crystalline alloys. It is something that you have. Magnetic materials made of such amorphous alloys do not have magnetocrystalline isomerism unlike ordinary crystalline materials, and especially transition metal-metalloid amorphous alloys have a small coercive force (Hc) and have excellent properties. It has excellent properties and uses as a soft magnetic material, such as high electrical resistance, high hardness, good workability in thin plate processing, and easy and inexpensive manufacturing method. It has the above advantages. Conventionally, such amorphous magnetic alloys contain Fe, Co, and Ni as transition metal components, and Si,
Those containing metalloid components such as B, C, and P are known. These have properties depending on their composition, and their uses can be considered depending on their properties, and some of them have been put into practical use. Among these, the Fe-based transition metal, which has Fe as its main component, has a large magnetostriction, but has a large saturation magnetic flux density (Bs) and is low in cost.
Suitable for use as a transformer material. Co-based transition metals, whose main component is Co, are more Bs-based than Fe-based ones.
Although the material is low and the cost is high, it is suitable as a material for magnetic heads because a composition with zero magnetostriction can be obtained. Ni-based materials containing more than a certain amount of Ni have Ni replacing Fe and Co to some extent, so their magnetic permeability is higher than the first two, but their Bs is lower than the first two, so their practical use is not expected. Not yet. As described above, amorphous magnetic alloys with various compositions are known, but the reality is that no one has emerged that greatly exceeds crystalline magnetic alloys in both magnetic permeability and saturation magnetic flux density. It is. For this reason, if magnetic alloys with these compositions can be made amorphous and then subjected to some kind of treatment to particularly increase their magnetic permeability and reduce magnetic loss, they would be preferable as materials for magnetic heads, transformers, etc. The development of such technology is expected. One such technique that has been conventionally used is heat treatment. This heat treatment is performed on an amorphous thin plate after obtaining an amorphous thin plate by ultra-quenching from the liquid phase.
The material is heated to a temperature below the crystallization temperature (Tcry) and then cooled, thereby eliminating internal strain during ribbon production by ultra-quenching and increasing magnetic permeability. However, this heat treatment results in Tc>Tcry
The disadvantage is that it cannot be applied to alloys of In general, Tc and Bs have a positive correlation, and in particular, in Co-based alloys with zero magnetostriction, Tc is
It has the disadvantage that it is almost equal to Tcry and cannot be used as a technique for improving the magnetic permeability of alloys with saturation magnetic flux density higher than this. Also, conversely, Tc＜Tcry
In order to obtain a large magnetic permeability when the Tc becomes large for the alloy, it is necessary to rapidly cool it after heat treatment or to perform complicated cooling temperature control. Although such heat treatment does improve the magnetic permeability of alloys with Tc < Tcry, internal strain occurs during cooling, and as a result, the initial magnetic permeability in particular is lower than that of conventional crystalline alloys. However, it is not possible to obtain particularly good values. It has also been found that this internal strain causes the magnetic permeability to change over time. Therefore, such heat treatment techniques are not effective. In contrast, a technology was developed in which a thin plate obtained by ultra-quenching was heat-treated in a magnetic field.
It is disclosed in Publication No. 73923, Publication No. 52-114421, etc. In particular, in JP-A No. 52-114421, the maximum magnetic permeability μm is obtained by heat treatment in the magnetic field.
It is stated that the results are significantly improved. In this case, it is said that the heat treatment temperature is below the crystallization temperature, and the strength of the magnetic field used is 500 Oe or below, and although no specific method for applying the magnetic field is mentioned, the magnetic field is From the statement "Align the figures in the easy axis direction" (upper left column of page 6 of the same publication), it can be inferred that the magnetic field is applied only from a certain direction. Therefore, the present inventors conducted a wide variety of additional tests and studies on the magnetic field heat treatment technology described in the above-mentioned publication. As a result, the following facts were revealed. That is, if a magnetic field is applied in a certain direction, induced magnetic anisotropy is generated in the amorphous magnetic alloy thin plate with the easy axis in the direction of the magnetic field application. In this case, the axis of easy magnetization is easily oriented, and therefore the residual magnetic flux density (Br) becomes large. At this time, if a magnetic field is applied in the opposite direction, the magnetization and the energy of the magnetic field are reduced, so the 180° movement of the domain wall easily causes magnetization reversal, and the coercive force (Hc) becomes small. Therefore, as mentioned above, since the residual magnetic flux density (Br) increases, it is natural that the maximum magnetic permeability μmBr/Hc as a static magnetization characteristic increases. However, when this magnetic field heat treatment was performed and the magnetic properties were measured, it was confirmed that the magnetic permeability under alternating current conditions decreased. In other words, the initial magnetic permeability decreases, and the magnetic permeability (μ10) under a magnetic field of about 10 mOe decreases.
It also hardly increases. On the other hand, conventionally, particle accelerators that accelerate charged particles such as various ions, electrons, and protons using electric or magnetic fields and give high kinetic energy include DC type accelerators such as Kotscroft type and Vandegraaf type, as well as various types of particle accelerators. Linear accelerators that use electric or magnetic fields, and rotary accelerators such as cyclotrons, synchrotrons, and betatrons are known. Among these, linear accelerators repeatedly accelerate charged particles using an alternating electric field to reach high energy, and generally generate a high-voltage alternating electric field of 20 to 100 MHz and accelerate particles passing through the center. It is something. On the other hand, among these linear accelerators, the linear induction accelerator is known as one for accelerating large currents (Reuyu of Science).
Instruments Vol. 35, p. 886, 1964). This method uses a toroidal magnetic core made of soft magnetic material as a one-turn electric field converter, and generates an electric field in a direction perpendicular to the toroid by passing a pulse current through it, and is a means of heating high-temperature plasma in nuclear fusion. It is considered to be a promising method. In this case, in such a magnetic core, the acceleration force applied to the charged particles is determined by the magnetization change width divided by the magnetization reversal speed, so the magnetization reversal speed must be fast and the magnetization change width must be large. . In addition to such linear induction accelerators, in rotary accelerators such as synchrotrons, when an alternating current is applied, the magnetic core that generates an accelerating electric or magnetic field that changes at a constant frequency, for example, generates an electric or magnetic field converter. In this case as well, the magnetic core is required to have high-speed magnetization reversal and a large magnetic flux change width, as described above. In addition, in various particle beam controllers, a magnetic core is used to convert excitation pulse current, etc. into a pulsed or alternatingly changing electric or magnetic field, and to control the particle beam flux in various ways using this electric or magnetic field. Even in such cases, a high magnetization reversal speed and a large magnetic flux change width are required. By the way, as a crystalline soft magnetic material, Si-
Fe alloy, Fe-Ni alloy, sendust, ferrite, etc. are known. In this, as mentioned above,
Ferrite or Fe-Ni alloy is mainly used as a material for a magnetic core that has a high magnetization reversal speed and accelerates or controls charged particles. However, ferrite has a small saturation magnetic flux density (Bs) of about 5 kG, and the width of change in magnetic velocity due to magnetization reversal is small, so acceleration force and energy conversion efficiency are not sufficient. Further, although the Fe-Ni alloy has a larger Bs than ferrite, its magnetization reversal speed is lower than that of ferrite, and its acceleration force and energy conversion efficiency are not sufficient. Also, Fe ₅₀ Ni ₅₀ has a low electrical resistance, and the one with the highest electrical resistance
However, since it is small at 35μΩ・cm, when it is applied to a magnetic core, it must be made into a thin plate to reduce eddy current loss, and the material cost is high because the thin plate is difficult to process. Furthermore, since the magnetostriction is not zero, there is also the drawback that it is easily influenced by external pressure. In contrast, amorphous magnetic alloys have not yet surpassed the properties of existing crystalline soft magnetic materials when applied to magnetic cores for accelerating or controlling charged particles as described above. In other words, in the magnetic core for accelerating or controlling charged particles as described above, the state of residual magnetization (Br) or saturation magnetization (Bs) of the soft magnetic material constituting the magnetic core can be changed by pulsed current or alternating current. , to generate electric and magnetic fields for acceleration by reversing magnetization. Therefore, as mentioned above, for such magnetic core materials, the acceleration force to charged particles is determined by (magnetic flux change width) / (magnetization reversal time), especially when pulsed current excitation is performed (Br + Bs) / (magnetization reversal time) must be large. On the other hand, Fe-based amorphous magnetic alloys whose main component is Fe as the transition metal have high Bs and
It has a Bs equal to or higher than that of crystalline Fe-Ni alloys, has a small coercive force Hc, and has a high electrical resistance.It can be obtained as a thin plate itself, has low magnetic loss, and has an amorphous structure that allows it to be used externally. It has excellent properties such as low sensitivity to pressure applied by the alloy, and for example, the magnetic flux change width Br+Bs during pulsed current excitation also shows a value close to that of the crystalline Fe-Ni alloy. However, its magnetization reversal time is longer than that of ferrite and crystalline Fe-Ni alloys, so
The acceleration force determined by the magnetic flux change width divided by the magnetization reversal time has not yet surpassed that of a crystalline soft magnetic material. By the way, Bs is determined by the composition of the amorphous magnetic alloy, but it also depends on the magnetic reversal time and Br.
changes depending on the history. Therefore, by performing some kind of treatment on Fe-based amorphous alloy, which is a high Bs material,
Depending on the history of the process, the magnetization reversal time and
If the Br value can be improved, the accelerating force for charged particles will be improved, making it preferable as a magnetic core as described above, and it should also be possible to surpass the properties of crystalline soft magnetic materials. In view of these circumstances, the present inventors set out to investigate the causes of various disparities that conventionally occur when heat treating thin plates of amorphous magnetic alloy obtained by ultra-quenching. Various studies were conducted. As a result, the following was found. That is,
In conventional heat treatment in a magnetic field, a magnetic field is applied from a fixed direction, so that the axis of easy magnetization is induced as described above. In this case, when the magnetic field is changed quasi-statically, the influence of the moving speed (v) of magnetic permeability does not appear. A high μm is therefore obtained. However, magnetic permeability under an alternating magnetic field depends on the moving speed of the domain wall and is approximately proportional to it. Furthermore, the braking coefficient (β) that reduces this moving speed is proportional to the square root of the magnetic anisotropy (K). Therefore, when an easy axis of magnetization is induced in a thin plate by heat treatment in a magnetic field and anisotropy is generated, the domain wall movement speed decreases, and the magnetic permeability under an alternating magnetic field, that is, the dynamic characteristic value of magnetic permeability, especially the initial permeability. The magnetic flux decreases. Therefore, based on this knowledge, the present inventors
In order to eliminate the disparity caused by conventional heat treatment in a magnetic field, the amorphous magnetic alloy is first heated and maintained at a temperature below the Curie point and below the crystallization temperature.
We have proposed a heat treatment method that applies a rotating magnetic field. According to this heat treatment method, the direction of the component of the applied magnetic field in the direction of the thin plate surface is rotated by one rotation so that the magnetic anisotropy induced in the thin plate becomes isotropic. As a result, the damping coefficient of domain wall movement decreases and local anisotropy disappears, making it easier to form a reflux domain structure, resulting in a decrease in the dynamic characteristic values of magnetic permeability, especially the initial permeability. is not only prevented, but on the contrary, it is significantly improved, and its static value is also significantly improved. Furthermore, magnetic loss is also significantly reduced. However, the inventor's previous proposal succeeded in discovering and demonstrating the principle that the above-mentioned excellent effects can be achieved by making the induced magnetic anisotropy isotropic by rotating the applied magnetic field. However, the only concrete methods disclosed were either rotating the external magnetic field applied to the thin plate sample or rotating the thin plate in a static magnetic field. As long as such means are followed, even if it is possible to obtain significantly superior magnetic properties, there are some difficulties in processing efficiently in large quantities. In other words, since the sample to be processed must be arranged in the form of a flat plate, for example, when applying a thin plate to a magnetic head, the sample to be processed must be a thin plate cut into a predetermined shape for the head, or a relatively small thin plate. No. Further, when the magnetic core is formed as a wound magnetic core for application to a transformer, such means cannot be used. The present invention has been made in view of the above circumstances, and is based on the previous proposal of the present inventors, in which isotropy of induced magnetic orientation is achieved in the macroscopic and microscopic ranges by heat treatment in a rotating magnetic field. , and based on the principles of improving the dynamic and static characteristic values of magnetic permeability of the amorphous magnetic alloy thin plate, reducing its change over time, and further reducing magnetic loss, the same effect can be achieved. The main purpose is to propose a concrete method that can efficiently heat-treat large quantities. The present inventor has completed the present invention as a result of conducting various studies for this purpose. That is, the present inventor proposed the formula Fe _a M _b (where a+b=100at% and 15≦b≦30at%
%. M is a vitrifying element containing one or more of B, Si and C. Furthermore, 20 at% or less of the Fe content may be replaced by one or more transition metal elements. ) In a method for heat treatment of an amorphous magnetic alloy thin plate having a composition represented by: the thin plate is wound into a substantially cylindrical shape, the thin plate is wound with a wire so that a magnetic field is generated in one direction of the thin plate, and The thin plate wound into a substantially cylindrical shape is placed in an external magnetic field, and a current flows through the winding while heating and maintaining the thin plate at a temperature below the Curie point of the amorphous magnetic alloy and below its crystallization temperature. By changing the magnetic field generated in the thin plate, the direction of the composite magnetic field of the magnetic field generated in the thin plate and the external magnetic field is rotated, and then cooled, and the magnetic anisotropy induced by the composite magnetic field is changed. It lies in making gender isotropic. According to the present invention, the magnetic properties of the amorphous magnetic alloy thin plate obtained as in the previous proposal by the present inventors are improved. That is, compared to the above heat treatment in the absence of a magnetic field, the static and dynamic characteristic values of magnetic permeability are significantly improved. Furthermore, magnetic loss is also significantly reduced. In addition, unlike heat treatment in a magnetic field where a magnetic field is applied from a fixed direction, the dynamic characteristic value of magnetic permeability, especially the initial magnetic permeability, does not decrease.On the contrary, the dynamic characteristic is significantly improved, and the magnetic Losses are also reduced.
Therefore, the restrictions on the composition of amorphous alloys, which have hitherto been limited depending on the use, are relaxed, and as a result, practical materials with excellent properties for various uses become possible. In addition, it is also possible to effectively eliminate internal distortion during thin plate manufacturing. Furthermore, the present invention can also be applied to alloys where Tc>Tcry, and as a result, it is possible to obtain high magnetic permeability and low magnetic loss. For this reason, especially for Co-based amorphous alloy materials with low magnetostriction,
Obtains extremely excellent properties in practical use, such as high saturation magnetic flux density and high magnetic permeability, which are higher than those of Sendust alloy. Furthermore, since it is possible to slowly cool alloys where Tc<Tcry after heat treatment, the magnetic permeability is significantly improved. Furthermore, when heat treated above Tc, embrittlement and oxidation occur in materials with high Tc, but in the present invention, heat treatment can be performed at a relatively low temperature below Tc, so embrittlement does not occur, and No oxidation occurs even if the process is carried out inside the room. Note that the effect of significantly improving magnetic permeability and magnetic loss is an effect unique to amorphous magnetic alloys, and even if the present invention is applied to crystalline magnetic alloys, K ₁ or K Either of ₂
Such an effect is not realized due to the presence of magnetocrystalline anisotropy of the order of 10 ³ erg/cm ³ . In addition, since there is no Tcry in the heat treatment for strain removal,
Possible at high temperatures above Tc. Furthermore, the Fe-based amorphous magnetic alloy obtained by the present invention has a high saturation magnetic flux density (Bs), which is 16KG (Fe ₅₀ Ni ₅₀ ) for the crystalline Fe-Ni alloy.
Moreover, the magnetic loss is small, the coercive force (Hc) is small, and the electrical resistivity ρ is low at about 30 μΩcm. In addition, in the present invention, the physical properties of the amorphous magnetic alloy having such a composition are improved so that the alloy becomes isotropic with virtually no magnetic anisotropy, so that the residual flux density (Br) becomes approximately Bs/2, the magnetization reversal time becomes much shorter, and the magnetic flux reversal width, for example, Br+Bs divided by this reversal time, becomes much larger. Furthermore, magnetic loss and
Hc also becomes smaller. Therefore, a magnetic core for accelerating or controlling charged particles formed from such an amorphous magnetic alloy exhibits a much greater acceleration force than a magnetic core formed from a crystalline soft magnetic material. In the present invention, in addition to realizing all the effects based on the previous proposal of the present inventors, the process can be performed extremely efficiently and in large quantities at once. That is, when mass-producing amorphous magnetic alloy thin sheets by ultra-quenching from the liquid phase, it is preferable to continuously wind the thinned alloy around a roll. It can be applied to itself, making it possible to process a large amount at once. In order to make the thin plate treated according to the present invention into a magnetic head or various magnetic cores, it may be cut, laminated, or wound into a magnetic core. Further, especially when used as a wound core, the present invention can be applied after forming a thin plate as a wound core, and there is an advantage that the treated wound core can be used as it is as various cores. Furthermore, in addition to applying the present invention to the thin plate wound around the above-mentioned roll, the present invention can also be applied while continuously moving the thin plate in a spiral shape.
At that time, continuous processing of large quantities becomes possible as well. The present invention will be explained in detail below. The present invention is applicable to nearly all substantially amorphous magnetic alloy sheets. However, in order to apply the present invention and obtain desirable characteristics as various practical materials, it is necessary to use a material that contains at least one of Fe, Co, and Ni, and also contains semimetallic components such as Si, B, C, and P. Those having the composition described in JP-A-55-152164 (Japanese Patent Application No. 54-60359) are particularly preferred.
At this time, the magnetic isotropy of the amorphous magnetic alloy is significantly improved, the magnetic loss is significantly reduced, or the magnetic permeability is significantly improved. Furthermore, the amorphous magnetic alloy used for the magnetic core for accelerating or controlling charged particles preferably has the composition shown below. That is, the composition of the amorphous magnetic alloy is 85~56at
% of Fe and a total amount of 15 to 30 at% of one or more vitrifying elements. In this case, examples of the vitrifying element include B, Si, C, P, Al, Ge, and the like. In addition to Fe and the vitrification element, other additive elements may be included. In that case, other additive elements include Co, Ni, Cr, Ti, Nb, W, Mo, Rh,
Transition metals such as Ru can be mentioned, and the content of one or more of them is within a total amount of about 17 at% or less. Among such compositions, the composition represented by the following formula is particularly preferable. In the formula Fe _a M _b , a+b=100at%, and 15≦b≦30at
%. M is one or more vitrification elements,
It mainly consists of 1 to 3 of B, Si, and C, and if necessary, it can be mixed with Al, P, Ge, Ga, In, Sn, As, Sb, Bi,
One or more types of Pb etc. may be substituted. In addition, 20at% or less of Fe should be replaced by Ni, Co, Cr, Ti, Nb,
One or more transition metals such as W, Mo, Zr, V, Ta, and Zn may be substituted. In this case, the elements that replace Fe include Ni, Cr, and
It is preferably one or more of NO, Nb, and W, or 15 at% or less of Co. The reason why the composition of the Fe-based amorphous magnetic alloy in the present invention is thus limited is as follows. Among transition metals, Fe is known to have the highest magnetization, and in order to obtain high Bs, Fe must be the main component. Other transition metals can be substituted with Fe in a total amount of 20at% or less, but in this case, Ni, Cr, Mo, Nb, W, etc. may be used to replace Fe to improve corrosion resistance, etc. It has the effect of raising the temperature, but the amount of Fe substitution is 5at.
% or more, and the saturation magnetic flux density (Bs) becomes smaller than the Bs of crystalline Fe ₅₀ Ni ₅₀ alloy, which is 16 KG, so it is preferably 5 at % or less. Also, Co is to some extent
When Fe is substituted, the Bs increases, but beyond a certain level, the Bs decreases, and since Fe is an expensive element, the amount of substitution is preferably 0 to 15 t%. on the other hand,
The vitrification element promotes amorphization, but if it is smaller than 15 at% or larger than 30 at%, the degree of amorphousness deteriorates, so it needs to be in the range of 15 to 30 at%. In this case, the vitrification elements consist of 1 to 3 types of Si, B, and C, regardless of their component ratios,
It is preferable to replace half or less of these with Al, Ge, P, etc. The Fe-based amorphous magnetic alloy having such a composition exhibits extremely excellent properties, especially as a magnetic core for accelerating or controlling charged particles. Such thin plates of alloys of various compositions are obtained by ultra-quenching from the liquid phase. In order to obtain an amorphous magnetic alloy thin plate by ultra-quenching from the liquid phase, an alloy of the corresponding composition is melted to form a melt, and this melt is heated from the molten state to approximately 10 ⁴ °C/sec or more, usually 10 ⁴ Ultra-rapid cooling at a cooling rate of ~10 ⁶ °C/sec,
It may be cooled and solidified. In order to ultra-quench the molten alloy liquid, various methods such as the known twin roll method, single roll method, or inside injection method may be used. Therefore, the melting conditions for the alloy, the jetting conditions for the alloy liquid, the shape and dimensions of the nozzle during jetting, the shape, dimensions, material, etc. of the cooling body such as twin rolls are within the range of conditions for the known ultra-quenching method. It may be determined as appropriate. Also, when melting the alloy, it should be done in an inert gas such as argon, or
Alternatively, it is preferable to eject the melt while flowing an inert gas, but the ejection of the melt may also be performed in an atmosphere of either an inert gas or air. Incidentally, such an amorphous magnetic alloy thin plate is
It is sufficient to have a thickness of about 200 μm, particularly 20 to 60 μm, and generally a plate-like shape, and its dimensions can be various. In the present invention, such an amorphous magnetic alloy thin plate is wound into a substantially cylindrical shape and subjected to a predetermined treatment according to Japanese Patent Application Laid-Open No. 55-152164 (Japanese Patent Application No. 54-60359). In this case, in order to wind it into a substantially cylindrical shape, it is usually rolled in the longitudinal direction of the thin plate, with the width direction line segment of the thin plate always being approximately parallel to this imaginary axis. It is sufficient to wind it one or more times, leaving a hollow space in the center, so that the cross section is ring-shaped, usually circular.
In this case, it is preferable that the cross-section of the ring is a closed ring without an opening, so as to reduce as much as possible the demagnetizing field for the magnetic field generated by the winding, for example, by energizing the winding, which will be described later. Further, in the case of winding into a substantially cylindrical shape, there are cases in which the thin plates are wound in a ring-shaped cross-section, usually in a circular ring-like shape, with the thin plates overlapped in the longitudinal direction or the width direction, and also in a case in which the thin plates are wound in a spiral shape in the longitudinal direction. This spiral winding is effective in that the thin plate can be continuously moved within a spiral trajectory and the heat treatment can be continuously performed as described below. On the other hand, for superimposed winding, the thin plate immediately after super-quenching is wrapped around a hollow winding roll and fixed, or the thin plate is wound multiple times with an insulating layer interposed between the thin plates and the thin plate itself is hollow inside. It is possible to use a magnetic core formed as a rectangular or circular wound core, in which case the effect of efficient heat treatment according to the present invention will be realized. The thin plate thus wound into a substantially cylindrical shape is wound so that a magnetic field is generated in one direction of the thin plate. In general, the winding may be configured such that when the winding is energized, a magnetic field is generated substantially in the winding direction of the thin plate, that is, usually in the longitudinal direction. Therefore, this winding may be applied over the entire length of the cylindrical thin plate in the winding direction, usually in the longitudinal direction, or at a predetermined portion thereof, so as to surround the thin plate in the width and thickness directions. Note that the winding wires formed in this way are not energized from an external power source, and even if the winding wires are short-circuited via capacitors or coils as necessary, the thin plate wound into a cylindrical shape will not run in one direction. It may be possible to generate a magnetic field, and it may be configured in such a manner. In this case, by applying an external magnetic field (described later), an induced current is generated in one direction of the thin plate, usually in the winding direction, and this induced current generates a secondary induced current in the winding. occurred 2
This is because the secondary induced current generates a magnetic field in the direction of winding the thin plate. On the other hand, this cylindrically wound thin plate is placed in an external magnetic field. In this case, it is sufficient that the external magnetic field application direction has a component in the direction perpendicular to the winding direction of the thin plate within the plane of the thin plate, usually in the width direction. However, the purpose of the present invention, which is to rotate the composite magnetic field of the magnetic field generated in the thin plate by the above-mentioned winding and this external magnetic field, and to make the induced magnetic anisotropy by the composite magnetic field isotropic, can be more effectively achieved. To achieve this, it is preferable that the external magnetic field be applied in the direction in which the thin plate is wound, that is, substantially perpendicular to the longitudinal direction, and substantially parallel to the width direction in the plane of the wound thin plate. This external magnetic field may be applied by a known electromagnet, Helmhotz coil, solenoid coil, permanent magnet, or the like. In such a configuration, the heat treatment of the present invention
It must be kept below the crystallization temperature of the amorphous magnetic alloy forming the thin plate. This is because the characteristics of an amorphous magnetic alloy are lost. At the same time, its holding temperature must be below the Curie point. This is because spontaneous magnetization does not occur above the Curie point and induced magnetic anisotropy does not occur. On the other hand, the lower limit of the holding temperature is generally 100°C or higher, more preferably 150°C or higher. Further, the holding time is generally within 500 hours, preferably about 1 minute to 500 hours. As for the heating method,
In addition to performing the heating in a resistance-type electric furnace, high-frequency heating, infrared heating, and various other methods are possible. Under such temperature-maintaining conditions, the external magnetic field is applied to the thin plate, and the magnetic field is generated in the thin plate by the winding. At this time, at least one of the external magnetic field and the magnetic field generated in the thin plate by the winding is changed, and the direction of the composite magnetic field of the above two magnetic fields applied or generated on the thin plate is rotated, and the direction of the composite magnetic field induced by this composite magnetic field is changed. make the magnetic anisotropy isotropic. In this case, as long as the direction of this composite magnetic field is rotated, the induced magnetic anisotropy induced within the thin plate becomes isotropic, and the desired effect of the present invention is achieved. However, in order to make the anisotropy more isotropic and further improve the magnetic properties, it is preferable to rotate the induced magnetic anisotropy axis induced by the synthetic magnetic field at least once. All you have to do is rotate it at least approximately 180 degrees. At this time, it is preferable that the combined magnetic field rotates at a substantially constant speed, but the rotation may be continuous or intermittent. Further, at this time, forward and reverse rotations may be repeated alternately. Further, the rotation speed is not particularly limited as long as it is not extremely high speed and as long as the desired rotation is performed within the above-mentioned heating holding time, but generally it may be about 10 to 10 ⁵ rpm. There are various ways of rotating the composite magnetic field, but among these, the composite magnetic field rotates by an angle of approximately 180° or more in one direction within the heating holding time. Alternatively, it is preferable to repeat such rotation alternately in a forward direction and a reverse direction. In order to rotate the composite magnetic field in this way, it is sufficient to change at least one of the external magnetic field and the magnetic field generated by the windings, usually preferably both. To change the external magnetic field, the field axis is usually kept constant and the field strength is changed. For this purpose, the current applied to the electromagnet, coil, etc. may be changed. Further, the magnetic field strength may be changed in one direction, or may be changed in positive and negative directions. on the other hand,
To change the magnetic field generated by a winding, it is usually enough to change the current flowing through the winding to change the magnitude of the generated magnetic field in the positive and negative directions or only in one direction. As described above, when the windings are short-circuited via capacitance or inductance as necessary, the magnitude of the magnetic field generated by the windings changes in response to changes in the external magnetic field strength. In addition, this external magnetic field whose magnitude changes either positively or negatively or only in one direction,
As mentioned above, the effect obtained is greater when the axes of the magnetic field and the magnetic field generated by the winding are perpendicular to each other. In this way, the direction of the composite magnetic field is rotated, and there are various ways of rotating and means for imparting the rotation, but in general, it is done as follows. It is preferable to do so. When the combined magnetic field is rotated by at least 180° in the preferred manner as described below, the induced magnetic anisotropy not only becomes macroscopically isotropic, but also microscopically shows within a magnetic domain of about 100 μm. This is because the magnetic permeability and magnetic loss are improved more than expected when macroscopically isotropic. First, in the case of continuously rotating the composite magnetic field, the external magnetic field (H ₁ ) and the magnetic field generated by the winding (H ₂ ) are usually perpendicular to each other, and as shown in Figure 1a, both It is preferable to change the waveform as an alternating sine wave, make the frequencies of the two the same, and change the phase of the two by ±π/2.
When such a configuration is adopted, the composite magnetic field rotates continuously by 180 degrees or more in a fixed direction. On the other hand, even when the composite magnetic field is rotated continuously, positive and
The counter-rotation can also be carried out periodically, then the frequencies are equal and ±π/
Among the alternating sine waves H ₁ and H ₂ whose phases differ by 2,
It is preferable to invert one half cycle or an integral multiple thereof. On the other hand, when rotating the composite magnetic field intermittently, H ₁ and H ₂ may be generated in a pulsed manner. In this case, with equal pulse width
H ₁ and H ₂ are generated synchronously at equal intervals, and the pulse heights of both have as envelopes the sine waves of H ₁ and H ₂ shown in Figure 1 a, b, etc., respectively. None, the composite magnetic field may be rotated intermittently, but H ₁ and H ₂ of equal pulse width are alternately generated at equal intervals as shown in Figure 1c and d, and at least H ₁ It is also possible to alternately generate one of H ₁ and H 2 in positive and negative states, and rotate this intermittently so that the combined magnetic field becomes H ₁ or H ₂ itself. In such a case, the magnitude of the external magnetic field H ₁ may be varied within a range of about 50 Oe or more, which nearly saturates the amorphous magnetic alloy. However, if the thickness of the thin plate and the demagnetizing field based on the unevenness existing on the surface are taken into consideration, it is preferable that the maximum value is approximately 200 Oe or more, more preferably about 500 Oe or more. On the other hand, by energizing the winding,
Alternatively, the magnetic field generated by the secondary induced current generated in the winding has a small demagnetizing field, so it is generally 1~
It is sufficient to vary it within a range of about 100 Oe. After applying the above-described magnetic field in such a heated state, the thin plate or thin film is cooled. This cooling may be done after stopping the magnetic field, but
Preferably, it is carried out in the magnetic field mentioned above. Also,
Although the cooling rate can be changed in various ways, slow cooling is generally preferred. Note that the heat treatment in a magnetic field as detailed above may be performed in vacuum, in an inert gas, or even in air. If we measure the ferromagnetism using a thin plate of the amorphous alloy that has undergone the heat treatment described above as a sample according to the present invention in accordance with a conventional method, we will find that since it is macroscopically isotropic, the resonant magnetic field will vary depending on the angle of the external magnetic field. is essentially unchanged, the angular dependence of the resonant magnetic field is very small, and it is also microscopically isotropic, so the half-width of the resonance line is extremely small. In this case, ferromagnetic resonance is usually performed by setting a disk-shaped sample in a ferromagnetic resonance cavity and applying 9.34 GHz microwaves, and applying an external magnetic field of about 1300 Oe in the sample plane, in the direction of the magnetic field application. The angle dependence of the resonant magnetic field can be expressed as the ratio of the anisotropic magnetic field Ha to the unique resonant magnetic field Ho.
When Ha/Ho is measured, the thin plate material obtained according to the present invention has a value of Ha/Ho of 10% or less, particularly 5% or less. On the other hand, in the case of a thin plate immediately after quenching, Ha/Ho is approximately 20%, and when heat treated in the static magnetic field described above, Ha/Ho is approximately 15%.
That's about it. In addition, at this time, the half-width of the resonance line ΔH
The value ΔH/Ho normalized by Ho is approximately 30% or less for the thin plate material obtained by the present invention, while it is approximately 50% or more and 30 to 40% immediately after quenching and after static magnetic field treatment, respectively. That's about it. Therefore, if such ferromagnetic resonance is measured and the angular dependence of the resonant magnetic field is observed, especially Ha/Ho and the half-width of the resonance line, especially ΔH/Ho, the magnetic resonance of the present invention can be confirmed. This method serves as a means of confirming whether or not it is isotropic without having anisotropy, and the above-mentioned results are obtained when using other conventional processing methods for amorphous magnetic alloy thin sheets. This is an indicator of the distinguishability between the amorphous magnetic alloy of the present invention and the conventional one. A preferred example of the apparatus used in the heat treatment method detailed above is shown in FIG. In FIG. 2, a thin plate 1 of an amorphous magnetic alloy is wound in a circular ring in the longitudinal direction around a winding roll, for example as a wound magnetic core or immediately after ultra-quenching. On the other hand, the thin plate 1 wound in a circular ring is connected to the electromagnet 2.
When an alternating sine wave current i ₁ is applied from a power source E to the insides of the coils 1 and 23, the external magnetic field H ₁ generated thereby is arranged in the width direction of the thin plate, that is, parallel to the winding axis. On the other hand, the circular thin plate 1 is provided with a winding 3 made of a covered conductor, and the winding 3 is connected to an AC power source E via a phase controller P.
A sine wave current i ₂ having a phase different from that of i ₁ by π/2 can be supplied. Furthermore, the entire thin plate 1 is placed in an electric furnace 4. In such a configuration, when the electric furnace 4 is energized to heat and maintain the thin plate 1 at a predetermined temperature and the power source E is turned on at the same time, the electromagnet 2
1 and 23, _and the external magnetic field _H1 shown in Fig. 1a is applied in the width direction of the thin plate 1, while _i2 flows in the winding 3, and the external magnetic field H1 shown in Fig. 1a is applied in the longitudinal direction of the thin plate 1. A magnetic field H ₂ is generated. As a result, the combined magnetic field of H ₁ and H ₂ rotates in a constant direction at a constant period. Electric furnace 4 after a certain period of time
When the current is turned off and the amorphous magnetic alloy thin plate 1 is cooled, the magnetic anisotropy induced in the amorphous magnetic alloy thin plate 1 becomes locally isotropic, and the desired effect of the present invention is achieved. On the other hand, FIG. 3 shows a case where continuous processing is performed instead of a case where batch processing is performed as in FIG. 2. In this case, the thin plate (not shown) is capable of moving continuously in the direction of the arrow a in a spiral shape, for example, in the guide path 5 made of glass. On the other hand, this guide route 5
An external magnetic field H ₁ can be applied from a solenoid coil 25 parallel to the spiral axis of the sheet, and a winding 3 is provided in the guide path 5 to apply a magnetic field H ₂ in the longitudinal direction of the thin plate passing through the guide path 5. It is assumed that it can occur. With this configuration, the current flowing to the solenoid coil 25 and the current-carrying terminals 33, 35 of the winding 3 is changed, H ₁ and H ₂ are changed in a preferable manner as in the previous period, and the difference between H ₁ and H ₂ is changed. By rotating the composite magnetic field and heating the continuously moving thin plate using the electric furnace 4, the heat treatment of the present invention can be continuously performed while the thin plate is continuously moving. Further, FIG. 4 shows another example. In this case, the example shown in FIG. 4 differs from FIG. 2 in that the winding 3 is not connected to an external power source but is short-circuited via a capacitance or inductance, in this case a capacitance C. In such a case, if, for example, an alternating sine wave current i ₁ is applied to the electromagnets 21 and 23 from the external power source E as described above, a magnetic field H ₁ is generated, and an induced current i ₁ ' is generated in the longitudinal direction of the thin plate 1. On the other hand, this induced current i ₁ ' generates in the winding 3 a secondary induced current i ₂ ' having a different phase determined by the capacitance C. This secondary induced current
Due to i ₂ ′, a magnetic field H ₂ having a different phase from H ₁ is generated in the longitudinal direction of the thin plate 1, and if the intensity of H ₁ is changed, H ₁
The combined magnetic field of H 2 and H ₂ rotates over time, achieving the desired effect of the present invention. The amorphous magnetic alloy thin plate processed by the method of the present invention as described in detail above can be used as it is or after being processed in a specified manner to be used as various cores such as magnetic cores for accelerating or controlling charged particles, magnetic heads, or other applications. It exhibits extremely excellent properties when used in That is, the present invention has the following effects. The amorphous magnetic alloy thin plate obtained by the present invention is
The static and dynamic characteristic values of magnetic permeability are significantly improved. Furthermore, magnetic loss is also significantly reduced. In addition, unlike heat treatment in a magnetic field where a magnetic field is applied from a fixed direction, the dynamic characteristic value of magnetic permeability, especially the initial permeability, does not decrease.On the contrary, the dynamic characteristic is significantly improved, and the magnetic Losses are also reduced. Therefore, the restrictions on the composition of amorphous alloys, which have hitherto been limited depending on the use, are relaxed, and as a result, practical materials with excellent properties for various uses become possible. In addition, it is also possible to effectively eliminate internal distortion during thin plate manufacturing. Furthermore, the present invention can also be applied to alloys where Tc>Tcry, and as a result, it is possible to obtain high magnetic permeability and low magnetic loss. For this reason, particularly for Co-based amorphous alloy materials with low magnetostriction, extremely excellent properties in practical use such as high saturation magnetic flux density and high magnetic permeability, which are higher than those of Sendust alloy, can be obtained. Also, for alloys where Tc<Tcry, slow cooling is possible after heat treatment, so the magnetic permeability is significantly improved. Furthermore, in heat treatment above Tc, embrittlement and oxidation occur in materials with high Tc, but in the present invention,
Since the heat treatment can be carried out at a relatively low temperature below Tc, embrittlement does not occur, and even if carried out in air, oxidation does not occur. Furthermore, the amorphous magnetic alloy obtained by the present invention has a large saturation magnetic flux density (Bs), a small magnetic loss, a small coercive force (Hc), and a low electric resistivity ρ. In addition, in the present invention, the physical properties of the amorphous magnetic alloy having such a composition are improved so that it becomes isotropic with virtually no magnetic anisotropy, so that the residual magnetic density (Br) The magnetization reversal time becomes about Bs/2, and the magnetization reversal time becomes much shorter, and the magnetic flux reversal width, for example, the value obtained by dividing Br+Bs by this reversal time, becomes much larger. Furthermore, magnetic loss and Hc are also smaller. Therefore, a charged particle acceleration or control magnetic core made of such an amorphous magnetic alloy exhibits a much greater acceleration force than a magnetic core made of a crystalline soft magnetic material. EXAMPLES The present invention will be described in more detail below with reference to Examples. Example 1 A ribbon-shaped continuous thin plate of an amorphous magnetic alloy having a composition of Fe ₈₃ B ₁₂ Si ₅ and having a thickness of 30 μm was obtained by a known high-speed quenching method. Then, from this thin plate, an inner diameter of 40
A toroidal wound magnetic core with a diameter of 50 mm, an outer diameter of 50 mm, and a thickness of 10 mm was formed. Next, the obtained magnetic core was subjected to the heat treatment in a magnetic field according to the present invention using the apparatus shown in FIG. That is, the entire apparatus is placed under a vacuum of 10 ^-1 Torr, a winding 3 is applied, and this is placed in an electric furnace 4. Electromagnets 21, 23 were placed. , maximum value 20Oe, period 1 as shown in Figure 1 a by winding 3
generates a sinusoidal magnetic field H ₂ of seconds, and electromagnet 21,
The magnetic core was heated to 300° C. in an electric furnace _{4 while generating a sinusoidal magnetic field H 1 having} a maximum value of 5000 Oe as shown in FIG.
After 30 minutes, the electric furnace was shut off, and the mixture was slowly cooled in vacuum while rotating the combined magnetic field of H ₁ and H ₂ . For Sample 1 treated in this way, the residual magnetic flux density Br, the saturation magnetic flux density Bs, and Bs+Br were measured. Also,
A 1.2 mm diameter disk sample was obtained by etching from the thin plate constituting the magnetic core treated in the same manner as sample 1, and this was set in the cavity of a ferromagnetic resonance absorber and etched at a microwave frequency of 9.34 GHz.
An external magnetic field of about 1300 Oe is rotated within the sample plane to perform ferromagnetic resonance measurements, and the unique resonance magnetic field Ho,
Measure the anisotropic magnetic field Ha and the half-width ΔH of the resonance line,
Ha/Ho and ΔH/Ho were calculated. These results are shown in Table 1. Furthermore, one turn of primary coil and secondary coil was applied to the above sample 1, and the primary coil was energized at 10 ¹ , 10 ³ and 10 ⁵ AT/m, respectively.
A distance-shaped excitation magnetic field was applied, the voltage induced in the secondary coil was measured, its rise time Δt was measured, and the magnetization reversal time was measured. The results are also shown in Table 1. In addition, Table 1 shows the 60
Magnetic loss at Hz and 1KG is also listed. Separately, for comparison, Sample 2 was obtained from a thin plate immediately after quenching without any heat treatment in the magnetic field described above. In addition, a magnetic core obtained from a thin plate immediately after quenching was heat-treated in the same manner as above without applying any H ₁ to obtain Sample 3, which was heat-treated in a static magnetic field. These samples 2 and 3 were measured in exactly the same manner as sample 1, and the results shown in Table 1 were obtained. For further comparison, 100 μm thick crystalline Fe ₅₀ Ni ₅₀
Using a thin alloy plate and Ni-Zn ferrite, a toroidal wound magnetic core with exactly the same dimensions as Sample 1 was formed (Samples 4 and 5), and Bs, Br, Br + BsΔt were prepared in the same manner as above.
and magnetic loss were measured, and the results shown in Table 1 were obtained. From the results in Table 1, in the case of the present invention, the induced magnetic anisotropy is isotropic, exhibiting excellent magnetic properties, and Δt is extremely small even up to an extremely high excitation magnetic field, and extremely large (Br+Bs)/
It can be seen that Δt, that is, a large acceleration force of charged particles can be obtained when used as a magnetic core for accelerating charged particles.

[Table] Example 2 Changed the composition to Example 1 (Fe _0.85 Co _0.15 ) ₈₀ B ₂₀ (Sample 6), (Fe _0.85 Co _0.15 ) ₈₀ (Si _0.25 B _0.75 ) ₂₀ (Sample 7), Fe ₇₈ Mo ₂ B ₂₀ (Sample 8), Fe ₇₈ Ni ₂ B ₂₀ (Sample 9) A thin plate having the compositions was obtained, and this was made into a winding core in exactly the same manner as Sample 1, except that the heat treatment temperature was 350°C. Samples 6 to 9 were obtained by performing similar heat treatment in a rotating magnetic field. Regarding these, Br, Bs, Br+Bs, Ha/Ho,
When ΔH/Ho, ΔH, Δt, and magnetic loss were measured, the results shown in Table 1 were obtained. The effects of the present invention are clear from the results in Table 1. In addition, samples obtained according to the present invention (sample No. 1, 6 to
9), it has been confirmed that the magnetic permeability is significantly improved compared to the comparative examples (sample Nos. 2 to 5).

[Brief explanation of drawings]

Figure 1 a, b, c, and d are lines showing examples of changes over time (t) in the magnetic field strength (H) of the external magnetic field (H ₁ ) and the magnetic field (H ₂ ) generated by the winding in the present invention, respectively. FIG. 2, FIG. 3, and FIG. 4 are each schematic diagrams showing an example of the apparatus used in the present invention. Explanation of symbols, 1... Amorphous magnetic alloy thin plate, 2
1, 23... Electromagnet, 25... Solenoid coil, 3... Winding wire, 4... Electric furnace, 5... Guide path.

Claims (1)

[Claims] 1 Formula Fe _a M _b (wherein a+b=100at%, 15≦b≦30at
%. M is a vitrifying element containing one or more of B, Si and C. Also, of the Fe amount a,
20at% or less may be replaced by one or more transition metal elements. ) When heat-treating an amorphous magnetic alloy thin plate having a composition represented by the formula, the thin plate is wound into a substantially cylindrical shape, and the thin plate is wound so that a magnetic field is generated in one direction of the thin plate. Furthermore, the thin plate wound into a substantially cylindrical shape is placed in an external magnetic field, and while the thin plate is heated and held at a temperature below the Curie point of the amorphous magnetic alloy and below its crystallization temperature, a flow flows into the winding. By changing the current, the magnetic field generated in the thin plate is changed, and the direction of the composite magnetic field of the magnetic field generated in the thin plate and the external magnetic field is rotated, and then cooled, and the magnetic anisotropy induced by the composite magnetic field is A method for heat treatment of an amorphous magnetic alloy thin plate characterized by making the properties isotropic.