JP2019087665A - Magnetic material and method for manufacturing the same - Google Patents

Abstract

To provide: a novel magnetic material having high magnetization, low coercive force, and high magnetic stability, which has a saturation magnetization higher than that of a ferrite-based magnetic material and an electric resistivity higher than that of a conventional metal-based magnetic material, and can solve the problems involving an eddy current loss; and a method for manufacturing the magnetic material.SOLUTION: Disclosed is a magnetic material having soft or half-hard magnetism, comprising: a first phase including crystals of a bcc structure containing an FM component (where the FM component is a ferromagnetic component including Fe, and Ni and/or Co) and an M component (where the M component is one or more of Zr, Hf, V, Nb, Ta, Cr, Mo, W, Cu, Zn and Si); and a second phase including an M component, in which a content of the M component, when the total content of the FM and M components contained in the phase is set to 100 atom%, is larger than a content of the M component when the total content of the FM and M components in the first phase is set to 100 atom%.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a magnetic material exhibiting a soft magnetic material or a semi-hard magnetic material, in particular, a magnetic material exhibiting soft magnetism, and a method of manufacturing the same.

  Global environmental problems such as global warming and resource exhaustion are becoming more serious, and social demands for energy saving and resource saving of various electronic and electrical devices are increasing day by day. Above all, there is a demand for further enhancement of the performance of soft magnetic materials used in drives such as motors and transformers of transformers. In addition, various information communication devices have been reduced in size and multifunctionality, faster in processing speed, higher in recording capacity, and further managed in various ways such as infrastructure and other environmental health preservation and complicated physical distribution systems and diversified security reinforcement. In order to solve the problem, it is required to improve the electromagnetic properties, reliability, and sensitivity of various soft magnetic materials and semi-hard magnetic materials used for various elements, sensors, and systems.

  Demand for next-generation vehicles equipped with large motors driven by high-speed rotation (hereinafter referred to as rotational speeds exceeding 400 rpm) such as electric vehicles, fuel cell vehicles and hybrid vehicles meets the needs of the times for these environmental and energy problems It is further expected to continue to Above all, improvement in performance and cost reduction of soft magnetic materials for stators used in motors are one of the important issues.

  The existing soft magnetic materials used for the above applications are roughly classified into two types, metal-based magnetic materials and oxide-based magnetic materials.

  The former metal-based magnetic material includes silicon steel (Fe-Si) which is a crystalline material containing Si, which is a typical case of electromagnetic steel, and Sendust (Fe-Al-Si) which is an intermetallic compound further containing Al. C) Low carbon content and low impurity content pure iron with a carbon content of 0.3% by mass or less, electromagnetic soft iron (Fe), permalloy mainly composed of Fe-Ni, metglas (Fe-Si-B), etc. Amorphous alloys, and nanocrystalline soft magnetic materials such as Fenmets, which are nanocrystal-amorphous phase separated types in which fine crystals are precipitated by applying appropriate heat treatment to the amorphous alloys (Fe as a typical composition thereof -Cu-Nb-Si-B, Fe-Si-B-P-Cu, etc.). The term "nano" as used herein refers to a size of at least 1 nm and less than 1 μm. In magnetic materials other than nanocrystalline soft magnetic materials, facilitating the movement of the domain wall with a composition as uniform as possible is important for reducing the coercivity and reducing the core loss. The nanocrystalline soft magnetic material is an inhomogeneous system including a crystal phase, an amorphous phase, a Cu-enriched phase and the like, and the magnetization reversal is considered to be mainly due to the magnetization rotation.

  Examples of the latter oxide-based magnetic materials include ferrite-based magnetic materials such as Mn--Zn ferrite and Ni--Zn ferrite.

  Silicon steel is the most widely used soft magnetic material for high-performance soft magnetic material applications, and its high saturation magnetization with a saturation magnetization of 1.6 to 2.0 T and a coercive force of 3 to 130 A / m. It is a magnetic material of magnetic force. This material is a material in which Si is added to about 4% by mass to Fe, and the coercive force is reduced by reducing the magnetocrystalline anisotropy and the saturation magnetostriction constant without largely damaging the large magnetization of Fe. is there. In order to improve the performance of this material, materials appropriately controlled in composition are appropriately combined with hot and cold rolling and annealing to remove foreign matter that impedes the movement of the domain wall while increasing the crystal grain size. It is necessary to. In addition to non-oriented steel plates in which the orientation direction of the crystal grains is random, as a material to further reduce the coercivity, a directional steel plate in which the (100) direction of Fe-Si, which is an easy magnetization direction, is highly oriented in the rolling direction It is widely used.

  This material is a rolled material with a thickness of less than 0.5 mm in general, and a homogeneous metal material with a low electrical resistivity of approximately 0.5 μΩm. Usually, the surface of each silicon steel plate is covered with an insulating film It is applied to large-sized equipment by giving thickness and suppressing eddy current loss that occurs in high-speed applications such as next-generation vehicles by punching out with a die, laminating, and welding. Therefore, the process cost for punching and stacking and the deterioration of the magnetic characteristics are a serious problem.

  The nanocrystalline soft magnetic materials, including Fe-Cu-Nb-Si-B, are heat-treated at temperatures higher than the crystallization temperature for alloys that have become amorphous by quenching once, so that crystal grains of about 10 nm can be obtained. It is a soft magnetic material having a randomly oriented nanocrystal-type structure which is precipitated in an amorphous state and has an amorphous grain boundary phase. The coercivity of this material is extremely low at 0.6 to 6 A / m, and the saturation magnetization is higher at 1.2 to 1.7 T than that of amorphous materials, so the market is currently expanding. This material is a relatively new material developed in 1988, and the principle of its magnetic property expression is to make the crystal grain size smaller than the ferromagnetic exchange length (also called exchange coupling length), and to randomly oriented main phase The ferromagnetic phase of (1) is ferromagnetically coupled through the amorphous interface phase, thereby averaging the magnetocrystalline magnetic anisotropy and achieving a low coercive force. This mechanism is called a random magnetic anisotropy model or a random anisotropy model (see, for example, Non-Patent Document 1).

  However, since this material is manufactured after first producing a thin strip by the liquid super-quenching method, the product thickness is about 0.02 to 0.025 mm, and insulation, cutting, alignment, lamination, lamination, The process of welding and annealing is more complicated than silicon steel, and has problems such as processability and thermal stability. Furthermore, the electrical resistivity is as low as 1.2 μΩm, and the problems of eddy current loss similar to other rolled materials and strips are pointed out.

  In order to solve this problem, an attempt has been made to produce a bulk molding material by pulverizing the thin strip nanocrystalline soft magnetic material using the SPS (discharge plasma sintering) method. Since the coercive force is 300 A / m and the saturation magnetization is 1 T, the magnetic characteristics are greatly deteriorated as compared with the 0.02 mm ribbon (see Patent Document 2). At present, there is no better way to make products thicker than 0.5 mm other than laminating.

Among the existing soft magnetic materials, the ferrite-based oxide material is the one with the largest eddy current loss problem in high-rotation applications. The electrical resistivity of this material is 10 ⁶ to 10 ¹² μΩm, and it can be easily bulked to 0.5 mm or more by sintering, and it can be made into a compact without eddy current loss, so for high rotation and high frequency applications It is a suitable material. Moreover, since it is an oxide, it does not rust and is excellent in the stability of the magnetic characteristics. However, the coercivity of this material is relatively high at 2 to 160 A / m, and in particular, because the saturation magnetization is as small as 0.3 to 0.5 T, it is not suitable for use as, for example, a high performance high rotation motor for the next generation automobile.

  In general, metallic soft magnetic materials such as silicon steel are rolled materials and used because they are thin and laminated, but they are used with low electrical resistance, and eddy current loss occurs for high-performance motors with high rotation speed. There is a problem, and it is necessary to do the lamination that can solve it. Therefore, the process becomes complicated, and the insulation treatment before lamination is essential, and further, the magnetic property deterioration due to punching and the cost increase for the process cost become major problems. On the other hand, oxide-based soft magnetic materials such as ferrite have high electrical resistance and no problem with eddy current loss, but their saturation magnetization is as small as 0.5 T or less, so they are suitable for high-performance motors for next-generation vehicles Absent. On the other hand, from the viewpoint of oxidation resistance, oxide soft magnetic materials are more stable and superior to metal soft magnetic materials.

  The upper limit of the thickness that can be used for the non-oriented electrical steel sheet made of silicon steel, which is widely produced for high-performance motors for next-generation vehicles using permanent magnets, is shown in Patent Documents 1 and 2 In the case of using a thin silicon steel plate such as 0.3 mm thick, it will insulate about 300 sheets, since the thickness is about 0.3 mm in thickness, but it is 9 cm in thickness of the motor for the next generation car, for example. Would have to be stacked. The steps of insulating, punching, aligning, welding and annealing such thin plates are complicated and expensive. In order to increase the thickness of the laminated plate as much as possible, it is necessary to increase the electrical resistivity of the material.

  As described above, a magnetic material having high oxidation resistance (in particular, excellent in magnetic stability having both high saturation magnetization and low coercivity) than conventional oxide-based magnetic materials (particularly ferrite-based magnetic materials) The emergence of soft magnetic materials has been desired. Furthermore, a soft magnetic material capable of exhibiting the advantages of both an oxide magnetic material and a metal magnetic material, specifically, a higher electric resistance than a metal silicon steel plate or the like, and a metal It is hoped that soft magnetic materials capable of exhibiting the advantages of high saturation magnetization of magnetic system magnetic materials and small eddy current loss such as oxide magnetic materials and requiring neither lamination nor complicated processes are desired. It was rare.

International Publication No. 2017/164375 International Publication No. 2017/164376

G. Herzer, IEEE Transactions on Magnetics, vol. 26, No. 5 (1990) pp. 1397-1402 Y. Zhang, P .; Sharma and A. Makino, AIP Advances, vol. 3, No. 6 (2013) 062118

The present invention can realize both a saturation magnetization and a low and / or stable coercive force which are much larger than those of conventional ferrite-based magnetic materials, and a new magnetic material excellent in oxidation resistance and a method for producing the same Intended to provide. In addition, since the electrical resistivity is higher than that of the existing metal-based magnetic materials, the above-mentioned problems such as the eddy current loss can be solved, and further, high magnetic stability, high magnetic saturation suppression ability, and high frequency absorption An object of the present invention is to provide a new magnetic material capable of achieving various required performances such as performance and a method of manufacturing the same.
In particular, according to the present invention, the α- (Fe, M) phase and the M component (where the M component is any of Zr, Hf, V, Nb, Ta, Cr, Mo, W, Cu, Zn, Si) Or one or more components) New magnetic properties that can achieve saturation magnetization and coercivity even better than the saturation magnetization and low coercivity realized by using a magnetic material with nano-dispersion of the enrichment phase It aims at providing a material and its manufacturing method.

  Further, in the present invention, it is possible to manufacture a compact having a thickness of 0.5 mm or more, 1 mm or more, and 5 mm or more by a simple process without complicated processes such as lamination, and at the same time eddy current. It is an object of the present invention to provide a powder sintered magnetic material that can be reduced.

  In order to solve the above problems, 0.3T of the existing ferrite, which has a general saturation magnetization (this is a density close to that of the metal system in the magnetic material of the present invention, so using the density of Fe Calculated to be 30 emu / g.) Magnetic materials of the same order or higher are required. In particular, in the case of a soft magnetic material, its saturation magnetization is preferably 100 emu / g or more, more preferably 150 emu / g or more. At the same time, it is also required to be able to express the coercivity of the soft magnetic region or the semi-hard magnetic region. Further, it is also required to be excellent in oxidation resistance.

  The present inventors, taking these circumstances and the like into consideration, a magnetic material, a metallic magnetic material and an oxide based magnetic material having an electromagnetic property superior to that of a conventional oxide based magnetic material (in particular, a ferrite based magnetic material) Magnetic materials with excellent electromagnetic properties that combine the advantages of both materials, as well as magnetic materials with stable magnetic properties in air, were also studied intensively. As a result, M-ferrite (in the present invention, completely different from conventionally used homogeneous crystalline or amorphous material or nanocrystal soft magnetic material in which homogeneous nanocrystals are precipitated in amorphous state) By disproportionation during the reduction reaction of “M component—ferrite”, a magnetic material containing various two or more crystal phases, or one crystal phase and an amorphous phase is found, and its composition and crystal structure The present invention was achieved by controlling the crystal grain size and the powder grain size, establishing the method of manufacturing the magnetic material, and establishing the method of solidifying the magnetic material without laminating it. . The "ferrite" according to the present invention refers to a ferrite in which a part of Fe, which is a ferromagnetic component (component exhibiting a ferromagnetism) contained in the ferrite, is substituted by Ni and / or Co.

That is, the present invention is as follows.
(1) FM component (here, FM component is a ferromagnetic component containing Fe and containing Ni and / or Co) and M component (where M component is Zr, Hf, V, Nb, A first phase having a bcc structure crystal containing Ta, Cr, Mo, W, Cu, Zn, Si) and a phase containing an M component, which are contained in the phase The content (atomic%) of the M component when the total of the FM component and the M component is 100 atomic% is the content of the M component when the total of the FM component and the M component contained in the first phase is 100 atomic% A soft or semi-hard magnetic material containing a second phase which is higher than the content (atomic%).
(2) The magnetic material according to (1), wherein the magnetic material is soft magnetic.
(3) The amount of Fe (atomic%) in the FM component in the first phase and the amount of Ni and / or Co (atomic%) respectively represent the total of all the components constituting the FM component as 100 atomic%. The magnetic material according to (1) or (2), which is 01 atomic percent or more and 99.999 atomic percent or less and 0.001 atomic percent or more and 49.99 atomic percent or less.
(4) The first phase is FM _100-x M _x (where x is an atomic percentage 0.001 ≦ x ≦ 33.33, and FM contains Fe and is strong including Ni and / or Co) And M is a magnetic component, and has a composition represented by a composition formula of Zr, Hf, V, Nb, Ta, Cr, Mo, W, Cu, Zn, and Si. 1) Magnetic material in any one of (3).
(5) The content (atomic%) of Ni and / or Co in the magnetic material is the above when the total of the content (atomic%) of the FM component and the M component in the entire magnetic material is 100 atomic%. The magnetic material as described in (3) or (4) which is below content (atomic%) of M component.
(6) the first _phase, with _{FM 100-x (M 100-} y TM y) x / 100 ( where, x, y is 0.001 ≦ x ≦ 33.33,0.001 ≦ y atomic percent < 50, FM is a ferromagnetic component containing Fe and containing Ni and / or Co, M is any of Zr, Hf, V, Nb, Ta, Cr, Mo, W, Cu, Zn, Si The magnetic material according to any one of (1) to (5), which has any one or more kinds, and TM has a composition represented by a composition formula of any one or more of Ti and Mn.
(7) The M component content (atomic%) where the second phase has a bcc structure crystal containing an FM component and an M component, and the total of the FM component and the M component contained in that phase is 100 atomic% Is 1.5 times to 10 ⁵ times or less the content (atomic%) of the M component when the sum of the FM component and the M component contained in the first phase is 100 atomic%, and / Or the magnetic material in any one of (1)-(6) which is the quantity of 2 atomic% or more and 100 atomic% or less.
(8) Containing Ni and / or Co when the second phase has a bcc structure crystal containing an FM component and an M component, and the total of the FM component and the M component contained in the phase is 100 atomic% The amount (atomic%) is 10 ^-5 times or more with respect to the content (atomic%) of Ni and / or Co when the total of the FM component and the M component contained in the first phase is 100 atomic%. The magnetic material according to any one of (1) to (7), wherein the amount is less than .909 times or not less than 1.1 times and not more than 10 ⁵ times.
(9) The magnetic material according to any one of (1) to (8), wherein the second phase contains an oxide phase containing an M component.
(10) The magnetic material according to any one of (1) to (9), wherein the second phase contains at least one of an M-ferrite phase or a wustite phase.
(11) The magnetic material according to any one of (1) to (10), wherein a volume fraction of a phase having a bcc structure crystal containing an FM component and an M component is 5% by volume or more of the entire magnetic material.
(12) With respect to the composition of the entire magnetic material, the FM component is 20 atomic% or more and 99.998 atomic% or less, the M component is 0.001 atomic% or more and 50 atomic% or less, and the O component is 0.001 atomic% or more and 55 The magnetic material as described in (9) or (10) which has a composition of the range of atomic% or less.
(13) The magnetic material according to any one of (1) to (12), wherein the average crystal grain size of the first phase or the second phase or the entire magnetic material is 1 nm or more and less than 10 μm.
(14) At least the first phase is FM _100-x M _x (where x is an atomic percentage 0.001 ≦ x ≦ 33.33, FM contains Fe, and contains Ni and / or Co) Is a ferromagnetic component, and M has a bcc phase represented by the composition formula of any one or more of Zr, Hf, V, Nb, Ta, Cr, Mo, W, Cu, Zn, and Si). The magnetic material according to any one of (1) to (13), wherein the crystallite size of the bcc phase is 1 nm or more and 100 nm or less.
(15) A ferromagnetic component in which at least the first phase is FM _100-x M _x (where x is an atomic percentage 0.001 ≦ x ≦ 1 and FM contains Fe and contains Ni and / or Co) M is a bcc phase represented by the composition formula of Zr, Hf, V, Nb, Ta, Cr, Mo, W, Cu, Zn, Si) The magnetic material according to any one of (1) to (13), wherein the crystallite size of the bcc phase is 1 nm or more and 200 nm or less.
(16) It is a magnetic material in the form of powder, and in the case of a soft magnetic material, it has an average powder particle size of 10 nm to 5 mm, and in the case of a semihard magnetic material, 10 nm to 10 μm The magnetic material in any one of (1)-(15) which has the following average powder particle sizes.
(17) The magnetic material according to any one of (1) to (16), wherein at least one phase of the first phase or the second phase is ferromagnetically coupled to the adjacent phase.
(18) The first phase and the second phase are directly or continuously bonded via the metal phase or the inorganic phase to form a block as a whole of the magnetic material, (1) to (17) Magnetic material as described in any of the above.
(19) Described in (16) by reducing M-ferrite powder having an average powder particle size of 1 nm or more and less than 1 μm in a reducing gas containing hydrogen gas at a reduction temperature of 400 ° C. or more and 1500 ° C. or less Of manufacturing magnetic materials.
(20) By reducing M-ferrite powder having an average powder particle size of 1 nm or more and less than 1 μm in a reducing gas containing hydrogen gas to generate a first phase and a second phase by disproportionation reaction And the method of manufacturing the magnetic material in any one of (1)-(17).
(21) A method for producing the magnetic material according to (18) by sintering the magnetic material produced by the production method according to (19) or (20).
(22) After the reduction step in the production method according to (19), or after the reduction step or production step in the production method according to (20), or after the sintering step in the production method according to (21) A method of producing a soft magnetic or semi-hard magnetic material which is annealed once.

According to the present invention, the saturation magnetization is much larger than that of the conventional ferrite-based magnetic material, the coercivity lower in the range of 1 to 700 A / m, and / or the stable retention even when placed in the air at 80 ° C., for example. Both magnetic force can be realized, and a new magnetic material excellent in oxidation resistance and its manufacturing method can be provided. It is possible to provide a magnetic material having a saturation magnetization of 150 emu / g or more and capable of expressing the coercivity of a soft magnetic region or a semi-hard magnetic region, and a method of manufacturing the same. Here, stable coercivity means stable coercivity as a practical characteristic, and specifically, for example, a harsh atmosphere such as 80 ° C. even when used in an environment in a mobile device Even if it is placed inside, unlike amorphous or nanocrystalline magnetic materials, it can exhibit characteristics similar to or superior to those of ferrite materials, meaning that it can provide a stable coercivity as compared to them.
In particular, according to the present invention, the α- (Fe, M) phase and the M component (where M is any of Zr, Hf, V, Nb, Ta, Cr, Mo, W, Cu, Zn, Si) It is possible to achieve more excellent saturation magnetization and coercivity than the saturation magnetization and low coercivity realized by using a magnetic material in which the enrichment phase is nano-dispersed. It is possible to provide a new magnetic material and a method of manufacturing the same.
According to the present invention, a magnetic material having high saturation magnetization and small eddy current loss, particularly a soft magnetic material suitably used for a high rotation motor, etc., further having high oxidation resistance, or magnetic saturation suppression ability or high frequency absorption It is possible to provide various soft magnetic materials and semi-hard magnetic materials that can meet the required performance such as performance.
According to the present invention, since it can be used in the form of a powder material like ferrite, it can be easily bulked by sintering etc. Therefore, such as lamination by using a metallic soft magnetic material which is an existing thin plate It is also possible to solve problems such as complicated processes and high costs resulting therefrom.

It is a SEM image of Fe _93.0 Ni _2.0 Cr _5.0 soft magnetic material. It is a SEM image of (Fe _0.930 Ni _0.020 Cr _0.050 ) ₄₃ O ₅₇ ferrite nanopowder. (A) is an SEM-EDX analysis image of Fe _93.0 Ni _2.0 Cr _5.0 soft magnetic material (the numerical values in the figure indicate the Cr content (atomic%) in the cross portion, and the radius is 100 nm to 150 nm (B) is a SEM-EDX analysis image of the Fe _93.0 Ni _2.0 Cr _5.0 soft magnetic material (the numerical values in the figure are Ni at the cross portion). Indicates the content (atomic%), and is an average value in a region of a radius of 100 nm to 150 nm. (A) is an SEM-EDX analysis image of Fe _85.1 Ni _4.3 V _10.6 soft magnetic material (the numerical values in the figure indicate the V content (atomic%) in the cross portion, radius 100 nm to 150 nm) (B) is an SEM-EDX analysis image of the Fe _85.1 Ni _4.3 V _10.6 soft magnetic material (numerical values in the figure are Ni at the cross portion). Indicates the content (atomic%), and is an average value in a region of a radius of 100 nm to 150 nm.

Hereinafter, the present invention will be described in detail.
In the present invention, "magnetic material" refers to a magnetic material referred to as "soft magnetic" (i.e., "soft magnetic material") and a magnetic material referred to as "semi-hard magnetic material" (i.e. "semi-hard magnetic material "). Here, “soft magnetic material” refers to a magnetic material having a coercive force of 800 A / m (≒ 10 Oe) or less, and “semi-hard magnetic material” refers to a coercive force exceeding 800 A / m to 40 kA / m (磁性 500 Oe) or less magnetic material. In order to make an excellent soft magnetic material, it is important that it has low coercivity, high saturation magnetization or permeability, and low core loss. The causes of iron loss are mainly hysteresis loss and eddy current loss, but reduction of the former requires smaller coercivity, and reduction of the latter requires increasing the electrical resistivity of the material itself It is important to increase the electrical resistance of the entire molded body to be put to practical use. A semi-hard magnetic material is required to have an appropriate coercivity depending on the application and to have high saturation magnetization and residual magnetic flux density. Among them, soft magnetic or semi-hard magnetic materials for high frequency generate large eddy currents, so that the materials have high electrical resistivity, reduce the particle diameter of the powder, or thin plate or strip thickness It will be important to

  In the present invention, "ferromagnetic coupling" refers to a state in which adjacent spins in a magnetic substance are strongly coupled by exchange interaction, and in the present invention, in particular, two adjacent crystal grains (and / or amorphous grains). ) In which the spins in the crystal are strongly connected by exchange interaction across the crystal boundary. As used herein, "grains" such as crystal grains are lumps that can be recognized as being composed of one or more "phases" and separated from the three-dimensional space with a boundary. Since the exchange interaction is an interaction that extends only to the distance based on the short distance order of the material, when the nonmagnetic phase exists at the crystal boundary, the exchange interaction does not work on the spin in the regions on both sides, and the crystal grains on both sides There is no ferromagnetic coupling between (and / or amorphous particles). In the present application, the term "crystal grain" sometimes includes amorphous grains. Further, the characteristics of the magnetic curve of the material in which ferromagnetic coupling is made between different kinds of adjacent crystal grains having different magnetic properties will be described later.

The term "disproportionation" as used in the present invention means that a phase in which two or more compositions or crystal structures are different is generated by a chemical reaction from a phase in homogeneous composition, and in the present invention, the homogeneous composition As a result of the reduction reaction involving reduction materials such as hydrogen involved in the phase of. The chemical reaction that leads to this "disproportionation" is referred to herein as the "disproportionation reaction", but water is often by-produced during this "disproportionation" reaction.
The "M-ferrite" referred to in the present invention is a material in which the Fe component of magnetite Fe ₃ O ₄ is substituted by the M component, and the M component is Zr, Hf, V, Nb, Ta, Cr, Mo, W is one or more of W, Cu, Zn, and Si, and the M component may be simply described as M. Further, the M component oxide is a substance or material in which an M component and oxygen O are bonded, and among them, one which is nonmagnetic (in the present application, also includes a case of very low magnetism). Furthermore, when described as "TM component" or "TM", they refer to any one or more of Ti and Mn.

In the present application, "containing FM component and M component" means that the magnetic material of the present invention necessarily contains the FM component as the component (this "FM component" contains Fe and contains Ni and / or Co. Ferromagnetic component means) and M component (this “M component” means any one or more of Zr, Hf, V, Nb, Ta, Cr, Mo, W, Cu, Zn, Si Means to contain. In this case, a part of the M component may be optionally replaced by a fixed amount with another atom (specifically, any one or more of Ti and Mn, which is also referred to as a TM component in the present application). In addition to the FM component and the M component, oxygen (O component) may be contained. Furthermore, when an O component or iron oxyhydroxide is present as a secondary phase, the O component may be contained as an OH group bonded to the H component (OH group mainly present on the surface of the magnetic powder), and And other unavoidable impurities, alkali metals such as K derived from the raw material, and Cl may be contained. An alkali metal such as K is a suitable component in that it may exert an accelerating effect on the reduction reaction.
The "FM component" refers to a component which necessarily contains Fe and which Ni and / or Co comprise by substituting a part of Fe, and this component has ferromagnetic properties. The substitution amount of Ni and / or Co to Fe is preferably 0.001 atomic% or more and 49.99 atomic% or less as described later. In the present invention, the crystal structure of the phase having the FM component as the main component is mostly bcc structure, and the crystal structure is equivalent to α-Fe, so in this case only the FM component is the main component The phase is called the α-FM phase. In this case, when Fe is the main component, it may be called an α-Fe phase. Further, in the present invention, even if "FM" is simply written in a formula such as "FM-M" or in a sentence, it means "FM component" as defined above.
Further, in the present invention, when referred to as ferrite, ferrihydrite, wustite, hematite, iron oxyhydroxide, etc., the contained ferromagnetic component is not only Fe, but part of Fe is substituted with Ni and / or Co. If included, it is included.
Although "magnetic powder" generally refers to powder having magnetism, in the present application, the powder of the magnetic material of the present invention may be referred to as "magnetic material powder". That is, "magnetic material powder" is included in "magnetic powder".

  The present invention includes a phase (first phase) in which the M component is contained in the α-FM phase composed of Fe as the main component, and an M component-enriched phase in which the M component content is higher than that phase (second The present invention relates to a magnetic material containing a phase), and the best mode is a "powder" in which both phases are mixed and combined at the nano level. These magnetic material powders are compacted as they are or sintered and used in various devices. In addition, depending on the application, it can be molded by blending an organic compound such as resin, an inorganic compound such as glass or ceramic, or a composite material thereof.

Hereinafter, the composition, crystal structure and form of the first phase containing the FM component and the M component, and the second phase enriched with the M component, the crystal particle size and the powder particle size, and their production methods, among them In particular, a method of producing a nano-composite oxide powder to be a precursor of the magnetic material of the present invention, a method of reducing the powder, a method of solidifying the reduced powder, and annealing in each step of these production methods The method will be described.
In addition, in this invention, although component content may only be described as "content", this also includes the case where it shows with atomic ratio and atomic percentage (%). However, when component content is shown by atomic percentage (%), it may be described as "content (atomic%)."

<Phase 1>
In the present invention, the first phase is a crystal having a bcc structure cubic crystal (space group Im3m) including an FM component and an M component as a crystal structure. As described above, the FM component means a ferromagnetic component containing Fe and containing Ni and / or Co, and the M component is Zr, Hf, V, Nb, Ta, Cr, Mo, W, Cu, Zn , Or any one or more of Si.
The contents (atomic%) of Fe and Ni and / or Co contained in the FM component of the first phase are preferably such that the total (total content) of all the components constituting the FM component is 100 atomic%, Fe is 50.01 atomic percent to 99.999 atomic percent, and Ni and / or Co is 0.001 atomic percent to 49.99 atomic percent.
The M component content (atomic%) of the first phase is preferably 0.001 atomic% or more to 33.33, assuming that the total (total content) of the FM component and the M component contained in the phase is 100 atomic%. It is less than atomic percent. In this case, the composition of the first phase is expressed as FM _100-x M _x (x is an atomic percentage 0.001 ≦ x ≦ 33.33) using the composition formula.

  Here, unless otherwise specified, the M component content or the FM component content is the sum of the FM component and the M component contained in the phase (in the present application, it may be referred to as the total content as described above, It refers to the value of the atomic ratio of the M component or the FM component to the total amount. In the present invention, this may be expressed in atomic percent, where the total (total content) of the FM component and the M component contained in the phase is 100 atomic%.

As a property common to the respective M components, it is preferable to set the M component content to 33.33 atomic% or less in order to suppress the decrease in the magnetization. In addition, when the M component content is 20 atomic% or less, it is more preferable because magnetization exceeding 1 T can be realized depending on the manufacturing method and conditions. If the content is further 10 atomic% or less, it is particularly preferable because the saturation magnetization can be made to a magnetic material exceeding 1.6 T. Moreover, unlike the case of the FM component alone, making the content 0.001% or more makes it possible to adjust the magnetic characteristics in the soft magnetic region by the effect of the addition of the M component, for example, to add the magnetic saturation suppression capability. preferable. Therefore, the range of the content of particularly preferable M component is 0.01 atomic percent or more and 10 atomic percent or less, and in this region, depending on the manufacturing conditions, a semi-hard magnetic material can be prepared from soft magnetic, particularly high frequency It can be a soft magnetic or semi-hard magnetic material having absorption ability, and it becomes possible to manufacture a magnetic material having more preferable electromagnetic properties. If it is desired to make the magnetization of a soft magnetic material with a higher degree of magnetization at the expense of a little coercive force, it is preferable to set the M component content of the first phase to 5 atomic% or less.
The first phase of the FM-M composition having this bcc structure is also referred to as an α- (FM, M) phase in the present application, since the α-phase, which is the room temperature phase of Fe, has the same symmetry as the crystal.

Assuming that the M component content of the first phase of the present invention is 100% atomic percent, 0.001 atomic percent or more and less than 50 atomic percent of the M component is a TM component (that is, any one or more of Ti and Mn) Can be replaced by). Therefore, in the present invention, when the M component contained in the first phase has a composition substituted by the TM component, the combination of M in the composition and the TM component is the above-mentioned "M component". Correspondingly, the M component content (specifically, the sum of the M component content and the TM component content in the composition) is 100 atomic%. Among these M components, adding a large number of element species to the soft magnetic material of the present invention has the effect of increasing the entropy of the magnetic material and reducing the coercivity.
When Cr is contained in the M component, a soft magnetic material or a semi-hard magnetic material having a large saturation magnetization is obtained. The use of V, Cr and Mo as the M component is effective in that the nanocrystallites of the present invention can be easily produced without largely depending on the temperature lowering rate in the reduction treatment and the annealing treatment. The use of Zr, Hf, Cr, V, Zn, Ta, Cu, or Si as the M component is preferable as a component of the soft magnetic material of the present invention because the anisotropic magnetic field is reduced.
When Zr, Hf, V, Nb, Ta, Mo, and W are used as the M component, the addition of 1 atomic percent or less by atomic percentage when the M component content of the first phase is 100 atomic percent, the reduction step It is possible to suppress “inappropriate grain growth” of
The use of Cu or Zn as the M component is preferable because it improves the oxidation resistance and the formability.
Furthermore, when the TM component is co-added, not only the above effects but also a unique synergistic effect in which low coercivity and high magnetization are compatible may be exhibited. For example, when the first phase has a composition formula of FM _{100 -x} M _x (where x is an atomic percentage 0.001 ≦ x ≦ 33.33), the M component is 0.01 atomic% or more depending on the TM component. Assuming that substitution is made in the range of less than atomic%, the composition formula is FM _{100 −x} (M _{100 −y} TM _y ) _{x / 100} (x, y is an atomic percentage, 0.001 ≦ x ≦ 33.33, 0 .001 ≦ y <50, M is at least one of Zr, Hf, V, Nb, Ta, Cr, Mo, W, Cu, Zn, Si, and TM is at least one of Ti and Mn) Be done. In any of the TM components, addition of 0.001 atomic% or more by atomic percentage when the M component content of the first phase is 100 atomic% is preferable from the viewpoint of the effect by the above co-addition, 50 atomic% The addition of less than this is preferable from the viewpoint of preventing inhibition of various effects by the M component in the magnetic material of the present invention.

The amount of Fe (atomic%) in the FM component is 50.01 atomic% or more and 99.999 atomic% or less, where the total (total content) of all the components constituting the FM component is 100 atomic%. The amount of Ni and / or Co in the components (atomic%) is defined as Ni in the range of 0.001 atomic% to 49.99 atomic%, assuming that the total (total content) of all the components constituting the FM component is 100 atomic%. It is preferable that it is / or Co. Co coexistence not only increases the saturation magnetization but also has the effect of decreasing the coercivity. Ni is preferably added because the saturation magnetization is improved by the addition of about 5 at.% Or less and the coercive force is reduced by 0.001 to 49.99 at.%. It is possible to co-add Ni and Co in consideration of the balance of saturation magnetization and coercivity, and adjust their ratio to the range of 0: 100 to 100: 0 as appropriate. Note that Ni and Co in the FM component may be referred to as "Ni / Co component".
Similar to the M component, the Ni and Co are disproportionated in the Fe component, and the content of these components in the phase may have fluctuation generally larger than ± 4.76%. Specifically, taking a material having a Co content of 10 at.% As an example, it may be said that a phase having a Co content of less than 9.524 and a phase having more than 10.476 at. It is. This further includes another phase that is distinguished from the phase having crystals of bcc structure (also referred to as “first phase” in the present application) including the FM component and the M component (this second phase is referred to as “second phase” in the present application). Content (atomic%) of Ni and / or Co when the sum of the FM component and the M component contained in the phase (second phase) is 100 atomic%) Or less than 0.909 or 1.1 times or more the content (atomic%) of Ni and / or Co when the total of the FM component and the M component is 100 atomic%. It means that there is.
As described above, in the present invention, the magnetic anisotropy of the first phase and the second phase is further different or the fine composition is caused by disproportionation of Ni and Co present in the FM component as well as the M component. A structure with fluctuations is created, and fluctuations in composition are diversified or stabilized to become a soft magnetic material having a low and / or stable coercive force or a semihard magnetic material with an increased squareness ratio be able to.
Here, unless otherwise specified, the amount of Ni and / or Co is the amount (atomic ratio) to the total sum of all the components constituting the FM component containing them (ie, the amount relative to the FM component (atom Ratio)). Usually, since the first phase is composed of Fe, Ni and / or Co, in that case, the relative to the total (sometimes referred to as the total amount in the present application) of Fe, Ni and Co contained in that phase. It refers to the atomic ratio of Ni and Co. The amount of Ni and / or Co is also referred to as “the amount of Ni and / or Co” or “the amount of Ni / Co”. In the present application, the value of the atomic ratio may be expressed as atomic percentage (that is, the sum of all components constituting the FM component may be expressed as 100 atomic%). Furthermore, in the present application, the “amount of Ni and / or Co” or “the amount of Ni / Co” is simply “the amount of Ni” when Co is not contained and only Ni is contained, and Ni is not contained and only Co is contained. If it does, it is also simply referred to as "Co amount".
In addition, when saying "content of Ni and / or Co to the total of FM component and M component" (in the present invention, it is also simply referred to as "content of Ni and / or Co" or "Ni / Co content") Is the denominator in calculating the amount of Ni and / or Co to Fe, that is, the total amount includes not only the FM component but also the M component, and Ni and / or Co for the sum of the FM component and M component It means the amount (atomic ratio). In the present application, the value of the atomic ratio may be expressed as atomic percentage (that is, the sum of the FM component and the M component may be expressed as 100 atomic percent).
In the present invention, the amount of Ni / Co in the first phase is preferably 0.001 atomic% or more and 49.99 atomic% or less, when the total of all the components constituting the FM component is 100 atomic%. Furthermore, when the total of the FM component and the M component is 100 atomic percent, the FM component content is 66.67 atomic percent or more and 99.999 atomic percent or less, and the M component content is 0.001 atomic percent or more and 33.33 atoms % Or less is preferable. Therefore, the above-mentioned preferable range of “the content of Ni and / or Co when the total of the FM component and the M component is 100 atomic%” (that is, the Ni / Co content) is the above-mentioned FM in the first phase. It will be in the range of 0.001 atomic% or more and 49.99 atomic% or less among the component contents. The Ni / Co content is referred to as Ni content when Co is not contained but only Ni is contained, and when Ni is not contained but only Co is contained, it is referred to as Co content.
If the total content of the FM component and the M component contained in the entire magnetic material is 100 atomic%, the Ni / Co content is greater than the content of the M component (ie, the FM component in the entire magnetic material and When the total content of the M component (atomic%) is 100 atomic%, the Ni / Co content (atomic%) in the magnetic material exceeds this M component content (atomic%), The choice of synthesis conditions should be used with caution as it may interfere with phase separation due to disproportionation of the M component. In particular, depending on the amount of Co, phase separation due to disproportionation of the M component may be reduced, and the coercivity may be increased and / or destabilized. In addition, when the total content of the FM component and the M component contained in the entire magnetic material is 100 atomic%, the soft magnetic property having a low and / or stable coercive force when the Ni / Co content is less than 0.001 atomic%. As the effect of using the material disappears, it may be difficult to manufacture a stable magnetic material. In other words, when the total of the FM component and the M component included in the entire magnetic material is 100 atomic%, the Ni / Co content is unique by limiting the content to 0.001 atomic% or more and the M component content or less. The magnetic material of the preferable composition range which can achieve the object of the present invention can be obtained even without synthesis conditions.
In the first phase, the amount of Ni is preferably 49.99 atomic% or less with respect to the FM component in the phase in order to suppress the decrease in the magnetization. In addition, depending on the manufacturing method and conditions, it is more preferable that the amount of Ni is 20 atomic% or less because magnetization exceeding 2 T can be realized. Furthermore, a magnetic material whose saturation magnetization exceeds 2.1 T can also be manufactured as the amount of Ni is 12 atomic% or less. Moreover, it is preferable to make it 0.001 atomic% or more, in contrast to the case of Fe alone, in that it is possible to adjust the magnetic characteristics in the soft magnetic region by the effect of Ni addition. The most preferable range of the amount of Ni is 0.01 atomic percent or more and 20 atomic percent or less with respect to the FM component in the first phase, and in this region, soft magnetic materials of various coercivities are prepared depending on manufacturing conditions It becomes a magnetic material having more preferable electromagnetic characteristics.
In the first phase, the amount of Co is preferably 49.99 atomic% or less with respect to the FM component in the phase in order to suppress the decrease in magnetization. Depending on the manufacturing method and conditions, huge magnetization exceeding 2.3 T can be realized. Further, when the amount of Co is 33.33 atomic% or less with respect to the FM component in the first phase, a magnetic material having a giant saturation magnetization exceeding 2.4 T can be manufactured. Thus, it is a major feature of the magnetic material of the present invention containing Co that a giant saturation magnetization as large as about 10% larger than pure iron (saturation magnetization 2.16 T) can be obtained.
In addition, the fact that a magnetic material exhibiting a large saturation magnetization over pure iron in a wide range of Co content is obtained is another unique feature of the present material. Furthermore, making the amount of Co 0.001 at% or more with respect to the FM component in the first phase, unlike the case of Fe alone, allows adjustment of the magnetic characteristics in the soft magnetic region by the effect of Co addition. It is preferable in that The particularly preferable range of the amount of Co is 0.01 atomic% or more and 33.33 atomic% or less with respect to the FM component in the first phase, and in this area, soft magnetic materials having various coercivities depending on the manufacturing conditions It becomes a magnetic material that can be prepared and has more favorable electromagnetic properties.
The "inappropriate grain growth" means that the nano-fine structure of the magnetic material of the present invention is broken and the grains grow while accompanied by a homogeneous crystal structure. On the other hand, “grain growth”, which is suitable in the present invention, means that the grain size of the powder grows large while maintaining the nano-fine structure, which is the feature of the present invention In some cases, the nano-fine structure appears in the crystal due to phase separation or the like, or both. Unless otherwise stated, the term "grain growth" in the present invention refers to grain growth that is not inappropriate and refers to grain growth that is generally appropriate. In addition, even if any grain growth of appropriate grain growth and inappropriate grain growth occurs, the surface area of the magnetic material per unit mass or per unit volume decreases, and thus, the oxidation resistance generally tends to be improved. It is in.

  In the present invention, “M component” or “M component” or “M component” is described in a formula such as “α- (Fe, M)” phase or in a context in which the composition of the magnetic material is discussed. In this case, not only the case of the M component alone, but also the composition in which 0.001 atomic percent or more and less than 50 atomic percent of the M component content is replaced with the TM component. In addition, it is necessary to remove impurities mixed in the process as much as possible, but elements of H, C, Al, S, N, alkali metals such as Li, K, Na, alkaline earths such as Mg, Ca, Sr, rare earths And unavoidable impurities such as halogens such as Cl, F, Br and I. However, the content thereof is 5 atomic% or less, preferably 2 atomic% or less, more preferably 0. 5 or less of the whole (that is, when the total of the FM component and M component contained in the first phase is 100 atomic%). The content is 1 atomic% or less, particularly preferably 0.001 atomic% or less. The higher the content of these impurities, the lower the magnetization, and in some cases, the adverse effect on the coercivity, and in some applications, the target range may be exceeded. On the other hand, there is also a component that acts as a reduction aid when contained to a certain extent like alkali metals such as K, and the total (that is, the sum of the FM component and M component contained in the first phase is 100 atomic%) In some cases, a magnetic material having a high saturation magnetization can be obtained by including in the range of 0.001 atomic percent or more and 5 atomic percent or less of the case (a). Therefore, the above-mentioned impurities are most preferably not included as long as the object of the present invention is inhibited.

  In the present invention, the α-Fe phase not containing the M component is distinguished from the first phase and the second phase. Even if it is a powder of nano range, the alpha-Fe phase which does not contain M ingredient is because the influence which it has on electric resistivity is not good, and it is because it becomes poor in oxidation resistance and is a material inferior to cutting workability. However, the α-Fe phase not containing the M component may be present as a separate phase as long as the object of the present invention is not impaired. In the case of the soft magnetic material of the present invention, the volume fraction of the α-Fe phase not containing the M component is preferably less than 50% by volume with respect to the entire magnetic material of the present invention.

  The volume fraction referred to here is the ratio of the volume occupied by the target component to the total volume of the magnetic material.

<Phase 2>
In the present invention, in the second phase, the content of the M component with respect to the sum of the FM component and the M component contained in the phase is greater than the content of the M component with respect to the sum of the FM component and the M component contained in the first phase. There are many phases. In other words, in the present invention, the second phase is the atomic percentage of the M component to the sum of the FM component and the M component contained in the phase, and the atom of the M component to the sum of the FM component and the M component contained in the first phase. It is a phase greater than a percentage. The second phase is a cubic crystal, α- (FM _1-y M _y ) phase (space group Im 3 m, the same crystal phase as the first phase, but having a higher M component content than the first phase) ), SiFe phase (space group P213), γ- (Fe, M) phase (space group Fm3m, γ- (FM, M) phase), wustite phase (typical composition is (FM _1-z M _z ) _a O phase, a is generally 0.85 to less than 1, and in this specification, this phase may be simply referred to as (M, FM) O phase, (FM, M) O phase), M component-ferrite Phase (representative composition is (FM _1-w M _w ) ₃ O ₄ phase), Cu phase (space group Fm 3 m), Nb phase (space group Im 3 m), Ta phase (space group Im 3 m), β-cristobalite phase (SiO 2) ₂ ) Laves phase which is a hexagonal crystal such as α-FeV phase (typical examples are WFe ₂ phase, MoFe ₂ phase) , Α-Hf phase (may contain up to about 20 atomic percent O), ZnO (wurtzite type, space group P63 mc), β-tridymite (SiO ₂ ), etc., trigonal α-quartz (SiO ₂ ) ₂ ) such as rhombohedral M-hematite phase (typical composition is FM _1-u M _u O ₃ phase), Cr ₂ O ₃ phase such as tetragonal β-cristobalite phase (SiO ₂ ), σ -FeV phase, Cr ₅ Si ₃ phase, NbO ₂ phase, etc., monoclinic ZrO ₂ phase such as α-tridymite (SiO ₂ ), orthorhombic V ₂ O ₅ phase, Ta ₂ O ₅ phase, etc. And Zr ₂₅ Fe ₇₅ eutectic phase composition phase (composition ratio is described by two significant figures), etc., or a mixture thereof. The amorphous phase, eutectic point composition phase and eutectoid point composition phase (also referred to as "amorphous phase etc." in this application) differ depending on the M component content and reduction conditions, but when an amorphous phase or the like is present Is present in the form of islands separated from the first phase without taking a fine structure such as floating in the amorphous sea as microcrystals become islands like the existing nanocrystal-amorphous phase separation type material described above There are many things to do. The content of the amorphous phase or the like is between 0.001 and 10% by volume, and it is preferable from the viewpoint of suppressing the decrease in the magnetization that it is not more than this, and in order to make the magnetic material of high magnetization further preferable. Is less than 5% by volume. The amorphous phase or the like may be intentionally included in order to control the disproportionation reaction itself, but in this case, it is preferable to be more than 0.001% by volume from the viewpoint of exerting the reaction control effect.
The volume fraction referred to here is the ratio of the volume occupied by the target component to the volume of the entire magnetic material.

  The second phase described above is inferior to the first phase in saturation magnetization, but the coexistence of these phases significantly increases the electrical resistivity. Furthermore, in the present invention, the coercivity is improved when the semi-hard magnetic material is formed. On the contrary, in the present invention, when the soft magnetic material is formed, a small coercive force can be realized by ferromagnetically coupling with the phase depending on the crystal structure, composition, microstructure, interface structure, etc. of the phase. Furthermore, also in the second phase, as in the first phase, less than 50 atomic% of the M component content (however, the content of the M component of the second phase is 100 atomic%) can be replaced with the TM component . Here, in the present invention, the “M component” of the second phase also has a composition in which the M component contained in the second phase is substituted by the TM component as in the “M component” of the first phase described above. Means the combination of the M component and the TM component in the composition.

<Secondary phase, other phases>
A phase which contains neither the FM component nor the M component, and is mixed only with the compound of the TM component is not included in the first phase or the second phase. However, it may contribute to the improvement of the electrical resistivity, oxidation resistance, sinterability, and electromagnetic properties of the semi-hard magnetic material of the present invention. A phase that does not contain the M component, such as the compound phase of the TM component or the FM compound phase described above, and a phase in which the content of the TM component is equal to or greater than the content of the M component element are referred to as “subphase” in the present application.

Phases other than the first phase and the second phase that do not contain M component, wustite phase, magnetite phase (Fe ₃ O ₄ ), maghemite phase (γ-Fe ₂ O ₃ ), hematite phase (α-Fe ₂ O ₃₎ Subphases such as α-Fe phase and γ-Fe phase (in the present invention, when a part of Fe is substituted by Ni and / or Co among the above-mentioned subphases, for example, it is FM _{3 in the} case of magnetite O ₄ and as shown in, sometimes referred replace "Fe" to "FM".) or, goethite or without containing M components, Akagenaito, lepidocrocite, ferro oxy height, ferrimagnetic hydrate light Iron oxyhydroxide phase such as Greenlast, hydroxide such as potassium hydroxide and sodium hydroxide, chloride such as potassium chloride and sodium chloride, fluoride, carbide, nitride, hydride, sulfide, nitrate Salts, carbonates, sulfates, silicates, phosphates etc. may also be included, but these volumes are also stable over time as the magnetic material of the invention has a high saturation magnetization. In order to exhibit magnetic properties and high magnetization, it is required to be smaller than the volume of the first phase. From the viewpoint of suppressing the decrease in saturation magnetization, the preferable range of the content of these phases is 50% by volume or less with respect to the volume of the entire magnetic material.

  The content of the TM component of all the phases including the first phase, the second phase and the subphase should not exceed the content of the M component contained in the first phase and the second phase with respect to the whole phase. When the TM component is contained in excess of the M component content, the effect on the electromagnetic characteristics unique to the M component, for example, the reduction of the magnetocrystalline anisotropy, the improvement of the electrical resistivity, and the oxidation resistance by passivation of the powder surface It is because the peculiar feature such as improvement is lost. In the present application, the M component content of the first phase and / or the second phase means an amount including such a TM component.

<When the second phase has the same crystal structure as the first phase>
The second phase may have the same crystal structure as the first phase, but it is desirable that the compositions be sufficiently different from each other, for example, the second relative to the sum of the FM component and the M component in the second phase. The M content (atomic%) of the phase is greater than the M content (atomic%) of the first phase relative to the sum of the FM and M components in the first phase, and the difference is 1.5 times It is preferable that the content of the M component of the second phase with respect to the sum of Fe and M components in the second phase is 2 atomic% or more.
The M component content itself of the second phase does not exceed 100 atomic percent, and when the lower limit value of the M component content of the first phase is 0.001 atomic percent, the M component content of the second phase is second It does not exceed 10 ⁵ times the M component content of one phase. The M component content of the second phase is preferably 90 atomic% or less of the M component content of the first phase. When the M component content exceeds 90 atomic% while the second phase maintains the same crystal structure as the first phase at normal temperature (thus, the M component content of the second phase is the M component content of the first phase) If it exceeds 9 × 10 ⁴ times), the thermal stability of the entire magnetic material of the present invention may be deteriorated.

  In the above, when the “M component content” of the second phase is “1.5 times or more” of the first phase, the M component content of each phase is determined by one or more significant figures, The M component content of the second phase is 1.5 or more times the M component content of the first phase.

  The present invention aims to reduce the coercive force by utilizing the above-mentioned random magnetic anisotropy model or the fluctuation of the magnetic anisotropy according to the model, and is a crystallographically independent first phase And the second phase are magnetically coupled at the nano level by exchange coupling, or there is a spatial change in the M component content in the bcc phase including the first phase and the second phase at the nanoscale (This is sometimes referred to as "concentration fluctuation" in the present invention). However, if the M component composition ratio of the two phases is too close, the crystal orientations of the crystal phases may be aligned in the same direction, and the magnitude of the magnetocrystalline anisotropy constant is often the second The phase is smaller, but if the total content of Fe and M in the second phase is 100 atomic% and the content of the M component is less than 2 atomic%, the crystal magnetic anisotropy becomes large and averaged. The value of the magnetocrystalline anisotropy does not become sufficiently small, so that a sufficiently low coercivity can not be realized. Therefore, the M component content of the second phase is preferably 2 atomic% or more, more preferably 5 atomic% or more, based on the total of Fe and M components in the second phase. In the latter case, the magnetocrystalline anisotropy of the two phases is reduced to half or less compared to the case where the M component is not contained. If the M component content is 8 atomic% or more, it is further preferable because the magnetocrystalline anisotropy becomes extremely small.

  If there is a phase (first phase) in which the M component content is lower than the M component content of the entire magnetic material of the present invention, the phase (second phase) in which the M component content is higher than the magnetic material of the present invention is also the same In the magnetic material. Therefore, as long as they are ferromagnetically coupled and isotropic, the magnetic material of the present invention, specifically, a soft magnetic material can be obtained. The magnetic material of the present invention, specifically a semi-hard magnetic material, can be obtained by interposing at the interface of the first phase and increasing the electric resistance by setting the coercivity in an appropriate range. In addition, even if the isotropic state is not sufficiently, if there is a spatial concentration fluctuation of the M component content in a certain crystal phase, a fluctuation occurs in the magnetic anisotropy, and the random anisotropy model Coercivity may decrease due to different mechanisms. In the magnetic material of the present invention in which the coercivity is lowered by such a mechanism, the content of the M component becomes 10 atomic% or less when the total of the M component and Fe in the magnetic material is 100 atomic%. Often These are highly homogeneous compositions, in which the different phases are thoroughly removed, and magnetic steel sheets designed so as not to inhibit domain wall movement, magnetics of the present invention not found in many existing soft magnetic materials such as Sendust. It is a feature of the material, and it can be said that magnetization reversal is a feature common to magnetic materials caused by the rotation of magnetization.

  A state in which only the first phase or only the second phase is magnetically coupled at the nano level by exchange coupling may be included, and even in this case, the crystal axis orientations of adjacent nanocrystals are not aligned. It is important that there is a nanoscale spatial distribution of M component content in the bcc phase that is isotropic or contains the first and second phase. However, in the present invention, a magnetic material composed of microcrystallines of only the first phase or a magnetic material composed of microcrystallines of only the second phase can not be achieved, and even when such a structure is included, In the present invention, the first phase and the second phase are always present in the magnetic material. The reason for this is that the formation of nanocrystals itself is a powder of ferrite containing an M component, which is used to produce the magnetic material of the present invention, wherein the powder has a nanoscale size (herein The reason is that it is greatly involved in the disproportionation reaction in each process of the reduction process starting from the reduction of the ferrite nanopowder or the M component ferrite nanopowder). In the present application, a ferrite powder of nanoscale size is also referred to as "ferrite nanopowder", and the nanoscale refers to a scale of 1 nm or more and less than 1 μm unless otherwise specified.

<Identification of the second phase>
The following describes how to identify the second phase. First, as described above, the first phase is the α- (FM, M component) phase, which mainly ensures high saturation magnetization. In the second phase, the content of the M component when the total of the FM component and the M component contained in the phase is 100 atomic%, the total of the FM component and the M component contained in the first phase is 100 atomic% The phase is more than the content of the M component in the case. In the present invention, the second phase may be an α- (FM, M component) phase that is higher than the M component content of the entire magnetic material, or may be another crystalline phase or an amorphous phase, or a mixed phase thereof. In any case, the soft magnetic material of the present invention has the effect of keeping the coercivity low, and even including the semi-hard magnetic material, has the effect of imparting oxidation resistance and improving the electrical resistivity. Therefore, since the second phase is a phase having these effects, the magnetic material of the present invention can be confirmed by confirming the presence of any of the previously exemplified phases, in which the content of the M component is higher than that of the first phase. I understand that there is. If such a second phase does not exist and is constituted only by the first phase, any one of the magnetic properties such as the coercive force, the oxidation resistance and the electrical conductivity is inferior, and in the processability, It becomes a magnetic material which is scarce and complicates the molding process.

  When the second phase is the α- (FM, M component) phase, the composition of the first phase and the M component may change continuously. Alternatively, depending on the method of identifying the material, it may be observed that the M component composition of the first phase and the second phase changes continuously. Also in such a case, if the M component content of the second phase is at least 1.5 times the M component content of the first phase, or the M component content of the second phase is 2 atomic% or more, the first It is desirable that the M component content of the second phase is greater than the M component content of the phase, or 1.5 times or more and 2 atomic% or more of the M component content of the first phase. When Cr is the main component of M, the content of M in the second phase is 1.5 times or more the content of M in the first phase, which makes it possible to adjust the electromagnetic characteristics such as the coercivity. When the M component is mainly contained, twice or more is more preferable, and when it is twice or more also when Cr is mainly contained, a preferable range is to obtain a soft magnetic material having a small coercive force.

  The composition ratio of the FM component and the M component when the first phase and the second phase are combined is preferably 1: 1 or less, in other words, the total amount of the FM component and the M component in the first phase and the second phase It is desirable that the content of the M component is 0.01 atomic percent or more and 50 atomic percent or less when 100 atomic percent is

  It is preferable that the content of all the M components in the first phase and the second phase is 50 atomic% or less in order to avoid a decrease in saturation magnetization, and that it is 0.01 atomic% or more is oxidation resistance There is no addition effect of M component to etc., and it is preferable in order to avoid that a coercive force becomes high to such an extent that it does not respond to the target application. Furthermore, from the viewpoint of a good balance between oxidation resistance and magnetic properties, the content of the M component including the first phase and the second phase is preferably 0.05 atomic% or more and 33 atomic% or less, among which A particularly preferable range is 0.1 atomic percent or more and 25 atomic percent or less.

  Although the volume ratio of the first phase to the second phase is arbitrary, the first phase, or the first phase and the first phase, relative to the volume of the entire magnetic material of the present invention including the first phase, the second phase and the subphase. The total volume of the α- (FM, M component) phase in the second phase is preferably 5% by volume or more and 99.99% by volume or less. Since the α- (FM, M component) phase bears the main magnetization of the magnetic material of the present invention, it is preferably 5% by volume or more and 99.99% by volume or less to avoid a decrease in magnetization. Furthermore, it is preferably 25% by volume or more, more preferably 50% by volume or more. In order to realize particularly high magnetization without significantly lowering the electrical resistivity, it is desirable to set the total volume of the α- (FM, M component) phase to 75% by volume or more.

  In the second phase of the soft magnetic material of the present invention, it is preferable that a ferromagnetic or antiferromagnetic (herein, weak magnetism is also included in this phase) phase, because the crystal magnetism of the first phase is the reason It is because it has the effect of reducing anisotropy.

<Example of Preferred Second Phase>
In the magnetic material of the present invention, as a representative example of the second phase preferable as ferromagnetism, the M component content of the second phase when the total sum of the FM component and the M component in the second phase is 100 atomic%, The (alpha)-(FM, M component) phase whose M component content is more than the 1st phase when the sum total of the FM component and M component in a 1st phase is 100 atomic% is mentioned. Among these, the M component content is preferably 0.1 atomic percent or more and 20 atomic percent or less, more preferably 2 atomic percent or more and 15 atomic percent or less, and is 5 atomic percent or more and 10 atomic percent or less Is particularly preferred.

Also in the first phase, when the total content of the FM component and the M component in the first phase is 100 atomic%, low coercivity is realized when the M component content is 5 atomic% to 10 atomic%. However, when the M component content is increased to this extent, saturation magnetization close to 2T may not be able to be exhibited.
Therefore, by combining the first phase having an M component content of more than 0 atomic percent and less than 5 atomic percent and the second phase having an M component content of 5 atomic percent or more, a magnetic material having large saturation magnetization and small coercivity It is preferred to realize the material.

Then, M-ferrite phase and wustite phase are mentioned as a preferable 2nd phase. The former is ferromagnetic and the latter is antiferromagnetic, but any one can promote ferromagnetic coupling if it is between the first phase. These oxide phases may be nano-sized and have a very fine structure, and particularly in the wustite phase, a few atomic layers are finely dispersed in the bcc phase or layered between the bcc microcrystalline phases. It may also exist. When such an oxide layer is present, the crystal orientation of the bcc phase may be aligned in a region of several hundred nm to several tens of μm, but even in such a microstructure, the crystal grain size of the present invention, etc. The magnetic material of the present invention is included in the range of In particular, when the magnetic material having the above structure is a soft magnetic material, the coercivity is lowered by a mechanism slightly different from random anisotropy. It is assumed that the mechanism is as follows.
By disproportionation, the M component content of the first phase with respect to the sum of the FM component and the M component in the first phase, and the M component content of the second phase with respect to the sum of the FM component and the M component in the second phase If there is a difference between the two, and if there is a spatially fluctuating concentration of nanoscale fine M component content, a spatial fluctuation of magnetic anisotropy will occur, and when an external magnetic field is applied, all at once It is included in the mechanism of magnetization reversal (as if the resonance phenomenon occurred). The above-mentioned fluctuation in concentration has a similar effect of reducing the coercive force not only when the second phase is an oxide phase but also when it is an α- (FM, M component) phase.

Incidentally, there is also known an example in which the ferrite phase promotes ferromagnetic coupling (in this respect, WO 2009/057742 (hereinafter referred to as "patent document 3"), N. Imaoka, Y. Koyama). , T. Nakao, S. Nakaoka, T. Yamaguchi, E. Kakimoto, M. Tada, T. Nakagawa, and M. Abe, J. Appl. Phys., Vol. 103, No. 7 (2008) 07E129 (hereinafter referred to as In all cases, a ferrite phase exists between Sm ₂ Fe ₁₇ N ₃ phases of a hard magnetic material, and these phases are ferromagnetically coupled to constitute an exchange spring magnet. is there.

  However, the present invention relates to a soft magnetic material and a semi-hard magnetic material, and the function to be exhibited is completely different from the above hard magnetic exchange spring magnet. In the present invention, if the presence of the second phase, which is the M-ferrite phase or the wustite phase, mediates the exchange interaction between the first phase, if such a second phase exists to surround the first phase, The electrical resistance is also high and the coercivity is reduced. Therefore, it is one of the highly preferable second phases particularly in the soft magnetic material of the present invention.

  On the other hand, the presence of a nonmagnetic M-component oxide phase in the second phase is preferable because the electrical resistance is particularly improved. Even if it exists between the first phase, ferromagnetic coupling such as M-ferrite phase occurs to have no direct effect on the magnetic properties, but to cover the surface of these ferromagnetic coupled powders The presence of the M component oxide not only improves the electrical resistance and the oxidation resistance, but in some cases, may have the effect of reducing the coercive force.

  In the magnetic material of the present invention, the second phase is an oxide phase (specifically, any one of an M-ferrite phase, a wustite phase, or an M component oxide phase (an oxide phase containing an M component), Alternatively, in the case of a mixed phase consisting of any one or more of them, the volume fraction of the oxide phase is preferably 95% by volume or less of the entire magnetic material, more preferably 75% by volume or less, and 50 Volume% or less is more preferable. For example, the M-ferrite phase is lower in magnetization than the α- (FM, M) phase although it is ferromagnetic, and the wustite phase is also antiferromagnetic but weakly magnetic and lower in magnetization than the M-ferrite phase. In addition, the M component oxide phase is nonmagnetic. Therefore, in the mixed oxide phase obtained by combining the above oxide phases, the magnetization of the magnetic material of the present invention becomes extremely low when the volume fraction exceeds 95% by volume of the entire magnetic material regardless of the types of the oxides to be combined. . In order to avoid it, the volume fraction of the mixed oxide phase is preferably 95% by volume or less of the entire magnetic material. In the case of a mixed oxide phase combining the wustite phase and the M component oxide phase as main components, the magnetization will be low if the content of these total oxide phases exceeds 75% by volume, so avoid it. Preferably, it is 75% by volume or less of the entire magnetic material. In the case of an oxide phase containing an M component oxide phase as a main component, the characteristics of the magnetic material of the present invention having high magnetization are lost when it exceeds 50% by volume. It is preferable to set it as 50 volume% or less of. When the magnetic material is particularly high in magnetization while maintaining the electrical resistivity to a certain extent, the M component oxide phase is preferably 25% by volume or less.

Conversely, if the M component oxide phase or the like is present, the electrical resistivity is increased, so the M component oxide phase or the like may be positively contained. In this case, the volume fraction is preferably 0.001% by volume or more, and particularly in the case where the M component oxide or the like is present without significantly reducing the magnetization, it is 0 when the electrical resistivity is to be effectively improved. .01% by volume or more is more preferable, and 0.1% by volume or more is particularly preferable.
Further, for example, even in the case where the oxide phase is a mixture of M-ferrite and wustite, the range of preferable volume fraction etc. is the same as in the case of the M component oxide phase.

  As described above, as the preferred phase of the second phase, the α- (FM, M) phase, the M-ferrite phase, the wustite phase, and the M component oxide phase having an M component content higher than the first phase are exemplified. Among them, the three phases other than the M component oxide phase are ferromagnetic or antiferromagnetic. Therefore, if these phases are separated without ferromagnetic coupling, the magnetic curve is additive, so the magnetic curves of these mixed materials are simply the sum of the respective magnetic curves, and the entire magnetic material There is a smooth step on the magnetic curve of For example, when the magnetization is measured in a wide magnetic field range of 0 to 7.2 MA / m from the external magnetic field, the 1/4 major loop (from 7.2 MA / m to the zero magnetic field) of the magnetic curve of the entire magnetic material If you look at the shape of the 1⁄4 major loop) of the magnetic curve of (1), it is certain that the smooth step due to the above circumstances or the inflection point based on it is certain on the 1⁄4 major loop I can guess. On the other hand, when these different magnetic materials are integrated by ferromagnetic coupling, no smooth step or inflection point is observed on the major loop in the range of 7.2 MA / m to zero magnetic field, and monotonously increases. Exhibits a convex magnetic curve. In order to estimate the presence or absence of ferromagnetic coupling, in addition to the observation of the fine structure in the above-mentioned grain boundary region and the like, detailed observation of the above magnetic curve is one guideline.

<Composition distribution>
In the embodiments of the present invention, the local compositional analysis of the metal element of the magnetic material of the present invention is mainly performed by EDX (energy dispersive X-ray spectroscopy), and the compositional analysis of the entire magnetic material is XRF (fluorescent X-ray) Elemental analysis was performed. In general, the M component content of the first phase and the second phase is measured by an EDX apparatus attached to SEM (scanning electron microscope), FE-SEM, or TEM (transmission electron microscope) (in the present invention, this is used) FE-SEM etc. which attached EDX may be described as FE-SEM / EDX etc.). Depending on the resolution of the device, if the crystal structure of the first phase and the second phase is a fine structure of 300 nm or less, accurate composition analysis can not be performed by SEM or FE-SEM, but M of the magnetic material of the present invention If it is for detecting only the difference of the component or the FM component, it can be used supplementarily. For example, to find a second phase less than 300 nm with an M component content of 5 atomic% or more, one point in the magnetic material is observed, and its quantitative value is 5 atomic% or more as an M component content. If it is confirmed that there is a tissue having an M component content of 5 atomic% or more, or a part of the tissue, within a range of 300 nm in diameter centered on that one point. Also, conversely, in order to find the first phase in which the M component content is 2 atomic% or less, one observation in the magnetic material is performed, and the quantitative value is 2 atomic% or less as the M component content. If it is confirmed that there is a structure with a M component content of 2 atomic% or less or a part of the structure within the range of 300 nm in diameter centering on that one point.
When composition analysis is performed using an EDX apparatus attached to a TEM, for example, the electron beam can be narrowed to 0.2 nm, and very fine composition analysis can be performed. However, on the contrary, it is necessary to handle a large amount of data, for example, 60,000 points, in order to thoroughly examine a certain area and obtain an overview of the material of the present invention.
That is, in view of the composition of the magnetic material of the present invention, it is necessary to specify structural features such as the composition of the first phase and the second phase, the crystal grain size, and the like by appropriately selecting the composition distribution measuring method described above.

  The composition of the α- (FM, M) phase can also be determined by confirming the position of the diffraction peak by means of XRD (X-ray diffractometer). The diffraction peak of the α- (FM, M) phase tends to shift to a lower angle as the M content increases, and the behavior of the (110) and (200) peaks is observed in this And α-FM (by referring to the method of the present invention, an FM component-ferrite nanopowder which does not contain an M component or a TM component is separately prepared and compared as a comparative example). The M component content of the (FM, M) phase can also be known with one significant digit. At this time, since Ni and Co have almost the same metal radius as Fe (each metal radius is 0.124 nm for Fe and 0.125 nm for Ni and Co), the diffraction position of the α-FM phase is Almost the same as the α-Fe phase, the above analysis can also be performed representatively at the diffraction position of the α-Fe phase.

  The present invention is characterized by disproportionation of the M composition and the existence of various crystal phases, and it is useful to verify whether or not their crystal axes are randomly oriented. Furthermore, in order to distinguish the α- (FM, M) phase from other oxide phases, it is convenient and effective to analyze an oxygen characteristic X-ray surface distribution map using, for example, SEM-EDX.

<Composition of the entire magnetic material>
The composition of the whole magnetic material in the present invention is 20 atomic% or more and 99.999 atomic% or less of the FM component, 0.001 atomic% or more and 50 atomic% or less of the M component, with respect to the composition of the entire magnetic material. It is preferable that oxygen be in the range of 0 atomic percent to 55 atomic percent and simultaneously satisfy them. Furthermore, an alkali metal such as K may be contained at 0.0001 atomic% or more and 5 atomic% or less. It is desirable that the subphases including K and the like do not exceed 50% by volume of the whole.

  When the FM component is 20 atomic% or more, the decrease in saturation magnetization can be avoided, and when it is 99.999 atomic% or less, the decrease in oxidation resistance and the poor processability can be avoided, which is preferable. When the M component is 0.001 atomic% or more, the low oxidation resistance and the poor processability can be avoided, and when the M component is 50 atomic% or less, the saturation magnetization can be avoided from being low, so this is preferable. . When the O (oxygen) component is an important element to constitute the second phase, the range of 55 atomic% or less is not only due to the low saturation magnetization but also due to the reduction of the M component-ferrite nanopowder It is preferable because disproportionation reaction to the first phase and the second phase does not occur, and it is possible to avoid the difficulty of developing a low coercivity into a soft magnetic material. The magnetic material of the present invention does not necessarily contain oxygen, but in order to obtain a magnetic material having extremely high oxidation resistance and electrical resistivity, it is preferable to contain as little as possible. For example, the surface of the metal powder reduced in the gradual oxidation step to be described later may be passivated, or an oxide layer mainly composed of M component oxide may be formed in part of the grain boundaries of the solid magnetic material by the operation. In the case where it is present, in this case, each composition range in the whole magnetic material of the present invention is 20 atomic% or more and 99.998 atomic% or less for the FM component, and 0.001 atomic% or more and 50 atomic% or less for the M component It is desirable for the O component to be in the range of 0.001 atomic percent or more and 55 atomic percent or less.

  More preferable compositions of the magnetic material according to the present invention are an FM component of 50 atomic% to 99.98 atomic%, an M component of 0.01 atomic% to 49.99 atomic%, and an O component of 0.01 atomic% or more The magnetic material of the present invention which is 49.99 atomic% or less and in this range has a good balance of saturation magnetization and oxidation resistance.

  Furthermore, the composition range of the FM component is 66.95 atomic% to 99.9 atomic%, the M component is 0.05 atomic% to 33 atomic%, and the O component is 0.05 atomic% to 33 atomic%. The magnetic material of the present invention is preferable in that it has excellent electromagnetic properties and excellent oxidation resistance.

  In the case of using the magnetic material of the present invention which is particularly excellent in the performance that the magnetization is 1 T or more within the above composition range, the FM component is 79.95 atomic% or more and 99.9 atomic% or less, and the M component is 0 It is preferable to set the composition range of .05 atomic% or more and 20 atomic% or less and the O component to be 0.05 atomic% or more and 20 atomic% or less.

  Although depending on the content of the M component, in the present invention, the semi-hard magnetic material tends to contain more oxygen than the soft magnetic material.

<Magnetic and electrical properties, oxidation resistance>
One of the present invention is a magnetic material having magnetic properties and electrical properties suitable for soft magnetic applications having a coercive force of 800 A / m or less and oxidation resistance, which will be described below.

The term "magnetic properties" as used herein refers to the magnetization J (T), saturation magnetization J _s (T), magnetic flux density (B), residual magnetic flux density B _r (T), and exchange stiffness constant A (J / m) of a material. , Magnetocrystalline anisotropy magnetic field H _a (A / m), magnetocrystalline anisotropy energy E _a (J / m ³ ), magnetocrystalline anisotropy constant K ₁ (J / m ³ ), coercive force H _cB ( A / m), intrinsic coercive force H _cJ (A / m), permeability μ μ ₀ , relative permeability μ, complex permeability μ _r μ ₀ , complex relative permeability μ _r , its real term μ ', imaginary term μ And at least one of the absolute values | μ _r | In the present specification, the unit of “magnetic field” is a combination of A / m of SI unit system and Oe of cgs Gaussian unit system. The formula is 1 (Oe) = 1 / (4π) × 10 ³ (A / m). That is, 1 Oe corresponds to about 80 A / m. The units of “saturation magnetization” and “residual magnetic flux density” in the present specification use T of the SI unit system and emu / g of the cgs Gaussian unit system in combination, the conversion formula is 1 (emu / g ) = 4π × d / 10 ⁴ (T), where d (Mg / m ³ = g / cm ³ ) is the density. Therefore, since Fe having a saturation magnetization of 218 emu / g is d = 7.87, the value M _s of the saturation magnetization in the SI unit system is 2.16T. In the present specification, unless stated otherwise, the term "coercivity" refers to the intrinsic coercivity _HcJ .

  The term "electrical characteristics" as used herein refers to the electrical resistivity (= volume resistivity) of a material (= m), and the term "oxidation resistance" as used herein refers to various oxidizing atmospheres such as room temperature air. It is a time-dependent change of the above-mentioned magnetic property.

  The above magnetic properties and electrical properties are collectively referred to as "electromagnetic properties".

In the magnetic material of the present invention, magnetization, saturation magnetization, magnetic flux density, residual magnetic flux density, and electrical resistivity are preferably higher, and for saturation magnetization, a height of 0.3 T or 30 emu / g or more is desirable, particularly soft magnetic In terms of materials, a height of 100 emu / g or more is desirable, and a height of 1.5 μΩm or more is desirable for the electrical resistivity. Other magnetic properties of the present invention, such as magnetocrystalline anisotropy constant, coercivity, permeability, relative permeability, etc., are suitable depending on the application, including whether it is a semihard magnetic material or a soft magnetic material. Control. In particular, the permeability and the relative permeability do not necessarily have to be high depending on the application, and if the coercivity is sufficiently low and the core loss is suppressed low, for example, the relative permeability is as large as around 10 ⁻¹ to 10 ⁵ In particular, by suppressing the magnetic saturation under a direct current superimposed magnetic field, it is possible to suppress the decrease in efficiency or to make it easy to control linearly, or it is described in the prior art of Patent Documents 1 and 2. Based on the relationship between the thickness of the material being used and the permeability, it is also possible to increase the limit thickness at which the eddy current loss occurs approximately 3.2 times each time the permeability is lowered by one digit. One of the features of the present invention is to provide a magnetization reversal mechanism mainly by direct rotation of magnetization instead of magnetization reversal due to domain wall movement, so that the coercive force is low and the eddy current loss due to domain wall movement is also small, and iron loss is suppressed low. In addition, it is possible to reduce the magnetic permeability by causing some local magnetic anisotropy in the crystal boundary to suppress the magnetization rotation by the external magnetic field.
Here, a major feature of the present invention is that by using the M component of the present invention, the relative permeability can be freely controlled, for example, compared to the case where there is no M component or only the TM component. Accordingly, the magnetic saturation suppressing ability (the function or the characteristic of the magnetic material which does not cause magnetic saturation) can be given according to the above. Zn, Si, Cu and Ta are mentioned as M component which raises relative magnetic permeability, and Zr, Hf, V, Nb, Cr, Mo and W are mentioned as M component which lowers relative magnetic permeability. By appropriately mixing and adding M components having both properties, a magnetic material that meets the required performance can be supplied.

  Incidentally, in the present invention, the reason why the permeability can be adjusted is that the magnetic material has a large electrical resistivity just by sintering as it is, so that the iron loss due to the eddy current is small, and hence the coercivity is slightly sacrificed. This is because the total iron loss can still be kept small even if the hysteresis loss is slightly increased by designing the material to suppress the magnetic permeability.

According to the soft magnetic material of the present invention, an electric resistivity of 1.5 μΩm or more can be exhibited, and in a semi-hard magnetic material, an even higher electric resistivity can be exhibited.
In the soft magnetic material of the present invention exhibiting an electrical resistivity of 10 μΩm or more, the saturation magnetization tends to decrease as the electrical resistivity increases. Therefore, it is necessary to determine the composition and reduction degree of the raw materials according to the desired electromagnetic characteristics. There is. In particular, less than 1000 μΩm is preferable to obtain the feature that the magnetization of the magnetic material of the present invention is high. Therefore, the preferred range of the electrical resistivity is 1.5 μΩm or more and less than 1000 μΩm.

<Crystalline boundary>
Whether the magnetic material of the present invention becomes soft magnetic or semi-hard magnetic depends on the magnitude of the coercivity as described above, but it is particularly closely related to its fine structure. The α- (FM, M) phase may be observed in the continuous phase at first glance, but as shown in Fig. 1 (SEM image of Fe _93.0 Ni _2.0 Cr _5.0 soft magnetic material), many different phases Interfaces, grain boundaries, twins such as contact twins, intrusive twins, simple twins such as contact twins, concentrated twins, ring twins, repeating twins such as multiple twins, twins, intergrowths, 骸(In the present invention, in the case where crystals are divided not only by heterophase interfaces and polycrystalline grain boundaries but also by various crystal habits, crystal phases, intergrowth structures, dislocations, etc., their interfaces are collectively referred to) (Referred to as “crystal boundaries”), etc., and often present crystal boundaries as a curve group unlike linear grain boundaries which are usually seen, and further, in such a structure, There is a large difference in M component content depending on the location. The magnetic material of the present invention having the fine structure as described above is often a soft magnetic material.

  When the magnetic material of the present invention is a soft magnetic material, the first phase and the second phase start from the M-ferrite nanopowder when the second phase is the α- (FM, M) phase, With grain growth, as the reduction reaction progresses, the oxygen in the crystal lattice is lost along with the disproportionation reaction of the composition, and finally a large volume reduction up to 52% by volume occurs. Due to this, the α- (FM, M) phase, the first phase and the second phase, have various microstructures such as crystals of gemstones such as quartz, minerals such as pyrite and fluorite, and rocks. It is held in a reduced scale, and internally contains various phases and nanocrystals with various M component contents.

  The texture that looks like grain boundaries and intergrowths also has a difference in M component content depending on the observation site, and may be a heterophase interface.

<Random magnetic anisotropy model and mechanism of lowering coercivity unique to the present invention>
In the soft magnetic material of the present invention described by the random anisotropy model, it is important to satisfy the following three conditions.
(1) The grain size of the α- (FM, M) phase is small,
(2) ferromagnetic coupling by exchange interaction,
(3) It has random orientation.
With regard to (3), it is not necessarily essential especially in a region where the content of M component of the bcc phase is 10 atomic% or less, and in this case, the lowering of the coercive force occurs on the principle different from the random anisotropy model . That is, due to the interaction between any one or more of the first phase and the second phase, the first homology, the second homology, the fluctuation of the magnetic anisotropy based on the fluctuation of the concentration of the M component content on the nanoscale becomes As a result, the magnetization reversal is promoted and the coercivity is reduced. The magnetization reversal mechanism by this mechanism is unique to the present invention, and as far as the present inventors can know, it has been found for the first time by the present inventors.
In the magnetic material of the present invention, the grain growth occurs during reduction, when the particles are not fused so that the ferromagnetic phase continues, or when phase separation occurs such that the particles are separated. In order to bring the magnetic force into the soft magnetic region, it is then sintered and solidified, that is, “the first phase and the second phase are bonded directly or continuously through the metal phase or the inorganic phase. And it is desirable to make it as a mass as a whole.

  In order to achieve ferromagnetic coupling by the exchange interaction of the above (2), since the exchange interaction is an interaction or force acting within short distance order of several nm, direct coupling is achieved when the first homology is linked. Or, in the case where the first phase and the second phase or the second homology are linked, the second phase needs to be ferromagnetic or antiferromagnetic in order to transmit the exchange interaction. Even if part of the first phase and / or the second phase is in the superparamagnetic region, the material itself is ferromagnetic or antiferromagnetic in the bulk state, so that the surrounding ferromagnetic or antiferromagnetic phase and If there is sufficient exchange coupling, in some cases it can be a phase that transmits exchange interaction.

  In the case of the semi-hard magnetic material of the present invention, although not limited to the above, in order to obtain a semi-hard magnetic material having a high residual magnetic flux density, the above solidification is necessary.

<Average grain size of first phase, second phase, entire magnetic material>
The average crystal grain size of the first phase or second phase of the soft magnetic material of the present invention, or the average crystal grain size of the entire magnetic material is preferably 1 nm or more and less than 10 μm. When the average grain size of the first phase and the second phase is less than 10 μm, the average grain size of the entire magnetic material is also less than 10 μm.

  In particular, with regard to the soft magnetic material of the present invention, either the first phase or the second phase is in the nano region in order to realize the reduction of the coercive force by the above random magnetic anisotropy model or the mechanism unique to the present invention. Is preferred. When both the first phase and the second phase are ferromagnetic phases, both preferably have an average crystal grain size of less than 10 μm, and less than 1 μm realizes reduction in coercive force based on a random magnetic anisotropy model. It is preferable that the thickness is 500 nm or less, and more preferably 200 nm or less because it has a remarkable reduction effect of the coercive force by the mechanism unique to the present invention although it depends on the content of the M component. In the above case, the magnetic anisotropy energy of the first phase is often larger than that of the second phase, so in particular, if the first phase is less than 10 μm, preferably 500 nm or less, more preferably 200 nm or less The coercivity is extremely small, and it becomes a soft magnetic material suitable for various transformers, motors and the like.

  If the thickness is less than 1 nm, the film becomes superparamagnetic at room temperature and the magnetization and the magnetic permeability may be extremely reduced. Therefore, the thickness is preferably 1 nm or more. As mentioned above, if crystal grains of less than 1 nm or an amorphous phase is present, it is required to sufficiently connect these to crystal grains of 1 nm or more by exchange interaction.

  When the second phase is not a ferromagnetic phase, the second phase does not contribute to the reduction of the coercive force by the above-described random anisotropic model or the mechanism unique to the present invention, but the presence of the second phase increases the electrical resistivity, which is a preferable component. It is.

  In the case of the semi-hard magnetic material of the present invention, in order to express the coercivity contrary to the above, the first phase is maintained at an average grain size of nano level, and a suitable surface oxide layer is made the second phase, It is effective to make the second phase exist at the grain boundary of the first phase as an average crystal grain size of several nm, maintain high magnetization while expressing the coercivity of the semihard magnetic region, and impart oxidation resistance. It is.

<Measurement of grain size>
In the measurement of the crystal grain size of the present invention, an image obtained by a SEM method, a TEM method or a metallurgical microscope method is used. Within the observed range, not only the heterophase interface and the grain boundaries but also all the crystal boundaries are observed, and the diameter of the crystal region in the part surrounded by the boundaries is defined as the grain size. If it is difficult to see the crystal boundaries, it is better to etch the crystal boundaries using a wet method or dry etching method using a nital solution or the like. The average grain size is basically selected from a representative part and measured in a region including at least 100 crystal grains. Although it may be less than this, in that case, it is required that there is a part that is statistically sufficiently representative of the whole, and that the part is measured. The average crystal grain size is determined by photographing an observation area, defining an appropriate rectangular quadrilateral area on the photograph plane (enlarged projection plane to the photographing plane of the object), and applying the Jeffry method inside thereof. In addition, when it observes with SEM or a metallographic microscope, the crystal boundary width may be too small and may not be observed with respect to resolution, but in that case, the measured value of crystal grain size gives the upper limit of the actual crystal grain size. . Specifically, the upper limit may have a crystal grain size measurement value of 10 μm. However, there is a possibility that part or all of the magnetic material may cut the lower limit of the crystal grain size by 1 nm, for example, from phenomena such as not having a clear diffraction peak on XRD and superparamagnetism being confirmed on a magnetic curve. If indicated, the actual grain size must be determined again by TEM observation. Furthermore, in the present invention, it may be necessary to measure the crystal grain size regardless of the crystal boundary. That is, the crystal grain size of the magnetic material of the present invention having such a fine structure is the M component content, for example, when the crystal structure is finely modulated due to the fluctuation of the concentration of the M component content. The modulation width of is the grain size. The crystal grain size is often determined by TEM-EDX analysis or the like, but the size often corresponds approximately to the crystallite size described in the next section.

<Measurement of crystallite size>
A crystallite is a small single crystal at the microscopic level that constitutes a crystalline substance and is smaller than the individual crystals (so-called crystal grains) that constitute a polycrystal.
In the present invention, the disproportionation reaction causes phase separation, and a compositional range occurs in the M component content of the bcc phase of the first phase and / or the second phase. Since the X-ray diffraction line peak position changes depending on the M component content, for example, the line width of the diffraction line at (200) of the bcc phase is determined, and the error is increased even if the crystallite size is determined. Therefore, the crystallite size obtained by this method may not be recognized as significant in the case of crystals of bcc phase structure containing an M component. As described above, since the crystallite size may not be recognized as significant in this case, in the present application, the crystallite size obtained based on the diffraction line at (200) of the bcc phase is “apparent” as described above. It is called "crystallite size".
On the other hand, Ni and Co contained in the FM component have an atomic radius close to that of Fe, and the degree of disproportionation is not as high as that of the M component, and the change in crystallite size due to composition distribution is hardly observed. Therefore, as in the present invention, a crystal composed of the FM component obtained by the above method (for example, as a magnetic material, at least the first phase is FM _{100 -x} M _x, where x is an atomic percentage of 0. 0. 001 ≦ x ≦ 33.33, FM is a ferromagnetic component containing Fe and containing Ni and / or Co, M is Zr, Hf, V, Nb, Ta, Cr, Mo, W, Cu, The value of the crystallite size of the crystal having a composition represented by the composition formula of any one or more of Zn and Si) is significant. Further, even in the case of a crystal of bcc phase structure containing M component, as in the present invention, when the M component content of bcc phase is 0.001 atomic% or more and 1 atomic% or less (for example, at least the first phase is FM _100-x M _x (where x is an atomic percentage, 0.001 ≦ x ≦ 1, FM is a ferromagnetic component containing Fe and containing Ni and / or Co, and M is Zr, Hf, In the case of a magnetic material having a bcc phase represented by a composition formula of V, Nb, Ta, Cr, Mo, W, Cu, Zn, Si)), (200) The deviation of the crystallite size is very small, so even if the apparent crystallite size is measured within the range of 1 nm to 200 nm, it can be substantially regarded as the “crystallite size”. Therefore, the apparent crystallite size in such a case is simply referred to as "crystallite size" in the present application.
Specifically, the crystallite size of the bcc phase in the present invention was determined with the dimensionless form factor of 0.9 using the (200) diffraction line width excluding the influence of the Kα ₂ diffraction line and the Scherrer equation.
The bcc phase may be at least the first phase having the phase (i.e., only the first phase has the bcc phase, or both the first phase and the second phase have the bcc phase). The preferred crystallite size range of the bcc phase is 1 nm or more and 200 nm or less.
If it is less than 1 nm, it becomes superparamagnetic at room temperature and the magnetization and permeability may become extremely small. Therefore, 1 nm or more is preferable.
When the crystallite size of the bcc phase is 200 nm or less, the coercivity enters the soft magnetic region and becomes extremely small, which is preferable because it becomes a soft magnetic material suitable for various transformers, motors and the like. Furthermore, since 50 nm or less is a region with a low M component content, not only high magnetization exceeding 2T can be obtained, but also low coercivity can be achieved simultaneously, which is a very preferable range.
The apparent size of the crystallite size is, in a general crystal, a material in which the M component content of the bcc phase is 0.001 atomic% or more and 1 atomic% or less (eg, at least the first phase is FM _100-x M _x (where, x is 0.001 ≦ x ≦ 1 atomic percent, FM contains Fe, a ferromagnetic component and containing Ni and / or Co, M is Zr, Hf, V, Nb, Ta At least 50% smaller than the crystallite size of the magnetic material having a bcc phase represented by the composition formula of any one or more of Cr, Mo, W, Cu, Zn, and Si). Risk of However, for the reasons described above, the present invention (for example, as the magnetic material, at least the first phase is FM _{100 -x} M _x (where x is an atomic percentage 0.001 ≦ x ≦ 33.33, FM is a ferromagnetic component containing Fe and containing Ni and / or Co, M is any one or more of Zr, Hf, V, Nb, Ta, Cr, Mo, W, Cu, Zn, Si ))), For example, if the size of the apparent crystallite size is limited to 1 nm or more and 100 nm or less within the range of 1 nm or more and 200 nm or less, You can avoid the danger. As a result, the relationship between crystallite size and magnetic property preferences described above is maintained.

<Size of soft magnetic material>
The size of the powder of the soft magnetic material of the present invention is preferably 10 nm or more and 5 mm or less. If it is less than 10 nm, the coercivity does not become sufficiently small, and if it exceeds 5 mm, a large strain will be applied during sintering, and the coercivity will be large if there is no annealing treatment after solidification. More preferably, it is 100 nm or more and 1 mm or less, and particularly preferably 0.5 μm or more and 500 μm or less. If the average powder particle size falls within this range, it becomes a soft magnetic material with low coercivity. In addition, if the particle size distribution is sufficiently wide within each average powder particle size range specified above, high filling can be easily achieved with a relatively small pressure, and the magnetization per volume of the solidified molded body becomes large, preferable. If the powder particle size is too large, movement of the domain wall may be excited, and the foreign phase formed by the disproportionation reaction in the process of producing the soft magnetic material of the present invention prevents movement of the domain wall, but rather The magnetic force may increase. Therefore, when molding the soft magnetic material of the present invention, it may be preferable that the surface of the magnetic material powder of the present invention having an appropriate powder particle size be in an oxidized state. Since an alloy containing an M component may form a nonmagnetic M-component oxide phase passive film on the surface by oxidation, it is not only extremely excellent in oxidation resistance, but is also reduced in coercive force and electrical resistivity. It is also effective in terms of improvement. Not only the proper gradual oxidation of the powder surface, the handling of each process in air, the reducing atmosphere, but also the solidification treatment in an inert gas atmosphere etc. are effective.

<Size of semi-hard magnetic material>
The average particle size of the magnetic powder of the semi-hard magnetic material of the present invention is preferably in the range of 10 nm to 10 μm. If it is less than 10 nm, it is difficult to mold, and the dispersibility may be extremely poor even when dispersed and used in a synthetic resin or ceramic. Further, when the average powder particle size exceeds 10 μm, the coercive force reaches the soft magnetic region, and therefore belongs to the category of the soft magnetic material of the present invention. A more preferable average powder particle size is 10 nm or more and 1 μm or less, and in this range, it becomes a semi-hard magnetic material in which both saturation magnetization and coercivity are well balanced.

<Measurement of average powder particle size>
The powder particle diameter of the magnetic material of the present invention is evaluated mainly by measuring the volume equivalent diameter distribution using a laser diffraction type particle size distribution analyzer and measuring the median diameter obtained from the distribution curve. Alternatively, a representative portion is selected based on a photograph obtained by a SEM method or a TEM method of powder, or a metallurgical micrograph, and a diameter of at least 100 pieces is measured and determined. Although it may be less than this, in that case, it is required that there is a part that is statistically sufficiently representative of the whole, and that the part is measured. In particular, when measuring the particle size of the powder below 500 nm and the powder above 1 mm, priority is given to the method using SEM or TEM. When N types (N ≦ 2) of measuring methods or measuring devices are used in combination and a total of n measurements (N ≦ n) are performed, their numerical value R _n is R / 2 ≦ R _n ≦ 2R The mean powder particle size needs to be determined, with R being the geometric mean of the lower and upper limits.

  As described above, in principle, in the method of measuring the particle diameter of the magnetic material of the present invention, (1) when the measured value is 500 nm or more and 1 mm or less, the laser diffraction particle size distribution analyzer has priority, (2) In the case of less than 500 nm or more than 1 mm, preference is given to microscopy. (3) When (1) and (2) are used in combination at 500 nm or more and 1 mm or less, the average powder particle size is determined with the above R. In the present application, the symbol of powder particle diameter is one or two significant figures in the case of (1) or (2), and is represented by one significant figure in the case of (3). The reason why the powder particle size measurement method is used in combination is that if it has a powder particle size of just above 500 nm and 1 mm, in the method of (1), even one significant digit may be an incorrect value, Since it takes time to confirm that the information is not local information in the method (2), the value of the average powder particle diameter is first obtained by the method (1), and the value is simply obtained by the method (2). It is because it is very reasonable to compare and study both and to determine the average powder particle size with the above R by obtaining. In the present application, the average particle diameter of the powder of the magnetic material of the present invention is determined by the above method. However, if (1) and (3), or (2) and (3) do not match in single digit significant figure, measure precisely again in (1) or (2) according to the average powder particle size range. , R must be determined. However, apparently there is strong aggregation and it is inappropriate to determine the powder particle size in (1), or it is too uneven and the powder particle size estimated by the sample image is extremely different (2) And, depending on the specifications of the measuring device, the classification of 500 nm and 1 mm as the standard for determining the above powder particle size measuring method may be inappropriate, etc. In the case where an obvious inappropriate reason exists, any one of the methods (1), (2) or (3) may be reselected in a limited manner without adopting the above principle. As long as the magnetic material of the present invention is merely distinguished from other magnetic materials, it is sufficient if the average powder particle size is determined by one significant digit.

  For example, in the case of reducing M-ferrite nanopowder having an M component content of 10 atomic% or less to 1000 ° C. or higher, a macroscopic powder shape has a hollow portion which is a large number of through holes. It may be reticulated, so to speak, sponge-like. It is considered that these are formed by the fact that the grain growth proceeds by the reduction reaction and at the same time oxygen is removed from the crystal lattice to cause a large volume reduction. The powder particle size in this case is measured including the volume of the hollow portion inside.

<Solid magnetic material>
The magnetic material of the present invention is a magnetic material in which the first phase and the second phase are bonded directly or continuously via the metal phase or the inorganic phase to form a block as a whole (herein, It can also be used as "solid magnetic material". Also, as described above, when many nanocrystals are already bound in the powder, the powder may be an organic compound such as resin, an inorganic compound such as glass or ceramic, or a composite material thereof It is also possible to mix and mold.

<Filling rate>
The packing ratio is not particularly limited as long as the object of the present invention can be achieved, but in the case of the magnetic material of the present invention having a small amount of M component, 60% by volume or more and 100% by volume or less is oxidation resistance and electricity. It is preferable because it is excellent in terms of the balance between the resistivity and the height of magnetization.

  The packing ratio referred to here is the volume of the magnetic material of the present invention relative to the volume of the entire magnetic material of the present invention including voids (that is, the magnetic material of the present invention excluding portions other than the magnetic material of the present invention. The percentage of the volume occupied by the material alone is expressed as a percentage.

  The more preferable range of the filling rate is 80% by volume or more, and particularly preferably 90% by volume or more. The magnetic material of the present invention is originally high in oxidation resistance, but the higher the filling factor, the further the oxidation resistance is increased, and not only the application range to be applied is broadened, but the saturation magnetization is improved and the performance is high. A magnetic material is obtained. Further, in the soft magnetic material of the present invention, there is also an effect that the cohesion of the powders increases and the coercivity decreases.

<Features of magnetic powder of the present invention, solid magnetic material>
One of the major features of the magnetic material powder of the present invention is that it is a sinterable powder material like ferrite. Various solid magnetic materials having a thickness of 0.5 mm or more can be easily manufactured. Furthermore, even various solid magnetic materials having a thickness of 1 mm or more and 5 mm or more can be relatively easily manufactured by sintering or the like if the thickness is 10 cm or less.
Furthermore, one feature of the magnetic material of the present invention is that the electrical resistivity is high. The magnetic material powder of the present invention contains many crystal boundaries and various phases, while other metallic rolling materials and thin strip materials are manufactured by a manufacturing method which does not contain grain boundaries, heterophases and defects. And, as such, has the effect of increasing the electrical resistivity. Moreover, when solidifying the powder, the surface oxide layer of the powder before solidifying (ie, the M component oxide phase present on the surface of the first phase or the second phase, wustite, magnetite, M-ferrite) , A layer having a high oxygen content such as M-hematite or amorphous, among which an oxide layer containing a large amount of M component and / or a metal layer (that is, a metal layer containing a large amount of M component) The rate also rises.
In particular, as a preferable constituent compound of the surface oxide layer which raises the electrical resistivity, at least one of an M component oxide phase, wustite and M-ferrite can be mentioned.
The magnetic material of the present invention has the above-mentioned characteristics because the magnetic material of the present invention is formed by a method different from other metallic soft magnetic materials having high magnetization and high frequency application, that is, M -The main purpose is to provide a build-up bulk magnetic material in which the ferrite nanopowder is reduced to first produce a metal powder having nanocrystallites, which is then shaped into a solid magnetic material. It is.

  Further, as described above, since the electrical resistance is high compared to the existing metallic soft magnetic materials represented by silicon steel, for example, the lamination process usually required when manufacturing rotating equipment etc. is considerably simplified. it can. Assuming that the electrical resistivity of the magnetic material of the present invention is about 30 times that of silicon steel, the limit of thickness at which eddy current does not occur is about 5 times based on the descriptions of Patent Documents 1 and 2. Even if necessary, the number of stacks is 1/5. For example, even when applied to the stator of a motor in a high rotation range of 667 Hz, the thickness is allowed up to 1.5 mm.

  The solid magnetic material of the present invention does not contain a binder such as a resin, has a high density, and can be easily processed by an ordinary processing machine into an arbitrary shape by cutting and / or plastic processing. In particular, one of the major features is that it can be easily processed into a shape such as a prismatic column, a cylinder, a ring, a disc or a flat plate, which has high industrial utility value. Once processed into these shapes, it is also possible to cut them further and process them into a tile-like or a prism having an arbitrary base shape. That is, it is possible to easily perform cutting and / or plastic working on any shape and any form surrounded by a curved surface or a plane including a cylindrical surface. Here, cutting is general metal material cutting, and it is machining with a saw, lathe, milling machine, drilling machine, grinding wheel, etc., and plastic processing is die cutting, forming by molding, rolling, explosion, etc. Such as molding. In addition, annealing can be performed in the range from normal temperature to 1500 ° C. to remove distortion after cold working.

<Manufacturing method>
Next, although the manufacturing method of the magnetic material of this invention is described, it does not specifically limit to these.
The method for producing a magnetic material of the present invention is
(1) M-ferrite nano powder production process (2) The process may include both of the reduction process, and may further include any one or more of the following processes, if necessary.
(3) Step-wise oxidation step (4) Forming step (5) Annealing step Each step will be specifically described below.

(1) M-ferrite nano powder production process (In the present application, it is also referred to as "process of (1)")
As a preferable manufacturing process of the nano magnetic powder which is a raw material of the magnetic material of this invention, there exists a thing provided with the method synthesize | combined at all room temperature using a wet synthesis method.
Examples of known methods for producing ferrite fine powder include a dry bead mill method, a dry jet mill method, a plasma jet method, an arc method, an ultrasonic spray method, an iron carbonyl vapor phase decomposition method, etc. It is a preferable production method if the magnetic material of the present invention is constituted. However, in order to obtain nanocrystals whose composition is disproportionated, which is the essence of the present invention, it is most convenient and preferable to adopt a wet method mainly using an aqueous solution.
This manufacturing process is an application of the “ferrite plating method” described in Patent Document 3 to a manufacturing process of M-ferrite nanopowder used to manufacture the magnetic material of the present invention.
The usual “ferrite plating method” is applied not only to powder surface plating but also to thin films, etc., and the reaction mechanism etc. has already been disclosed (eg, Abe M, Journal of the Japan Society of Applied Magnetics, 22 Volume 9, No. 9 (1998), page 1225 (hereinafter referred to as "non-patent document 4") and WO 2003/015109 (hereinafter referred to as "patent document 4"), in this production process Unlike the above “ferrite plating method”, the powder surface which is the base material of plating is not utilized. In the present manufacturing process, raw materials used for ferrite plating (for example, chromium chloride and iron chloride) are reacted in a solution at a temperature of 100 ° C. or less to directly produce ferromagnetic crystalline M-ferrite nanopowder itself Synthesize. In the present application, this step (or method) is referred to as "M-ferrite nano powder production step" (or "M-ferrite nano powder production method").
Hereinafter, the “M-ferrite nano powder production process” having a spinel structure is exemplified and described.

  An appropriate amount of aqueous solution previously adjusted to an acidic region is placed in a vessel (also referred to as a reaction site in the present application), and reaction is performed under ultrasonic excitation at room temperature air, with mechanical agitation at an appropriate strength or rotation number. The pH adjustment solution is dropped simultaneously with the solution to gradually change the solution pH from the acidic to the alkaline region to generate M-ferrite nanoparticles in the reaction site. Thereafter, the solution and the M-ferrite nanopowder are separated and dried to obtain an M-ferrite powder having an average powder particle size of 1 nm or more and less than 1000 nm (1 μm). The above method is mentioned as an inexpensive method because the process is simple. In particular, in the examples given in the embodiments of the present invention, the entire process is performed at room temperature, and therefore, the manufacturing process without using this heat source reduces the burden of equipment cost and running cost. The method for producing the M-ferrite nanopowder used in the present invention is, of course, not limited to the above-mentioned production method, but the initial solution of the reaction site before the start of the reaction used in the above production method A description will be added below regarding the reaction solution, the reaction solution, and the pH adjusting solution.

  As the reaction site solution, an acidic solution is preferable, and a solution obtained by dissolving a metal salt, a double salt thereof, a complex salt solution and the like in addition to inorganic acids such as hydrochloric acid, nitric acid, sulfuric acid and phosphoric acid in a hydrophilic solvent such as water A hydrophilic solvent solution such as an iron chloride solution, an M component chloride solution or the like, or an aqueous solution of an organic acid (for example, acetic acid or oxalic acid), or a combination thereof can also be used. Providing a reaction solution in advance as a reaction field solution is effective for efficiently advancing a synthesis reaction of M-ferrite nanopowder. If the pH is less than -1, the material for providing the reaction site may be limited, and mixing of unavoidable impurities may be permitted, so it is desirable to control between -1 and less than 7 . A particularly preferable pH range is 0 or more and less than 7 in order to increase the reaction efficiency in the reaction site and minimize elution and precipitation of unnecessary impurities. More preferably, it is 1 or more and less than 6.5 as a pH range in which the reaction efficiency and the yield are well balanced. As a solvent as a reaction site, a hydrophilic solvent among organic solvents and the like can also be used, but water is preferably contained so that the inorganic salt can be sufficiently ionized.

The reaction solution may be an FM component chloride containing iron chloride, a chloride such as M component chloride, an FM component nitrate containing iron nitrate, a nitrate such as M component nitrate, or an FM component and / or an M component (optionally Water-based solutions of inorganic salts such as nitrites, sulfates, phosphates, or fluorides, which may also contain components), and in some cases, hydrophilic solvents such as water of organic salts A solution based on the main component can also be used as needed. Also, a combination of them may be used. However, it is essential that the reaction solution contains an FM component ion and an M component ion. Regarding the FM component ions in the reaction solution, the case of only bivalent FM ions (Fe ²⁺ and Ni ²⁺ and / or Co ²⁺ ) and trivalent FM component ions (Fe ³⁺ and Ni ³⁺ and / or / or Either a mixture with Co ³⁺ ) or only trivalent FM component ions may be used, but in the case of only FM ³⁺ ions, it is necessary to include a metal ion having a divalent or lower M component element. is there. The valence of the M component ion in the reaction solution is typically monovalent, divalent, trivalent, tetravalent, pentavalent or hexavalent, but in the reaction solution or reaction field solution, it is divalent. The above hexavalent or less is particularly excellent in terms of the homogeneity of the reaction.

For M component chloride (a substance in which M component and chlorine are combined, water molecules may be contained as a hydrate like CrCl ₃ ) aqueous solution or TM component chloride aqueous solution When preparing from solid solution or undiluted solution to obtain aqueous solution of arbitrary concentration, there is a danger of reacting explosively when dissolved in water. Is recommended. In addition, since it emits hydrogen chloride when exposed to the atmosphere, it is preferable to handle it in a glove box with reduced oxygen concentration. Furthermore, by making the aqueous solution acidic with hydrochloric acid or using concentrated hydrochloric acid, the M component chloride, oxychloride, etc. do not precipitate, or the component that does not dissolve remains, and even though it is colored, it is transparent. Aqueous solution is obtained.

  Examples of the pH adjusting solution include alkaline solutions such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium hydrogencarbonate and ammonium hydroxide, acidic solutions such as hydrochloric acid, and combinations thereof. It is also possible to use a pH buffer solution such as a mixed solution of acetic acid and sodium acetate and to add a chelate compound and the like.

The oxidizing agent is not necessarily essential, but it is an essential component when only Fe ²⁺ ions are contained as Fe ions in the reaction field solution and the reaction solution. Examples of oxidizing agents include nitrite, nitrate, hydrogen peroxide water, chlorate, perchloric acid, hypochlorous acid, bromate, organic peroxide, dissolved oxygen water, etc., and combinations thereof Be By stirring in the atmosphere or in an atmosphere where the oxygen concentration is controlled, the M-ferrite nanoparticle reaction site is continuously supplied with dissolved oxygen having a function as an oxidizing agent, and the reaction is controlled. It is also effective to In addition, inert gas such as nitrogen gas or argon gas is continuously or temporarily introduced by bubbling to the reaction site, etc., and the effect of other oxidizing agents is inhibited by limiting the oxidizing action of oxygen. It is also possible to control the reaction stably.

In a typical M-ferrite nanopowder manufacturing method, the formation of M-ferrite nanoparticles proceeds by the following reaction mechanism. The nuclei of M-ferrite nanoparticles are formed in the reaction solution directly or via an intermediate product such as Greenlast. The reaction solution contains Fe ²⁺ ions, which are adsorbed on the already generated powder nuclei or on the OH groups on the surface of the powder which has grown to some extent, and release H ⁺ . Next, when an oxidation reaction is performed by oxygen in the air, an oxidizing agent, an anodic current (e ⁺ ) or the like, a part of the adsorbed Fe ²⁺ ions are oxidized to Fe ³⁺ ions. ^{FM 2+} ions including ^{Fe 2+} ions in the solution, or ^{Fe 2+ FM 2+} ions including ions (or, ^{FM 3+} ions, further ^{FM 2+} ions mixed valence ions including) and ^{M 3+} ions ^{(or, M 2+} ions , M ^{4 +} ions, M 5 ⁺ ions, M ^{6 +} ions, and mixed valence ions including M ^{3 +} ions) are adsorbed again onto metal ions that have already been adsorbed, while H ⁺ is accompanied by hydrolysis. It releases to form a ferrite phase having a spinel structure. Since OH groups exist on the surface of this ferrite phase, metal ions are adsorbed again, and the same process is repeated to grow into M-ferrite nanoparticles.

In this reaction mechanism, in order to change from FM ²⁺ ion mainly composed of Fe ²⁺ ion and M ^{3 +} to ferrite of spinel structure directly, Fe ²⁺ ion and ferrite are selected by the equilibrium curve in pH-potential diagram of Fe. It is preferable to slowly shift the reaction system from the stable region of Fe ²⁺ ions to the region where ferrite precipitates while adjusting the pH and the redox potential so as to cross the dividing line. For example, when M ³⁺ is used, the reaction is trivalent from the initial stage of the reaction except in a special case, and there is almost no influence on the change of the redox potential, and in many cases the reaction due to the change of the redox potential of Fe To the ferrite solid phase) is described. Even when ions of M component elements of other valences are included and the oxidation number of the ions changes to participate in the reaction, by using or predicting a pH-electrogram corresponding to the composition or temperature, Similar arguments can be made. Therefore, it is desirable to generate the ferrite phase while appropriately adjusting the conditions such as the type, concentration, and addition method of the pH adjuster and the oxidizing agent.

In the well-known ferrite nanopowder production method, the reaction solution is adjusted on the acid side, and the reaction field is made a basic region by adding an alkaline solution at a stretch, etc., and the particles are instantaneously formed by coprecipitation. It often occurs. In the case of producing an M-ferrite nanopowder, it can be considered that due to the difference in the solubility product of the Fe component and the M component, consideration is given so as not to be uneven. Of course, since it may be prepared by this method and very small nanoparticles can be produced, it can also be used as a ferrite raw material of the magnetic material of the present invention.
On the other hand, in the embodiment of the present invention, while the reaction solution is dropped and the raw material in the M-ferrite nanopowder manufacturing method is supplied to the reaction site, the pH adjuster is also dropped simultaneously, and the pH is gradually changed from acidic to basic. The process is designed such that the M component is steadily incorporated into the Fe-ferrite structure by changing it into According to this process, in the step of producing M-ferrite nanoparticles, H ⁺ released when ferrite is formed by the mechanism as described above is continuously introduced into the reaction site of the pH adjusting solution. As it is neutralized, the formation and growth of M-ferrite particles occur one after another. Also, at the initial stage of the reaction, there is a period in which the green last occurs and the reaction site becomes green (the period during which the reaction site and the pH of the reaction liquid become yellow and yellow green is in the previous stage). It is important that the M component is mixed in the last, and when this is finally converted to ferrite, the M component is incorporated in the lattice, and in the subsequent reduction reaction, it is in the first phase or the second phase. Then, the M component is incorporated into the α-Fe phase having the bcc structure.

  In addition to the above, other factors to control the reaction include agitation and reaction temperature.

  Although dispersion is very important in order to prevent aggregation of fine particles generated by M-ferrite nanopowder synthesis reaction and inhibition of homogeneous reaction, a method of simultaneously performing reaction excitation while dispersing with ultrasonic waves, Any of known methods depending on the purpose of reaction control, such as a method of transporting or circulating the dispersion with a pump, a method of simply stirring with a stirring spring or a rotating drum, or a method of rocking or vibrating with an actuator or the like. Or a combination thereof.

  The reaction temperature is generally between 0 to 100 ° C. from the freezing point to the boiling point of water under atmospheric pressure, since the reaction is performed in the presence of water in the method for producing M-ferrite nanopowder used in the present invention. To be elected.

  In the present invention, the method (for example, the supercritical reaction method) of synthesizing M-ferrite nanopowder in a temperature range exceeding 100 ° C. by placing the whole system under high pressure, etc. As long as ferrite nanopowder can be formed, it belongs to the magnetic material of the present invention.

  In addition to the above temperature and ultrasonic waves, pressure and photoexcitation may be effective as a method for exciting the reaction.

Furthermore, in the present invention, when the M-ferrite nanopowder manufacturing method is applied using an aqueous solution containing FM ²⁺ mainly containing Fe ²⁺ as the reaction liquid (especially FM mainly containing Fe for M-ferrite nanoparticles is In the case of reaction under the conditions of mixing as divalent ions), if the content of the M component is less than 40 atomic%, the divalent ions of Fe in the ferrite coating layer of the finally formed magnetic material of the present invention It is important that The amount is preferably 0.001 or more in the Fe ²⁺ / Fe ³⁺ ratio. As this identification method, it is good to use an electron beam microanalyzer (EPMA). Specifically, the surface of the M-ferrite nanoparticles is analyzed by EPMA to obtain an X-ray spectrum of FeL _α -FeL _β , and the difference between the two materials is obtained, and iron oxide containing Fe ²⁺ (eg magnetite) The amount of Fe ²⁺ ions in the M-ferrite nanoparticles can be identified by comparison with the spectra of iron oxide and Fe ³⁺ only iron oxide (eg hematite and maghematite) standard samples.

  At this time, the measurement conditions of EPMA are an acceleration voltage of 7 kV, a measurement diameter of 50 μm, a beam current of 30 nA, and a measurement time of 1 second / step.

  Typical impurity phases of M-ferrite nanopowders include oxides such as M-hematite, iron oxyhydroxide such as goethite, achagenite, lepidocrocite, ferrooxyhytite, ferrihydrite and greenlast (or There are hydroxides such as oxyhydroxide FM) which is a solid solution with nickel oxyhydroxide, cobalt oxyhydroxide etc., potassium hydroxide, sodium hydroxide etc., among which ferrihydrite phase, M-hematite phase These are phases that do not necessarily need to be removed because they form the α- (FM, M) phase and the other second phase after reduction. These ferrihydrite phase and M-hematite phase are observed as a plate-like structure having a thickness of several nm in SEM observation and the like. However, since the particles have a large area for the thickness, they may promote large inappropriate grain growth in the reduction reaction process, and there are many impurities other than the FM component, the M component, and oxygen. It is desirable that the volume fraction is smaller than that of ferrite nanopowder. In particular, when the atomic ratio of the M component to the FM component is more than 0.33 and 0.5 or less, the M component ratio of phases other than ferrihydrite and M-ferrite nanopowder centering on M-hematite is Degree of aggregation such as ferrihydrite phase (especially to avoid uneven distribution to several microns or so) because it becomes larger than M-ferrite nano powder and it is difficult to control disproportionation occurring during reduction It is desirable to be careful enough. In addition, regardless of the above, the content of the ferrihydrite phase easily incorporating the M component and the M-ferrite phase to the total magnetic material is intended so as not to precipitate the inappropriate subphase not containing the above-mentioned M component. It is also possible to co-exist in the range of 0.01% by volume to 33% by volume. This is more industrially advantageous because it is not necessary to strictly maintain the control conditions at the time of ferrite nanopowder production.

  The average powder particle size of the M-ferrite nanopowder which is the raw material of the present invention is preferably 1 nm or more and less than 1 μm (1000 nm). More preferably, it is 1 nm or more and 100 nm or less. If it is less than 1 nm, the reaction during reduction can not be sufficiently controlled, resulting in poor reproducibility. If it exceeds 100 nm, inappropriate grain growth of the metal component reduced in the reduction step becomes remarkable, and in the case of a soft magnetic material, the coercivity may increase, so 100 nm or less is preferable. Also, at 1 μm or more, the α-FM phase is separated, M is not taken into this phase, and only the magnetic material of the present invention having poor electromagnetic properties and oxidation resistance may be obtained. Less than 1 μm is preferred.

  The M-ferrite nanopowder used in the present invention is mainly produced in an aqueous solution by decantation, centrifugation, filtration (in particular, suction filtration), membrane separation, distillation, vaporization, organic solvent substitution. Water is removed by solution separation by magnetic field recovery of powder, or a combination thereof. Thereafter, it is vacuum dried at normal temperature or at a high temperature of 300 ° C. or lower, or dried in air. Hot-air drying in air, inert gas such as argon gas, helium gas, nitrogen gas (however, in the present invention, nitrogen gas may not be an inert gas depending on the temperature range during heat treatment) or hydrogen It can also be dried by heat treatment in a reducing gas such as a gas or a mixed gas thereof. As a drying method that removes unnecessary components in the solution and does not use any heat source, discard the supernatant after centrifugation, disperse the M-ferrite nanopowder in purified water, repeat the centrifugation, and finally ethanol etc. And a method of substituting with a hydrophilic organic solvent having a low boiling point and a high vapor pressure, and vacuum drying at room temperature.

(2) Reduction step (In the present application, it is also referred to as "step (2)")
It is a step of reducing the M-ferrite nanopowder produced by the above method to produce the magnetic material of the present invention. In this reduction step, the homogeneous cobalt ferrite nanopowder undergoes disproportionation reaction, and the magnetic material of the present invention separates into a first phase and a second phase.

  The method of reduction in the gas phase is most preferable, and as the reducing atmosphere, organic compound gas such as hydrogen gas, carbon monoxide gas, ammonia gas, formic acid gas and mixed gas of them and inert gas such as argon gas or helium gas And low-temperature hydrogen plasma, subcooled atomic hydrogen, etc., and these can be circulated in a horizontal or vertical tubular furnace, rotary reactor, closed reactor, etc., refluxed or sealed to be used as a heater. Methods of heating, methods of heating with infrared light, microwaves, laser light and the like can be mentioned. There is also a method of reacting continuously by using a fluidized bed or the like. Also, a method of reduction with solid C (carbon) or Ca, a method of mixing calcium chloride and the like and reducing in an inert gas or reducing gas, and industrially, M component oxide is once used as a chloride. There is also a method of reducing with Mg. In any case, if the magnetic material of the present invention is obtained, it falls within the scope of the production method of the present invention.

  However, a preferable method in the production method of the present invention is a method of reducing as a reducing gas in hydrogen gas or a mixed gas thereof with an inert gas. In order to produce the magnetic material of the present invention phase-separated in nanoscale, the reduction with C or Ca is too strong in reducing power, and it is very difficult to control the reaction for constructing the soft magnetic material of the present invention There are also problems such as the generation of toxic CO after reduction and the coexistence of calcium oxide which must be removed by washing with water, but the reduction by hydrogen gas is consistently under clean conditions. It is because reduction processing can be performed.

However, from the viewpoint of thermodynamics, FM oxide is reduced in H ₂ gas flow as assumed from Ellingham diagram, but except for Cu, M component oxide is not necessarily easily obtained in H ₂ gas It is understood that it is not reduced. For example, at 1000 ° C., in the case of Fe, the H ₂ / H ₂ O ratio when being reduced from magnetite to metallic iron is approximately 1, whereas it is approximately 10 ⁵ to 10 ^{6 in} SiO ₂ , H ₂ It is understood that although the gas is flowing, Si oxides are unlikely to be reduced. Therefore, a simple mixture or solid solution of Fe oxide and Si oxide should normally be considered to be α-Fe and SiO ₂ by hydrogen reduction.
Therefore, the fact that M ions in M-ferrite are reduced to the valence of M component metal when reducing M-ferrite with hydrogen gas except for Cu has not been known so far, and this time We think that the inventor found for the first time. At the moment, we consider the reason as follows.

  The M-ferrite of the present invention has a diameter of 1 nm or more and less than 1000 nm (1 μm), and the M component is atomically dispersed in a very active nanopowder, and further, the affinity between M and FM Are alloyed as α- (FM, M) under hydrogen gas flow. The reactivity of the powder in the nano range is high, and because the redox atmosphere is at the nano scale, results that go beyond the common knowledge of gold chemistry, contrary to the classical thermodynamic expectations that often characterize macroscopic properties Bring Conventionally, M oxides such as Si and V which could be substantially reduced only in the presence of Ca and C, but according to the method of the present invention, some M components are the first phase or the first phase It can be reduced to the metallic state and present as an alloy, such as in the alpha- (FM, M) phase of the phase and the second phase. At this time, the present inventors estimate that the coexistence of a small amount of an alkali metal such as K also affects the promoting action of the reaction.

  Also, in the equilibrium phase diagram of the FM-M component (for example, the Fe-M component), the solid solution limit of M in the α- (FM, M) phase generally increases as the temperature increases, but the production method of the present invention In the above, it can not always be said that the average M component content in the α- (FM, M) phase becomes higher as the reduction temperature is higher. It differs depending on the type and content of the M component of the entire M-ferrite nano powder, the setting of temperature rising / falling conditions, and the type of the coexisting second phase and subphase. Further, unlike the conventional metal-based magnetic material manufacturing technology in which the entire phenomenon is once melted, the above phenomenon is a process of reducing M-ferrite nanopowder and growing particles, and then preferably sintering the powder It is also one of the features of the process of the present invention which is called built-up type.

  The oxygen content in the material of the present invention is generally determined by the inert gas melting method, but when the oxygen content before reduction is known, the weight difference between before and after reduction indicates the present invention. The oxygen content in the material of can be estimated. However, at the same time, when a halogen element such as chlorine whose content is easily changed before and after reduction, an alkali element such as K and Na, or a volatile component such as water or an organic component is contained in large amounts, In order to accurately estimate the oxygen content, it is preferable to separately identify the contents of these elements and components.

  By the way, among alkali metals derived from raw materials, for example, K starts to be dissipated by vaporization from inside the magnetic material at 450 ° C, and it depends on the kind and content of M component and reduction time, but most of it is 900 ° C or more It is removed. Therefore, in the initial stage of the reduction reaction, in some cases where it is undesirable for the alkali metal derived from the raw material to be retained to take advantage of its catalytic function, depending on the application, it is undesirable to remain at the product stage. By appropriate selection, the alkali metal can be appropriately removed to the finally acceptable range. The final range of the content of alkali metals such as K which can be easily removed while having an effective effect on reduction is such that the lower limit is 0.0001 atomic% or more and the upper limit is 5 atomic% or less The upper limit value can be further controlled to 1 atomic% or less, and can be 0.01 atomic% when controlled most precisely. Of course, depending on the reduction conditions, it is also possible to further reduce the alkali metal such as K to below the detection limit. The halogen element such as Cl (chlorine) remaining in the M-ferrite nanopowder is released out of the material system mainly as hydrogen halide such as HCl under a reducing atmosphere. Residual Cl and the like begin to decrease significantly at reduction temperatures of 450 ° C or higher, depending on the M component and K content, and changes in their contents in the reduction step, but if a reduction temperature of approximately 700 ° C or higher is selected Can be removed almost completely from the inside of the material.

Before and after the reduction reaction of the present invention, the weight loss due to the O component becoming mainly H ₂ O due to transpiration is the type and content of the M component, the content of the TM component, the amount of oxygen, the amount of subphases and impurities, water Although depending on the amount of volatile components such as, or the reduction reaction conditions such as reducing gas species, etc., it is usually between 0.1% by mass and 80% by mass.

  As in a part of the embodiments of the present invention, local oxygen content is determined based on photographs such as SEM or EDX, or phases identified by XRD or the like are observed on an image by microscopic observation such as SEM. It can also be identified. This method is suitable for estimating the oxygen content of the first phase and the second phase and the distribution thereof.

  Hereinafter, the method for producing the magnetic material of the present invention by heat treatment in a reducing gas will be described in detail. The heat treatment in a typical reduction step raises the temperature of the material linearly or exponentially from room temperature to a constant temperature in a reducing gas flow, using one or more heating rates, and immediately performs one or two. By lowering the temperature linearly or exponentially to room temperature using a temperature-falling rate higher than the species, or during temperature rising or temperature lowering in the temperature rising / falling process, or at any stage after temperature rising, constant time (= reduction time B) by adding a process of holding the temperature (hereinafter referred to as a constant temperature holding process). Unless otherwise specified, the reduction temperature in the present invention refers to the highest temperature among the temperature at which the temperature raising process is switched to the temperature lowering process and the temperature in the process of maintaining the temperature for a certain period of time.

  When the method of reducing M-ferrite with hydrogen gas is selected as the method of manufacturing the soft magnetic material of the present invention, the reduction temperature is generally 400 ° C. or more and 1500 ° C. or less, depending on the type of M component and the content of TM component. It is good to choose the temperature range.

  However, when reduction is performed at 419 ° C. or higher, the magnetic material during reduction may be dissolved depending on the M component content, but the region where the M component content is usually 0.01 atomic% or more and 33 atomic% or less In this case, the reduction treatment can be performed by freely selecting in the temperature range of 400 ° C. or more and 1500 ° C. or less. In general, the temperature of 400 ° C. or higher is preferable because the reduction rate is very slow, and the reduction time can be prevented from becoming long due to poor productivity.

  In the method for producing the soft magnetic material of the present invention, the preferable reduction temperature range is 400 ° C. or more and 1500 ° C. or less, and the more preferable reduction temperature range is 800 ° C. or more and 1200 ° C. or less. When the M component is reduced to metal, it is caused by the coarsening of the tissue due to the reduction reaction immediately below the melting point of the magnetic material of the present invention, the reaction with a reactor such as a ceramic container, or the reduction of the reduction reaction rate due to low temperature. This is because the decrease in productivity can be avoided.

  In the case of reduction at the same temperature, the reduction reaction proceeds as the reduction time is longer. Therefore, as the reduction time is longer, the saturation magnetization is higher. However, with regard to the coercive force, even if the reduction time is increased or the reduction temperature is increased, the coercivity is not necessarily reduced. The reduction time is desirably selected appropriately depending on the desired magnetic properties.

  When a method of reducing M-ferrite with hydrogen gas is selected as a method for producing the semi-hard magnetic material of the present invention, reduction is generally performed in the range of 400 ° C. or more and 1500 ° C. or less, although it depends on the type and content of M component. Preferably the temperature is chosen. The reason is that if the temperature is less than 400 ° C., the reduction rate is very slow and the reduction time becomes long and the productivity is poor, and conversely, if it exceeds 1500 ° C., there is a risk of melting of Fe. This is because the features of the nanocrystals of the present invention may be inhibited and the coercivity may not be properly controlled. A more preferable reduction temperature range is about 450 ° C. or more and 850 ° C. or less, and a particularly preferable range is about 500 ° C. or more and 700 ° C. or less.

  From the above, when the soft magnetic or semihard magnetic material of the present invention is produced by the method of reducing M-ferrite with hydrogen gas, the reduction temperature is preferably in the range of 400 ° C. or more and 1500 ° C. or less.

  When the magnetic material of the present invention contains an M component other than Cu, the reduction rate is extremely slow compared to Fe-ferrite, for example, an intermediate of magnetite and maghemite (see Patent Document 3 and Non-patent Document 3). For example, in the case of Fe-ferrite which does not contain an M component having an average powder particle size of 100 nm or less, reduction to almost 100% by volume of α-Fe is carried out only by reduction in hydrogen at 450 ° C. for 1 hour. Even under the conditions of 425 ° C. and 4 hours, the Fe-ferrite is reduced to an extent not observed even by X-ray diffraction. On the other hand, for example, even if Hf is contained at only 10 atomic%, the M-ferrite phase does not disappear unless reduction conditions of 550 ° C. for 1 hour, and only α- (FM, M) phase on XRD It does not.

  In the magnetic material of the present invention, such a reduction rate of M-ferrite allows reduction at high temperature, and the nano-fine structure becomes extremely coarse while M is contained in the α-Fe phase. Without disproportionation reaction, an aggregate of microcrystalline structures including the first phase and the second phase can be obtained.

  In the magnetic material of the present invention, it is desirable that the first phase and the second phase be separated in nanoscale in the reduction step in the production thereof. In the case of the soft magnetic material of the present invention, in particular, phases of various M components and crystal structures are separated by disproportionation reaction, and their orientations are random, or M in the nano scale Fluctuations in the concentration of the component and the FM component content need to be inherent, and furthermore, the respective crystal phases need to be ferromagnetically coupled.

The reduction proceeds and grain growth of the M-ferrite nanoparticles occurs, but at that time, depending on the reduction temperature, due to the type and content of the M component of the original M-ferrite nanoparticles, The crystal structure and M component content of one phase and the second phase change in various ways. In the temperature range of 400 ° C. or more and 1500 ° C. or less, generally, the higher the temperature reduced to the metal phase, the higher the M component content of the first phase.
Therefore, the composition of the crystal phase changes depending on the temperature rising rate in the temperature rising process and the temperature distribution in the reaction furnace.

  For example, the relationship between the temperature rise / fall rate and the crystal phase appearing in the magnetic material of the present invention will be described, using Fe as an essential component of the FM component and Hf as the M component.

According to the Fe-Hf equilibrium diagram, Hf can be dissolved to some extent in the α-Fe phase at around 1100 ° C., but Hf hardly dissolves in the α-Fe phase at normal temperature. The Hf content in the α- (Fe, Hf) phase of the magnetic material of the present invention can be present far beyond the solid solution source which is this equilibrium composition, but these are naturally non-equilibrium phases. If it was possible to carry out an operation of lowering the temperature from the reduction temperature to normal temperature over an infinite time (the temperature decrease rate is infinitesimally small), almost Hf can not coexist in the α-Fe phase. Conversely, if it is possible to perform an operation to lower the temperature at a rate of infinity from about 1100 ° C. (temperature reduction rate is infinite), α- (Fe, Hf) having a Hf content of several atomic% at the reduction temperature Even if a phase is present, the α- (Fe, Hf) phase having various Hf contents does not separate from the phase due to the disproportionation reaction. Therefore, also in the present invention, the soft magnetic material of the present invention can not be constructed by any of the above-described manufacturing methods in the limit, if the Fe-Hf equilibrium diagram is followed. That is, it is necessary to control the microstructure of the soft magnetic material of the present invention by appropriately selecting the temperature lowering rate which is not close to the above-mentioned two limits (not super slow cooling or super quenching).
However, the magnetic material of the present invention has a microstructure which is completely different from that of the bulk existing material, and does not have a composition distribution according to the equilibrium diagram at normal temperature, but at around the reduction temperature. In the magnetic material, a uniform phase may be generated along the equilibrium phase diagram, which extends to the nano area, in which case speed control of temperature rise and fall including the temperature rising process is important for the microstructure There is. From this point of view, as the temperature raising and lowering temperature in the reduction step of the present invention, optimum conditions differ depending on the target electromagnetic characteristics and the content of the M component, but usually between 0.1 ° C / min and 5000 ° C / min. It is desirable to select appropriately.

In particular, in the case of producing the soft magnetic material of the present invention, when the M component content is more than 20 atomic%, the coercive force is low when the temperature rise / fall rate is performed at a rate of 1 ° C./min to 500 ° C./min. It is preferable because the soft magnetic material can be prepared.
In the above-described reduction reaction using hydrogen gas, the phase separation process caused by the “disproportionation” reaction varies depending on the type of the M component and the conditions of the reduction step. The disproportionation phase separation as described above is described in the TM component and Fe component composition regions already in Patent Documents 1 and 2, but in the present invention, along with disproportionation of the M component different from the TM component, By disproportionating the Ni and / or Co component in the FM component, the saturation magnetization is higher and the coercivity is lower and / or stable than in the case where the Ni and / or Co component is not in the FM component. It can be a soft magnetic material having a semi-hard magnetic material with an increased squareness ratio.

  The magnetic material of the present invention may contain an M component oxide phase as the second phase, but the presence of this phase on grain boundaries or on the surface of powder particles exerts a strong oxygen blocking effect, and the magnetic material of the present invention It greatly contributes to the improvement of the oxidation resistance of the material. In particular, the semi-hard magnetic material of the present invention not only makes the effect of oxidation resistance remarkable but also exerts an effect on the improvement of coercivity.

In the present invention, the reason why appropriate grain growth occurs while maintaining the nano-fine structure even in a high temperature region, for example, higher than 800 ° C., is unclear. However, even if the raw material is M-ferrite nanopowder and this is hydrogen-reduced to be in a metallic state like the first phase, the original particle shape and composition distribution are quite fine if appropriate reduction conditions are selected. Without being reflected in the structure, improper grain growth has not occurred such that the composition distribution becomes homogeneous and the grain size becomes coarse. Since grain growth occurs together with the reduction reaction in this way, disproportionation proceeds while leaving a structure resembling intergrowth and crystallization, considering that volume reduction due to reduction occurs up to 52% by volume. Can be easily guessed. Furthermore, from the high temperature phase which is partially homogenized while maintaining the nano-fine structure while also involving the difference in the reduction rate of the phase separated due to disproportionation in the initial stage of the reduction reaction, The phase separation by disproportionation reaction during the temperature decrease mainly occurs in the α- (FM, M) phase, and the nanoparticles and the nanostructure are precipitated, and finally, the overall nanoscale is very fine. It is considered that a disproportionation structure is constructed.
With regard to the reduction rate, in the oxide phase containing M component such as M-ferrite phase, it is also known that the higher the M component content, the slower the reduction reaction rate becomes. It is believed that eliminating them also works well for maintaining nanostructures.
The above series of considerations are also supported by the fact that the magnetic material of the present invention usually loses its characteristics once it has melted.

(3) Stepwise oxidation step (also referred to as "step (3)" in the present application)
Since the magnetic material of the present invention after the reduction step contains nano metal particles, there is a possibility that when it is taken out to the atmosphere as it is spontaneously ignited and burned. Therefore, although not an essential step, it is preferable to carry out a gradual oxidation treatment immediately after the completion of the reduction reaction, if necessary.
The gradual oxidation mainly oxidizes the surface of nano metal particles after reduction to passivate it as wustite, magnetite, M-ferrite, M component oxide phase, etc. to rapidly oxidize internal magnetic material bodies. To suppress According to the production method of the present invention, the M component is contained as the metal component in the first phase or the first and second phases up to the reduction step. In the magnetic material of the present invention, the M component precipitates on the alloy surface in the gradual oxidation step to form a passivated film, but has a significant oxidation resistance as compared to the FM magnetic material not containing the M component. The gradual oxidation is performed, for example, in the vicinity of normal temperature to 500 ° C. in a gas containing an oxygen source such as oxygen gas, but a mixed gas containing an inert gas having a lower oxygen partial pressure than the atmosphere is often used. When the temperature exceeds 500 ° C., it becomes difficult to control and provide a thin oxide film of about nm on the surface regardless of any low oxygen partial pressure gas. In addition, there is also a gradual oxidation method in which the reactor is gradually opened at normal temperature to raise the oxygen concentration so as not to be exposed to the atmosphere rapidly after being evacuated once.
In the present application, a process including the above-mentioned operation is referred to as a "slow oxidation process". After this process, handling in the next process, the molding process, becomes very easy.

  As a method of removing the oxide film again after this step, there is a method in which the forming step is carried out in a reducing atmosphere such as hydrogen gas. However, since the surface oxidation reaction in the gradual oxidation process is not a complete reversible reaction, it is not possible to remove all of the surface oxide film.

  Of course, in the case where the handling from the reduction step to the forming step is performed by an apparatus designed to be able to operate in an oxygen-free state such as a glove box, this gradual oxidation step is not necessary.

  Furthermore, in the case of the magnetic material powder of the present invention in which the M component content is large, the reduction temperature and time are sufficiently long, and the grain is grown, it is stable without passing through the gradual oxidation step and being released as it is into the atmosphere. A passivating film may be formed, in which case no special gradual oxidation step is required. In this case, opening to the atmosphere can be regarded as a gradual oxidation process.

  In order to secure oxidation resistance and magnetic stability by gradual oxidation, the ferromagnetic coupling may be broken by the layer of the oxide layer or the passive film, so grain growth should be caused as much as possible before gradual oxidation is performed. Is preferred. If this is not the case, it is preferable to carry out the next molding step without going through the gradual oxidation step as described above, and it is desirable to continue the reduction step and the molding step by a deoxygenation or low oxygen process.

(4) Forming step (In the present application, it is also referred to as "step (4)")
The magnetic material of the present invention is a magnetic material in which the first phase and the second phase are bonded directly or continuously via the metal phase or the inorganic phase to form a block as a whole (ie, solid material). It is used as a magnetic material). The magnetic material powder of the present invention is used alone in various applications by solidifying itself or forming by adding a metal binder, other magnetic material, resin or the like. In the state of the magnetic material powder after the step (2) or further after the step (3), the first phase and the second phase are continuous either directly or through the metal phase or the inorganic phase. In this case, it functions as a solid magnetic material without undergoing the main forming process.

  As a method of solidifying only the magnetic material of the present invention, it is put into a mold and compacted by cold compaction and used as it is or subsequently, it is compacted by cold rolling, forging, shock wave compression molding etc. In many cases, sintering is performed while performing heat treatment at a temperature of 50 ° C. or higher. The method of sintering by heat treatment as it is without pressure application is called pressureless sintering. The heat treatment atmosphere is preferably a non-oxidizing atmosphere, and the heat treatment may be performed in a rare gas such as argon or helium, or in an inert gas such as nitrogen gas, or in a reducing gas containing hydrogen gas. It is also possible in the atmosphere if the temperature condition of 500 ° C. or less. Further, as in the case of pressureless sintering, sintering may be performed not only when the pressure of the heat treatment atmosphere is normal pressure, but also in a pressurized gas phase atmosphere of 200 MPa or less or sintering in vacuum.

  The heat treatment temperature is preferably 50 ° C. or more and 1500 ° C. or less in pressure molding, and 400 ° C. or more and 1500 ° C. or less in pressureless sintering, in addition to cold forming performed at less than 50 ° C. Generally, the most preferable range of molding temperature is 50 ° C. or more and 1400 ° C. or less, since the material may melt at temperatures above 1400 ° C.

  This heat treatment can be carried out simultaneously with the powder compacting, and also by pressure sintering methods such as hot pressing, HIP (hot isostatic pressing), electric current sintering, and SPS (discharge plasma sintering), It is possible to mold the magnetic material of the present invention. In order to make the pressing effect of the present invention remarkable, it is preferable to set the pressing force in the heating and sintering step within the range of 0.0001 GPa to 10 GPa. If it is less than 0.0001 GPa, the effect of pressurization is poor, and there is no change in pressure-less sintering and electromagnetic characteristics, so that pressure sintering is disadvantageous because the productivity falls. When the pressure exceeds 10 GPa, the pressurizing effect is saturated, so even if it is applied unreasonably, the productivity is only lowered.

  In addition, the large pressure gives induced magnetic anisotropy to the magnetic material, and the magnetic permeability and the coercive force may deviate from the range to be controlled. Therefore, the preferable range of the pressing force is 0.001 GPa or more and 2 GPa or less, more preferably 0.01 GPa or more and 1 GPa or less.

  Among the hot pressing methods, the super-high pressure HP method of heat-treating and hot pressing while applying large pressure from uniaxial to triaxial directions by preparing the compact in a plastically deformed capsule is unnecessary excessive. It is possible to prevent oxygen contamination. Unlike a hot press method that uses a uniaxial compressor and pressurized heat treatment in a cemented carbide or carbon mold, a material with a pressure of 2 GPa or more, which is difficult even with a tungsten carbide cemented carbide mold, can be used without problems such as mold breakage In addition, the capsule can be molded without being exposed to the atmosphere because the capsule is plastically deformed and sealed inside by pressure.

  Before molding, coarse grinding, pulverizing or classification can also be performed using known methods in order to adjust the powder particle size.

  In the case where the powder after reduction is a lump of several mm or more, the coarse crushing is a step performed before molding, or a step performed when powdering again after molding. Use a jaw crusher, hammer, stamp mill, rotor mill, pin mill, coffee mill, etc.

  Furthermore, it is also effective to carry out particle size adjustment using a sieve, a vibration type or a sonic type classifier, a cyclone or the like after coarse grinding, in order to further control the density and the formability at the time of forming. After rough grinding and classification, annealing in an inert gas or hydrogen can remove structural defects and distortions, which may be effective in some cases.

  The pulverization is carried out when it is necessary to pulverize the magnetic material powder after reduction or the magnetic material after molding to submicron to several tens μm.

  As a method of pulverization, in addition to the methods mentioned above for coarse powder, dry or wet pulverizers such as rotary ball mill, vibration ball mill, planetary ball mill, wet mill, jet mill, cutter mill, pin mill, automatic mortar and the like and those A combination of

As a typical example of the method for producing the solid magnetic material of the present invention, after the M-ferrite nanopowder is produced according to the step (1) and subsequently reduced according to the step (2), the step (3) It may be molded only in the process of 4) or the process of (4). As one of the particularly preferable production methods, M-ferrite nanopowders are prepared by the wet method exemplified in the step (1), and then reduced by the method containing hydrogen gas shown in the step (2), A step of forming by the sintering method under normal pressure or pressurization shown in the step (4) after performing gradual oxidation exposed to a low partial pressure of oxygen at normal temperature shown in the step 3), in particular (3) After the deoxidization of the surface of the material powder is performed as the step of (4), there is a manufacturing method using a step of forming in hydrogen to avoid mixing of oxygen in the additional material as the step of (4). The present solid magnetic material can be formed to a thickness of 0.5 mm or more, and can be processed into an arbitrary shape by cutting and / or plastic processing.
Step of (1) → step of (2), step of (1) → step of (2) → step of (3), step of (1) → step of (2) → step of (5) described below Step of (1) → step of (2) → step of (3) → magnetic material powder obtained in the step of (5) described later, or magnetic material powder obtained in the above step (4) A magnetic material powder obtained by re-pulverizing the magnetic material formed in the above step, and a magnetic material powder obtained by annealing the magnetic material powder obtained in the above step in the step (5) described later in a magnetic sheet for high frequency In the case of application to composite materials with resins such as these, compression molding is performed after mixing with a thermosetting resin or thermoplastic resin, or injection molding is performed after kneading with a thermoplastic resin, and further extrusion molding, roll It is molded by molding or calendar molding.

  As a type of sheet shape, for example, when applied to an electromagnetic noise absorbing sheet, a batch type sheet by compression molding with a thickness of 5 μm or more and 10000 μm, a width of 5 mm or more and 5000 mm or less, and a length of 0.005 mm or more and 1000 mm or less Examples include various roll-like sheets formed by molding, and cutting or forming sheets having various sizes including an A4 size.

(5) Annealing Step The magnetic material of the present invention typically has a first phase and a second phase, and one or both crystal grain sizes are in the nano range.

Annealing for various purposes such as crystal distortion and defects occurring in each step and stabilization of a non-oxidizing active phase may be preferable as long as the object of the present invention is not impaired.
For example, in order to perform stable reduction simultaneously with drying for the purpose of removing volatile components such as contained water after the M-ferrite nanopowder production process of (1), improper grain growth inhibition or lattice in a later process For the purpose of removing defects and the like, so-called preliminary heat treatment (annealing) may be performed in which a fine particle component of about several nm is heat-treated. In this case, it is preferable to anneal at about 50 ° C. to 500 ° C. in the atmosphere, in an inert gas or in vacuum.
In addition, the coercivity of the soft magnetic material of the present invention can be reduced by removing distortions or defects of crystal lattices or microcrystals caused by volume reduction due to grain growth or reduction after the reduction step (2). . After this step, in applications where powder is used as it is, for example, in applications such as powder magnetic cores where powder is solidified with resin or ceramic, after this step or after this step, a grinding step etc. Later, annealing under appropriate conditions may be able to improve the electromagnetic properties.
In addition, in the gradual oxidation process of (3), the annealing may be useful for removing distortions and defects near the surface, the interface, and the boundary which are generated by the surface oxidation.
Annealing after the forming step (4) is the most effective, removing distortions and defects in the crystal lattice, microstructure, etc. that occur in subsequent cutting and / or plastic working such as preforming, compression molding, hot pressing, etc. Because of this, an annealing process may be carried out actively after this process. In this process, it is also expected that the accumulated distortion, defects and the like can be alleviated at once in the process prior to that. Furthermore, after the above-described cutting and / or plastic working, the steps (1) to (4), the steps (2) to (4), the steps (3) and (4), and the step (4) It is also possible to carry out annealing by putting together the strain at the same time or the strain etc. accumulated.

  The annealing atmosphere may be any in vacuum, under reduced pressure, under normal pressure, under pressure of 200 MPa or less, and as a gas species, inert gas represented by a rare gas such as argon, nitrogen gas, etc. A reductive gas such as hydrogen gas, or an atmosphere containing an oxygen source, such as in the air, is also possible. Annealing temperature is from normal temperature to 1500 ° C., and depending on the case, treatment at low temperature of liquid nitrogen temperature to normal temperature is also possible. The apparatus for the annealing process is substantially the same as the apparatus used in the reduction process and the forming process, and can be implemented by combining known apparatuses.

Hereinafter, the present invention will be more specifically described by way of examples and the like, but the present invention is not limited at all by these examples and the like.
The evaluation method of the present invention is as follows.

  Hereinafter, the present invention will be more specifically described by way of examples and the like, but the present invention is not limited at all by these examples and the like.

The evaluation method of the present invention is as follows.
(I) Saturation magnetization and coercivity magnetic powder are placed in a polypropylene case (inner diameter: 2.4 mm, thickness of powder layer is approximately 1.5 mm) made of polypropylene, using a vibrating sample magnetometer (VSM) The full loop of the magnetic curve was drawn in the region of an external magnetic field of -7.2 MA / m or more and 7.2 MA / m or less, and values of saturation magnetization (emu / g) and coercivity (A / m) at room temperature were obtained. The saturation sum magnetization was corrected with a 5N Ni standard sample and determined by the saturation asymptotic law. The coercivity corrected the deviation of the magnetic field in the low magnetic field region using the paramagnetic Pd and / or Gd ₂ O ₃ standard sample. The coercivity was also measured by the VSM method using a Helmholtz-type coil, and the validity of the above measured value was confirmed. In this measurement, if no smooth step or inflection point is found on the magnetic curve up to the zero magnetic field after magnetizing to 7.2 MA / m, “inflection point on 1⁄4 major loop” "No" I judged. In the case of magnetic powder, the direction of the measurement magnetic field is the axial direction.
Incidentally, in all of the examples shown below, it was confirmed that "the inflection point on the 1/4 major loop" was "absent", and it was found that ferromagnetic coupling was recognized.
The magnetic properties of the molded body were measured using a direct-current magnetization measuring machine (direct-current BH loop tracer) equipped with a small single-plate measurement jig and a solid magnetic material of sample size 15 mm × 5 mm × 1 mm. For the measurement of the magnetization of the molded body, the magnetization in the external magnetic field 150 Oe was expressed as saturation magnetization, and the value was expressed in T (Tesla).
(II) Oxidation resistance The saturation magnetization σ _st (emu / g) of a magnetic powder left at room temperature for 60 days in the atmosphere was measured by the above method and compared with the initial saturation magnetization σ _s0 (emu / g) Rate of decline,
Was evaluated by expression of _{Δσ s (%) = 100 ×} (σ s0 -σ st) / σ s0. As the absolute value of Δσ _s approaches 0, it can be judged that the oxidation resistance performance is high. In the present invention, a magnetic powder having an absolute value of Δσ _s of 1% or less was evaluated as having good oxidation resistance in a period of 60 days.
(III) Electrical Resistivity A compact with a sample size of 15 mm × 5 mm × 1 mm was measured by the four-terminal method. It measured also by van der Pauw (van der Pauw) method, and the validity of the said measured value was confirmed.
(IV) Fe content, Ni content and / or Co content, oxygen content, bcc- (FM, M) phase volume fraction Fe and Co content in powder or bulk magnetic material, fluorescent X-ray elemental analysis It quantified by the method (XRF). The Fe and M component contents of the first phase and the second phase in the magnetic material were quantified by EDX attached thereto based on the image observed by FE-SEM. When the EDX measured value of a certain component is 0.00 at%, the content of that component is set to zero. Moreover, about the volume fraction of a bcc- (FM, M) phase, it quantified by the image analysis combining the method using said FE-SEM with the result of a XRD method. In order to distinguish mainly between the observed phase, which is the bcc- (FM, M) phase or the oxide phase, an oxygen characteristic X-ray surface distribution chart using SEM-EDX was used. Furthermore, the validity of the value of bcc- (FM, Co) phase volume fraction was also confirmed from the value of saturation magnetization measured in (I).
The oxygen content of the magnetic material after the reduction step was also confirmed by the decrease in weight after reduction. Furthermore, image analysis by SEM-EDX was used to identify each phase.
The amount of K was quantified by fluorescent X-ray elemental analysis.
(V) Average powder particle size Magnetic powder was observed with a scanning electron microscope (SEM) or a transmission electron microscope (TEM) to determine the powder particle size. The part representative of the whole was selected, and the number of n was determined to be 100 or more, with one significant digit.
When using a laser diffraction type particle size distribution analyzer in combination, the volume equivalent diameter distribution was measured and evaluated by the median diameter (μm) obtained from the distribution curve. However, only when the calculated median diameter was 500 nm or more and less than 1 mm, that value was adopted, and it was confirmed that the powder particle diameter estimated by the method using the above-mentioned microscope matches the significant digit one digit.
(VI) Average Grain Size The magnetic material was observed with a scanning electron microscope (SEM) or a transmission electron microscope (TEM), and the size of the portion surrounded by the crystal boundary was determined by one significant digit. As the measurement area, a portion representative of the entire area was selected, and the n number was 100 or more. The crystal grain size was determined by separately measuring the average value of the whole and the average value of only the first phase and the second phase.
(VII) Crystallite size For the line width of the (200) diffraction line of the bcc phase measured by X-ray diffraction, Schiller's equation was applied to determine the crystallite size with the dimensionless form factor of 0.9. .

Example 1 and Comparative Example 1
CrCl ₃ · 6 H ₂ O aqueous solution (chromium (III) chloride hexahydrate), NiCl ₂ · 6 H ₂ O (nickel (II) chloride hexahydrate), FeCl ₂ · 4 H ₂ O (iron (II) chloride) Separately, an aqueous solution of hydrate) was separately prepared, and these were mixed to prepare a mixed aqueous solution of CrCl ₃ and FeCl ₂ which was adjusted to 25.1 mM into a reactor to make a reaction field solution. Subsequently, while vigorously stirring in the atmosphere, a 280 mM aqueous solution of potassium hydroxide (pH adjusting solution) is added dropwise to gradually increase the pH of the system from the acidic side to the alkaline side within the range of 3.71 to 10.88. The mixture is allowed to react at the same time for 15 minutes, and then the addition of the pH adjustment solution and the reaction solution is stopped, and the mixture is allowed to react at the same time as the mixture solution of 83.8 mM CrCl ₃ , NiCl ₂ and FeCl _2. The stirring was continued for another 15 minutes. After that, solid components are precipitated by centrifugation, redispersed in purified water and repeated centrifugation to adjust the pH of the supernatant solution to 7.83 and finally disperse the precipitate in acetone, followed by centrifugation. The

After that, by performing hot-air drying at 50 ° C. overnight, Cr-ferrite nanopowder having a composition of (Fe _0.930 Ni _0.020 Cr _0.050 ) ₄₃ O ₅₇ and having an average powder particle size of 30 nm. I got The SEM image of this nanopowder is shown in FIG. In addition, as a result of analyzing this nanopowder by X-ray diffraction, it is confirmed that the cubic Cr-ferrite phase is the main phase and that rhombohedral ferrihydrite is slightly contained as the impurity phase. It was done. Accordingly, this powder does not contain the α- (FM, Cr) phase, and this is used as the powder of Comparative Example 1. The particle diameter, magnetic properties, etc. of the powder are shown in Table 1.

This Cr-ferrite nano powder is charged in a crucible made of alumina, heated in hydrogen gas at 10 ° C./min up to 300 ° C., held at 300 ° C. for 15 minutes, then 10 ° C. After raising the temperature by min, reduction treatment was performed at 1100 ° C. for 1 hour. Thereafter, the temperature was lowered at 95 ° C./min up to 400 ° C., and it was allowed to cool for 40 minutes from 400 ° C. to room temperature. Subsequently, gradual oxidation treatment is performed at 20 ° C. for 1 hour in an argon atmosphere with an oxygen partial pressure of 1% by volume, and the content ratio of chromium, nickel and iron (the total content of chromium, The content ratio when it was _mixed ) obtained a magnetic material of the composition of Fe _93.0 Ni _2.0 Cr _5.0 . The O content relative to the entire magnetic material was 1.7 atomic%, and the K content was zero. The average powder particle size of this FM-Cr magnetic material was 30 μm. The analysis on this magnetic material was conducted by the following method, and this magnetic material was referred to as Example 1.

  As a result of observing the obtained magnetic material by an X-ray diffraction method, only the α- (FM, Cr) phase is clearly recognized, whereby the α- (FM, Cr) phase which is the bcc phase is the main component That was confirmed.

In addition, this magnetic material powder was also observed by the FE-SEM / EDX method which is suitable for knowing the local Cr content of the magnetic material and the presence and degree of disproportionation (a magnification of 20,000 times ). The results are shown in FIGS. 3 (A) and 3 (B). Content of Cr in each phase of the magnetic material (numerical values in the figure are values of the atomic ratio of Cr with respect to the total of Cr and FM in each phase expressed as a percentage by the Cr content in each phase) Is shown in FIG. 3 (A). As shown in FIG. 3 (A), it was found that the content of Cr in each phase of the present magnetic material was disproportionately distributed to 3.30 at% or more and 10.69 at% or less. Note that, in FIG. 3, innumerable crystal boundaries in a curved shape curved at intervals of about 10 nm were observed also in a region seen as one α- (FM, Cr) phase. Therefore, even in the region of the α- (FM, Cr) phase, the Cr content is included in the phase that can be distinguished by the Cr content, for example, the α- (FM, Cr) phase having a Cr content of 3.30 at%. 10.69 atomic% of the α- (FM, Cr) phase is present, the amount being 3.2 times within the range of 1.5 to 10 ⁵ times the phase thereof, ie α From the results, it is also clear from the results that there is a phase corresponding to the second phase in addition to the first phase in the (FM, Cr) phase.
About the content of Ni component of each phase (The numerical value in the figure is the content of Ni in each phase and the value of atomic ratio of Ni to the total of FM component and M component of each phase is expressed as percentage) , FIG. 3 (B). As shown in FIG. 3B, the phase having a Cr content of 3.30 at% as the first phase contains 1.29 at% of Ni, and the Cr content of the second phase has a content of 10.9 at%. The phase of 69 at% contains 2.12 at% of Ni. The Ni content in the second phase was found to be 1.6 times, which is an amount of 1.1 times to 10 ⁵ times the content of the first phase.
Furthermore, when the same measurement as in FIG. 3 was performed with three fields of view different from those in FIG. 3 (therefore, measurement was performed at a total of 34 measurement points in combination with the measurement in FIG. 3). Cr content in the steel is disproportionately distributed as 1.83 at% or more and 10.69 at% or less, and the Cr content is Cr relative to the α- (FM, Cr) phase having 1.83 at% 5.8 times a is 10.69 atomic% of α- (FM, Cr) in the range content is less than 10 ⁵ times 1.5 times or more than its phase phase was also confirmed that the present ( Not shown). The Ni content of the phase having a Cr content of 1.83 atomic% is 0.34 atomic%, and the Ni content contained in the second phase is lower than the Ni content contained in the first phase. It turned out that it is 2.6 times which is the quantity of 1.1 times or more and 10 ⁵ times or less.
From the results of the entire phase measured at the above 34 points, it can be said that in the present example, at least the Cr content is largely disproportionated and distributed in the range of 1.83 atomic% to 10.69 atomic%. The average value of the Cr content of these 34 phases is 3.43 atomic%, which is lower than 5.0 atomic% of the Cr content which is the above-mentioned XRF measurement value, and the visual field is further increased. And, as a result of the existence of many second phases having a Cr content higher than 2.75 atomic%, which is 1.5 times 1.83 atomic%, larger disproportionation as a whole is occurring. It turned out that the possibility is high.
The average crystal grain size of the entire magnetic material was 200 nm. In addition, as a result of observing near the crystal boundary at a magnification of 750,000 times, it was confirmed that there was no hetero phase in the vicinity of the crystal boundary.

The above result of X-ray diffraction (that is, only the α- (FM, Cr) phase which is the bcc phase is clearly observed for the observed magnetic material) and the above result of FE-SEM (that is, the observed magnetism In combination with the material having a crystalline phase with a Cr content of 1.83 at.% To 10.69 at.%), The observed magnetic material comprises an α- (FM, Cr) phase, It was found that an α- (FM, Cr) phase having a Cr content higher than that of the phase was formed. If this is applied to the definitions of the first phase and the second phase described above, the former phase corresponds to the first phase, and the latter corresponds to the second phase.
The volume fraction of the bcc phase was estimated to be 99% by volume by these image analysis, X-ray diffraction and oxygen content. In addition, by determining the second phase as described above, the crystal grain sizes of the first phase and the second phase can be determined from the SEM image, and as a result of image analysis, those values were all 200 nm. .

  In addition, the crystallite size in this example was 100 nm.

The saturation magnetization of this magnetic material was 229.0 emu / g, and the presence of Ni in the FM phase confirmed that the magnetization exceeded 218 emu / g of α-Fe. The coercivity was 610 A / m, and there was no inflection point on the quarter major loop.
Therefore, since the magnetic material of Example 1 had a coercive force of 800 A / m or less, it was also confirmed that the magnetic material of this example was a soft magnetic material.
The average crystal grain size of the entire magnetic material was 200 nm. The crystal grain sizes of the first phase and the second phase were also almost the same size as the overall average grain size. In addition, as a result of observing near the crystal boundary at a magnification of 750,000 times, it was confirmed that there was no hetero phase in the vicinity of the crystal boundary.
The measurement results of the phase, composition, particle size and magnetic properties of this example are collectively shown in Table 1.

Comparative Example 2
An Fe-Cr magnetic material was produced in the same manner as in Example 1 except that the Ni component was not added.
The measurement results of the phase, composition, particle size and magnetic properties of this comparative example are shown in Table 1.
When Ni was not present in the FM phase, the saturation magnetization was reduced by 212.6 emu / g to nearly 10% as compared with Example 1. In addition, the coercivity was increased to 810 A / m as compared with Example 1, and it was found that the magnetic material of this comparative example was a semi-hard magnetic material.

[Comparative examples 3 to 5]
Ferrite nano powder was produced in the same manner as in Example 1 except that the Ni component and the Cr component were not added.
Example 1 except that the ferrite nanopowder is reduced under the conditions of 425 ° C. for 1 hour (Comparative Example 2), 4 hours (Comparative Example 3) at the same temperature, and 450 ° C. for 1 hour (Comparative Example 4) Fe metal powder was produced by the same method as in. The measurement was performed in the same manner.
The measurement results of the particle size and the magnetic properties are shown in Table 1.
In addition, these metal powders have the property that the magnetic characteristics are rapidly deteriorated only by leaving them in the room temperature atmosphere. The change rate Δσ _s (%) of the saturation magnetization of the comparative examples 3 to 5 at t = 60 was 5.4, 19.0, 21.3.
In addition, (DELTA) (sigma) _s of Example 1 was 0.0%.
The magnetic material of Example 1 was found to be excellent in oxidation resistance.

[Examples 2 to 5]
An FM-M component magnetic material was produced in the same manner as in Example 1 except that the contents of the M component and Ni and / or Co were as shown in Table 1. An SEM-EDX analysis image of the Fe _85.1 Ni _4.3 V _10.6 soft magnetic material obtained in Example 2 is shown in FIG.
The measurement results of the phase, composition, particle size and magnetic properties of this example are shown in Table 1. The coercivity of the magnetic materials of Examples 2 and 5 was 800 A / m or less, and it was found to be the soft magnetic material of the present invention. In addition, since the coercivity of the magnetic materials of Examples 3 and 4 was more than 800 A / m and 40 kA / m or less, it was found to be the semi-hard magnetic material of the present invention. Furthermore, the saturation magnetizations of the magnetic materials of Examples 3 and 5 are 229.5 emu / g and 219.4 emu / g, respectively, and by the presence of Co or Ni in the FM phase, the magnetization 218 emu / g of α-Fe is obtained. It confirmed that it exceeded.
The “second phase M component content / first phase M component content” in the table means “the sum of the FM component and the M component in the first phase is 100 atomic%, and the content in the first phase is The ratio of the content of the M component in the second phase to the total content of the FM component and the M component in the second phase with respect to the M component content is 100 atomic%. Specifically, an arbitrary part of the magnetic powder is photographed with an SEM at a magnification of 1 to 50,000 times, and a radius of 150 to 200 nm at a plurality of points for an area smaller than about 12 μm × about 9 μm. When EDX measurement using an electron beam of a beam diameter was performed, the measurement point having the minimum M component content was determined as the first phase, and the measurement point having the maximum M component content was determined as the second phase. And the case where the said ratio is 1.5 times or more and less than 2 times was described as "> = 1.5." As shown in the table, in any of the examples, it was confirmed that the above ratio was 1.5 times or more.
Furthermore, “Ni / Co content ratio” in the table is “the content of Ni and / or Co in the first phase when the total of the FM component and the M component in the first phase is 100 atomic%. It means the ratio of the content of Ni and / or Co in the second phase, where the total of the FM component and the M component in the second phase is 100 atomic% with respect to (atomic%). Specifically, the Ni / Co content at the measurement point having the maximum M component content (atomic%) with respect to the Ni / Co content (first phase) at the measurement point having the minimum M component content It is the ratio of the second phase). And if the above ratio is an amount of 10 ⁻⁵ times or more and less than 0.909 times, “<0.909”, and if it is an amount of 1.1 times to 10 ⁵ times or less, “≧ 1.1” Marked. As shown in the table, in any of the examples, the above ratio was confirmed to be an amount of 10 ^{−5 to} 0.909 times or an amount of 1.1 to 10 ⁵ times.
In any of the examples, the average grain size of the first phase and the second phase matched the average grain size of the whole. In addition, as a result of observing near the crystal boundary at a magnification of 750,000 times, it was confirmed that there was no hetero phase in the vicinity of the crystal boundary.
FIG. 4A shows the result of observation of Example 2 by the FE-SEM / EDX method which is suitable to know the local V content of the magnetic material and the presence and degree of disproportionation. However, in this figure, the imaging magnification was analyzed by 50,000. The V content in each phase of the magnetic material (the numerical value in the figure is the V content in each phase and represents the value of the atomic ratio of V to the sum of V and FM in each phase as a percentage), It was found that the distribution was disproportionately distributed to 1.21 atomic% or more and 66.92 atomic% or less. Therefore, even in the region of the α- (FM, V) phase, the V-containing phase can be distinguished by the V content, for example, the V-content relative to the α- (FM, V) phase having 1.21 atomic% amount, that the than the phase is less than 10 ⁵ times 1.5 times 66.92 atomic% of α- (FM, V) phase is present, i.e., α- (FM, V) phase with respect to It became clear from this result that a phase corresponding to the second phase is also present in addition to the first phase. The content of the Ni component in each phase of FIG. 4 (A) is shown in FIG. 4 (B). According to the definition of the present invention, the first phase, which has a V content of 1.21 atomic%, contains 3.95 atomic% of Ni, and the second phase, a V content of 66.92 atomic% One phase contains 2.47 atomic percent of Ni. It was found that the Ni content in the second phase is 0.625 times, which is an amount of 10 ⁻⁵ times or more and less than 0.909 times, with respect to the Ni content in the first phase.

[Example 6]
In the same manner as in Comparative Example 1, (Fe _0.971 Ni _0.028 Mn _0.001 ) ₃ O ₄ ferrite nanopowder was produced. This was mixed with silica powder, and reduction reaction was performed in the same manner as in Example 1 to obtain Fe _94.4 Si _2.8 Ni _2.7 Mn _0.1 magnetic powder.
The magnetic properties of this magnetic powder are shown in Table 1.
[Example 7]
The magnetic material powder of Example 6 was charged into a tungsten carbide cemented carbide mold, and cold compression molding was performed under the conditions of room temperature and 1 GPa in air.
Then, the temperature of the cold-pressed compact is raised at 10 ° C./min to 300 ° C. in an argon stream, held at 300 ° C. for 15 minutes, then raised at 300 ° C. to 900 ° C. at 10 ° C./min, The solid magnetic material of the present invention was obtained by immediately cooling to 400 ° C. at 75 ° C./min and cooling from 400 ° C. to room temperature over 40 minutes.
The density of this solid magnetic material was 6.08 g / cm ³ . In addition, the oxygen content in the entire magnetic material including the M component, the TM component, the FM component, and the O component of this solid magnetic material was 1.1 atomic%. The average crystal grain size of the first phase, the second phase, and the whole was 300 nm, and the crystallite size was 50 nm. The “second phase M component content / first phase M component content” was 1.5 or more, and the “Ni / Co content ratio” was less than 0.909. The saturation magnetization and coercivity obtained by the DC magnetization measurement apparatus were 0.821 T and 330 A / m, and there was no inflection point on the 1⁄4 major loop. Moreover, the electrical resistivity of this solid magnetic material was 28 μΩm.
According to this embodiment, the solid magnetic material of the present invention has a higher electric resistivity by an order of magnitude than 1.5 μΩm, which is the feature, and further, existing materials such as 0.1 μΩm of pure iron and 0.5 μΩm of electromagnetic steel sheet. In comparison, it has been found that the electrical resistivity is about two digits higher. Therefore, according to the present invention, it was found that problems such as eddy current loss can be solved.
In addition, in view of the results of Examples 1 to 7 and Comparative Examples 1 to 5, the electrical resistivity of the present magnetic powders of Examples 1 to 6 is higher than that of the conventional general metal-based magnetic material 1 From the fact that it can be inferred to have a value of 5 μΩm or more, it was found that according to the present magnetic powder, it is possible to solve problems such as eddy current loss.
Incidentally, the first phase and the second phase in the present magnetic powder of the above Examples 1 to 7 from the observation results by the FE-SEM / EDX method suitable for knowing the presence and the degree of disproportionation in this example. The phase is not derived respectively from the main raw material phase and the auxiliary raw material phase of the raw material ferrite powder, and the homogeneous raw material ferrite phase is a phase separation caused by the disproportionation reaction by the reduction reaction. all right.

According to the magnetic material of the present invention, the conventional magnetic material has contradictory characteristics, high saturation magnetization, high electric resistivity, and can solve the problem of eddy current loss, and requires complicated processes such as lamination process. It is possible to provide a magnetic material having excellent electromagnetic properties combining the advantages of both metal-based materials and oxides, as well as a magnetic material having stable magnetic properties even in air.
The present invention further includes various actuators such as transformers, heads, inductors, reactors, cores (magnetic cores), yokes, magnet switches, choke coils, noise filters, ballasts, etc. mainly used for power equipment, transformers, and information communication related equipment. , Voice coil motors, induction motors, motors for rotary machines such as reactance motors, and linear motors, especially for automobile drive motors and generators exceeding 400 rpm, machine tools, various generators, various industrial machines such as various pumps The present invention relates to a soft magnetic material used for a rotor, a stator, and the like of a motor for a home electric appliance such as a motor, an air conditioner, a refrigerator, and a vacuum cleaner.
Further, the present invention relates to a soft magnetic material used for sensors via a magnetic field such as an antenna, a microwave element, a magnetostrictive element, a magnetoacoustic element, a Hall element, a magnetic sensor, a current sensor, a rotation sensor, and an electronic compass.
In addition, detection of relays such as monostable and bistable electromagnetic relays, torque limiters, relay switches, switches such as solenoid valves, rotating machines such as hysteresis motors, stabilization couplings with functions such as brakes, magnetic fields and rotational speeds etc. The invention relates to a semi-hard magnetic material used for magnetic recording media such as sensors, magnetic tags, biases such as spin valve elements, tape recorders, VTRs, hard disks, etc.
In addition, high-frequency transformers and reactors, as well as electromagnetic noise absorbing materials, magnetic materials that suppress obstacles due to unnecessary electromagnetic interference such as electromagnetic wave absorbing materials and magnetic shielding materials, materials for inductor elements such as inductors for noise removal, RFID ( (Radio Frequency Identification) It is used for soft magnetic or semi-hard magnetic materials for high frequency such as tag materials and noise filter materials.

Claims (22)

FM component (here, FM component is a ferromagnetic component containing Fe and is Ni and / or Co) and M component (where M component is Zr, Hf, V, Nb, Ta, Cr) A first phase having a bcc structure crystal containing any one or more of Mo, W, Cu, Zn, and Si);
The content (atomic%) of the M component when the sum of the FM component and the M component contained in the phase is 100 atomic%, which is the phase containing the M component, is the FM component and the M contained in the first phase Including a second phase that is higher than the content (atomic%) of the M component when the total of the components is 100 atomic%
Soft magnetic or semi-hard magnetic material.   The magnetic material according to claim 1, wherein the magnetic material is soft magnetic.   The amount of Fe (atomic%) in the FM component and the amount of Ni and / or Co (atomic%) in the first phase are 50.01 atomic%, assuming that the total of all the components constituting the FM component is 100 atomic%. The magnetic material according to claim 1 or 2, wherein the content is at least 99.999 atomic percent and at least 0.001 atomic percent to 49.99 atomic percent. The first phase is FM _100-x M _x (where x is an atomic percentage 0.001 ≦ x ≦ 33.33, FM is a ferromagnetic component containing Fe and containing Ni and / or Co) And M is any one or more of Zr, Hf, V, Nb, Ta, Cr, Mo, W, Cu, Zn, and Si). The magnetic material according to any one of 3.   When the sum total of the content (atomic%) of the FM component and the M component in the whole magnetic material is 100 atomic%, the content (atomic%) of Ni and / or Co in the magnetic material is the M component. The magnetic material according to claim 3 or 4, wherein the content is (atomic%) or less. First _{phase, FM 100-x (M 100} -y TM y) x / 100 ( where, x, y is an 0.001 ≦ x ≦ 33.33,0.001 ≦ y < 50 atomic percent , FM is a ferromagnetic component containing Fe and containing Ni and / or Co, M is any one of Zr, Hf, V, Nb, Ta, Cr, Mo, W, Cu, Zn and Si The magnetic material according to any one of claims 1 to 5, which has the composition represented by the following composition formula: TM is any one or more of Ti and Mn. When the second phase has a bcc structure crystal containing an FM component and an M component, and the sum of the FM component and the M component contained in the phase is 100 atomic%, the M component content (atomic%) is 1.5 times to 10 ⁵ times or less the content (atomic%) of the M component when the total of the FM component and the M component contained in the first phase is 100 atomic%, and / or 2 atoms The magnetic material according to any one of claims 1 to 6, wherein the amount is in the range of% to 100 at%. The content of Ni and / or Co when the second phase has a bcc structure crystal containing an FM component and an M component, and the total of the FM component and the M component contained in the phase is 100 atomic% (atom 10 ⁻⁵ times or more and less than 0.909 times the content of Ni and / or Co when the sum of the FM component and the M component contained in the first phase is 100 atomic% or The magnetic material according to any one of claims 1 to 7, wherein the amount is 1.1 times or more and 10 ⁵ times or less.   The magnetic material according to any one of claims 1 to 8, wherein the second phase comprises an oxide phase containing an M component.   The magnetic material according to any one of claims 1 to 9, wherein the second phase contains at least one of M-ferrite phase and wustite phase.   The magnetic material according to any one of claims 1 to 10, wherein a volume fraction of a phase having a bcc structure crystal containing an FM component and an M component is 5% by volume or more of the entire magnetic material.   With respect to the composition of the whole magnetic material, the FM component is 20 atomic% or more and 99.998 atomic% or less, the M component is 0.001 atomic% or more and 50 atomic% or less, and the O component is 0.001 atomic% or more and 55 atomic% or less The magnetic material according to claim 9 or 10, having a composition in the range of   The magnetic material according to any one of claims 1 to 12, wherein an average crystal grain size of the first phase or the second phase or the entire magnetic material is 1 nm or more and less than 10 μm. At least a first phase is FM _{100 -x} M _x (where x is an atomic percentage 0.001 ≦ x ≦ 33.33, FM contains Fe and is a ferromagnetic component containing Ni and / or Co M is a bcc phase represented by the composition formula of Zr, Hf, V, Nb, Ta, Cr, Mo, W, Cu, Zn, Si) The magnetic material according to any one of claims 1 to 13, wherein the crystallite size of the bcc phase is 1 nm or more and 100 nm or less. At least the first phase is FM _{100 -x} M _x (where x is an atomic percentage, 0.001 ≦ x ≦ 1, FM is a ferromagnetic component containing Fe and containing Ni and / or Co, M has a bcc phase represented by a composition formula of Zr, Hf, V, Nb, Ta, Cr, Mo, W, Cu, Zn, Si), and the bcc phase The magnetic material according to any one of claims 1 to 13, wherein the crystallite size is 1 nm or more and 200 nm or less.   A magnetic material in the form of powder, having an average powder particle size of 10 nm or more and 5 mm or less in the case of a soft magnetic magnetic material, and an average of 10 nm or more and 10 μm or less in the case of a semihard magnetic material The magnetic material according to any one of claims 1 to 15, having a powder particle size.   The magnetic material according to any one of claims 1 to 16, wherein at least one phase of the first phase or the second phase is ferromagnetically coupled to the adjacent phase.   18. The method according to any one of claims 1 to 17, wherein the first phase and the second phase are directly or continuously bonded via the metal phase or the inorganic phase to form a block as a whole of the magnetic material. Magnetic material as described in.   The magnetic material according to claim 16 by reducing M-ferrite powder having an average powder particle size of 1 nm or more and less than 1 μm in a reducing gas containing hydrogen gas at a reduction temperature of 400 ° C. or more and 1500 ° C. or less. How to manufacture.   An M-ferrite powder having an average powder particle size of 1 nm or more and less than 1 μm is reduced in a reducing gas containing hydrogen gas to generate a first phase and a second phase by disproportionation reaction. The method of manufacturing the magnetic material as described in any one of 1-17.   A method of producing a magnetic material according to claim 18, by sintering a magnetic material produced by the method according to claim 19 or 20.   After the reduction step in the production method according to claim 19, or after the reduction step or production step in the production method according to claim 20, or after the sintering step in the production method according to claim 21, at least once. A method of producing a soft magnetic or semi-hard magnetic material which is annealed.