JP2013102122A - Magnetic member and manufacturing method for magnetic member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic member that has excellent magnetic properties and is suitable for being used as a permanent magnet material, and to provide a manufacturing method for the magnetic member.SOLUTION: A magnetic member 1 comprises a surrounding phase 11 in which a Fe-based magnetic phase 10 of a minor axis of 100 nm or less is dispersed and which includes an MA-Fe oxide 12 containing MA and Fe, where MA is an element containing at least one element selected from Ca, Sr, Ba and Y. The magnetic member 1 is obtained as follows. From a solution alloy 30 prepared by a solution treatment of a raw material alloy including MA and Fe, a deposited phase 42 containing at least MA and Fe is deposited. Then, a parent phase 41 of a deposited alloy 40 is separated into the Fe-based magnetic phase 10 and an X alloy phase 51, where X is an element containing at least one element selected from Al, Ni and Co. Finally, an oxidation treatment is performed on a phase separation material 50 containing the Fe-based magnetic phase 10 and the deposited phase 42 to form the MA-Fe oxide 12 from the deposited phase 42. The magnetic member 1 becomes excellent in magnetic properties by surrounding the Fe-based magnetic phase 10 with the MA-Fe oxide 12 as a ferrite magnet component, in addition to the Fe-based magnetic phase 10.

Description

  The present invention relates to a magnetic member suitable for a magnet material such as a permanent magnet, and a manufacturing method thereof. In particular, the present invention relates to a magnetic member having excellent magnetic properties and a method for manufacturing the same.

  As permanent magnets used for motors and generators, metal magnets made of metal materials such as Fe-Al-Ni-Co alloys and Fe-Cr-Co alloys, typically described in Patent Document 1. The so-called alnico magnets and ferrite magnets mainly composed of iron oxide are widely used. Further, rare earth magnets containing rare earth elements such as Nd (neodymium) and Sm (samarium) are used as permanent magnets that are particularly excellent in magnetic properties.

  Fig. 3 shows a typical manufacturing process for metal magnets such as alnico magnets. After melting and casting a raw material alloy such as an Fe-Al-Ni-Co alloy and subjecting the obtained ingot 100 to solution treatment, a ferromagnetic phase 120 mainly composed of a ferromagnetic material such as FeCo, and an AlNi phase The magnet 400 is obtained by performing two-phase separation (spinodal decomposition) with the nonmagnetic phase 130 mainly composed of such a weak magnetic material (or nonmagnetic material). The ferromagnetic phase 120 is typically an elongated rod-like single domain particle, more specifically, a nanometer order of a short diameter (width) of several nanometers to several tens of nanometers, and a long diameter (length in the longitudinal direction) of several μm. It is excellent in magnetic properties due to shape magnetic anisotropy by forming very elongated particles such as micro order of about tens of μm. The nonmagnetic phase 130 is interposed so that no magnetic interaction occurs between the adjacent ferromagnetic phases 120.

Japanese Patent Laid-Open No. 10-280011

  Rare earth magnets have excellent magnetic properties, but contain rare elements such as Sm and Nd in the magnetic phase. In recent years, the use of rare earth elements such as Sm and Nd is desired to be reduced in view of the inferior stability of resource procurement and the instability of price fluctuations. In addition, rare earth magnets have a large change in magnetic characteristics with respect to temperature.

  Ferrite magnets and alnico magnets have a relatively excellent resource aspect, such as Fe, as the main element of the magnetic phase. However, ferrite magnets are one of the magnetic properties desired for permanent magnets: although coercivity is somewhat high, another one: saturation magnetization and remanent magnetization are very low compared to rare earth magnets, making them suitable for high-performance applications Difficult to do.

  Metal-based magnets such as alnico magnets are very excellent in temperature stability and have higher saturation magnetization and residual magnetization than ferrite magnets. However, for example, in the Alnico magnet, the crystal anisotropic magnetic field of the FeCo alloy (ferromagnetic phase) itself, which is the main phase, is low. Therefore, the expression of the coercive force of the alnico magnet is mainly due to the shape magnetic anisotropy caused by the shape whose short axis is nano-order, and the alnico magnet has a relatively low coercive force. In addition, the Alnico magnet contains a nonmagnetic component such as AlNi in an amount of about 40 atomic%, so that the saturation magnetization and the residual magnetization are low as compared with the rare earth magnet.

  Accordingly, one of the objects of the present invention is to provide a magnetic member having excellent magnetic properties. Another object of the present invention is to provide a method for producing a magnetic member capable of producing a magnetic member having excellent magnetic properties with high productivity.

  The present inventors have studied a configuration for improving magnetic properties for a metal-based magnet having a ferromagnetic phase containing Fe, such as FeCo. A metal-based magnet has a low magnetic property by containing a large amount of weak magnetic material as described above. Therefore, the present invention proposes that at least a part of the weak magnetic material is a magnetic material, and particularly contains an iron oxide such as a ferrite magnet component.

  The magnetic member of the present invention is composed of an Fe-based magnetic phase mainly composed of Fe and an ambient phase surrounding the Fe-based magnetic phase. The Fe-based magnetic phase has a minor axis of 100 nm or less. The surrounding phase contains MA-Fe oxide containing MA and Fe, where MA is one or more elements selected from Ca, Sr, Ba and Y.

  The magnetic member of the present invention is made of a ferromagnetic material and contains an MA-Fe oxide such as barium ferrite or strontium ferrite around the nano-order Fe-based magnetic phase. With this configuration, the magnetic member of the present invention can have both characteristics of a conventional metal magnet such as an alnico magnet, that is, high saturation magnetization and residual magnetization, and characteristics of a ferrite magnet, that is, high coercive force. . Therefore, the magnetic member of the present invention has high saturation magnetization, residual magnetization, and coercive force without using rare elements such as Sm and Nd, or while reducing the amount of rare elements used. It can utilize suitably for the material of.

  As one form of the magnetic member of the present invention, the Fe-based magnetic phase is at least one of a Fe phase substantially composed of Fe and a FeCo phase containing 50% by mass or less of Co, and the surrounding phase is Al and Examples include an AlNi-based alloy containing Ni as a main element and the MA-Fe oxide, and the MA-Fe oxide contains MA, Fe, and Al.

  The above-mentioned form can be manufactured by a manufacturing method including a process similar to the manufacturing process of a conventional metal magnet in which a phase separation treatment is performed after solution of a raw material alloy, for example. Because it can be mass-produced, it is excellent in productivity.

  As an embodiment of the magnetic member of the present invention, there is an embodiment in which the Fe-based magnetic phase is columnar and the major axis is 1000 nm or more.

  In the above embodiment, the aspect ratio of the Fe-based magnetic phase (ratio of minor axis to major axis: major axis / minor axis) is sufficiently large, and the magnetic properties are further improved by the shape magnetic anisotropy.

  As one form of the magnetic member of the present invention, the surrounding phase contains an AlNi-based alloy containing Al and Ni as main elements and the MA-Fe oxide, and the total atomic weight of Fe and Al in the surrounding phase Thus, a form in which the Fe content is more than 50 atomic% can be mentioned.

  In the above-mentioned form, not only the Fe-based magnetic phase but also Fe is sufficiently present in the surrounding phase. Since the Fe in the surrounding phase exists in the oxide and functions as a ferrite magnet component, the above form is excellent in magnetic properties.

  As one form of the magnetic member of the present invention, a form in which the total content of MA in the magnetic member is 3% by mass or more and 8% by mass or less can be given.

  In the above form, the element represented by MA is sufficiently present as a ferrite magnet component, and is excellent in magnetic properties.

A magnetic member having both the magnetic characteristics of a metal magnet such as an alnico magnet as described above and a ferrite magnet can be manufactured by the following manufacturing method using an alloy as a starting material, for example. The method for producing a magnetic member of the present invention includes the following preparation step, solution treatment step, precipitation step, separation step, and oxidation step (hereinafter, this production method may be referred to as production method (I)).
Preparatory process: MA, Fe, and X, where MA is one or more elements selected from Ca, Sr, Ba and Y, and X is one or more elements selected from Al, Ni and Co The process of preparing a raw material alloy.
Solution treatment step: a step of subjecting the raw material alloy to a solution treatment at a temperature not lower than 1000 ° C. and not higher than the liquidus temperature of the raw material alloy.
Precipitation step: From the solution-treated alloy subjected to the solution treatment, a MA-Fe precipitation phase containing at least MA and Fe is precipitated, and the MA-Fe is added to the Fe-X alloy containing Fe and X. A step of allowing an Fe precipitate phase to exist.
Separation step: a step of separating the Fe-X alloy into an Fe-based magnetic phase mainly composed of Fe and an X alloy phase mainly composed of X.
Oxidation step: a step of producing an MA-Fe oxide containing MA and Fe from the MA-Fe precipitated phase by subjecting the phase separation material that has undergone the separation step to oxidation treatment.

Moreover, the magnetic member which has both the magnetic characteristics of the above-mentioned metallic magnet and a ferrite magnet can be manufactured with the following manufacturing methods using a compound as a starting material. The method for producing a magnetic member of the present invention includes the following preparation step, sintering step, reduction step, precipitation step, separation step, and oxidation step (hereinafter, this production method may be referred to as production method (II)). ).
Preparatory step: When one or more elements selected from Ca, Sr, Ba and Y are MA, and one or more elements selected from Al, Ni and Co are X, a powder composed of a carbonate of MA A step of preparing a raw material powder obtained by mixing a powder composed of an oxide of X and a powder composed of an oxide of Fe.
Sintering step: A step of forming a sintered body made of a composite oxide containing MA, Fe, and X by pre-sintering the raw material powder and then performing main sintering.
Reduction step: a step of forming a base alloy containing MA, Fe, and X by subjecting the sintered body to a reduction treatment.
Precipitation step: a step of precipitating the MA-Fe precipitation phase containing at least MA and Fe from the base alloy and causing the MA-Fe precipitation phase to exist in the Fe-X alloy containing Fe and X.
Separation step: a step of separating the Fe-X alloy into an Fe-based magnetic phase mainly composed of Fe and an X alloy phase mainly composed of X.
Oxidation step: a step of producing an MA-Fe oxide containing MA and Fe from the MA-Fe precipitated phase by subjecting the phase separation material that has undergone the separation step to oxidation treatment.

  In the production method of the magnetic member of the present invention, in the case of the production method (I), in the case of the production method (II), a raw material alloy containing a specific element is used, and precipitates are deposited from the solution alloy obtained by solutionizing this raw material alloy. A composite oxide sintered body containing a plurality of elements is produced using a plurality of compound powders containing specific elements, and precipitates are deposited from a base alloy obtained by reducing the sintered body. Fe is present both in the precipitate and in the parent phase existing around the precipitate. That is, the method for producing a magnetic member of the present invention includes a step of forming a state in which both the precipitate and the parent phase existing around the precipitate contain Fe. In the method for producing a magnetic member of the present invention, the Fe-based magnetic phase is allowed to appear from the Fe-containing parent phase: Fe-X alloy, and the Fe-based magnetic phase and the precipitate: MA-Fe precipitated phase are provided. The material is oxidized to produce the MA-Fe oxide from the MA-Fe precipitate phase. The manufacturing method of the magnetic member of the present invention: The manufacturing method (I) uses a raw material alloy containing a specific element, and is similar to the manufacturing process of a conventional metal magnet: In addition to the process of phase separation after solution treatment By providing a precipitation process and an oxidation process, magnetic members containing MA-Fe oxides such as barium ferrite and strontium ferrite around the Fe-based magnetic phase made of nano-order ferromagnetic materials can be produced with high productivity. Can be manufactured. Manufacturing method of magnetic member of the present invention: The manufacturing method (II) is a process in which a base alloy obtained by reducing a composite oxide containing a specific element is manufactured and phase separation is performed in the same manner as in the manufacturing process of a conventional metal magnet. In addition, by providing a precipitation process and an oxidation process, magnetic members containing MA-Fe oxides such as barium ferrite and strontium ferrite are produced around the Fe-based magnetic phase composed of nano-order ferromagnetic materials. It can be manufactured with good performance. In the method for producing a magnetic member of the present invention, the Fe-based magnetic phase is at least one of an Fe phase and an FeCo phase, and an AlNi-based alloy and the MA-Fe oxide phase are included around the Fe-based magnetic phase. It can utilize suitably for manufacture.

  In particular, in the production method (II), since the vapor pressure is higher than that of Fe such as Ca, Ba, and Sr and a metal that is easily volatilized is handled in a compound state, the amount of MA added can be easily controlled. Specifically, in the production method (II), a predetermined amount of MA is converted into a complex oxide without controlling the pressure in the melting furnace to prevent volatilization or setting an addition amount with the expectation of volatile matter. It is contained stably and accurately. Further, in the production method (II), Ca and the like are not volatilized and the melting furnace is not contaminated. Furthermore, in the production method (II), by using MA carbonate as the MA compound, it can be handled even in an air atmosphere and is excellent in workability, and can be easily changed to an oxide in the sintering process. Industrial mass production of magnetic members can be performed satisfactorily. In addition, in the production method (II), by performing preliminary sintering, the carbonate can be changed to oxide once after being changed into oxide. Can be manufactured. Furthermore, in the production method (II), the above-mentioned specific magnetic member can be satisfactorily produced not only when the amount of MA added is small but also when it is large (for example, more than 5% by mass).

  As one form of manufacturing method (I), the form which includes the said precipitation process and the said separation process in the cooling process of the said solution treatment process is mentioned. In the cooling process, the MA-Fe precipitation phase is precipitated by cooling at a cooling rate of 5 ° C / sec or less to the lower limit temperature of the precipitation temperature range of the MA-Fe phase in the solution alloy, and the remaining Fe- In the phase separation temperature region of the X alloy, the Fe-based magnetic phase and the X alloy phase are phase-separated by cooling at a cooling rate of 0.05 ° C./sec or more and less than 5 ° C./sec.

  In the above embodiment, since the precipitation step and the separation step are performed in the cooling process from the heating temperature at the time of the solution treatment, heating may be performed once and the productivity is improved. In the above-mentioned form, the MA-Fe precipitation phase can be sufficiently precipitated by controlling the temperature lowering rate during precipitation to a specific range and gradually cooling, leaving the element represented by MA in the Fe-X alloy. hard. In addition, the above-described form sufficiently controls the temperature drop rate during the subsequent phase separation of the Fe-X alloy to a specific range and gradually cools, thereby sufficiently dispersing the dispersed phase (Fe-based magnetic phase) and the X alloy phase. In addition, it can be separated so as to form a fine structure to suppress the inclusion of non-magnetic components such as Al in the dispersed phase, and the deterioration of magnetic properties due to the presence of the dispersed phase containing Al can be suppressed. .

  As one form of manufacturing method (I), the said preparation process WHEREIN: The form which prepares the powder compact which shape | molded the powder which consists of the said raw material alloy is mentioned.

  In the above-described form, the degree of freedom in shape can be increased, and in the oxidation process, the particles constituting the powder compact can be used as an oxygen supply path, and compared with the case of using a cast material (ingot). A thing can be produced | generated efficiently.

  As one form of manufacturing method (II), the form which includes the said precipitation process and the said separation process in the cooling process of the said reduction | restoration process is mentioned. In the cooling process, the MA-Fe precipitated phase is precipitated by cooling the MA-Fe phase in the base alloy to the lower limit temperature of the precipitation temperature range at a rate of 5 ° C / sec or less. Then, the Fe-based magnetic phase and the X alloy phase are phase-separated by cooling at a temperature drop rate of 0.05 ° C./sec or more and less than 5 ° C./sec.

  The above form also has the same effect as the form in which precipitation and phase separation are performed in the cooling process of the solution treatment step in the production method (I). Specifically, (1) the number of heating times can be reduced and the productivity is excellent, (2) the MA-Fe phase can be sufficiently precipitated, and (3) the dispersed phase and the X alloy can be sufficiently separated.

  As one form of the manufacturing method of the magnetic member of this invention, the form performed by applying the magnetic field of 2T or more in the said isolation | separation process is mentioned.

  In the above embodiment, since the major axis of the Fe-based magnetic phase can be made sufficiently long and the aspect ratio can be made into a columnar shape, a magnetic member having excellent magnetic properties due to shape magnetic anisotropy can be obtained.

  As one form of the method for producing a magnetic member of the present invention, the oxidation treatment is a heat treatment in an atmosphere containing oxygen, and in the oxidation step, the phase separation material is applied with a hydrostatic pressure of 100 MPa or more, or uniaxial The form which performs the said oxidation process in the state accommodated in the metal mold | die which can be pressurized, and is pressurized is mentioned.

  The said form makes it easy to perform industrial mass production by making oxidation treatment into heat processing, and is excellent in productivity. And the said form can absorb the volume expansion by the production | generation of an oxide by the deformation | transformation of a Fe-based magnetic phase, etc. by producing | generating an oxide in the state which applied the stress to the phase-separation raw material. Therefore, the said form cannot produce the crack by expansion | swelling etc. easily, and can manufacture the magnetic member excellent in dimensional accuracy and an external appearance with sufficient productivity.

  The magnetic member of the present invention is excellent in magnetic properties. The method for producing a magnetic member of the present invention can produce a magnetic member having excellent magnetic properties with high productivity.

It is explanatory drawing which shows an example of the magnetic member of this invention, and process explanatory drawing of the manufacturing method (manufacturing method (I)) of the magnetic member of this invention. It is explanatory drawing which shows an example of the magnetic member of this invention, and process explanatory drawing of the manufacturing method (manufacturing method (II)) of the magnetic member of this invention. It is process explanatory drawing which shows typically the process of manufacturing the conventional alnico magnet.

Hereinafter, the present invention will be described in more detail.
[Magnetic member]
(Overall composition and organization)
The magnetic member of the present invention is composed of a composition containing Fe, one or more elements selected from MA: Ca, Sr, Ba and Y, and O (oxygen), and a plurality of elements in the surrounding phase. It is composed of a structure in which a nano-order dispersed phase is dispersed. The metal element, which is the main constituent element of the magnetic member of the present invention, depends on the raw material used for production. The magnetic member of the present invention is characterized by containing Fe in both the dispersed phase and the surrounding phase, and containing Fe in the surrounding phase as MA-Fe oxide containing MA.

  The higher the total content of MA in the magnetic member, the more MA-Fe oxide can be contained. When the content is 3% by mass or more, the effect of improving the magnetic properties due to the inclusion of MA-Fe oxide is sufficient. Can be played. However, when manufacturing the magnetic member of the present invention having a large total content of MA using the manufacturing method (I) using an alloy for the above-mentioned raw material, using an alloy having a large total content of MA as a raw material, The following points are a concern. (1) The amount of volatilization during dissolution increases. (2) The furnace is easily contaminated. (3) When a compound containing MA and X (e.g., Ca-Al compound) is cooled and solidified from a high-temperature molten state (e.g., during cooling in the solution treatment step), the final In this case, the MA-Fe-O phase is not produced or is hardly produced, and there is a possibility that an MA oxide not containing Fe is produced. (4) By using X for the above-mentioned compound, spinodal decomposition does not occur sufficiently in the separation step, and there is a possibility that the Fe-based magnetic phase cannot be generated sufficiently. For these reasons, since the magnetic properties are deteriorated, the total content of MA is preferably 5% by mass or less when the above production method (I) is used. On the other hand, when the production method (II) using the compound powder as the raw material is used, the formation of the unnecessary compound (compound containing MA and X) can be suppressed because there is no cooling step from a high temperature melting state. Therefore, when the production method (II) is used, the magnetic member of the present invention can be produced over a wide range from the case where the amount of MA is small to the large amount. However, if a material having too much total MA content is used, in addition to the MA-Fe oxide in the oxidation step, an oxide of MA inferior in magnetic properties is easily generated. Therefore, even when the above production method (II) is used, the total content of MA is preferably 8% by mass or less.

  The magnetic member of the present invention allows the inclusion of inevitable impurities. As for content of an unavoidable impurity, 1 mass% or less is mentioned, for example. Inevitable impurities include, for example, the lubricant used at the time of manufacture (when using a powder molded body, the lubricant mixed in the powder molded body, the lubricant applied to the molding die, or the ingot, when using the ingot. And compounds derived from the applied lubricant) (BN (boron nitride), MoS (molybdenum sulfide), etc.).

(Dispersed phase)
The dispersed phase is an Fe-based magnetic phase composed of a ferromagnetic material containing Fe. Specifically, an Fe phase substantially composed of Fe (Fe: 80 mass% or more and inevitable impurities), FeCo phase containing Fe in a range of more than 0 mass% and 50 mass% or less together with Fe, Fe, Co And FeCoNi phase containing Ni. The saturation magnetization of FeCo is about 2.3T to 2.4T, higher than about Fe: 2T, and the form containing the FeCo phase is more excellent in magnetic properties. The Co content in the FeCo phase is more preferably 25% by mass or more and 50% by mass or less. Other, Fe group magnetic phase, alpha "iron nitride phase containing Fe ₁₆ N ₂ and the like. Iron nitride nitrogen interstitial α" Fe ₁₆ N ₂ (tetragonal, a = 5.72Å, c = 6.29 mm, crystal symbol: I4 / mmm) has been reported in principle calculations and thin film experiments, etc., which are very excellent in magnetic properties, especially with a large saturation magnetization of 2.3 T to 2.8 T Yes. Therefore, the form containing α ″ Fe ₁₆ N ₂ phase has higher saturation magnetization and remanent magnetization and further excellent magnetic properties. Dispersion phase: Fe-based magnetic phase includes Fe phase, FeCo phase, FeCoNi phase and α ” form containing one selected from Fe ₁₆ N ₂ phase, or may be in a form containing two or more. The Fe phase, FeCo phase, FeCoNi phase, and α ″ Fe ₁₆ N ₂ phase can all be confirmed to be ferromagnetic from their compositions.

  The shape of the Fe-based magnetic phase may be columnar (bar-shaped) or granular, and can be changed depending on the production conditions. The minor axis of the Fe-based magnetic phase refers to a columnar shape: the length of the short side, and a granular shape: the maximum diameter. When the minor axis is nano-order such as 100 nm or less, preferably 50 nm or less, the single domain structure can be stabilized and the magnetic properties are excellent. Further, when the minor axis is 10 nm or more, and further 20 nm or more, (1) it is possible to prevent a decrease in ferromagnetism due to the occurrence of a phenomenon (superparamagnetism) in which spontaneous magnetization disappears due to fluctuations in electron motion due to heat, (2) The effect is that the Fe-based magnetic phase is sufficiently present with respect to the surrounding phase and the magnetic properties are excellent. When the Fe-based magnetic phase is columnar, the magnetic properties are superior to the granular case due to shape magnetic anisotropy. In the case of a columnar shape, the aspect ratio (major axis / minor axis) becomes sufficiently large when the major axis is large, specifically, 1000 nm or more, and further 1200 nm or more. The larger the aspect ratio, the better the magnetic properties due to the shape magnetic anisotropy. Therefore, the aspect ratio is preferably 20 or more.

  The content of the Fe-based magnetic phase in the magnetic member is about 45% to 70% by volume, preferably about 60% to 70% by volume. In this case, the Fe-based magnetic phase is sufficiently present, and the surrounding phases can be interposed so that the magnetic effects of the Fe-based magnetic phases do not affect each other. The distance between adjacent Fe-based magnetic phases is preferably 5 nm or more, more preferably 10 nm or more, and if it is about 30 nm or less, a small magnetic member can be obtained. The distance between the Fe-based magnetic phases is the average distance along the minor axis direction of the Fe-based magnetic phase between the adjacent Fe-based magnetic phases in the columnar form described above, and is the most in the adjacent Fe-based magnetic phase in the granular form. The distance between adjacent points.

(Ambient phase)
In the magnetic member of the present invention, the Fe-based magnetic phase functions as a soft magnetic material of a nanocomposite magnet (exchange spring magnet), and the MA-Fe oxide in the surrounding phase functions as a hard magnetic material, which makes it extremely powerful. Can be a good magnet. The greater the content ratio of MA-Fe oxide in the surrounding phase, the better the magnetic properties. Therefore, it is preferable to contain 33% by volume or more of MA-Fe oxide with respect to the entire surrounding phase. A form in which the entire surrounding phase is substantially composed of MA-Fe oxide, that is, a magnetic member substantially composed of an Fe-based magnetic phase and MA-Fe oxide has the best magnetic properties.

The content of the MA-Fe oxide constituting the surrounding phase and the composition of the phase other than the MA-Fe oxide vary depending on the production conditions. For example, when using a manufacturing method including the above-described precipitation step, separation step, and oxidation step, the composition of the surrounding phase can be changed depending on the composition of the raw material to be prepared and the manufacturing conditions, and the surrounding phase is added to the MA-Fe oxide. AlNi-based alloys (for example, alloys in which the proportion of AlNi in the alloy is 80 atomic% or more, further 90 atomic% or more and the balance is made of inevitable impurities), oxides containing the element represented by the above X ( For example, NiO or the like may be included. Or, for example, nano iron powder, or coating of MA-Fe oxide around the α "Fe ₁₆ N ₂ powder produced from nano iron powder by sol-gel method, etc., and press molding this powder to produce a magnetic member Then, it can be set as the form from which the surrounding phase comprised only the MA-Fe oxide substantially.

  If the MA-Fe oxide contained in the surrounding phase is an oxide containing Ba or Sr, this form is more excellent in magnetic properties because the surrounding phase contains a barium ferrite component or a strontium ferrite component. The form in which the MA-Fe oxide contained in the surrounding phase is an oxide containing Ca is, for example, an alloy containing Ca as a raw material, and a manufacturing method including a precipitation step after the above-mentioned solution treatment: a manufacturing method ( I) and a production method comprising a precipitation step after reducing the sintered body described above using a carbonate powder containing Ca as a raw material: Since a magnetic member can be produced by the production method (II), productivity It is excellent and preferable. When the MA-Fe oxide contained in the surrounding phase is an oxide containing Y, yttrium garnet with large magnetocrystalline anisotropy can be formed, and the magnetic anisotropy of the ferromagnetic phase: Fe-based magnetic phase can be enhanced. Thus, the coercive force can be increased.

  When the MA-Fe oxide further contains rare earth elements such as La (excluding Y) in addition to MA and Fe, the magnetic properties are further improved. However, in order to reduce the amount of rare earth elements used, the content of rare earth elements (excluding Y) in the MA-Fe oxide should be equal to or less than the MA content in this MA-Fe oxide. Is preferred. In addition, examples of the MA-Fe oxide include Al, Ni, Mn, Ti, and Cu.

The MA-Fe oxide preferably has excellent magnetic properties when the constituent element is MA-Fe-O or La-MA-Fe-O. MA-Fe oxide is represented by MA (Fe, x) ₁₂ O ₁₉ , MA (Fe, x) ₁₈ O ₂₇ , MA ₃ (Fe, x) ₅ O ₁₂ , MA (Fe, x) ₂ O ₄ (When x includes La, Al, Ni, Mn, Ti, and Cu described above, these elements are used), and preferably contains at least one MA-Fe oxide. In particular, it is preferable that MA (Fe, x) ₁₂ O ₁₉ and MA ₃ (Fe, x) ₅ O ₁₂ are included because of excellent magnetic properties. The atomic ratio of the constituent elements of the MA-Fe oxide can be adjusted by, for example, the content of each element constituting the alloy used as a raw material and the amount of compound powder containing each element, and a desired atomic ratio (for example, The composition of the raw material alloy may be adjusted so that MA (Fe, x) ₁₂ O ₁₉ and MA ₃ (Fe, x) ₅ O ₁₂ ) can be generated.

  In a form in which the surrounding phase contains an AlNi-based alloy phase in addition to the MA-Fe oxide, if there is too much Al, which is a nonmagnetic element, the magnetic properties will be reduced, so the total of Fe and Al in the surrounding phase The Fe content is preferably more than 50 atomic%, more preferably 55 atomic% or more, and particularly preferably 60 atomic% or more with respect to the atomic weight. The atomic ratio of Fe and Al in the surrounding phase can be adjusted by, for example, the composition of the alloy used for the raw material and the phase separation conditions as described above. In addition, when the total content of MA such as Ca is high (preferably, the total content is 5% by mass or more), it is easy to produce MA-Fe oxide, so the Fe content in the surrounding phase is increased. It tends to be. Therefore, the atomic ratio of Fe or Al in the surrounding phase can be adjusted by the total content of MA.

  Measurement and confirmation of the composition, shape and size of the Fe-based magnetic phase and the composition of the surrounding phase include, for example, taking a cross-section of a magnetic member, and a transmission electron microscope of this cross-section: TEM image and peak intensity of X-ray diffraction (peak Area) etc. can be used. In addition, for the analysis of the composition, energy dispersive X-ray spectroscopy: EDX can be used.

(Magnetic properties)
The magnetic member of the present invention is excellent in magnetic properties, and particularly has high saturation magnetization, residual magnetization, coercive force, and maximum energy product. For example, there is an embodiment in which the residual magnetization Br is 1 T or more, the coercive force Hc is 150 kA / m or more (further 180 kA / m or more), and the maximum energy product (BH) max is 50 kJ / m ³ or more.

[Method of manufacturing magnetic member]
In the production of the magnetic member of the present invention, as in the conventional method for producing a metal-based magnet such as an alnico magnet, the solution comprises a solution treatment step and a separation step, and further comprises a precipitation step and an oxidation step (I): dissolution method Alternatively, the production method (II): reduction method in which precipitation, separation, and oxidation are sequentially performed on an alloy obtained by reducing a composite oxide produced using a plurality of kinds of compound powders can be suitably used. Hereinafter, the preparation process (I) preparation step, solution treatment process, preparation process (II) preparation process, sintering process, and reduction process will be described in detail. Since the steps after the precipitation step overlap in the production method (I) and the production method (II), they will be described together.

(Production method (I): Preparation process)
An alloy having a composition capable of generating a desired Fe-based magnetic phase and an ambient phase containing MA-Fe oxide as a raw material alloy, specifically, selected from Fe, MA: Ca, Sr, Ba and Y An iron alloy containing at least one element is prepared. When an iron alloy containing about 40% to 55% by mass of Fe is used as a raw material, a magnetic member containing about 45% to 70% by volume of an Fe-based magnetic phase can be produced. If the total content of MA in the raw material alloy is 3% by mass or more and 5% by mass or less as described above, it is possible to suppress contamination in the furnace due to MA volatilization in the preparation process, and in the precipitation process described later, MA- It is preferable because the Fe precipitation phase can be sufficiently precipitated, spinodal decomposition can be sufficiently performed in the separation step described later, and MA-Fe oxide can be sufficiently generated in the oxidation step described later. Furthermore, by using a Fe-MA-X alloy containing at least one element selected from X: Al, Ni and Co as a raw material, it is possible to improve the precipitate containing Fe in the precipitation step described later. It can be deposited. As for total content of X, 40 mass%-about 50 mass% are mentioned, for example. In addition, if the alloy contains one or more elements selected from Cu, Nb, Ti, and Mn in a total amount of 5% by mass or less, the Fe content in the Fe-based magnetic phase is increased. And the magnetic properties can be improved by the effect of miniaturizing and stabilizing the Fe-based magnetic phase.

  The raw material alloy has a high degree of freedom in shape when a powder formed body obtained by forming a powder made of this raw material alloy (hereinafter referred to as a raw material alloy powder) into a desired shape, and the oxidation treatment is a heat treatment in the oxidation step described later. In this case, oxidation can be efficiently performed between the particles as an oxygen supply path. This oxygen penetrates the grain boundaries of the crystals constituting the grains and penetrates into the raw material alloy. As the raw material alloy, a cast material (ingot) can be used.

  The raw material alloy powder can be obtained by, for example, pulverizing a molten cast ingot made of the above-mentioned raw material alloy or a foil-like body obtained by a rapid solidification method with a crushing device such as a jaw crusher, a jet mill or a ball mill, or using an atomizing method such as a gas atomizing method. Can be manufactured. In particular, use of the atomizing method is preferable because a powder having an average particle size of 10 μm to 500 μm can be produced with high productivity. You may further grind | pulverize the powder manufactured by the atomizing method so that it may become a desired magnitude | size. By appropriately changing the pulverization conditions and the production conditions, the particle size distribution of the powder and the shape of the particles can be adjusted. When the raw material alloy powder has an average particle size of 10 μm to 500 μm, particularly 50 μm to 200 μm, it is excellent in fluidity and can be easily filled into a molding die, and can be easily molded and used for mass production.

When the raw material alloy powder is configured to have an insulating coating made of an insulating material on the outer periphery of each particle constituting the alloy powder, a magnet having high electric resistance is obtained. For example, when this magnet is used in a motor, a vortex Current loss can be reduced. Insulating coatings include, for example, crystalline films of oxides such as Si, Al and Ti, amorphous glass films, ferrites such as y-Fe-O (metal elements such as y = Ba, Sr, Ni, and Mn), Examples thereof include a film made of a metal oxide such as magnetite (Fe ₃ O ₄ ), a resin such as a silicone resin, and an organic-inorganic hybrid compound such as a silsesquioxane compound. For the purpose of improving thermal conductivity, a Si-N or Si-C ceramic coating may be applied. The crystalline film, glass film, oxide film, ceramic film and the like may have an antioxidant function, and in this case, oxidation of particles can be prevented during molding. In the case of providing both the insulating coating and the ceramic coating, it is preferable to provide the insulating coating so as to contact the surface of the particles and to provide the ceramic coating thereon. When a powder having a coating such as an insulating coating is used, each particle constituting the powder is preferably nearly spherical in order to suppress damage to the coating during pressure molding. The insulating coating does not have to be dense as long as it exists to the extent that the particles can be insulated, and by not being dense, oxidation and nitriding (described later) can be sufficiently performed.

  As a raw material of the powder molded body, a mixed powder obtained by mixing components such as wax and resin that can be removed by heating or vaporizing in the process after the molding of the powder molded body is mixed with the raw material alloy powder. When the mixed powder is used, the friction between the molding die and the raw material alloy powder can be reduced by the wax or the like, or the insulation coating can be prevented from being damaged by the resin, and the moldability is excellent.

  Fill the raw material alloy powder (which may be the above-mentioned mixed powder) into a molding die of a desired shape, and press-mold at an appropriate pressure (for example, 0.5 GPa to 2.0 GPa) to obtain the desired shape The powder compact is obtained. As the pressure is increased, a powder molded body having a higher relative density tends to be obtained. For example, in the production method (I), it is preferable to mold the powder molded body so that the relative density is about 90% to 95%. In the production method (II) for sintering, the relative density of the powder compact may be adjusted so that the relative density after sintering is about 90% to 95%. The relative density of the powder compact is, for example, 50 % To about 55%. When the molding die is heated, it is possible to promote the deformability of the raw material alloy powder by heating and to reduce the pressure during molding. This molding may be performed in an air atmosphere, but in order to prevent oxidation of Fe and Al contained in the raw material alloy powder, a non-oxidizing atmosphere (for example, an inert atmosphere such as Ar) or a low oxygen atmosphere ( (Oxygen: vacuum atmosphere of 100 ppm by volume or less) is preferable. In this case, inhibition of spinodal decomposition due to the inclusion of oxide can be suppressed.

(Production method (I): Solution process)
The raw material alloy (powder compact or cast material) is subjected to a solution treatment to eliminate the concentration gradient (segregation) of each element and achieve homogenization. The heating temperature is higher than the temperature at which spinodal decomposition occurs. As the heating temperature is higher, segregation can be reduced. If the heating temperature is too high, a liquid phase is generated and the shape of the powder compact or cast material changes, which is not preferable. The conditions for the solution treatment can be appropriately selected according to the composition of the raw material alloy, and include heating temperature: 1000 ° C. to 1300 ° C., heating time: 10 minutes to 10 hours. The solution treatment is also preferably the above-described non-oxidizing atmosphere or low-oxygen atmosphere in order to prevent oxidation.

(Production method (II): preparation process)
In manufacturing method (II), simply speaking, by producing and reducing a composite oxide, an alloy similar to the alloy that has undergone the solution treatment step in manufacturing method (I) described above, that is, an Fe-based magnetic phase and MA-Fe An alloy having a composition capable of producing an ambient phase containing an oxide is obtained. In producing such a complex oxide, a plurality of kinds of compound powders are used. Specifically, a compound powder containing Fe, a compound powder containing one or more elements selected from MA: Ca, Sr, Ba and Y, and one or more elements selected from X: Al, Ni and Co. The contained compound powder is used. Any compound that can be sintered in an oxygen-containing atmosphere such as an air atmosphere to form a composite oxide can be used. Representative compounds include oxides, carbonates, hydroxides, and nitrates. In particular, the compound containing Fe and the compound containing X are preferably oxides. Fe oxides (Fe ₂ O ₃ ) and X oxides (for example, Al ₂ O ₃ , NiO, CoO, etc.) are all excellent in stability in the air atmosphere, making it easy to perform mixing operations, etc. In addition, complex oxides are easily generated and are easily available (commercially available products can be used). On the other hand, Ca, Sr, and Ba oxides are unstable in the air atmosphere and easily react with water to form hydrates and hydroxides. Although the oxide of Y is stable in the air atmosphere, it is too stable to form a complex oxide. On the other hand, carbonates of Ca, Sr, Ba, and Y are excellent in stability in the air atmosphere, and are easily available and easy to use, and also complex oxides are easily generated. Therefore, in view of industrial productivity, the MA compound is preferably a carbonate. When using the MA oxide, it is preferable to control the atmosphere so that it does not easily react with water or to dry before and after mixing.

  The compounding ratio of each compound powder is adjusted so that an alloy containing a desired amount of MA, Fe, and X can be obtained. In the production method (II), when many compound powders containing Fe and many compound powders containing MA are used, the Fe-based magnetic phase is contained in an amount of about 60% to 70% by volume as described above, and MA is used. A magnetic member containing a large amount of -Fe oxide can be produced. For example, when the total content of MA, Fe, and X in the raw material (hereinafter referred to as the main element total amount) is 100% by mass, the Fe content with respect to the main element total amount is 80% by mass or more, When the total content of MA with respect to the total amount of the main elements is 5% by mass or more, preferably 8% by mass or less, when the magnetic member is 100% by volume, the content of MA-Fe oxide: 15% by volume to 25% A magnetic member having excellent magnetic properties of about% volume% can be produced. When the total amount of main elements in the raw material is 100% by mass, the Fe content is about 40% by mass or more, and the total X content is, for example, about 8% by mass to 50% by mass. In addition, when a compound powder (for example, oxide powder) containing one or more elements selected from Cu, Nb, Ti, and Mn is used, the magnetic characteristics can be improved as in the above-described production method (I). As described above, the total content of Cu, Nb, Ti, and Mn is preferably 5% by mass or less with respect to the total amount of main elements in the raw material and the total amount of Cu, Nb, Ti, and Mn.

  Compound powders of various sizes can be used. Those having an average particle size of about 0.5 μm to 10 μm are easy to mix and use. Moreover, it is easy to mix each compound powder as an average particle diameter is comparable. For mixing, an appropriate apparatus such as a ball mill or a jet mill can be used.

(Production method (II): Sintering process)
A powder compact obtained by forming the mixed raw material powder into an appropriate shape is subjected to a heat treatment: a sintering treatment to obtain a composite oxide containing MA, Fe, and X: a sintered body. The powder compact can be obtained by filling a raw material powder into a molding die having a desired shape and press-molding it at an appropriate pressure (for example, about 0.1 MPa to 0.1 GPa). When the raw material powder is composed entirely of oxide, the composite oxide can be produced satisfactorily even by one sintering. On the other hand, when the raw material powder contains compounds other than oxides such as carbonates, hydroxides, and nitrates, heating produces gases such as CO ₂ and NOx, H ₂ O (water), etc. It becomes difficult to obtain a dense complex oxide because it contains gas or water, or voids are generated due to deaeration or evaporation. Therefore, when the raw material powder contains a compound other than an oxide, it is preferable to sinter in multiple steps. For example, when MA carbonate, Fe oxide, and X oxide are used as raw material powder, pre-sintering is performed, and CO ₂ is removed from the carbonate in this process to form an oxide. It is possible to generate a composite oxide by performing sintering (final sintering).

  When forming a sintered body consisting of complex oxides by conducting multiple times of sintering such as pre-sintering and main sintering, powder forming by grinding and re-molding the obtained sintered body It is preferable that the body is subjected to the following sintering, that is, a form in which sintering → pulverization → molding is repeated, so that a dense sintered body can be finally obtained. In this form, the shape of the powder compact before the final sintering can be any shape, and the powder compact before the final sintering is determined according to the shape of the magnetic member to be finally obtained, for example. The shape is preferable because a sintered body having a near net shape is obtained.

  The atmosphere of the sintering step is an atmosphere containing oxygen (preferably oxygen content: 5% by volume or more). In particular, an air atmosphere is preferable because it is easy to use. The heating temperature (sintering temperature) is about 800 ° C. to 1000 ° C. in the pre-sintering, about 900 ° C. to 1300 ° C. in the main sintering, and the holding time is 1 to 24 hours for both the pre-sintering and the main sintering. Degree.

(Production method (II): Reduction process)
The sintered body made of the composite oxide containing MA, Fe, and X is subjected to a reduction treatment, oxygen is removed from the composite oxide, and an alloy containing MA, Fe, and X: a base alloy is formed. The reducing process atmosphere typically includes a reducing gas atmosphere such as a hydrogen atmosphere or a mixed atmosphere of hydrogen and an inert gas such as argon or nitrogen. The heating temperature (reduction temperature) is about 600 ° C. to 800 ° C., and the holding time is about 1 hour to 12 hours. The reduction temperature is a temperature at which elements that are more volatile than Fe: Ca, Sr, Ba do not volatilize or are hard to volatilize, and the reduction treatment can be performed stably.

  The base alloy obtained by the reduction is a homogeneous alloy in which MA, Fe, and X are sufficiently dissolved in the same manner as the solution alloy in the production method (I). In particular, in the production method (II), the use of powder as a raw material makes it easier to obtain an alloy composed of homogeneous components as compared with a solution alloy obtained by subjecting a melt cast material to a solution treatment. In addition, since the base alloy is made of a sintered body obtained by sintering a powder compact, pores inevitably generated in the reduction process and the oxidation process described later can be used as a supply path for a reducing gas and oxygen. Oxidation can be performed efficiently. The base alloy can be subjected to the solution treatment described in the production method (I).

(Precipitation process)
The method for producing a magnetic member of the present invention includes a solution alloy subjected to a solution treatment (production method (I)) or a base alloy obtained by subjecting a composite oxide to a reduction treatment (production method (II)). One of the features is that it comprises a precipitation step of depositing a MA-Fe precipitation phase containing MA and Fe to form a precipitated alloy. The precipitation alloy has a structure in which an MA-Fe precipitation phase is dispersed in, for example, a crystal grain boundary or a triple point of the crystal grain boundary in an Fe-X alloy containing Fe and X. This step forms a structure containing Fe in both the precipitated phase and the parent phase. When using an alloy containing Al as an element represented by X as a raw material alloy or a compound used as a raw material, the precipitated phase should contain Al, that is, the precipitated phase should be composed of MA-Al-Fe. Allow. This precipitation can be performed by holding the solution alloy or base alloy in a precipitation temperature range (for example, about 850 ° C. to 950 ° C. or about 650 ° C. to 750 ° C., although depending on the composition of the solution alloy or base alloy). . For example, in the manufacturing method (I), when the cooling process from the heating temperature of the solution treatment is a rapid cooling in the solution treatment step (temperature decrease rate: over 5 ° C / sec), the solution alloy is heated again to the precipitation temperature range. After the precipitation temperature range is maintained, rapid cooling can be mentioned. Alternatively, in the production method (I), if the cooling process from the heating temperature of the solution treatment includes a precipitation step, that is, at least gradually cooling to the lower limit temperature of the precipitation temperature range to precipitate the precipitate: MA-Fe precipitate phase. Then, the solution treatment step and the precipitation step can be performed continuously, the number of heating times can be reduced, and the productivity is excellent. The slow cooling is preferable when the temperature lowering rate is 5 ° C./sec or less, particularly 1 ° C./sec or less because the precipitate can be sufficiently generated. For example, in the production method (II), in the reduction process, when the cooling process from the heating temperature of the reduction treatment is rapid cooling (temperature decrease rate: over 5 ° C / sec), the base alloy is heated again to the precipitation temperature range, and the precipitation temperature After holding the zone, it can be cooled rapidly. Alternatively, in the production method (II), when the precipitation process is included in the cooling process from the heating temperature of the reduction treatment, that is, the precipitate: MA-Fe precipitate phase is precipitated by gradually cooling to at least the lower limit temperature of the precipitation temperature range. The reduction process and the precipitation process can be performed continuously, the number of heating times can be reduced, and the productivity is excellent. The slow cooling is preferable when the temperature lowering rate is 5 ° C./sec or less, particularly 1 ° C./sec or less because the precipitate can be sufficiently generated. The Fe-X alloy becomes a precursor phase of the Fe-based magnetic phase. Further, the MA-Fe precipitation phase becomes a precursor phase of the MA-Fe oxide and does not substantially change in the separation step described later.

(Separation process)
The separation step can be basically performed in the same manner as the phase separation step in the conventional method for producing a metal magnet. In this step, the parent phase of the precipitated alloy: the Fe—X alloy is mainly phase-separated into a nano-order Fe-based magnetic phase and an X alloy phase. More specifically, the precipitated alloy is maintained in the phase separation temperature region of the parent phase: Fe—X alloy. The phase separation temperature range is typically the temperature range of the phase separation temperature center temperature ± 50 ° C determined from the equilibrium diagram and differential thermal analysis curve (DTA curve). However, for example, about 550 ° C. to 850 ° C. may be mentioned. For example, in the precipitation step, when the cooling process from the precipitation temperature range is rapid cooling (temperature decrease rate: 5 ° C./sec or more), after heating the precipitation alloy to the phase separation temperature range again, and maintaining the phase separation temperature range , Rapid cooling. Alternatively, if the cooling process from the precipitation temperature range includes a separation step, that is, if the phase separation is performed by gradually cooling to at least the lower limit temperature of the phase separation temperature range, the precipitation step and the separation step can be performed continuously. Therefore, the number of heating times can be reduced and the productivity is excellent. In particular, when the cooling process of the solution treatment step or the reduction step described above includes a precipitation step and a separation step, the productivity is further improved.

  In the slow cooling of the separation process, if the temperature drop rate is 0.05 ° C / sec or more, phase separation can be performed well, the growth of the generated Fe-based magnetic phase is suppressed, and the Fe-based magnetic phase is separated into nano-order single domains. Can be structured. The higher the temperature drop rate, the easier it is to suppress the above growth, 0.1 ° C / sec or higher, and more preferably 0.2 ° C / sec or higher. However, if it is too large, phase separation cannot be performed sufficiently. Is preferably 1 ° C./sec or less, and more preferably about 0.5 ° C./sec.

  In the separation process, especially when a magnetic field is applied during the temperature drop in the phase separation temperature range, the Fe-based magnetic phase is a columnar body with a very large aspect ratio such as a minor axis of 100 nm or less and a major axis of 1000 nm or more. It can be. The greater the applied magnetic field, the longer the major axis and the larger the aspect ratio. When the applied magnetic field is small, the major axis is shortened, and when the magnetic field is not applied, the Fe-based magnetic phase can be made granular. The magnitude of the magnetic field can be selected so as to satisfy a desired aspect ratio, and is preferably 2T or more, particularly 3T or more, and there is no particular upper limit. For example, when a high-temperature superconducting coil is used to apply the magnetic field, the excitation speed is high and the productivity is excellent.

  The separation step can be performed in an inert atmosphere (for example, an inert gas atmosphere such as Ar) or a reduced pressure atmosphere (a vacuum atmosphere having a pressure lower than the standard atmospheric pressure (final vacuum degree: for example, 10 Pa or less)).

  After a phase separation reaction has progressed and a time sufficient to sufficiently reduce the unreacted phase has elapsed, cooling spots are less likely to occur when cooled quickly to 200 ° C. or lower. It is possible to suppress the coarsening and prevent the magnetic characteristics from being deteriorated due to the coarsening. For this cooling, for example, a forced cooling means that immerses a heated material in a liquid cooling medium such as oil or water can be used.

  An aging treatment can be further performed so as not to substantially change the size of the Fe-based magnetic phase obtained through the separation step. By the aging treatment, the separation between the Fe-based magnetic phase and the X alloy phase can proceed completely. An oxidation step described later may also serve as the aging treatment.

(Oxidation process)
In the method for producing a magnetic member of the present invention, a phase separation material containing an MA-Fe precipitated phase and an Fe-based magnetic phase is subjected to an oxidation treatment, and the MA-Fe precipitated phase existing around the Fe-based magnetic phase is subjected to MA. -Fe oxide is one of the characteristics. This oxidation treatment can be performed in a short time, for example, as a plasma treatment, but is preferably a heat treatment in an oxygen-containing atmosphere for industrial mass production. When the oxygen-containing atmosphere is, for example, an ozone atmosphere, the oxidation energy can be increased and oxidation can be performed in a short time. However, if the atmosphere has an oxygen concentration of 5% by volume or more, the oxidation can be sufficiently performed. In particular, when an air atmosphere is used, the atmosphere control is easy and the productivity is excellent. The heating temperature is about 250 ° C. to 550 ° C., and the holding time is about 0.5 hours to 24 hours.

  In the oxidation process, volume expansion may occur due to the formation of oxides. Due to this volume expansion, the magnetic member is cracked or has a poor appearance. Therefore, the oxidation treatment is preferably performed in a state where stress is applied to the phase separation material. For example, the oxidation treatment may be performed in a state where the phase separation material is disposed in a mold capable of applying a hydrostatic pressure or in a state where the phase separation material is stored in a mold capable of uniaxial pressure. The pressurizing pressure is preferably 100 MPa or more, and if it is too large, cracking may occur in the material due to this pressurization. Therefore, 300 MPa or less is preferable, and about 100 MPa to 200 MPa is easy to use. In this case, it is preferable that the oxidation treatment is a heat treatment in the above-described oxygen-containing atmosphere because a large amount of oxidation can be performed at one time.

(Other processes)
≪Pressure process≫
When the material subjected to the oxidation process is pressurized and densified, a high-density magnetic member can be obtained, and the magnetic characteristics can be improved. The pressure at this time is easily 300 MPa to 1 GPa. This pressurization is preferably performed by press molding in a state where the mold is constrained or a hydrostatic pressure pressurization method is used so that the material does not elastically deform. In the case of performing nitridation described later, this pressurizing step is preferably performed after nitriding.

≪Nitriding process≫
When an iron alloy with a low Co content (5% by mass or less) is used as a raw material and the Fe phase is generated in the separation step described above, nitriding is performed in a pressurized state exceeding atmospheric pressure after the oxidation treatment, and Fe A nitriding step for generating an α "Fe ₁₆ N ₂ phase from the phase can be provided. The conditions for the nitriding treatment are heating in an atmosphere containing nitrogen element: a nitrogen (N ₂ ) atmosphere or an ammonia (NH ₃ ) atmosphere. Temperature: 200 ° C. to 400 ° C., holding time: 0.5 hour to 100 hours, pressurization strains the Fe crystal lattice, widens the lattice spacing in a certain direction, and N atoms are ordered between the expanded lattices Α ”Fe ₁₆ N ₂ can be efficiently generated by preferential entry with a specific direction. Further, in the case where a powder compact is used as a raw material and is not densified, a gap between particles can be used for a nitrogen supply path, and nitriding can be performed efficiently. The pressurizing pressure is preferably 70 MPa to 300 MPa, and 70 MPa to 150 MPa is easy to use. A uniaxial press pressurization etc. can be utilized for pressurization. In this nitriding, a microscopic space is created between the metal phase such as FeCo phase and the oxide phase such as MA-Fe-O phase due to the expansion of the crystal lattice due to the oxidation of the MA-Fe precipitate phase described above. It is considered that nitrogen is supplied.

(Other manufacturing methods)
In addition, for the production of the magnetic member of the present invention, a production method for forming a powder coated with MA-Fe oxide using the sol-gel method or the like as described above can be used.

  Hereinafter, more specific embodiments of the present invention will be described with reference to the drawings while giving test examples. In the figure, the same reference numeral indicates the same name.

[Test example]
Using an iron alloy or compound powder as a raw material, a magnetic member having a structure in which a plurality of magnetic phases were dispersed in a matrix was prepared by the following procedure, and the magnetic characteristics were examined. In this test, samples No. 1 to No. 12 used powder molded bodies made of iron alloys, and produced magnetic members in the order of preparation step → solution treatment step → precipitation step → separation step → oxidation step. Samples No. 13 to No. 16 prepared a plurality of compound powders, and produced magnetic members in the order of preparation process → sintering process → reduction process → deposition process → separation process → oxidation process.

(Sample No. 1 to No. 12)
A raw material having a composition (mass%) shown in Table 1 was melted to prepare a molten iron alloy (see FIG. 1 (A), elements shown in FIG. 1 (A) are examples), and an iron having an average particle size of 80 μm. Alloy powder is produced by gas atomization method (Ar atmosphere). The average particle size is set to a particle size (50% particle size) with an integrated weight of 50% by a laser diffraction particle size distribution device. Each particle 20p composing the obtained alloy powder is composed of a single-phase structure having the composition shown in Table 1.

  The produced alloy powder was compression-molded (molding pressure: 1 GPa) to produce a cylindrical powder compact 20 having a diameter: φ10 mm × height: 10 mm. When the relative density of the obtained powder compact 20 was determined, all the samples were about 92%. For the relative density, the actual density is measured using a commercially available density measuring device, and the actual density / true density is calculated by calculating the true density of the cast material composed of the iron alloy having each composition shown in Table 1. Is required.

The obtained powder compact 20 is subjected to a solution treatment in a vacuum atmosphere (degree of vacuum: 5 × 10 ⁻² Pa) at 1150 ° C. × 1 hour to obtain a solution alloy 30 (FIG. 1 (B)). In the cooling process from the heating temperature of the solution treatment, the temperature is lowered while controlling the temperature range up to 850 ° C. at a temperature lowering rate of 2 ° C./sec. This slow cooling step corresponds to a precipitation step. The temperature lowering rate in the precipitation step and the next separation step was adjusted by controlling the temperature in the heating furnace used for the solution treatment. By this precipitation step, a precipitated alloy 40 is obtained for a sample using a raw material having a specific composition (FIG. 1 (C)). Precipitated alloy 40 is composed of MA-Fe (here, (Ca, Ca) in a parent phase 41 made of Fe-X alloy (here, Fe-Al-Ni-Co-Cu-Nb alloy or Fe-Al-Ni alloy). The precipitate phase 42 composed of Ba, Sr, Y) -Al-Fe) has a dispersed structure. The precipitated phase 42 is preferably present along the crystal grain boundary of the parent phase 41, and more preferably present so as to surround the periphery of the crystal grain.

  Following the precipitation step, the temperature range from 850 ° C. to 730 ° C. (corresponding to the phase separation temperature range in the composition shown in Table 1) is controlled to the temperature decrease rate (° C./sec) shown in Table 1 and shown in Table 1. The temperature was lowered while a magnetic field (T) was applied. This step corresponds to a separation step. By this separation step, the sample having the precipitated phase 42 is converted into the X alloy phase 51 in which the parent phase 41 is composed of the Fe-based magnetic phase 10 and the X alloy (here, Al-Ni-Cu-Nb alloy or AlNi alloy). A phase-separated material 50 having a structure in which the Fe-based magnetic phase 10 and the precipitated phase 42 are dispersed in the X alloy phase 51 is obtained (FIG. 1D). Samples No. 11 and No. 12 have a temperature drop rate of 2 ° C./sec from the heating temperature of the solution treatment to 650 ° C., and the temperature drop rate shown in Table 1 is the temperature range of 650 ° C. to 300 ° C. (° C./sec).

  The phase separation material 50 is housed in a mold, and is subjected to an oxidation treatment by heat treatment in an oxygen-containing atmosphere (here, an air atmosphere) at a temperature (° C.) × 10 hours shown in Table 1 to obtain the magnetic member 1 (FIG. 1 (E)). The mold used was one that can be applied with hydrostatic pressure, and was subjected to oxidation treatment by applying the pressure (MPa) shown in Table 1.

(Sample No. 13 to No. 16)
Fe oxide (Fe ₂ O ₃ ) powder, Al oxide (α-Al ₂ O ₃ ) powder, Ni oxide (NiO) powder, Co oxide (CoO) A powder made of carbonate (MACO ₃ ) of one element selected from powder, MA: Ca, Ba, Sr and Y was prepared (see FIG. 2 (a). The elements in FIG. 2 (a) are examples) . Each compound powder was prepared so that the content of each element of Fe, Al, Ni, and MA would be the amount shown in Table 1 when the total content of Fe, Al, Ni, and MA was 100% by mass. All the compound powders were commercially available powders, and those having an average particle diameter substantially equal (about 1 μm to 5 μm) were used.

  The prepared oxide powder and carbonate powder are weighed to a predetermined mixing ratio and mixed by a ball mill (dry type), and this mixed powder is used as a raw material powder 60 (FIG. 2 (b)). The raw material powder 60 was compression-molded into a desired shape (molding pressure: 200 kPa), and the obtained powder compact was pre-sintered under conditions of 900 ° C. × 10 hours in an air atmosphere. The obtained preliminary sintered body was pulverized and molded again (molding pressure: 200 kPa), and the obtained powder compact was subjected to main sintering under conditions of 1100 ° C. × 10 hours in the air atmosphere. And, a composite oxide of MA, Fe, X: (MA, Fe, X) -Ox, and a cylindrical sintered body 61 having a diameter: φ10 mm × height: 10 mm was obtained (FIG. 2 (c)). . When the relative density of the obtained sintered body 61 was determined in the same manner as in sample No. 1 and the like, all the samples were about 90% to 95%.

  The obtained sintered body 61 is subjected to a reduction treatment in a hydrogen stream at 800 ° C. for 1 hour to obtain an alloy composed of MA, Fe, and X: a base alloy 62 (FIG. 2 (d)). In the cooling process from the heating temperature of this reduction process (slow cooling process), the temperature is decreased while controlling the temperature decrease rate, and the precipitation process is performed. Specifically, following the reduction treatment, the atmosphere was switched to Ar, and then the temperature was lowered while controlling the temperature range up to 650 ° C. to 1 ° C./sec. The temperature lowering rate in the precipitation step and the next separation step was adjusted by controlling the temperature in the heating furnace used for the reduction treatment. By this precipitation process, MA-Fe (here, (Ca, Ba, Sr) -Al-Fe) is formed in the parent phase 41 made of Fe-X alloy (here, Fe-Al-Ni alloy). A precipitated alloy 40 having a structure in which the precipitated phase 42 is dispersed is obtained (FIG. 2 (e)).

  Following the precipitation step, the temperature range from 650 ° C. to 300 ° C. (including the phase separation temperature range in the composition shown in Table 1) is controlled to the temperature drop rate (° C./sec) shown in Table 1, and shown in Table 1. The temperature was lowered while a magnetic field (T) was applied. This step corresponds to a separation step. By this separation step, the sample having the precipitated phase 42 is separated into the parent phase 41 into an Fe-based magnetic phase 10 and an X alloy phase 51 made of an X alloy (here, an AlNi alloy). A phase separation material 50 having a structure in which the base magnetic phase 10 and the precipitated phase 42 are dispersed is obtained (FIG. 2 (D)).

  As with sample No. 1, etc., phase separation material 50 is housed in a mold, and the temperature (° C.) × 10 hours shown in Table 1 in an oxygen-containing atmosphere (here air atmosphere), the pressure (MPa) shown in Table 1 The magnetic member 1 is obtained by performing an oxidation treatment by heat treatment to which is applied (FIG. 2 (E)).

  For each magnetic member obtained, the cross section in the direction perpendicular to the direction of application of the magnetic field in the separation step was taken, and after thinning by ion milling, observed with a transmission electron microscope: TEM (about 50000 times) It was confirmed that the sample was also composed of a plurality of nano-order dispersed phases and surrounding phases surrounding these dispersed phases. In addition, the composition of the dispersed phase and the composition of the surrounding phase were identified from the X-ray diffraction results of the cross section of each magnetic member and the spot analysis of electron diffraction during TEM observation. The results are shown in Table 2. As shown in Table 2, it was confirmed that the dispersed phase of any sample was composed of a phase containing Fe, and the oxide containing MA was present in the surrounding phase. In particular, a sample containing an oxide containing Fe and MA was confirmed. For example, in sample No. 5, as conceptually shown in FIG. 1 (E), in sample No. 13, as conceptually shown in FIG. It was confirmed that the base magnetic phase 10 was present and that the MA-Fe oxide 12 (Ca- (Fe, Al) -O in sample No. 5 and No. 13) was present in the surrounding phase 11. In addition, in each of the samples No. 1 to No. 10, the content of the dispersed phase in each magnetic member is 45% to 60% by volume, and the samples No. 11 to No. 16 are 70% by volume. It was about.

  Using TEM analysis results and X-ray diffraction results, the compositions other than the oxides that make up the surrounding phase were examined. All samples were substantially Al-Ni-Cu-Nb alloys or AlNi alloys. Consisted of. In addition, the atomic ratio (atomic%) of Fe and Al in the surrounding phase was investigated using the analysis result by the TEM and the X-ray diffraction result. The results are shown in Table 2.

  Using the TEM observation image of the cross section, the minor axis (nm) and major axis (nm) of the dispersed phase were measured. Specifically, in the TEM observation image, the length in the longitudinal direction of the dispersed phase (≈the length of the longer side) is the major axis, and the length orthogonal to the major axis (≈the length of the shorter side) is The major axis and minor axis of each dispersed phase were measured as the minor axis, and the average of the dispersed phase in the TEM observation image is shown in Table 2. The measurement of the minor axis and the major axis can be easily performed using a commercially available image processing apparatus and using an image processed image of a TEM observation image.

About each obtained magnetic member, using a BH tracer (DCBH tracer made by Riken Denshi Co., Ltd.), residual magnetization: Br (T), coercive force: Hc (kA / m), maximum energy product: (BH) max ( kJ / m ³ ) was measured. The results are shown in Table 2.

As shown in Table 2, one or more elements selected from MA: Ca, Sr, Ba and Y are contained in the surrounding phase surrounding the nano-order Fe-based magnetic phase with a minor axis of 100 nm or less, and Fe It can be seen that the sample containing the MA-Fe oxide has excellent remanence, coercive force, maximum energy product, and excellent magnetic properties. Specifically, here, at least one of remanent magnetization: 1 T or more, coercive force: 180 kA / m or more, and maximum energy product: 50 kJ / m ³ or more is satisfied. : It is understood that both of 180 kA / m or more are satisfied. Therefore, even if these samples do not contain rare earth elements (excluding Y), they are excellent in magnetic properties and can be expected to be suitably used as a material for permanent magnets.

Moreover, the following can be said from this test result.
(1) The Fe-based magnetic phase is columnar, and the longer the major axis, the better the magnetic properties.
(2) When the content of Fe in the surrounding phase is more than 50 atomic% in comparison with Al, MA-Fe oxide is sufficiently present and the magnetic properties are excellent.
(3) When the total content of MA in the magnetic member is 3% by mass or more, the MA-Fe oxide is sufficiently present and the magnetic properties are excellent.

(4) A magnetic member comprising MA-Fe oxide in the surrounding phase by subjecting a raw material alloy containing a specific element to solution treatment, then precipitating a MA-Fe precipitate phase and further subjecting it to an oxidation treatment. Can be manufactured.
(5) By applying a magnetic field of 2 T or more in the separation step, the Fe-based magnetic phase can be made into a columnar shape having a major axis of 1000 nm or more, and a magnetic member having excellent magnetic properties can be produced by shape magnetic anisotropy.
(6) In the separation step, by setting the temperature drop rate to 0.05 ° C / sec or more and less than 5 ° C / sec, it is difficult for Al to be contained in the Fe-based magnetic phase, and this Al is preferentially oxidized in the oxidation step, and Fe A decrease in magnetic properties due to the inclusion of Al oxide in the base magnetic phase can be suppressed.
(7) In the oxidation step, cracking and the like can be prevented by performing an oxidation treatment in a state where the pressure is increased to 100 MPa or more.

  (8) After reducing the composite oxide sintered body prepared using compound powder containing a specific element, the MA-Fe precipitated phase is precipitated, and further oxidized, A magnetic member comprising MA-Fe oxide can be manufactured. In particular, in this production method, the MA content can be easily increased (for example, 5% by mass or more). Therefore, the Fe ratio in the MA-Fe oxide can be easily increased, and a magnetic member having excellent magnetic properties can be easily obtained. In addition, the sample obtained by this manufacturing method has a higher ratio of MA used as a raw material in the magnetic member as the final product compared to samples No. 7 and No. 8, and is excellent in productivity. In the production method using an alloy as a raw material (production method (I)), when MA is excessively used as a raw material as in samples No. 7 and No. 8, 10% to 20% of MA that did not volatilize during dissolution. It is considered that about% (volume%) is precipitated in the magnetic member as a Ca—Al compound.

  In addition, this invention is not limited to embodiment mentioned above, In the range which does not deviate from the summary of this invention, it can change suitably. For example, the composition of the Fe-based magnetic phase, the composition of the MA-Fe oxide, the production conditions (solution treatment, sintering treatment, reduction treatment, oxidation treatment heating temperature, heating time, temperature drop rate, etc.), production method, etc. Can be changed.

  The magnetic member of the present invention can be suitably used as a permanent magnet, for example, a permanent magnet used in various motors, in particular, a high-speed motor provided in a hybrid vehicle (HEV), a hard disk drive (HDD), or the like. In addition, the magnetic member of the present invention is expected to be usable for electromagnetic interference / absorbing materials up to a frequency region (terahertz region) where the skin depth of the Fe-based magnetic phase is close to the minor axis of the Fe-based magnetic phase. The manufacturing method of the magnetic member of this invention can be utilized suitably for manufacture of the magnetic member suitable for the raw material of a permanent magnet.

1 Magnetic member 10 Fe-based magnetic phase 11 Ambient phase 12 MA-Fe oxide
20 Powder compact 20p particle 30 Solution alloy
40 Precipitated alloy 41 Parent phase 42 Precipitated phase 50 Phase separation material 51 X Alloy phase
60 Raw material powder 61 Sintered body 62 Base alloy
100 Ingot 120 Ferromagnetic phase 130 Nonmagnetic phase 400 Magnet

Claims (12)

A magnetic member composed of a Fe-based magnetic phase mainly composed of Fe and a surrounding phase surrounding the Fe-based magnetic phase,
The Fe-based magnetic phase has a minor axis of 100 nm or less,
The surrounding phase is a magnetic member containing an MA-Fe oxide containing MA and Fe, where MA is one or more elements selected from Ca, Sr, Ba and Y. The Fe-based magnetic phase is at least one of a Fe phase substantially composed of Fe and a FeCo phase containing 50% by mass or less of Co,
The surrounding phase contains an AlNi-based alloy containing Al and Ni as main elements and the MA-Fe oxide,
2. The magnetic member according to claim 1, wherein the MA-Fe oxide contains MA, Fe, and Al.   3. The magnetic member according to claim 1, wherein the Fe-based magnetic phase is columnar and has a major axis of 1000 nm or more. The surrounding phase contains an AlNi-based alloy containing Al and Ni as main elements and the MA-Fe oxide,
The magnetic member according to any one of claims 1 to 3, wherein a content of Fe is more than 50 atomic% with respect to a total atomic weight of Fe and Al in the surrounding phase.   5. The magnetic member according to claim 1, wherein a total content of the MA is 3% by mass or more and 8% by mass or less. When one or more elements selected from Ca, Sr, Ba and Y are MA, and one or more elements selected from Al, Ni and Co are X, a raw material alloy containing MA, Fe and X A preparation process to prepare; and
A solution treatment step of subjecting the raw material alloy to a solution treatment at a temperature not lower than 1000 ° C. and not higher than a liquidus temperature of the raw material alloy;
The MA-Fe precipitation phase containing at least MA and Fe is precipitated from the solution-treated alloy subjected to the solution treatment, and the MA-Fe precipitation phase is contained in the Fe-X alloy containing Fe and X. A precipitation step in which
A separation step of separating the Fe-X alloy into an Fe-based magnetic phase mainly composed of Fe and an X alloy phase mainly composed of X;
A method for producing a magnetic member comprising: an oxidation step of subjecting the phase separation material that has undergone the separation step to an oxidation treatment to produce an MA-Fe oxide containing MA and Fe from the MA-Fe precipitated phase. Including the precipitation step and the separation step in the cooling step of the solution treatment step,
The MA-Fe precipitation phase is precipitated by cooling the MA-Fe phase in the solution alloy to the lower limit temperature of the precipitation temperature range of 5 ° C / sec or less, and the MA-Fe precipitation phase is precipitated. 7. The method for producing a magnetic member according to claim 6, wherein the Fe-based magnetic phase and the X alloy phase are phase-separated by cooling at 0.05 ° C./sec or more and less than 5 ° C./sec.   8. The method for manufacturing a magnetic member according to claim 6, wherein in the preparation step, a powder molded body obtained by molding a powder made of the raw material alloy is prepared. When one or more elements selected from Ca, Sr, Ba, and Y are MA, and one or more elements selected from Al, Ni, and Co are X, a powder of MA carbonate, and A preparation step of preparing a raw material powder in which a powder made of an oxide and a powder made of an oxide of Fe are mixed;
After the preliminary sintering of the raw material powder, a main sintering is performed to form a sintered body made of a composite oxide containing MA, Fe and X, and
A reduction step of subjecting the sintered body to a reduction treatment to form a base alloy containing MA, Fe and X;
From the base alloy, a MA-Fe precipitation phase containing at least MA and Fe is precipitated, and a precipitation step in which the MA-Fe precipitation phase is present in an Fe-X alloy containing Fe and X;
A separation step of separating the Fe-X alloy into an Fe-based magnetic phase mainly composed of Fe and an X alloy phase mainly composed of X;
A method for producing a magnetic member comprising: an oxidation step of subjecting the phase separation material that has undergone the separation step to an oxidation treatment to produce an MA-Fe oxide containing MA and Fe from the MA-Fe precipitated phase. Including the precipitation step and the separation step in the cooling step of the reduction step,
The MA-Fe precipitation phase is precipitated by cooling the MA-Fe phase in the base alloy to a lower temperature lower than the precipitation temperature range of 5 ° C./sec or less, and in the phase separation temperature region, the temperature reduction rate is 0.05. 10. The method for manufacturing a magnetic member according to claim 9, wherein the Fe-based magnetic phase and the X alloy phase are phase-separated by cooling at a temperature of from 0 ° C./sec to less than 5 ° C./sec.   11. The method for manufacturing a magnetic member according to claim 6, wherein the separation step is performed by applying a magnetic field of 2T or more. The oxidation treatment is a heat treatment under an atmosphere containing oxygen,
12. The oxidation process according to any one of claims 6 to 11, wherein in the oxidation step, the oxidation treatment is performed in a state where the hydrostatic pressure of 100 MPa or more is applied to the phase separation material, or in a state where the phase separation material is stored in a mold capable of uniaxial pressing. 2. A method for producing a magnetic member according to claim 1.

Images