JP6769479B2 - Rare earth permanent magnet - Google Patents

Description

The present invention relates to a rare earth permanent magnet containing La as a part of R in the rare earth permanent magnet and characterized by a high coercive force.

Conventionally, as a high-performance rare earth permanent magnet, the Nd-Fe-B type permanent magnet described in Patent Document 1 is known, and is currently widely used in consumer, industrial, transportation equipment and the like. In recent years, with the spread of HVs and HEVs, the consumption of Nd, which is a rare element, has increased, so that a rare earth permanent magnet having a lower Nd content is required.

Non-Patent Documents 1 and 2 propose a rare earth permanent magnet having a ThMn _12- type crystal structure. These rare earth permanent magnets have a composition in which Nd is reduced or not contained, have high magnetization, and have a higher magnetocrystalline anisotropy.

JP-A-59-4608

Journal of Applied Physics, Vol. 70, p. 6009, 1991 Journal of Allys and Compounds, Vol. 5, pp. 144, 2012

However, the rare earth permanent magnets disclosed in Non-Patent Documents 1 and 2 have not obtained a sufficient coercive force for practical use. The coercive force of SmFe ₁₁ Ti described in Non-Patent Document 2 is as low as about 0.4 MA / m.

The present invention has been made in view of such a situation, and by using a resource-rich La in a rare earth permanent magnet having an RT compound having a ThMn _12- type crystal structure as a main phase. An object of the present invention is to provide a rare earth permanent magnet having a higher coercive force than the conventional one without significantly lowering the magnetization.

In order to solve the above-mentioned problems and achieve the object, the rare earth permanent magnet of the present invention is an RT compound having a main phase and a grain boundary phase, and the main phase has a ThMn ₁₂ type crystal structure. R requires La, and one or more rare earth elements selected from Y, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, and T is Fe, Or Fe and Co, or a part thereof with M (one or more selected from Ti, V, Cr, Mo, W, Zr, Hf, Nb, Ta, Al, Si, Cu, Zn, Ga and Ge). It is a substituted element, and the grain boundary phase has a La-rich phase σ, and the La-rich phase σ has a cubic crystal structure, a La composition ratio of 20 at% or more, and occupies the grain boundary phase. The cross-sectional area ratio of the La-rich phase σ is 20% or more.

The present inventors infer the mechanism of developing a higher coercive force than the conventional one as follows. Generally, a rare earth element and a transition metal element are known as a combination that easily reacts to form a compound, but the combination of La and a transition metal element is much less reactive than other rare earth elements. Therefore, the grain boundary phase containing La as a main component does not easily form a compound with Fe or Co, which are magnetic elements, and tends to be a non-magnetic phase. Therefore, the non-magnetic grain boundary phase between the main phases is magnetic between the main phases. It is expected to promote separation and develop a high coercive force. However, no report suggesting this effect has been made so far. The reason for this is that La at room temperature has a hexagonal crystal structure and has a large interfacial strain with the tetragonal main phase, which may reduce the magnetic properties of the main phase. On the other hand, at a high temperature of about 300 ° C. or higher, La has a cubic crystal structure. Therefore, the present inventors realize a La grain boundary phase having a cubic crystal structure at room temperature and reduce the interfacial strain between the grain boundary phase and the tetragonal main phase, so that the rare earth permanent magnet is high. It was found that a coercive force is exhibited.

The rare earth permanent magnet of the present invention uses an RT compound having a ThMn _12- type crystal structure as a main phase and uses resource-rich La, so that the coercive force is higher than before without significantly reducing the magnetization. Is obtained.

An embodiment (embodiment) for carrying out the present invention will be described in detail. The present invention is not limited to the contents described in the following embodiments. In addition, the components described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the components described below can be combined as appropriate.

In the rare earth permanent magnet according to the present embodiment, the main phase is an RT compound having a ThMn _12- type crystal structure. La is essential for La, and is one or more rare earth elements selected from Y, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu. The amount of R is preferably 4.2 at% or more and 25.0 at% or less. If the amount of R is less than 4.2 at%, the formation of the main phase is not sufficient, α-Fe having soft magnetism or the like is precipitated, and the coercive force is remarkably lowered. On the other hand, when R exceeds 25.0 at%, the volume ratio of the main phase decreases and the saturation magnetic flux density decreases. Within such a range, the saturation magnetic flux density can be improved.

In the rare earth permanent magnet according to the present embodiment, T is Fe, or Fe and Co, or a part thereof is M (Ti, V, Cr, Mo, W, Zr, Hf, Nb, Ta, Al, Si, Cu, It is an element substituted with one or more selected from Zn, Ga and Ge). The amount of Co is preferably larger than 0 at% and 50.0 at% or less with respect to the total amount of T. The saturation magnetic flux density can be improved by adding an appropriate amount of Co. Further, the corrosion resistance of the rare earth permanent magnet can be improved by increasing the amount of Co. The amount of M is preferably 0.4 at% or more and 25.0 at% or less with respect to the total amount of T. When M is less than 0.4 at% with respect to the total amount of T, R ₂ Fe ₁₇ and α-Fe having soft magnetism are precipitated and the volume ratio of the main phase is lowered, and when it exceeds 25.0 at%, the saturation magnetic flux density is remarkably increased. descend.

The rare earth permanent magnet according to this embodiment has a La-rich phase σ in the grain boundary phase. In the case of the combination of La and the transition metal element, the reactivity is very low as compared with other rare earth elements. Therefore, the La-rich phase σ containing La as a main component is difficult to form a compound with Fe and Co, which are magnetic elements, and tends to be a non-magnetic phase. Therefore, it is expected that the non-magnetic grain boundary phase promotes magnetic separation between the main phases and a high coercive force is exhibited. The La-rich phase σ may contain elements such as Fe and Ti in addition to La. Even when a magnetic element such as Fe is contained, the La solid solution reduces the original magnetic characteristics, so that magnetic separation between the main phases can be promoted. Therefore, the La-rich phase σ may have a La composition ratio of 20 at% or more. When the La composition ratio of the La-rich phase σ is 20 at% or more, the magnetic separation effect becomes high and the coercive force becomes high.

In the rare earth permanent magnet according to the present embodiment, the La-rich phase σ has a cubic crystal structure. La at room temperature has a hexagonal crystal structure and has a large interfacial strain with the tetragonal main phase, so it is possible that the magnetic characteristics of the main phase are deteriorated. On the other hand, at a high temperature of about 300 ° C. or higher, La has a cubic crystal structure. Therefore, the present inventors realize a La grain boundary phase having a cubic crystal structure at room temperature and reduce the interfacial strain between the grain boundary phase and the tetragonal main phase, so that the rare earth permanent magnet is high. It was found that a coercive force is exhibited.

In the rare earth permanent magnet according to the present embodiment, the grain boundary phases other than the La-rich phase σ include the existing R-rich phase, α-Fe phase, hexagonal La phase and the like. The cross-sectional area ratio of the La-rich phase σ to the grain boundary phase (part other than the main phase) is 20% or more, preferably 21% or more, and further 24% or more, 25% or more, 54% or more, 91. More preferred in the order of% or more. By setting the cross-sectional area ratio of the La-rich phase σ to the grain boundary phase to 20% or more, a magnetic separation effect between the main phases and an effect of reducing interfacial strain between the grain boundary phase and the main phase can be obtained, and a coercive force can be obtained. Is improved. Further, the La-rich phase σ is preferably uniformly distributed in the grain boundary phase. It is preferable that the ratio of the La-rich phase σ to the entire grain boundary phase is high.

The rare earth permanent magnet according to the present embodiment preferably contains an invading element X, and X is one or more elements selected from N, H, Be and C. The amount of X is preferably 0.0 at% or more and 14.0 at% or less. The coercive force can be improved by allowing X to penetrate into the crystal lattice of the main phase. This is because the invading element improves the crystal magnetic anisotropy.

The rare earth permanent magnet according to this embodiment allows the inclusion of other elements. For example, elements such as Bi, Sn, and Ag can be appropriately contained. It may also contain impurities derived from the raw material.

Hereinafter, suitable examples of the production method of the present invention will be described. As a method for manufacturing a rare earth permanent magnet, there are a physical film forming method such as sputtering and laser deposition, and an example of the manufacturing method by sputtering will be described.

As a material, first, a single element target material is prepared. The sputtering power of each single element target is adjusted so as to obtain a desired composition ratio, and a rare earth thin film permanent magnet is produced. Further, R, T, and X alloy target materials can be prepared and sputtered. Here, the composition ratio of the alloy target material and the composition ratio of the thin film produced by sputtering may deviate due to the difference in the sputtering rate of each element, and adjustment is necessary. Similarly, when it is desired to appropriately contain other elements such as Bi, Sn, Ag and the like, it can be contained by both the single element target material and the alloy target material. On the other hand, since it is desirable to reduce impurity elements such as oxygen as much as possible, the impurity content in the target material is also reduced as much as possible.

The target material oxidizes from the surface during storage. In particular, in the case of rare earth target materials, the rate of oxidation is high. Therefore, before using these target materials, it is necessary to sufficiently perform sputtering to expose the clean surface of the target material.

As the substrate for forming a film by sputtering, various metals, glass, silicon, ceramics and the like can be selected and used. However, it is desirable to select a substrate having a high melting point because it is necessary to carry out the treatment at a high temperature in order to obtain a desired crystal structure. In addition to the resistance to high temperature treatment, the adhesion to the rare earth thin film permanent magnet may be insufficient, and as a countermeasure, it is possible to improve the adhesion by providing a base film such as Cr, Ti, Ta, Mo. Usually done. A protective film such as Ti, Ta, or Mo can be provided on the upper part of the rare earth thin film permanent magnet to prevent oxidation.

Since it is desirable that the film forming apparatus that performs sputtering reduces impurity elements such as oxygen, nitrogen, and carbon as much as possible, the inside of the vacuum chamber is exhausted until it becomes ^10-6 Pa or less, more preferably ^10-8 Pa or less. It is desirable to be there. In order to maintain a high vacuum state, it is desirable to have a substrate introduction chamber connected to the film formation chamber. In addition, before using the target material, it is necessary to sufficiently perform sputtering to expose a clean surface of the target material. Therefore, the film forming apparatus is a shield that can be operated in a vacuum state between the substrate and the target material. It is desirable to have a mechanism. As the sputtering method, a magnetron sputtering method that enables sputtering in a lower pressure Ar atmosphere is preferable for the purpose of reducing impurity elements as much as possible. Here, the target material containing Fe and Co greatly reduces the leakage flux of magnetron sputtering and makes sputtering difficult, so that it is necessary to appropriately select the thickness of the target material. The power source for sputtering can be either DC or RF, and can be appropriately selected according to the target material.

By adjusting the R ratio of the charged composition, it is possible to control the amount of La in the grain boundary phase. In order to obtain a thin film having a desired composition, sputtering is performed by adjusting the film formation rate and the film formation time. When sputtering using a plurality of target materials, either multiple simultaneous simultaneous sputtering or laminated sputtering in which each target is alternately sputtered independently may be selected.

It is necessary to perform heat treatment after forming the magnetic layer. The atmosphere is a vacuum or Ar atmosphere, the temperature is raised in the range of 300 ° C./min to 1200 ° C./min, the temperature is maintained at 300 ° C. to 1200 ° C. for 1 hour to 24 hours, and then 300 ° C./min to 1000 ° C./min. Quench with. By performing the heat treatment for a long time after forming the magnetic layer, La is uniformly diffused in the grain boundary phase, and further quenching is performed to maintain the cubic crystal structure. That is, by performing this heat treatment, the formation of the La-rich phase σ is realized and the coercive force is improved.

It may be used as it is as a rare earth thin film magnet, but it can also be used as a rare earth bond magnet or a rare earth sintered magnet. The manufacturing method will be described below.

An example of a method for manufacturing a rare earth bond magnet will be described. First, a rare earth thin film magnet having a ThMn _12- type RT compound as a main phase produced by sputtering is peeled off from a substrate and finely pulverized to be powdered. Then, the resin binder containing the resin and the present powder are kneaded with a pressure kneader such as a pressure kneader, and a rare earth bond containing the resin binder and the permanent magnet powder containing the ThMn ₁₂ type RT compound as the main phase. Prepare a compound for magnets (composition). The resin includes thermosetting resins such as epoxy resin and phenol resin, styrene-based, olefin-based, urethane-based, polyester-based, polyamide-based elastomers, ionomers, ethylene-propylene copolymers (EPM), and ethylene-ethylacrylate copolymers. There are thermoplastic resins such as coalesced. Among them, the resin used for compression molding is preferably a thermosetting resin, and more preferably an epoxy resin or a phenol resin. Further, the resin used for injection molding is preferably a thermoplastic resin. Further, a coupling agent or other additives may be added to the compound for rare earth bond magnets, if necessary.

The content ratio of the rare earth permanent magnet powder containing the ThMn _12- type RT compound as the main phase and the resin in the rare earth bond magnet is, for example, 0.5% by mass or more and 20% by mass of the resin with respect to 100% by mass of the present powder. % Or less is preferable. If the resin content is less than 0.5% by mass with respect to 100% by mass of the rare earth permanent magnet powder, the shape retention tends to be impaired, and if the resin exceeds 20% by mass, the magnetism is sufficiently excellent. It tends to be difficult to obtain characteristics.

After preparing the above-mentioned compound for rare earth bond magnets, the compound for rare earth bond magnets is injection-molded to obtain a rare earth bond magnet containing a rare earth permanent magnet powder containing a ThMn _12- type RT compound as a main phase and a resin. Obtainable. When producing a rare earth bond magnet by injection molding, the compound for the rare earth bond magnet is heated to the melting temperature of the binder (thermoplastic resin) as necessary to bring it into a flowing state, and then the compound for the rare earth bond magnet is specified. Molding is performed by injecting into a mold having a shape. After that, it is cooled and a molded product (rare earth bond magnet) having a predetermined shape is taken out from the mold. In this way, a rare earth bond magnet is obtained. The method for producing a rare earth bond magnet is not limited to the above-mentioned injection molding method. For example, a rare earth permanent magnet powder containing a ThMn _12- type RT compound as a main phase by compression molding a compound for a rare earth bond magnet. A rare earth bond magnet containing the resin and the resin may be obtained. When producing a rare earth bond magnet by compression molding, after preparing the above-mentioned compound for a rare earth bond magnet, the compound for a rare earth bond magnet is filled in a mold having a predetermined shape, and pressure is applied to a predetermined compound from the mold. Take out the molded product (rare earth bond magnet) having a shape. The compound for rare earth bond magnets is molded with a mold and taken out by using a compression molding machine such as a mechanical press or a hydraulic press. After that, a rare earth bond magnet is obtained by putting it in a furnace such as a heating furnace or a vacuum drying furnace and curing it by applying heat.

The shape of the rare earth bond magnet obtained by molding is not particularly limited, and is changed according to the shape of the rare earth bond magnet, for example, flat plate shape, columnar shape, ring shape, etc., depending on the shape of the mold used. can do. Further, the obtained rare earth bond magnet may be plated or painted on the surface thereof in order to prevent deterioration of the oxide layer, the resin layer and the like.

When the compound for rare earth bond magnets is molded into a desired predetermined shape, the molded product obtained by applying a magnetic field may be oriented in a certain direction. As a result, the rare earth bond magnet is oriented in a specific direction, so that an anisotropic rare earth bond magnet having stronger magnetism can be obtained.

An example of a method for manufacturing a rare earth sintered magnet will be described. Similar to the rare earth bond magnet, a rare earth permanent magnet powder having a ThMn _12- type RT compound as a main phase is produced and molded into a desired predetermined shape by, for example, press molding. The shape of the obtained molded product is not particularly limited, and may be changed according to the shape of the rare earth sintered magnet, for example, a flat plate shape, a columnar shape, or a ring shape in cross section, depending on the shape of the mold used. it can.

The molded product is then subjected to a sintering step. The sintering holding temperature and the sintering holding time need to be adjusted according to various conditions such as composition, pulverization method, difference between average particle size and particle size distribution, and sintering method. As a result, a sintered body (rare earth sintered magnet) can be obtained.

The obtained rare earth sintered magnet may be made into a rare earth sintered magnet having a predetermined shape by cutting it to a desired size or smoothing the surface. Further, the obtained rare earth sintered magnet may be plated or painted on the surface thereof in order to prevent deterioration of the oxide layer, the resin layer and the like.

Further, when molding a rare earth permanent magnet powder containing a ThMn _12- type RT compound as a main phase into a predetermined shape, the molded product obtained by molding by applying a magnetic field is oriented in a certain direction. May be good. As a result, the rare earth sintered magnet is oriented in a specific direction, so that an anisotropic rare earth sintered magnet having stronger magnetism can be obtained.

The form relating to the production method for preferably carrying out the present invention has been described above. Next, in the rare earth permanent magnet containing the ThMn ₁₂ type RT compound of the present invention as the main phase, the composition of the main phase and the grain boundary phase A method for analyzing the crystal structure and the cross-sectional area ratio of the La-rich phase σ in the grain boundary phase will be described.

The composition of the rare earth permanent magnet containing the ThMn ₁₂ phase as the main phase can be determined by ICP mass spectrometry (ICP: Inductively Coupled Plasma Mass Spectrometry), and it is confirmed here that the composition is desired. ..

Regarding the crystal structure of the main phase of the rare earth permanent magnet as a sample, it is confirmed by X-ray diffraction (XRD: X-ray Diffraction) that the main production phase belongs to the ThMn ₁₂ type crystal structure.

The composition of the main phase is measured by energy dispersive X-ray spectroscopy (EDS: Energy Dispersive Spectroscopy). Specifically, a rare earth permanent magnet is processed into flakes with a thickness of 100 nm using a focused ion beam (FIB) device, and an EDS device provided in a scanning transmission electron microscope (STEM). To obtain an element mapping image using the above, and quantify the composition of the main phase based on the element mapping image. If there are elements that are difficult to detect with the EDS device, supplement them using infrared absorption or mass spectrometry. Here, it is confirmed that the main phase has a desired composition.

The composition of the grain boundary phase is measured by an EDS device as in the main phase. After extracting La of the grain boundary phase using the element mapping image obtained by the EDS apparatus, the composition is quantified.

The crystal structure of the grain boundary phase is determined by electron diffraction. The crystal structure is determined by performing electron diffraction analysis in a region where the La composition ratio of the grain boundary phase confirmed by the element mapping image is 20 at% or more. The region where the La composition ratio is 20 at% or more and the crystal structure is cubic is defined as the La-rich phase σ.

The cross-sectional area ratio of the La-rich phase σ to the grain boundary phase is the ratio of the cross-sectional area of the La-rich phase σ calculated from the element mapping image to the cross-sectional area of the entire grain boundary phase.

The magnetic characteristics are measured by applying a magnetic field of ± 3100 kA / m in the direction perpendicular to the substrate using a vibrating sample magnetometer (VSM).

Hereinafter, the contents of the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

As the film forming apparatus, an apparatus capable of exhausting up to ^10-8 Pa or less and having a plurality of sputtering mechanisms in the same tank was used. In this film forming apparatus, a single element target material of Sm, Er, Nd, La, Fe, Ti, Co, Mo, Nb, and a Mo target material used for a base film and a protective film are prepared according to the configuration of the sample to be produced. I put it on. For sputtering, a magnetron sputtering method was used to create an Ar atmosphere of 1 Pa, and an RF and DC power supplies were used. The power of the RF and DC power supplies and the film formation time were adjusted according to the composition of the sample. Sputtering conditions were adjusted so that the main phase was (R'1 _-x La _x ) T ₁₁ M. Specifically, R'was Sm, Er, or Nd, T was Fe, or Fe, and Co, and M was Ti, Mo, or Nb so that the compositions shown in Tables 1 to 3 were obtained. The size of the target material is 3 inches, the substrate is a Si substrate with a thermal oxide film of 10 mm x 10 mm, and sputtering is performed while rotating the substrate with the rotating mechanism of the sputtering device so that the in-plane uniformity of the film is sufficiently maintained. It was.

As for the film structure, first, Mo was formed as a base film at 200 ° C. at 50 nm. Next, Sm, Er, Nd are selected as R', Fe or Fe or Co is selected as T, Ti or Mo or Nb is selected as M, and (R', La) is used in the charged composition. _{It was set to 15.3} T _78.4 M _6.3, and the charged composition ratios of Sm, Er, Nd, and La were adjusted according to the examples and comparative examples shown in Tables 1 to 3 respectively. The Si substrate with a thermal oxide film was heated to 500 ° C., a film was formed aiming at a magnetic layer thickness of 1000 nm, and after the magnetic layer was formed, the temperature was raised at 900 ° C./min in an Ar atmosphere. Then, after heat treatment at 900 ° C. for 10 hours, the mixture was rapidly cooled at 500 ° C./min to 800 ° C./min. This is defined as the heat treatment method A.

On the other hand, the magnetic layer was formed under the same conditions as above, and the heat treatment was performed after the magnetic layer was formed. The heat treatment was performed under the same conditions as the heat treatment method A except that the heat treatment time was 10 minutes and the cooling was performed at 100 ° C./min. This is defined as the heat treatment method B.

A sample in which the Mo base film and the magnetic layer are formed by the above-described film forming method, and then the Mo protective layer is formed by the method described later without heat treatment is left without heat treatment.

After the heat treatment or after the formation of the magnetic layer, Mo was formed again as a protective film at 200 ° C. at 50 nm to prevent oxidation. Then, after cooling to room temperature in vacuum, it was taken out from the film forming apparatus.

By performing the heat treatment for a long time after forming the magnetic layer, La is uniformly diffused in the grain boundary phase, and further quenching is performed to maintain the cubic crystal structure. That is, by performing the heat treatment method A, the formation of the La-rich phase σ is realized and the coercive force is improved. On the other hand, in the heat treatment method B, the coercive force is not improved because the heat treatment time and the cooling time are insufficient. Similarly, the coercive force does not improve even without heat treatment.

The prepared sample was confirmed to have a desired composition by ICP mass spectrometry, and it was confirmed by XRD that the main production phase was attributed to the ThMn ₁₂ type crystal structure.

The method of discriminating the main phase and the La-rich phase σ and calculating the cross-sectional area ratio thereof will be described. With STEM-EDS, 20 points were measured at intervals of 300 μm in a field of view of 200 nm × 200 nm. The main phase, La-rich phase σ, and other grain boundary phases were discriminated by performing element mapping of R', La, T, and M and electron diffraction. The main phase was determined from the fact that the ratio of rare earth elements to T + M elements was approximately 1:12 using an EDS device. Further, a region where the La composition ratio is 20 at% or more and the T element ratio is less than the T element ratio of the main phase is extracted between the main phases or at the triple point, and the crystal structure of the region is cubic crystal by electron diffraction. When it was a system, it was judged to be La-rich phase σ. Further, the cross-sectional area of the La-rich phase σ in the field of view was integrated, and the ratio to the cross-sectional area of the grain boundary phase (part other than the main phase) was calculated. The results are shown in Table 1.

Then, using VSM, a magnetic field of ± 3100 kA / m was applied in the direction perpendicular to the film surface to perform magnetic hysteresis measurement. After confirming that the magnetic flux density was within the range of ± 5% when + 2400 kA / m was applied and when + 3100 kA / m was applied, the value when + 3100 kA / m was applied was taken as the saturated magnetic flux density. Table 1 shows the saturation magnetic flux density and the coercive force measured in this way.

(Example 1)
As shown in Table 1, Sm is selected for R'and Ti is selected for M so that the composition of the main phase is (R'1 _-x La _x ) Fe ₁₁ M, and the film forming method described above is used. A ThMn ₁₂ type crystal structure thin film permanent magnet of Sm _0.9 La _0.1 ) Fe ₁₁ Ti was obtained. The obtained thin-film permanent magnet was evaluated by the evaluation method described above. The results are shown in Table 1.

(Example 2)
A thin film permanent magnet was produced in the same manner as in Example 1 except that (Sm _0.7 La _0.3 ) Fe ₁₁ Ti. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

(Example 3)
A thin film permanent magnet was produced in the same manner as in Example 1 except that (Sm _0.5 La _0.5 ) Fe ₁₁ Ti. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

(Example 4)
A thin film permanent magnet was produced in the same manner as in Example 1 except that Er was selected for R'and used as Fe ₁₁ Ti (Er _0.9 La _0.1 ). Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

(Example 5)
A thin-film permanent magnet was produced in the same manner as in Example 1 except that Mo was selected as M and Fe ₁₁ Mo was used (Sm _0.9 La _0.1 ). Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

(Example 6)
A thin film permanent magnet was produced in the same manner as in Example 1 except that Fe and Co were selected for T and Fe ₁₀ CoTi was used (Sm _0.9 La _0.1 ). Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 1)
An SmFe ₁₁ Ti thin film permanent magnet was produced in the same manner as in Example 1. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 2)
A thin film permanent magnet of Fe ₁₁ Ti (Sm _0.95 La _0.05 ) was produced in the same manner as in Example 1. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 3)
A thin film permanent magnet of (Sm _0.9 La _0.1 ) Fe ₁₁ Ti was produced in the same manner as in Example 1 except that the heat treatment was performed by the heat treatment method B. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 4)
A thin-film permanent magnet was produced in the same manner as in Example 1 except that Fe ₁₁ Ti was used (Sm _0.9 La _0.1 ) and no heat treatment was performed. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

Further, when the penetrating element X is N, the nitriding treatment can be performed at the stage after the heat treatments A and B. This thin film permanent magnet was nitrided in nitrogen gas at 1 atm for 24 hours at 500 ° C. A higher saturation magnetic flux density could be obtained by letting R'become Nd and N as an invading element. The results are shown in Table 2.

(Example 7)
A thin film permanent magnet is used in the same manner as in Example 1 except that R'is Nd and N is allowed to enter as an intruding element by the above method to obtain Fe ₁₁ TiN _1.5 (Nd _0.9 La _0.1 ). Made. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 2.

(Example 8)
A thin-film permanent magnet was produced in the same manner as in Example 7 except that (Nd _0.5 La _0.5 ) Fe ₁₁ TiN _1.5 . Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 2.

(Example 9)
A thin-film permanent magnet was produced in the same manner as in Example 7 except that Fe and Co were selected as T and (Nd _0.9 La _0.1 ) Fe ₁₀ CoTiN _1.5 . Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 2.

(Comparative Example 5)
An NdFe ₁₁ TiN _1.5 thin film permanent magnet was produced in the same manner as in Comparative Example 1 by letting R'become Nd and N as an penetrating element by the above method. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 2.

(Comparative Example 6)
A thin-film permanent magnet is used in the same manner as in Comparative Example 2, except that R'is Nd and N is penetrated as an invading element by the above method to obtain Fe ₁₁ TiN _1.5 (Nd _0.95 La _0.05 ). Made. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 2.

(Comparative Example 7)
A thin-film permanent magnet is used in the same manner as in Comparative Example 3, except that R'is Nd and N is allowed to enter as an invading element by the above method to obtain Fe ₁₁ TiN _1.5 (Nd _0.9 La _0.1 ). Made. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 2.

(Comparative Example 8)
A thin film permanent magnet was produced in the same manner as in Comparative Example 4 except that (Nd _0.9 La _0.1 ) Fe ₁₁ TiN _1.5 . Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 2.

Further, even when the R amount and the M amount of the charged composition were changed, high magnetic properties were obtained. A ThMn ₁₂ crystal structure was obtained even with M = Nb, and high magnetic properties could be obtained. The results are shown in Table 3.

(Example 10)
Other than selecting Ti for M, setting the preparation composition to (R', La) _9.7 T _84.2 M _6.1, and setting the main phase composition to (Sm _0.9 La _0.1 ) Fe ₁₁ Ti. Made a thin film permanent magnet in the same manner as in Example 1. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 3.

(Example 11)
Select Ti for M, set the preparation composition to (R', La) _15.3 T _80.4 M _4.3, and set the main phase composition to (Sm _0.9 La _0.1 ) Fe _11.5 Ti _{0. A} thin film permanent magnet was produced in the same manner as in Example 1 except that the value was ₅ . Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 3.

(Example 12)
A thin film permanent magnet was produced in the same manner as in Example 10 except that Nb was selected for M and Fe ₁₁ Nb (Sm _0.9 La _0.1 ). Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 3.

(Example 13)
A thin-film permanent magnet was produced in the same manner as in Example 11 except that Nb was selected as M and (Sm _0.9 La _0.1 ) Fe _11.5 Nb _0.5 . Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 3.

Further, based on Example 1, even when the heat treatment time of the heat treatment method A was shortened, the La composition ratio of the La-rich phase σ was 20 at% or more, so that the magnetic characteristics were improved. .. The results are shown in Table 4. Table 4 shows the saturation magnetic flux density (mT), coercive force HcJ (kA / m), La composition ratio of La-rich phase σ, cross-sectional area ratio of La-rich phase σ in the grain boundary phase, and heat treatment time (time). Shown.

(Example 14)
A thin-film permanent magnet similar to that of Example 1 was produced, and the same heat treatment as the heat treatment time A was performed except that the heat treatment time was 3 hours. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 4.

(Comparative Example 9)
A thin-film permanent magnet similar to that of Example 1 was produced, and the same heat treatment as the heat treatment time A was performed except that the heat treatment time was 15 minutes. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 4.

(Examples 1 to 3 and Comparative Examples 1 to 4)
It was confirmed that the coercive force was improved as the cross-sectional area ratio of the La-rich phase σ in the grain boundary phase increased.

(Examples 4 to 6)
It was confirmed that the same result as Sm can be obtained even when R'is changed to Er. In addition, it was confirmed that the same result as Ti can be obtained even when M is set to Mo. It was confirmed that the same result as Fe was obtained even when T was set to Fe and Co.

(Examples 10, 11, 12, 13)
Even when the amount of R was reduced, the amount of M was reduced, and M was set to Nb in the charged composition, the coercive force did not change so much, and a high saturation magnetic flux density was obtained.

(Examples 7 to 9, Comparative Examples 5 to 8)
The same results as in Examples 1 to 6 were obtained even when N was introduced as an invading element.

(Example 14)
By changing the heat treatment time of the heat treatment method A, the La composition ratio of the La-rich phase σ could be adjusted, and the effect of improving the coercive force was obtained.

(Comparative Example 9)
By changing the heat treatment time of the heat treatment method A, the La composition ratio of the grain boundary phase becomes 20 at% or less, so that the magnetic separation effect is low and the coercive force is low.

Claims (2)

Has a main phase and a grain boundary phase
The main phase is an RT compound having a ThMn _12- type crystal structure.
R requires La and is one or more rare earth elements selected from Y, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu.
T is selected from Fe, or Fe and Co, or a part thereof of M (Ti, V, Cr, Mo, W, Zr, Hf, Nb, Ta, Al, Si, Cu, Zn, Ga and Ge. It is an element substituted with (1 or more)
The grain boundary phase has a La-rich phase σ and
The La-rich phase σ has a cubic crystal structure and a La composition ratio of 20 at% or more.
A rare earth permanent magnet in which the cross-sectional area ratio of the La-rich phase σ to the grain boundary phase is 20% or more. The rare earth permanent magnet according to claim 1, wherein the main phase further contains an invading element X (X is one or more elements selected from N, H, Be and C).