Magnetic powder, compound for bonded magnets, and bonded magnets

Abstract

To improve magnetic properties. [Solution] The magnetic powder contains Sm, Zr, Fe, B, and N. The atomic ratio of the Zr content to the sum of the Sm and Zr content is greater than 0.10 and less than 0.30. The B content is greater than 0.0 atomic% and less than 0.4 atomic%.

Description

Technical Field

[0001] The present invention relates to magnetic powder, a compound for bonded magnets, and bonded magnets.

Background Art

[0002] In Patent Document 1, a composition is Sm x Fe 100-x-v N v (7 ≦ x ≦ 12, 0.5 ≦ v ≦ 20), having a TbCu7-type crystal structure, and an isotropic SmFeN-based magnet powder with a flake thickness of 10 to 40 μm is disclosed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the magnet material described in Patent Document 1, when the ratio of the main phase SmFe9N w (1 ≦ w ≦ 2) phase is low and the ratio of the soft magnetic phase or non-magnetic phase is high, the magnetic properties may be low.

[0005] An object of the present invention is to provide magnetic powder, a compound for bonded magnets, and bonded magnets having high magnetic properties.

Means for Solving the Problems

[0006] One aspect of the magnetic powder of the present disclosure includes Sm, Zr, Fe, B, and N, and the atomic ratio of the content of Zr to the sum of the content of Sm and the content of Zr is greater than 0.10 and less than 0.30, and the content rate of B is greater than 0.0 atomic% and less than 0.4 atomic%.

[0007] One embodiment of the compound for bonded magnets of the present disclosure comprises the magnetic powder and a binder.

[0008] One embodiment of the bonded magnet of the present disclosure includes the compound for the bonded magnet. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide magnetic powder having high magnetic properties, a compound for bonded magnets, and bonded magnets. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a schematic cross-sectional view showing the particle cross-section of the magnetic powder according to this embodiment. [Figure 2] Figure 2 illustrates the relationship between the remanent magnetic flux density BrE calculated using the regression equation and the measured remanent magnetic flux density Br. [Figure 3] Figure 3 is a SEM image showing a cross-section of the particle near the free surface, as shown in Figure 1. [Figure 4] Figure 4 is a SEM image showing a cross-section of the particle near the roll surface, as shown in Figure 1. [Figure 5] Figure 5 is a graph showing the relationship between residual magnetic flux density Br and coercivity Hcj for Examples 1 to 7 and Comparative Examples 1 to 6 and 8. [Modes for carrying out the invention]

[0011] The embodiments relating to this disclosure will be described below. However, the invention relating to this disclosure is not limited by these embodiments. Furthermore, the numerical values ​​include a range of rounding. The upper and lower limits of the numerical ranges relating to the following description can be combined as appropriate.

[0012] (magnetic powder) Figure 1 is a schematic cross-sectional view showing the particle cross-section of the magnetic powder according to this embodiment. The magnetic powder according to this embodiment is a powder of an Sm-Fe-N isotropic magnetic material. That is, the magnetic powder according to this embodiment contains a plurality of magnetic powder particles 10, and each magnetic powder particle 10 can be said to be a particle of the Sm-Fe-N isotropic magnetic material.

[0013] (Composition of magnetic powder) The composition of the magnetic powder in this embodiment will be described below. The composition of the magnetic powder can also be rephrased as the composition of each magnetic powder particle 10. The magnetic powder in this embodiment contains Sm, Zr, Fe, B, and N.

[0014] (Sm) The Sm content of the magnetic powder is preferably 5.5 atomic% to 9.0 atomic%, more preferably greater than 6.0 atomic% and less than 8.0 atomic%, and even more preferably 6.4 atomic% to 7.4 atomic%. When the Sm content satisfies the lower limit of this range, the generation of the α-Fe phase can be suppressed, and the residual magnetic flux density of the magnet can be improved. When the Sm content satisfies the upper limit of this range, the coercivity can be improved while suppressing a significant decrease in residual magnetic flux density, resulting in a large maximum energy product (BH). max You can obtain this.

[0015] (Zr) The Zr content of the magnetic powder is preferably 0.1 atomic% to 3.0 atomic%, more preferably greater than 0.9 atomic% and less than 2.6 atomic%, and even more preferably 1.0 atomic% to 2.2 atomic%. A Zr content within this range increases the angularity and remanent magnetic flux density, resulting in a maximum energy product (BH). max It can be increased.

[0016] (Zr / (Sm+Zr)) The atomic ratio Zr / (Sm+Zr) of the magnetic powder to the sum of the Sm and Zr content is preferably greater than 0.10 and less than 0.30, and more preferably between 0.15 and 0.20. When the atomic ratio Zr / (Sm+Zr) satisfies the lower limit of this range, the main phase is SmFe9N w The stability of the crystal structure of the (1≦w≦2) phase can be improved, and the remanent magnetic flux density B r This can improve performance. By ensuring that the atomic ratio Zr / (Sm+Zr) meets the upper limit of this range, the decrease in magnetic properties can be suppressed.

[0017] (B) The B content of the magnetic powder is preferably greater than 0.0 atomic% and less than 0.4 atomic%. More preferably, the B content of the magnetic powder is 0.1 atomic% or more and 0.3 atomic% or less, and even more preferably 0.1 atomic% or more and 0.2 atomic% or less. When the B content satisfies the lower limit of this range, the crystal grains are refined, the coercivity can be improved, and the magnetic properties can be improved. When the B content satisfies the upper limit of this range, the decrease in nitrogen content can be suppressed, improving manufacturability, as well as improving the residual magnetic flux density and the magnetic properties.

[0018] (N) The nitrogen content of the magnetic powder is preferably between 10 atomic% and 20 atomic%, preferably between 11 atomic% and 15.0 atomic%, and more preferably between 12.0 atomic% and 14 atomic%. By having a nitrogen content within this range, the residual magnetic flux density can be improved, and the coercivity can also be improved.

[0019] (B / Zr) The atomic ratio B / Zr of the magnetic powder, which is the ratio of B content to Zr content, is preferably 0.01 to 0.20, more preferably 0.04 to 0.15, and even more preferably 0.05 to 0.10. By having the atomic ratio B / Zr within this range, the magnetic properties can be more effectively improved.

[0020] (Other ingredients) The magnetic powder may contain metal M other than Sm, Zr, and Fe. Metal M may be at least one of, for example, Co, Ti, V, Ta, Mo, W, Mn, Ni, Zn, Al, Hf, Si, and Ge. Note that metal M is not an essential component, and the magnetic powder may not contain metal M.

[0021] The Co content of the magnetic powder is preferably 10 atomic percent or less, more preferably 2 atomic percent or more and 8 atomic percent or less, and even more preferably 4 atomic percent or more and 6 atomic percent or less. A Co content that satisfies the lower limit of this range enhances magnetic properties and raises the Curie point, thereby improving high-temperature resistance. A Co content that satisfies the upper limit of this range suppresses a decrease in residual magnetic flux density, thereby reducing manufacturing costs.

[0022] The remainder of the magnetic powder is preferably Fe and unavoidable impurities. In this disclosure, unavoidable impurities refer to elements with a content of less than 0.1 atomic percent.

[0023] As described above, the magnetic powder according to this embodiment contains Sm, Zr, Fe, B, and N. The atomic ratio of the Zr content to the sum of the Sm and Zr content is greater than 0.10 and less than 0.30. The B content is greater than 0.0 atomic% and less than 0.4 atomic%. This improves the magnetic properties.

[0024] The magnetic powder according to this embodiment contains 5.5 atomic% to 9.0 atomic% of Sm, 0.1 atomic% to 3.0 atomic% of Zr, greater than 0.0 atomic% and less than 0.4 atomic% of B, 10 atomic% to 20 atomic% of N, and 10 atomic% or less of metal M, with the remainder being Fe and unavoidable impurities. The atomic ratio of the Zr content to the sum of the Sm and Zr content is greater than 0.10 and less than 0.30. The metal M is at least one of Co, Ti, V, Ta, Mo, W, Mn, Ni, Zn, Al, Hf, Si, and Ge. This improves the magnetic properties.

[0025] Note that, regarding the composition of the magnetic powder according to the present embodiment, elements other than N can be measured by ICP (Inductively Coupled Plasma) optical emission spectrometry, and N can be measured by inert gas fusion - thermal conductivity method.

[0026] (Magnetic properties of magnetic powder) The maximum energy product (BH) of the magnetic powder according to the present embodiment max is preferably greater than 18.5 MGOe, and more preferably 18.7 MGOe or more. By being within this range, high magnetic properties can be obtained. Note that 18.5 MGOe can be expressed as 147 kJ / m in the SI unit system 3 and the same applies to the expressions in the following examples.

[0027] The remanent magnetic flux density B of the magnetic powder according to the present embodiment r (kG), and the coercive force H cj (kOe) preferably satisfy the following formula (1). B r ≧ -0.08H cj +10.6 …(1) By satisfying the above formula (1), it can be said that the remanent magnetic flux density B r and the coercive force H cj are large, so the maximum energy product (BH) of the magnetic powder max can be increased, and high magnetic properties can be obtained. Note that the above formula (1) can be expressed as B r (T)≧ -0.0001×H cj (kA / m)+1.06 in the SI unit system, and the same applies to the expressions in the following examples.

[0028] The Kunick ratio of the magnetic powder according to the present embodiment is preferably less than 0.036, and more preferably 0.033 or less. Thereby, a decrease in the remanent magnetic flux density B r can be suppressed, the maximum energy product (BH) of the magnetic powder max can be increased, and high magnetic properties can be obtained.

[0029] Figure 2 shows the remanent magnetic flux density B calculated by the regression equationrE and the measured residual magnetic flux density B r This figure illustrates the relationship. Figure 2 shows the case of Comparative Example 2, which will be described later, as an example. In this disclosure, the Knick ratio is defined as the residual magnetic flux density B r This parameter indicates the degree of curvature of the nearby magnetization curve. Specifically, the Knick ratio can be calculated using the following equation (2). (Knic ratio) = [(Remanent magnetic flux density B calculated using the regression equation) rE )-(Residual magnetic flux density B r )] / (Residual magnetic flux density B calculated using the regression equation) rE ) …(2) The residual magnetic flux density B calculated using the regression equation related to equation (2) rE This is calculated by extrapolating the regression equation. Specifically, as shown in Figure 2, the magnetization J in the magnetic field from +5kOe to +15kOe of the magnetization curve is regression using a cubic equation, and the magnetic flux density at a magnetic field of 0kOe calculated using the obtained regression equation is the remanent magnetic flux density B. rE The cause of the cracks is the presence of SmFe9N, the main phase in the magnetic powder. w It is possible that other soft magnetic phases are present. The remanent magnetic flux density B was calculated using a regression equation. rE This is an approximate value of the remanent magnetization obtained when there is no degradation in properties due to the soft magnetic phase, and B rE and B r The knic ratio calculated from this serves as an indicator of how much the properties are degraded by the soft magnetic phase. A small knic ratio suggests that there are few phases that degrade the properties of the magnetic powder, and that high-quality magnetic powder has been obtained. The knic ratio can be controlled by the content of Sm, Zr, and B in the magnetic powder.

[0030] Here, the maximum energy product (BH) of the magnetic powder max , residual magnetic flux density B r and coercivity H cj This can be measured using a vibrating sample magnetometer (VSM).

[0031] The thickness of the magnetic powder particles is preferably between 8 μm and 24 μm, and more preferably between 10 μm and 20 μm. When the thickness of the magnetic powder particles satisfies the lower limit of this range, the specific surface area can be reduced, suppressing the decrease in magnetic flux density due to oxidation. When the thickness of the magnetic powder particles satisfies the upper limit of this range, nitriding can be performed effectively, improving coercivity. The thickness of the magnetic powder particles can be measured using a laser displacement meter. More specifically, the thickness of the magnetic powder particles can be measured by taking at least 50 particles obtained from the magnetic powder, measuring their length in the thickness direction (i.e., the direction with the smallest length) using a laser displacement meter, and calculating the arithmetic mean.

[0032] (Crystal phase of magnetic powder) As shown in Figure 1, it is preferable that at least some of the magnetic powder particles 10 contained in the magnetic powder according to this embodiment include a hard magnetic phase 11 and a soft magnetic phase 12. The hard magnetic phase 11 is a phase having a TbCu7 type structure (crystal group P6 / mmm), for example, SmFe9N w The phase is (1≦w≦2). The soft magnetic phase 12 is a phase having a body-centered cubic lattice structure (crystal group Im3m), for example, the α-Fe phase. In this embodiment, as shown in Figure 1, in the magnetic powder particles 10, the soft magnetic phase 12 is provided so as to cover both the free surface 10a side and the rolled surface 10b side of the hard magnetic phase. The presence or absence of the hard magnetic phase 11 and the soft magnetic phase 12 can be determined by observation of the particle cross-section of the magnetic powder using an SEM (Scanning Electron Microscope).

[0033] In this disclosure, the roll surface 10b is the surface of the ribbon that was in contact with the cooling roll in the cooling process of the magnetic powder described later. The free surface 10a is the surface of the ribbon opposite to the roll surface. In this embodiment, at least some of the magnetic powder particles 10 contained in the magnetic powder may include at least one of the surfaces of the free surface 10a and the roll surface 10b. That is, the magnetic powder may include magnetic powder particles 10 in which one surface is the free surface 10a. The magnetic powder may also include magnetic powder particles 10 in which one surface is the roll surface 10b. Furthermore, the magnetic powder may include magnetic powder particles 10 in which one surface is the free surface 10a and the other surface is the roll surface 10b. Note that the free surface 10a and the roll surface 10b are not essential components of the magnetic powder particles 10, and the magnetic powder particles 10 may not include the free surface 10a or the roll surface 10b.

[0034] (Content of soft magnetic phase) In this embodiment, the content of the soft magnetic phase 12 in the magnetic powder particles 10 is preferably greater than 0.0 volume% and less than 1.0 volume%, more preferably between 0.1 volume% and 0.9 volume%, and even more preferably between 0.2 volume% and 0.8 volume%. By satisfying the lower limit of this range for the content of the soft magnetic phase 12, the crystal structure of the hard magnetic phase 11 can be stabilized, thereby improving the magnetic properties. By satisfying the upper limit of this range for the content of the soft magnetic phase 12, the deterioration of magnetic properties due to the soft magnetic phase 12 can be suppressed.

[0035] The content of the soft magnetic phase 12 can be measured by observing the cross-section of the magnetic powder particles 10 in five fields of view using an SEM at a magnification of 50,000x, obtaining an SEM image of the cross-section of the magnetic powder particles 10, obtaining the ratio of the area occupied by the soft magnetic phase 12 in the observed image to the total area of ​​the cross-section of the magnetic powder particles, and converting this to a volume ratio. Similarly, the content of the soft magnetic phase 12 on the free surface 10a and the roll surface 10b can also be measured by obtaining an SEM image of the cross-section of the magnetic powder particles 10, obtaining the ratio of the area occupied by the soft magnetic phase 12 on the free surface 10a and the roll surface 10b in the observed image to the total area of ​​the cross-section of the magnetic powder particles 10, and converting this to a volume ratio.

[0036] Figure 3 is an SEM image showing a cross-section of the particle near the free surface of the particle shown in Figure 1. Figure 4 is an SEM image showing a cross-section of the particle near the roll surface of the particle shown in Figure 1. As shown in Figures 3 and 4, the soft magnetic phase 12 of the magnetic powder particle 10 contains α-Fe phase crystalline particles 12x. Hereafter, among the α-Fe phase crystalline particles 12x, the crystalline particles 12x on the free surface 10a side will be referred to as crystalline particles 12a, and the crystalline particles 12x on the roll surface 10b side will be referred to as crystalline particles 12b.

[0037] (Size of the soft magnetic phase) In this embodiment, the average size σ of the α-Fe phase crystal particles 12x contained in the soft magnetic phase 12 is preferably greater than 30 nm and 500 nm or less, more preferably greater than 30 nm and 300 nm or less, and even more preferably greater than 30 nm and 200 nm or less. The average size of the crystal particles 12a on the free surface 10a is preferably greater than 30 nm and 200 nm or less, more preferably greater than 30 nm and 150 nm or less, and even more preferably greater than 30 nm and 100 nm or less. The average size of the crystal particles 12b on the roll surface 10b is preferably greater than 30 nm and 500 nm or less, more preferably greater than 30 nm and 300 nm or less, and even more preferably greater than 30 nm and 200 nm or less. By satisfying the lower limit of this range for the average size of the α-Fe phase crystal particles 12x, the manufacturability of the magnetic powder can be improved. By ensuring that the average size of the α-Fe phase crystal grains (12x) meets the upper limit of this range, the reinforcing effect of the residual magnetism can be improved, and the decrease in the coercivity of the magnetic powder can be suppressed.

[0038] Furthermore, the ratio of the average size of the crystal particles 12b on the roll surface 10b to the average size of the crystal particles 12a on the free surface 10a is preferably 1 to 5, and more preferably 1 to 2. By having the size ratio of the crystal particles 12a and 12b within this range, the reinforcing effect of residual magnetism can be improved, and the decrease in the coercivity of the magnetic powder can be suppressed.

[0039] In this disclosure, the average size σ of the α-Fe phase crystal grains can be measured based on a cross-sectional microstructure image of magnetic powder particles 10 obtained by an electron microscope such as a scanning electron microscope (SEM). Specifically, the total cross-sectional area S of n α-Fe phase crystal grains is measured from the cross-sectional microstructure image. The diameter of the circle calculated by considering the total cross-sectional area S as the sum of the areas of n circles can then be calculated as the average size σ of the α-Fe phase crystal grains. That is, the average size σ of the α-Fe phase crystal grains can be calculated using the following equation (3) with respect to pi (π). Here, considering statistical accuracy and measurement conditions, the number of crystal grains n is set to 50 or more.

number

[0040] (Thickness of the soft magnetic phase) In this embodiment, the thickness of the soft magnetic phase 12 is preferably 30 nm to 500 nm, more preferably 30 nm to 300 nm, and even more preferably 30 nm to 200 nm. Furthermore, the thickness of the soft magnetic phase 12 on the free surface 10a is preferably 30 nm to 200 nm, more preferably 30 nm to 150 nm, and even more preferably 30 nm to 100 nm. The thickness of the soft magnetic phase 12 on the roll surface 10b is preferably 30 nm to 500 nm, more preferably 30 nm to 300 nm, and even more preferably 30 nm to 200 nm. By having the thickness of the soft magnetic phase 12 within this range, the reinforcing effect of the residual magnetism can be improved, and the decrease in the coercivity of the magnetic powder can be suppressed.

[0041] Furthermore, the ratio of the thickness of the soft magnetic phase 12 on the roll surface 10b to the thickness of the soft magnetic phase 12 on the free surface 10a is preferably 1 to 10, and more preferably 1 to 5. By having the thickness ratio of the soft magnetic phase 12 within this range, the reinforcing effect of residual magnetism can be improved, and the decrease in coercivity of the magnetic powder can be suppressed.

[0042] In this disclosure, the thickness of the soft magnetic phase 12 can be measured based on a cross-sectional microstructure image of the magnetic powder particles 10 obtained with an electron microscope such as a scanning electron microscope (SEM).

[0043] Furthermore, the magnetic powder particles 10 can be made into the crystalline phase specified above by appropriately adjusting their composition and the manufacturing conditions of the magnetic powder.

[0044] (Method for producing magnetic powder) The method for producing magnetic powder according to this embodiment includes a dissolution step, a rapid cooling step, a heat treatment step, and a nitriding step. However, the method for producing magnetic powder described in this embodiment is merely an example and is not limited thereto.

[0045] In the melting process, raw materials containing Sm, Zr, Fe, and metals M and B are blended and melted to produce molten metal. Specifically, the molten metal is produced by high-frequency induction melting of the raw material powder in an inert atmosphere such as an argon atmosphere.

[0046] In the rapid cooling process, the molten metal is sprayed onto a rotating cooling roll for rapid cooling. In the rapid cooling process, a ribbon is formed by causing the molten metal to collide with the cooling roll. The cooling roll is, for example, a metal roll such as copper. The speed of the cooling roll is not particularly limited, but it is preferably between 20 m / s and 100 m / s. This promotes the formation of the hard magnetic phase 11 of the TbCu7 type structure and improves the magnetic properties. At this time, of the surfaces of the ribbon, the surface in contact with the cooling roll becomes the roll surface, and the surface opposite the roll surface becomes the free surface. Here, the irregularities of the cooling roll surface are reflected in the roll surface, while the free surface does not come into contact with the cooling roll, so the roll surface is relatively rougher than the free surface. After that, the ribbon is crushed to obtain a flake-like powder.

[0047] In the heat treatment process, the powder obtained in the quenching process is heat-treated in an inert atmosphere at a temperature within the range of 500°C to 900°C. The inert atmosphere is, for example, an argon atmosphere.

[0048] In the nitriding process, the heat-treated powder is nitrided by heating it in a gas containing molecules with nitrogen atoms. Specifically, the powder is placed in a tubular furnace, and nitriding is carried out by flowing a gas containing molecules with nitrogen atoms through the tubular furnace. The gas containing molecules with nitrogen atoms is preferably nitrogen gas, a mixture of ammonia and hydrogen, etc. Here, the pressure of the gas used in the nitriding process and the heating temperature are adjusted according to the gas used. In a specific example, when using nitrogen gas, the heating temperature is set to 400°C to 500°C. The nitrogen content in the powder is also adjusted by adjusting the nitriding time. When the amount of powder is large, it is preferable to perform nitriding while stirring the powder in a rotary heating furnace in order to improve the uniformity of the product and the efficiency of the reaction.

[0049] By performing the above operations, the magnetic powder according to this embodiment can be obtained.

[0050] (Magnetic compound for bonding) The compound for bonded magnets according to this embodiment comprises the magnetic powder according to this embodiment and a binder. This makes it possible to provide a compound for bonded magnets with high magnetic properties.

[0051] The compound for bonded magnets according to this embodiment can be manufactured, for example, by mixing the magnetic powder according to this embodiment with the binder powder.

[0052] A binder is a material that binds magnetic powder particles together. The type of binder is not particularly limited; for example, phenolic resin, epoxy resin, nylon, etc., can be used. When the bonded magnet compound is used in the manufacture of bonded magnets produced by compression molding, the binder is preferably a thermosetting resin such as phenolic resin or epoxy resin. On the other hand, when the bonded magnet compound is used in the manufacture of bonded magnets produced by injection molding, the binder is preferably a thermoplastic resin such as nylon.

[0053] (Bonded magnet) The bonded magnet according to this embodiment includes the compound for bonded magnets according to this embodiment. This makes it possible to provide a bonded magnet with high magnetic properties.

[0054] The method for manufacturing the bonded magnet according to this embodiment is not particularly limited, and can be manufactured, for example, by a molding process and a magnetization process.

[0055] In the molding process, the compound for bonded magnets is molded using methods such as compression molding and injection molding. When bonded magnets are manufactured by compression molding, the compound for bonded magnets is placed in a press mold, a molded body is obtained by compression molding, and the binder is hardened by heating in an inert atmosphere such as a nitrogen atmosphere. Here, the compression molding to obtain the molded body is, for example, 10 t / cm². 2 This can be done under pressure, and the molded body can be heated, for example, at a heating temperature of 150°C for a heating time of 1 hour.

[0056] In the magnetization process, an external magnetic field is applied to the molded body to magnetize it. This allows for the production of the bonded magnet according to this embodiment.

[0057] (Examples) The following describes embodiments of this embodiment. Note that the following embodiments are not intended to limit the invention described herein.

[0058] Table 1 shows the composition, manufacturing conditions, and magnetic properties of the magnetic powders related to Examples 1 to 7 and Comparative Examples 1 to 8.

[0059] [Table 1]

[0060] (Examples 1-7 and Comparative Examples 1-8) Examples 1 to 7 and Comparative Examples 1 to 8 were prepared using the methods described in the embodiments above. Specifically, the powders in Examples 1 to 7 and Comparative Examples 1 to 8 were prepared by a dissolution step, a quenching step, a heat treatment step, and a nitriding step.

[0061] In Examples 1 to 7 and Comparative Examples 1 to 4, 7, and 8, the melting process involved blending Sm, Zr, Fe, Co, and B in the compositional ratios shown in Table 1 and dissolving them to produce molten metal. In Comparative Examples 5 and 6, the melting process involved blending raw materials containing Sm, Zr, Fe, and Co and dissolving them to produce molten metal. That is, B was not added in Comparative Examples 5 and 6. The molten metal was prepared by introducing the raw materials into a quartz nozzle with a 0.5 mm diameter pore at the bottom and dissolving the raw material powder by high-frequency induction under an argon atmosphere.

[0062] In the rapid cooling process, molten metal was sprayed onto a rotating cooling roll and impacted to form ribbons. The ribbons were then crushed to obtain flake-like powder. The flake-like powder was then sieved through a sieve with a mesh size of approximately 300 μm to collect the resulting powder.

[0063] In the heat treatment process, the powder obtained in the rapid cooling process was heat-treated for 60 minutes under an argon atmosphere at the heat treatment temperatures shown in Table 1.

[0064] In the nitriding process, the heat-treated powder was nitrided by heating it at 440°C for 15 hours under a nitrogen gas atmosphere.

[0065] The magnetic properties of the prepared magnetic powder include the remanent magnetic flux density B. r , coercive force H cj , Maximum energy product (BH) max The knic ratio was measured using a VSM. Here, in the measurement of magnetic properties, the average true density of the magnetic powder particles was 7.66 g / cm³. 3 That's what I decided.

[0066] The magnetic properties of the magnetic materials in Examples 1 to 7 and Comparative Examples 1 to 8 are shown in Table 1 and Figure 5. Figure 5 shows the residual magnetic flux density B for Examples 1 to 7 and Comparative Examples 1 to 6 and 8. r and coercivity H cj This graph shows the relationship. In Figure 5, the data for Comparative Example 7 is coercivity H cj It is omitted because it is small. Also, line A shown in Figure 5 represents the following equation (4). B r =-0.08H cj +10.6 …(4) In other words, in Figure 5, the region along line A and the region above line A is a region that satisfies the following equation (1). B r ≥-0.08H cj +10.6 …(1)

[0067] As shown in Table 1, in Examples 1 to 7, the atomic ratio Zr / (Sm+Zr) is greater than 0.10 and less than 0.30, while in Comparative Examples 1 and 3, the atomic ratio Zr / (Sm+Zr) is 0.10 or less, and in Comparative Examples 2 and 4, the atomic ratio Zr / (Sm+Zr) is 0.30 or more. Residual magnetic flux density B r and coercivity H cj Regarding the relationship, as shown in Figure 5, the plots for Examples 1 to 7 are above line A and satisfy equation (1), while the plots for Comparative Examples 1 to 4 are below line A and do not satisfy equation (1). Also, as shown in Table 1, the maximum energy product (BH) for Examples 1 to 7 max While it became larger than 18.5 MGOe, the maximum energy product (BH) for Comparative Examples 1 to 4 max The knic ratio was 18.5 MGOe or less. Furthermore, as shown in Table 1, the knic ratio for Examples 1 to 7 was less than 0.036, while the knic ratio for Comparative Examples 1 to 4 was 0.036 or greater. From this, it can be seen that the magnetic properties can be improved when the atomic ratio Zr / (Sm+Zr) is greater than 0.10 and less than 0.30.

[0068] As shown in Table 1, in Examples 1 to 5, the atomic ratio Zr / (Sm+Zr) is between 0.15 and 0.20, while in Example 6, the atomic ratio Zr / (Sm+Zr) is greater than 0.20, and in Example 7, the atomic ratio Zr / (Sm+Zr) is less than 0.15. Also, as shown in Table 1, the maximum energy product (BH) for Examples 1 to 5 max This is the maximum energy product (BH) related to Examples 6 and 7. maxIt is greater than this. From this, it can be seen that the magnetic properties can be further improved when the atomic ratio Zr / (Sm+Zr) is between 0.15 and 0.20.

[0069] As shown in Table 1, in Examples 1 to 7, the B content was greater than 0.0 atomic% and less than 0.4 atomic%, while in Comparative Examples 5 and 6, the B content was 0.0 atomic% or less, and in Comparative Examples 7 and 8, the B content was 0.4 atomic% or more. Residual magnetic flux density B r and coercivity H cj Regarding the relationship, as shown in Figure 5, the plots for Examples 1 to 7 are above line A and satisfy equation (1), while the plots for Comparative Examples 5 to 8 are below line A and do not satisfy equation (1). Also, as shown in Table 1, the maximum energy product (BH) for Examples 1 to 7 max While it became larger than 18.5 MGOe, the maximum energy product (BH) for Comparative Examples 5 to 8 max The knic content was 18.5 MGOe or less. Furthermore, as shown in Table 1, the knic content for Examples 1 to 7 was less than 0.036, while the knic content for Comparative Examples 5 to 8 was 0.036 or more. From this, it can be seen that the magnetic properties can be improved when the B content is greater than 0.0 atomic% and less than 0.4 atomic%.

[0070] As shown in Table 1, in Examples 1 to 7, the B content is between 0.1 atomic% and 0.3 atomic%, while in Comparative Examples 5 and 6, the B content is less than 0.1 atomic%, and in Comparative Examples 7 and 8, the B content is greater than 0.3 atomic%. As shown in Table 1, the maximum energy product (BH) for Examples 1 to 7 max This is the maximum energy product (BH) related to Comparative Examples 5 to 8. max The knic ratio increased. Also, as shown in Table 1, the knic ratio in Examples 1 to 7 was smaller than the knic ratio in Comparative Examples 5 to 8. From this, it can be seen that the magnetic properties can be improved by having a B content of 0.1 atomic% or more and 0.3 atomic% or less.

[0071] The inventions relating to this disclosure are not limited to the embodiments described above, and can be modified within the scope of the spirit of the inventions relating to this disclosure.

[0072] Furthermore, this embodiment may also be described in the following ways. [1] It includes Sm, Zr, Fe, B, and N. The atomic ratio of the Zr content to the sum of the Sm and Zr content is greater than 0.10 and less than 0.30. Magnetic powder with a B content greater than 0.0 atomic% and less than 0.4 atomic%. [2] The magnetic powder according to [1], wherein the atomic ratio is 0.15 or more and 0.20 or less. [3] The magnetic powder according to [1] or [2], wherein the content of B is 0.1 atomic% or more and 0.3 atomic% or less. [4] A magnetic powder according to any one of [1] to [3], having a maximum energy product greater than 18.5 MGOe. [5] Residual magnetic flux density B r (kG) and coercivity H cj (kOe) is a magnetic powder described in any one of [1] to [4] that satisfies the following formula (1). B r ≥-0.08H cj +10.6 …(1) [6] A magnetic powder according to any one of [1] to [5], wherein the knic ratio is less than 0.036. [7] A hard magnetic phase having a TbCu7 type structure, A soft magnetic phase having a body-centered cubic lattice structure The magnetic powder according to any one of [1] to [6], comprising at least a portion of magnetic powder particles containing the [8] The magnetic powder according to [7], wherein the content of the soft magnetic phase is greater than 0.0 volume% and less than 1.0 volume%. [9] The magnetic powder according to [7] or [8], wherein the average size of the crystal particles contained in the soft magnetic phase is greater than 30 nm and less than or equal to 500 nm.

[10] A compound for bonded magnets comprising the magnetic powder described in [1] and a binder.

[11] Bonded magnets, including the bonded magnet compound described in

[10] . [Explanation of symbols]

[0073] 10 magnetic powder particles 10a Free surface 10b Roll surface 11 Hard magnetic phase 12 Soft magnetic phase 12a, 12b, 12x crystal particles

Claims

1. It includes Sm, Zr, Fe, B, and N. The atomic ratio of the Zr content to the sum of the Sm content and the Zr content is greater than 0.10 and less than 0.

30. A magnetic powder in which the content of B is greater than 0.0 atomic% and less than 0.4 atomic%.

2. The magnetic powder according to claim 1, wherein the atomic ratio is 0.15 or more and 0.20 or less.

3. The magnetic powder according to claim 1, wherein the content of B is 0.1 atomic% or more and 0.3 atomic% or less.

4. The magnetic powder according to claim 1, wherein the maximum energy product is greater than 18.5 MGOe.

5. Residual magnetic flux density B ｒ (kG) and coercivity H ｃｊ (kOe) is the magnetic powder according to claim 1, satisfying the following formula (1). B ｒ ≧-0.08H ｃｊ +10.6 …(1)

6. The magnetic powder according to claim 1, wherein the knic ratio is less than 0.

036.

7. TbCu ７ A hard magnetic phase having a type structure, A soft magnetic phase having a body-centered cubic lattice structure The magnetic powder according to claim 1, comprising at least a portion of magnetic powder particles containing the above.

8. The magnetic powder according to claim 7, wherein the content of the soft magnetic phase is greater than 0.0 volume% and less than 1.0 volume%.

9. The magnetic powder according to claim 7, wherein the average size of the crystal particles contained in the soft magnetic phase is greater than 30 nm and less than or equal to 500 nm.

10. A compound for bonded magnets comprising the magnetic powder described in claim 1 and a binder.

11. A bonded magnet comprising the compound for bonded magnets described in claim 10.

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