Rare earth bonded magnet material and magnet

Abstract

The present disclosure relates to a rare earth bonded magnet material that includes crystal grains of an RE2Fe14B-type compound as a principal phase (11). RE represents at least one type of rare earth element. Grain boundary regions (12) that are present between the crystal grains have a layered structure that is formed by the layering of at least two types of grain boundary phases. The grain boundary phases contain at least one type of rare earth element, at least one type of transition metal element, and at least one element selected from the group that consists of F and O. The at least one type of transition metal element includes Fe or Co. The grain boundary phases have a different concentration of F or O from the principal phase (11) or have a different crystal structure and / or a different concentration of the at least one transition metal element from the principal phase (11).

Description

Materials and magnets for rare earth bonded magnets

[0001] The present disclosure relates to materials for rare earth bonded magnets, and further to magnets containing the same.

[0002] In International Publication No. 2021 / 182591 (Patent Document 1), an iron-based rare earth boron-based isotropic magnet alloy is disclosed, which has a RE ２ Fe １４ B-type tetragonal compound as the main phase, a B content concentration lower than that of the RE ２ Fe １４ B-type tetragonal compound, and a grain boundary phase surrounding the main phase.

[0003] In International Publication No. 2023 / 38135 (Patent Document 2), a magnet material for bonded magnets is disclosed, which has a RE ２ Fe １４ B-type tetragonal compound as the main phase, and an amorphous grain boundary phase containing F, RE, Fe, and B surrounding the main phase.

[0004] In International Publication No. 2024 / 57653 (Patent Document 3), an iron-based rare earth boron-based isotropic nanocomposite magnet alloy is disclosed, which has a RE ２ Fe １４ B-type tetragonal compound as the main phase, and a grain boundary phase surrounding the main phase containing a phase richer in Fe than the main phase.

[0005] In Japanese Patent Application Laid-Open No. 2012-15169 (Patent Document 4), an R-T-B-based rare earth permanent magnet is disclosed, which includes a main phase mainly containing R ２ Fe １４ B, and a grain boundary phase containing more rare earth elements than the main phase, and is made of a sintered body containing Ga. The grain boundary phase includes a first grain boundary phase, a second grain boundary phase, and a third grain boundary phase having different total atomic concentrations of rare earth elements.

[0006] International Publication No. 2021 / 182591, International Publication No. 2023 / 38135, International Publication No. 2024 / 57653, Japanese Patent Application Laid-Open No. 2012-15169

[0007] In Patent Documents 1 to ³, by performing super rapid cooling in a state where the B content in the alloy is lower than that in the prior art, a nano-level grain boundary phase containing rare earth elements, Fe, F, etc. is formed to improve the intrinsic coercive force HcJ (hereinafter, also referred to as HcJ).

[0008] To further improve the intrinsic coercivity HcJ, various methods are being considered, such as increasing the content of rare earth elements Fe and F, which are the main components of the grain boundary phase, or further reducing the content of B, which determines the total amount of the main phase, thereby lowering the proportion of the main phase and increasing the proportion of the grain boundary phase, which contributes to improving the intrinsic coercivity HcJ.

[0009] However, increasing the content of rare earth elements Fe and F, which are the main components of the grain boundary phase, tends to lead to significant disadvantages in production costs and productivity, such as an increase in expensive rare earth elements and an increase in slag consisting of rare earth element-fluorides during alloy melting due to the increase in F, which lowers the alloy yield. In addition, increasing the Fe content may lead to a decrease in intrinsic coercivity HcJ and prismaticity due to the generation of soft magnetic Fe-based compounds. Furthermore, if the B content is further reduced, the original main phase Nd ２ F １４ As the amount of B forming B decreases further, a very Fe-rich component with Nd:Fe = 2:14 is supplied to the grain boundaries, making it easier for the same property degradation as the increase in Fe content mentioned above to occur. In addition, the decrease in the proportion of the main phase, which is a magnetic phase with high magnetization, makes it easier for the remanent magnetization Br to decrease.

[0010] Patent Document 4 describes how adding Ga to an alloy with a lower B content than conventional methods generates multiple grain boundary phases and improves the intrinsic coercivity HcJ. However, because the multiple grain boundary phases exist separately and independently, the effect of improving the intrinsic coercivity HcJ due to the magnetic pinning effect caused by the stacking of multiple grain boundary phases cannot be observed. Furthermore, since this method involves sintering and annealing at high temperatures and for long periods of time, it is difficult to apply to nanocrystalline materials that are prone to property degradation due to crystal growth at high temperatures.

[0011] The purpose of this disclosure is to provide a material for rare-earth bonded magnets that can improve the intrinsic coercivity HcJ, and a magnet containing the same.

[0012] Materials for rare earth bond magnets according to embodiments of this disclosure are RE ２ Fe １４It is a material for a rare earth bonded magnet having crystal grains of a B-type compound as the main phase. RE represents at least one rare earth element. RE ２ Fe １４ The grain boundary region existing between the crystal grains of the B-type compound has a laminated structure in which two or more grain boundary phases are laminated. The grain boundary phase contains at least one rare earth element, at least one transition metal element, and at least one element selected from the group consisting of F and O. The at least one transition metal element includes Fe or Co. The grain boundary phase has a different concentration of F or O compared to the main phase, or at least one of the crystal structure and the concentration of the at least one transition metal element is different from that of the main phase.

[0013] A material for a rare earth bonded magnet according to another embodiment of the present disclosure is RE ２ Fe １４ It is a material for a rare earth bonded magnet having crystal grains of a B-type compound as the main phase. RE represents at least one rare earth element. RE ２ Fe １４ The grain boundary region existing between the crystal grains of the B-type compound has a laminated structure in which two or more grain boundary phases are laminated. The grain boundary phase contains at least one rare earth element, at least one transition metal element, and at least one element selected from the group consisting of F, O, and B. The at least one transition metal element includes Fe or Co. The grain boundary phase has a different concentration of F or O compared to the main phase, or at least one of the crystal structure and the concentration of the at least one transition metal element is different from that of the main phase.

[0014] According to the present disclosure, it is possible to provide a material for a rare earth bonded magnet capable of improving the intrinsic coercive force HcJ and a magnet containing the same.

[0015] Figure 1 is a schematic cross-sectional view of the rare-earth bonded magnet material of this disclosure. Figure 2 is a schematic cross-sectional view illustrating the layered structure in the grain boundary region. Figure 3 is a schematic cross-sectional view of the rare-earth bonded magnet material of this disclosure. Figure 4 is a schematic cross-sectional view illustrating the layered structure in the grain boundary region. Figure 5 shows transmission electron microscope images of the magnet materials obtained in Example 1 and Comparative Example 1. Figure 6 shows elemental mapping by EDX of the magnet material obtained in Example 1. Figure 7 shows the results of elemental quantitative analysis by EDX line analysis of the magnet material obtained in Example 1. Figure 8 shows transmission electron microscope images of the magnet material obtained in Example 1.

[0016] <Materials for Rare Earth Bonded Magnets> [First Embodiment] The rare earth bonded magnet material according to the first embodiment (hereinafter also referred to as the first rare earth bonded magnet material) is RE ２ Fe １４ This is a rare-earth bond magnet material whose main phase is the crystal grains of type B compounds. RE represents at least one rare-earth element. ２ Fe １４ The grain boundary regions between the crystal grains of a type B compound have a layered structure in which two or more grain boundary phases are stacked. The grain boundary phase contains at least one rare earth element, at least one transition metal element, and at least one element selected from the group consisting of F and O. The at least one transition metal element includes Fe or Co. The grain boundary phase has a different concentration of F or O compared to the main phase, or at least one of the crystal structure and the concentration of the at least one transition metal element differs from the main phase.

[0017] The first rare earth bond magnet material can be an isotropic bond magnet material. The first rare earth bond magnet material is preferably an isotropic bond magnet material. The first rare earth bond magnet material is RE ２ Fe １４ The presence of crystal grains and grain boundary regions of the type B compound can be confirmed by transmission electron microscopy (TEM) observation of a cross-section of the material for the first rare earth bond magnet. Figure 1 is a schematic diagram of the TEM observation image of a cross-section of the material for the first rare earth bond magnet. In the material for the first rare earth bond magnet 10, the main phase 11 is RE ２ Fe１４ It consists of crystal grains G of the B-type compound. The material for the RE-Fe-B type magnet may, for example, consist only of a main phase and a grain boundary region.

[0018] The crystal grains G constituting the main phase 11 are ２ Fe １４ crystal grains of the B-type compound. RE ２ Fe １４ The B-type compound may be tetragonal. RE represents at least one rare earth element. RE may be, for example, at least one rare earth element containing Nd, or at least one rare earth element containing Nd and Pr. RE may be Nd or Pr, or Nd and Pr. RE may contain at least one of Dy, Tb, La, Ce, and Gd. RE may be a rare earth element that does not contain heavy rare earth elements.

[0019] The main phase 11 may, for example, further contain O. In this specification, the types and concentrations of the elements contained in the main phase and the grain boundary phase can be quantified by energy dispersive X-ray spectroscopy (EDX), electron energy loss spectroscopy (EELS), etc. When quantifying by EDX, for example, it can be carried out using an observation image at a magnification of 150,000 times with a scanning transmission electron microscope (STEM / EDX).

[0020] The average crystal grain size of the crystal grains G may be, for example, 10 nm or more and 200 nm or less. From the viewpoints of intrinsic coercive force HcJ and the rectangularity of the demagnetization curve, the average crystal grain size of the crystal grains G is preferably 10 nm or more and less than 100 nm, more preferably 15 nm or more and 60 nm or less, and still more preferably 15 nm or more and 50 nm or less. The average crystal grain size means the average value of the diameters of each particle existing in the field of view when the particle diameters are measured at three or more points by the line segment method in the STEM observation image.

[0021] The grain boundary region 12 exists between the crystal grains G of the main phase 11. The grain boundary region 12 can exist in direct contact with the surface of the crystal grains G. The grain boundary region 12 can be a region in which at least one of the composition, crystal state, and crystal orientation differs from that of the main phase 11. The grain boundary region 12 also includes a portion of the main phase 11 at its outermost edge in which at least one of the composition, crystal state, and crystal orientation differs from that of the main phase 11. The grain boundary region 12 has a layered structure in which two or more grain boundary phases are stacked. The two or more grain boundary phases may be two or more grain boundary phases in which at least one of the crystal structure and the composition of constituent elements differs from each other. The presence of a layered structure in the grain boundary region 12 can be confirmed by observing a transmission electron microscope (TEM) or scanning transmission electron microscope (STEM) image of a cross-section after processing the material for the first rare earth bond magnet with a focused ion beam apparatus and an Ar milling apparatus to a sample thickness of ≤100 μm, under the conditions of acceleration voltage = 200 kV, field of view = 40-200 nm, and number of pixels 512 × 512. The grain boundary region 12 may have a layered structure throughout the entire grain boundary region, or only a part of the grain boundary region may have a layered structure. The ratio of the portion having a layered structure to the entire grain boundary region may be, for example, 10 area% to 100 area%. From the viewpoint of intrinsic coercivity HcJ and the angularity of the demagnetization curve, the ratio of the portion having a layered structure to the entire grain boundary region is preferably 50 area% to 100 area% and more preferably 75 area% to 100 area%. The ratio (area %) of the portion having a laminated structure to the entire grain boundary region refers to the ratio of the area of ​​the portion having a laminated structure to the total area of ​​the grain boundary regions present inside the material for the first rare earth bond magnet. The grain boundary region 12 may have a portion composed of only a single layer, for example, only one of the first grain boundary phase 13 or the second grain boundary phase 14. Preferably, the entire grain boundary region 12 has a laminated structure.

[0022] The grain boundary region 12 may be a laminated structure in which, for example, two, three, four, or five types of grain boundary phases are stacked. In the grain boundary region 12, the same type of grain boundary phase may be stacked. In the grain boundary region 12, the number of layers in the laminated structure may be two or more, for example, two, three, four, or five layers.

[0023] In Figure 1, the grain boundary region 12 has a stacked structure in which a first grain boundary phase 13 and a second grain boundary phase 14 are stacked. The stacked structure may exist so as to surround the crystal grains G. The first grain boundary phase 13 and the second grain boundary phase 14 may differ from each other in at least one of their crystal structure and constituent element composition. The presence of a uniformly distributed grain boundary region around the main phase weakens the exchange interaction acting between crystallites of the main phase, making it difficult for magnetization reversals occurring in some main phase crystallites to propagate to other main phases. This improves the intrinsic coercivity HcJ of the magnet. Furthermore, in the grain boundary region, the stacking of multiple phases with different domain wall energies creates a domain wall energy gap at the phase interface, resulting in the generation or enhancement of magnetic pinning, which hinders domain wall movement due to an external magnetic field. This makes it difficult for magnetization reversals occurring in some main phase crystallites to propagate to other main phases, thus making it easier to improve the intrinsic coercivity HcJ. It is desirable that at least one of these multiple phases contains Fe or Co elements, which have high domain wall energy, or is an Fe compound phase or a Co compound phase. Furthermore, the stacking of multiple magnetic phases increases the total thickness of the grain boundary region, magnetically separating the crystal grains of the main phase, making it more difficult for magnetization reversal to propagate, and as a result, the intrinsic coercivity HcJ tends to improve. The more layers there are in the stacked structure, the more likely it is that a magnetic energy gap will occur at the phase interface, and the thickness of the grain boundary region will tend to increase.

[0024] In the manufacture of rare-earth bond magnet materials of similar composition containing at least F and B, when the magnet material is manufactured using methods such as strip casting, die casting, or centrifugal casting, a crystalline or non-uniform, coarse grain boundary phase containing F (but not B, or containing trace amounts of B) is generated, making it difficult to achieve a state in which the grain boundary region uniformly covers the main phase. The grain boundary phase tends to be more easily formed by employing the melt spinning method, which is a rapid cooling method suitable for the manufacture of bond magnets having a fine structure (for example, a structure in which the average grain size of the main phase is 70 nm or less). Furthermore, in the manufacturing method of the first rare-earth bond magnet material, rapid cooling after heat treatment using a water-cooled cooling retort, or rapid cooling after heat treatment using a SiC susceptor with high heat dissipation, tends to suppress the reaction or integration of multiple phases due to preheating after heat treatment, resulting in a tendency to have a multi-phase laminated structure. Furthermore, this rapid cooling suppresses elemental diffusion due to preheating after heat treatment, resulting in a larger difference in composition between grain boundary phases. Consequently, the difference in domain wall energy increases, making magnetic pinning more likely to occur.

[0025] Figure 2 is a schematic cross-sectional view of the stacked structure of the grain boundary region 12 in the stacking direction. As shown in Figure 2, the grain boundary region 12 exists between the main phase 11 (crystal grains G). The grain boundary region 12 can have a stacked structure in which the second grain boundary phase 14, the first grain boundary phase 13, and the second grain boundary phase 14 are stacked in this order. In the grain boundary region 12, the second grain boundary phase 14 can exist so as to surround the main phase 11 (crystal grains G), and the first grain boundary phase 13 can exist so as to surround the second grain boundary phase 14.

[0026] The first rare-earth bond magnet material 10 may further have a third grain boundary phase between the second grain boundary phase 14 and the main phase 11 (crystal grain G) in the grain boundary region 12. The first grain boundary phase, the second grain boundary phase, and the third grain boundary phase may differ from each other in at least one of their crystal structure and constituent element composition. The third grain boundary phase may be, for example, a portion of the main phase at its outermost edge that differs from the main phase 11 in at least one of its composition, crystal state, and crystal orientation. Figure 3 is a schematic diagram of a STEM observation image of a cross-section of the first rare-earth bond magnet material 10 when the grain boundary region 12 has a third grain boundary phase. Figure 4 shows a layered structure when the grain boundary region 12 further has a third grain boundary phase 15. In Figure 4, the third grain boundary phase 15, the second grain boundary phase 14, the first grain boundary phase 13, the second grain boundary phase 14, and the third grain boundary phase 15 are stacked in this order between the main phase 11 (crystal grains G). The fact that the material for the first rare earth bond magnet has a first grain boundary phase, a second grain boundary phase, and a third grain boundary phase in the grain boundary region can be confirmed by transmission electron microscope (TEM) or scanning transmission electron microscope (STEM) images or line analysis using EDX of a cross-section observed or analyzed under the conditions of acceleration voltage = 200 kV, field of view = 40-170 nm, and number of pixels = 512 × 512, after processing the material for the first rare earth bond magnet to a sample thickness ≤ 100 μm using a focused ion beam apparatus and an Ar milling apparatus.

[0027] The grain boundary phase contains at least one rare earth element, at least one transition metal element, and at least one element selected from the group consisting of F and O. The at least one rare earth element included in the grain boundary phase may be, for example, at least one rare earth element including Nd, at least one rare earth element including Nd and Pr, or at least one selected from the group consisting of Nd and Pr. The at least one rare earth element included in the grain boundary phase may be, for example, Nd or Pr, or Nd and Pr. The at least one rare earth element included in the grain boundary phase may include at least one from Dy, Tb, La, Ce, and Gd. The at least one rare earth element included in the grain boundary phase may be a rare earth element that does not include heavy rare earth elements.

[0028] The grain boundary phase may contain at least one transition metal element, which may be a transition metal element containing Fe or Co, or may be a transition metal element containing Fe, or may be Fe.

[0029] The grain boundary phase may contain at least one element selected from the group consisting of F and O, and may contain F. The grain boundary phase may not contain F, or may not contain O.

[0030] The grain boundary phase has a different concentration of F or O compared to the main phase, or at least one of the crystal structure and the concentration of at least one transition metal element differs from the main phase.

[0031] The concentration of F or O in the grain boundary phase may be higher or lower than that of the main phase. If the concentration of F or O in the grain boundary phase is higher than that of the main phase, the concentration of F or O in the grain boundary phase may be, for example, 5 atomic percent or more higher, 10 atomic percent or more higher, or 20 atomic percent or more higher than that of the main phase. The concentration of F in the grain boundary phase may be higher than that of F in the main phase. The concentration of F or O may tend to increase from the outermost edge of the main phase to the center of the grain boundary phase, and the concentration of F may tend to increase from the outermost edge of the main phase to the center of the grain boundary phase. If the concentration of F or O in the grain boundary phase is higher than that of the main phase, the concentration of F or O in all grain boundary phases in the grain boundary region may be higher than that of the main phase. In the first rare earth bond magnet material 10, the concentration of F or O in at least one of the first grain boundary phase 13 and the second grain boundary phase 14 may be higher than that of the main phase, and the concentration of F or O in the second grain boundary phase 14 may be higher than that of the main phase. The comparison of the concentrations of F or O in the grain boundary phase and the main phase can be performed by EDX line analysis.

[0032] If the crystal structure of the grain boundary phase differs from that of the main phase, then the crystal structure of all grain boundary phases in the grain boundary region may differ from that of the main phase. The difference in the crystal structure of the grain boundary phase from that of the main phase can be confirmed, for example, by observing the main phase and the grain boundary phase using TEM or STEM, by observing differences in the presence or absence of lattice images and lattice fringes, differences in the directionality of lattice images and lattice fringes, differences in lattice spacing and electron diffraction patterns, etc.

[0033] If the concentration of at least one transition metal element in the grain boundary phase differs from that of the main phase, the concentration of Fe in the grain boundary phase may differ from that of the main phase. The concentration of Fe in the grain boundary phase may be, for example, 5 atomic percent or more lower than the concentration of Fe in the main phase, or 10 atomic percent or more lower, or 20 atomic percent or more lower. The concentration of at least one transition metal element may tend to decrease from the outermost edge of the main phase to the center of the grain boundary phase, and the concentration of Fe may tend to decrease from the outermost edge of the main phase to the center of the grain boundary phase. If the concentration of at least one transition metal element in the grain boundary phase differs from that of the main phase, the concentration of at least one transition metal element in all grain boundary phases in the grain boundary region may differ from that of the main phase. In the first rare earth bond magnet material 10, the concentration of at least one transition metal element in at least one of the first grain boundary phase 13 and the second grain boundary phase 14 may differ from that of the main phase, and the concentration of at least one transition metal element in the second grain boundary phase 14 may differ from that of the main phase.

[0034] The concentration of oxygen in the grain boundary phase may be lower than the concentration of oxygen in the main phase, for example, by 5 atomic percent or more, or by 10 atomic percent or more, or by 20 atomic percent or more. The concentration of oxygen in all grain boundary phases in the grain boundary region may be lower than the concentration of oxygen in the main phase. In the first rare earth bond magnet material 10, the concentration of oxygen in at least one of the first grain boundary phase 13 and the second grain boundary phase 14 may be lower than that of the main phase, and the concentration of oxygen in the second grain boundary phase 14 may be lower than that of the main phase.

[0035] The grain boundary phase may have a higher concentration of F and lower concentrations of Fe and O compared to the main phase. In the first rare earth bond magnet material 10, at least one of the first grain boundary phase 13 and the second grain boundary phase 14 may have a higher concentration of F and lower concentrations of Fe and O compared to the main phase 11, and the second grain boundary phase 14 may have a higher concentration of F and lower concentrations of Fe and O compared to the main phase 11.

[0036] In a first rare earth bond magnet material 10, the first grain boundary phase 13 may have a concentration of at least one rare earth element, at least one transition metal element, and at least one element from among F, O, and B that differs by 5 atomic percentages or more compared to at least one of the other grain boundary phases, and the concentrations of Fe, F, and O may differ by 5 atomic percentages or more.

[0037] At least one of the two or more grain boundary phases may be a ferromagnetic phase having a different Fe concentration than the main phase and a different Fe concentration than at least one of the other grain boundary phases.

[0038] The thickness of the grain boundary region in the stacking direction may be, for example, 1 nm to 50 nm. The thickness of the grain boundary region in the stacking direction can be determined by measuring the dimensions of the grain boundary region in the stacking direction in a STEM observation image of the cross-section of the material for the first rare earth bond magnet. If the thickness of the grain boundary region in the stacking direction is, for example, less than 1 nm, the effect of the exchange interaction acting between the main phase particles increases, which may lead to easier propagation of magnetization reversal and a decrease in intrinsic coercivity HcJ. Also, if the thickness of the grain boundary region in the stacking direction exceeds, for example, 50 nm, the proportion of the main phase in the entire material decreases, which may lead to an extreme decrease in remanent magnetization, prismaticity, and coercivity. The thickness of the grain boundary region in the stacking direction is preferably 2 nm to 40 nm, and more preferably 2 nm to 10 nm. The thickness of the grain boundary region in the stacking direction can be determined, for example, in a STEM observation image of the material for the first rare earth bond magnet. The thickness in the stacking direction of the grain boundary region can also be determined, for example, by processing the material for the first rare earth bond magnet to a sample thickness of ≤100 μm using a focused ion beam apparatus and an Ar milling apparatus, and then performing image analysis on a transmission electron microscope (TEM) or scanning transmission electron microscope (STEM) image of the cross-section observed under the conditions of acceleration voltage = 200 kV, field of view = 40-200 nm, and number of pixels 512 × 512.

[0039] The two or more grain boundary phases may be different from each other and may be either crystalline or amorphous. At least one of the two or more grain boundary phases may be crystalline, and all of the two or more grain boundary phases may be crystalline. Also, at least one of the two or more grain boundary phases may be amorphous, and all of the two or more grain boundary phases may be amorphous. For example, in the material 10 for the first rare earth bond magnet, the first grain boundary phase 13 may be amorphous, the second grain boundary phase 14 may be amorphous, the third grain boundary phase 15 may be amorphous, and the first grain boundary phase 13, the second grain boundary phase 14, and the third grain boundary phase 15 may all be amorphous. The inclusion of F in the grain boundary phases tends to facilitate the formation of amorphous grain boundary phases.

[0040] The volume ratio of grain boundary regions in the material for the first rare-earth bonded magnet may be, for example, 1% to 50% by volume. From the viewpoint of achieving both intrinsic coercivity HcJ and remanent magnetization Br, the volume ratio of grain boundary regions in the material for the first rare-earth bonded magnet is preferably 5% to 50% by volume. The coverage rate of the grain boundary regions on the outer periphery of the main phase may be, for example, 30% to 100% of the perimeter of the outer periphery of the main phase, and more preferably 50% to 100%. The volume ratio of grain boundary regions and the coverage rate of the grain boundary phase on the outer periphery of the main phase can be determined, for example, by processing the material for the first rare-earth bonded magnet to a sample thickness of ≤100 μm using a focused ion beam apparatus and an Ar milling apparatus, and then performing image analysis on scanning transmission electron microscope (STEM) images of the cross-section observed under the conditions of acceleration voltage = 200 kV, field of view = 150-550 nm, and number of pixels 512 × 512.

[0041] The alloy composition of the material for the first rare earth bond magnet is, for example, given by the following formula: T １００－ｘ－ｙ－ｚ (B １－ｎ C ｎ ) ｘ RE ｙ M ｚ (1) [In the formula, T represents at least one element selected from the group consisting of Fe, Co and Ni, which is a transition metal element that always contains Fe; RE represents at least one rare earth element; M represents at least one metallic element selected from the group consisting of Al, Si, V, Cr, Ti, Mn, Cu, Zn, Ga, Zr, Nb, Mo, Ag, Hf, Ta, W, Pt, Au and Pb; and the composition ratios x, y and z satisfy 4.2 atomic% ≤ x ≤ 5.6 atomic%, 11.5 atomic% ≤ y ≤ 14.0 atomic%, 0.0 atomic% ≤ z ≤ 5.0 atomic%, and 0.0 ≤ n ≤ 0.5, respectively.] It can be expressed as follows. Although not shown in the alloy composition of the material for the first rare earth bond magnet, the material for the first rare earth bond magnet may contain F and O as trace elements. Furthermore, for the analysis of the composition of the material for the first rare earth bond magnet, for example, ICP mass spectrometry or combustion ion chromatography may be used, and combustion-infrared absorption spectroscopy may also be used in combination.

[0042] RE is preferably at least one rare earth element containing at least one of Nd and Pr, more preferably at least one of Nd and Pr, and even more preferably Nd, or Nd and Pr. RE may contain at least one of Dy, Tb, La, Ce, and Gd. RE may be a rare earth element that does not contain heavy rare earth elements. Transition metal element T, which contains Fe as an essential element, occupies the remainder of the above-mentioned elements. Desired hard magnetic properties can be obtained by substituting a portion of Fe with one or two of Co and Ni, which are ferromagnetic elements like Fe. However, if the amount of substitution for Fe exceeds 30%, it will lead to a significant decrease in magnetic flux density, so it is preferable that the amount of substitution be in the range of 0% to 30%. Furthermore, adding Co not only contributes to improving magnetization but is also effective in reducing the viscosity of the molten metal and stabilizing the pouring rate from the nozzle during rapid cooling of the molten metal. Therefore, it is more preferable that the amount of Co replaced is 0.5% to 30%, and from the viewpoint of cost-effectiveness, it is even more preferable that the amount of Co replaced is 0.5% to 10%.

[0043] If the composition ratio x is less than, for example, 4.2 atomic percent, then RE ２ Fe １４ If the amount of B and C necessary for the formation of the type B tetragonal compound cannot be secured, the magnetic properties may decrease and the amorphous formation ability may decrease significantly. As a result, the α-Fe phase may precipitate during rapid cooling and solidification of the molten metal, and consequently, the angularity of the demagnetization curve may be impaired. Furthermore, if the composition ratio x exceeds 5.6 atomic%, there is a risk that grain boundary regions or grain boundary phases mainly composed of RE and Fe will not be formed, and the above-mentioned magnetic properties may not be secured. Therefore, it is preferable to set the composition ratio x in the range of 4.2 atomic% to 5.6 atomic%. It is preferable that the composition ratio x be 4.2 atomic% to 5.2 atomic%, and more preferably 4.4 atomic% to 5.0 atomic%.

[0044] By substituting a portion of B with C, the melting point of the molten alloy is lowered, reducing the amount of refractory material used during rapid solidification. This reduces the process cost related to rapid solidification and tends to improve the intrinsic coercivity HcJ. However, if the substitution rate of C for B exceeds 50%, the amorphous formation ability decreases significantly, which is undesirable. Therefore, the substitution rate of C for B is preferably in the range of 0% to 50%, i.e., 0.0 ≤ n ≤ 0.5. From the viewpoint of improving the intrinsic coercivity HcJ, the substitution rate of C for B is preferably 2% to 30%, and more preferably 3% to 15%. The material for the first rare earth bond magnet is preferably RE from the viewpoint of intrinsic coercivity HcJ. ２ Fe １４ The B content is lower than the stoichiometric composition of the type B compound.

[0045] If the composition ratio y is less than 11.5 atomic%, there is a risk that the grain boundary region or grain boundary phase will not be formed, and sufficient magnetic properties may not be ensured. Furthermore, if the composition ratio y exceeds 14.0 atomic%, there is a risk of a decrease in magnetization. Therefore, it is preferable that the composition ratio y is in the range of 11.5 atomic% or more and 14.0 atomic% or less. Note that F included in the grain boundary region or grain boundary phase is also included in Nd and Pr. That is, it is included in the raw materials used in manufacturing: Nd metal (Nd content of 95% by weight or more), Pr metal (Pr content of 95% by weight or more), or Nd-Pr metal (Nd / Pr weight ratio of 3.4 to 4.9% by weight, total of Nd and Pr of 95% by weight or more). From the viewpoint of achieving compatibility between intrinsic coercivity HcJ and magnetization, the composition ratio y is... ２ Fe １４ The stoichiometric composition of the type B tetragonal compound is preferably 11.76 atomic% to 13.5 atomic%, and more preferably 11.76 atomic% to 13.0 atomic%.

[0046] Rare earth elements RE require RE to obtain a higher intrinsic coercivity HcJ. ｙ = (Nd １－ｌ Pr ｌ ) ｙThis can be done, and it is preferable that the ratio l be 0.05 or more and 0.7 or less. However, if the ratio l of Pr to Nd is too low, the effect of improving HcJ will be small, and if the ratio l is too high, the absolute value of the temperature coefficient β related to the coercivity of the magnet alloy will be small, so there is a concern that the heat resistance will decrease. Therefore, it is preferable that the ratio l be 0.15 or more and 0.6 or less, and more preferably 0.2 or more and 0.5 or less.

[0047] In the material for the first rare earth bond magnet, one or more metal elements M selected from the group consisting of Al, Si, V, Cr, Ti, Mn, Cu, Zn, Ga, Zr, Nb, Mo, Ag, Hf, Ta, W, Pt, Au, and Pb may be added. The addition of metal elements M improves the ability to form amorphous material, improves the intrinsic coercivity HcJ due to the uniform refinement of the metal structure after crystallization heat treatment, and improves the angularity of the demagnetization curve, thereby improving the magnetic properties. However, if the composition ratio z of these metal elements M exceeds 5.0 atomic%, it may lead to a decrease in magnetization, so it is preferable that the composition ratio z is in the range of 0.0 atomic% or more and 5.0 atomic% or less. Furthermore, it is preferable that the composition ratio z is 0.0 atomic% or more and 4.0 atomic% or less, and more preferably 0.0 atomic% or more and 3.0 atomic% or less.

[0048] The material for the first rare earth bonded magnet may have an intrinsic coercivity HcJ of, for example, 1000 kA / m or more, preferably 1400 kA / m or more, and more preferably 1450 kA / m or more. The material for the first rare earth bonded magnet may have an intrinsic coercivity HcJ of, for example, 1600 kA / m or less.

[0049] The material for the first rare earth bonded magnet may be a single particle, an aggregate of particles (powder) (also called magnetic powder), or a thin strip. The material for the first rare earth bonded magnet may also be used as a mixed magnet material by mixing it with other bonded magnet materials. The content of the first rare earth bonded magnet material in the mixed magnet material containing the first rare earth bonded magnet material and other magnet materials may be, for example, 3% by mass or more and less than 100% by mass, 8% by mass or more and 99% by mass or less, or 20% by mass or more and 95% by mass or less. The material for the first rare earth bonded magnet may be a rare earth bonded magnet material that does not contain heavy rare earth elements.

[0050] The method for manufacturing the material for the first rare earth bond magnet may include, for example, a step of producing a rapidly solidified alloy and a step of flash annealing. In the step of producing a rapidly solidified alloy, first, a molten alloy having the above-described alloy composition is prepared. Next, this molten alloy is sprayed onto the surface of a rotating roll mainly composed of Cu, Mo, W, or at least one of these metals at an average pouring rate of 200 g / min or more and less than 2000 g / min per orifice hole placed at the tip of the nozzle, thereby RE ２ Fe １４ A rapidly solidified alloy is prepared having at least 1 volume percent of either a crystalline phase containing phase B or an amorphous phase. RE may be at least one rare earth element, and as described above, it can be at least one rare earth element including at least one of Nd and Pr. Details are as described above.

[0051] An average molten metal tapping rate of less than 200 g / min tends to result in poor productivity, while a rate of 2000 g / min or higher results in a molten metal rapid-cooling alloy structure containing a coarse α-Fe phase, which may prevent the acquisition of the aforementioned magnetic properties even after crystallization heat treatment. The average molten metal tapping rate is preferably 300 g / min to 1500 g / min, and more preferably 400 g / min to 1300 g / min.

[0052] The hole at the tip of the nozzle through which the molten metal is dispensed does not have to be a circular orifice; it can be a square, triangular, elliptical, or any other shape, and a slit shape is also acceptable as long as it can ensure a predetermined dispensing rate. In addition, the nozzle material can be any refractory material that does not react with the molten alloy or reacts poorly, but ceramic materials such as SiC, C, or BN are preferred, with BN being more preferred, and hard BN containing additives being even more preferred, as it reduces wear on the nozzle orifice due to the molten metal during dispensing.

[0053] When producing the above-mentioned rapidly solidified alloy, an oxygen-free or low-oxygen atmosphere is preferred for rapid solidification, as this prevents oxidation of the molten alloy, thereby suppressing an increase in molten metal viscosity and maintaining a stable pouring rate. To achieve this atmosphere, it is preferable to evacuate the rapidly solidifying apparatus to 20 Pa or less, preferably 10 Pa or less, and more preferably 1 Pa or less, then introduce an inert gas into the rapidly solidifying apparatus to reduce the oxygen concentration inside the apparatus to 500 ppm or less, preferably 200 ppm or less, and more preferably 100 ppm or less, before carrying out rapid solidification. As the inert gas, noble gases such as helium and argon or nitrogen can be used, but since nitrogen reacts relatively easily with rare earth elements and iron, noble gases such as helium and argon are preferred, and argon gas is more preferred from a cost standpoint.

[0054] In the process of producing a rapidly solidified alloy, the rotating roll used to rapidly cool the molten alloy is primarily composed of an alloy containing Cu, Mo, W, or at least one of these metals, and it is preferable that the base material contains such a primary component. This is because these base materials have excellent thermal conductivity and durability. Furthermore, by plating the surface of the base material of the rotating roll with Cr, Ni, or a combination thereof, the heat resistance and hardness of the base material surface of the rotating roll can be increased, suppressing melting and deterioration of the base material surface of the rotating roll during rapidly solidified. The diameter of the rotating roll is, for example, Φ200 mm or more and Φ20000 mm or less. If the rapidly solidified time is short, such as 10 seconds or less, it is not necessary to water cool the rotating roll, but if the rapidly solidified time exceeds 10 seconds, it is preferable to flow cooling water inside the rotating roll to suppress the temperature rise of the rotating roll base material. The water cooling capacity of the rotating roll is preferably calculated according to the latent heat of solidification per unit time and the molten metal extraction rate, and appropriately optimized.

[0055] In the flash annealing process, the rapidly solidified alloy can be heated at a rate of 10°C / min or more and less than 600°C / min to reach a constant temperature range above the crystallization temperature and below 850°C, and then rapidly cooled after 0.1 seconds or more and less than 7 minutes. By performing the flash annealing process, RE ２ Fe １４ Even at a B content lower than the stoichiometric composition of the type B compound, it tends to easily form a metallic structure having the aforementioned crystal grains and grain boundary regions. The processing temperature may be, for example, 620°C or higher, or 720°C or higher.

[0056] If the heating rate during flash annealing (crystallization heat treatment) is less than 10°C / min, there is a risk that a fine metallic structure cannot be obtained due to excessive grain growth, or that a layered structure of multiple grain boundary phases cannot be obtained as a result of elemental diffusion and phase integration between multiple adjacent grain boundary phases, and that the intrinsic coercivity HcJ may decrease. If the heating rate is 600°C / min or higher, there is a risk that the crystal grain growth and the formation of multiple grain boundary phases cannot keep up, and the metallic structure described above cannot be formed, which may lead to a decrease in magnetic properties, similar to the case of less than 10°C / min. Therefore, the heating rate is preferably 10°C / min or more and less than 600°C / min, more preferably 30°C / min or more and 600°C / min or less, and even more preferably 200°C / min or more and 400°C / min or less.

[0057] In flash annealing (crystallization heat treatment), in order to obtain good magnetic properties, it is preferable to rapidly cool immediately after reaching a crystallization heat treatment temperature (holding temperature) in a constant temperature range of above the crystallization temperature and below 850°C. The crystallization heat treatment temperature (holding temperature) may be, for example, 640°C or higher, or 640°C to 720°C. More specifically, the crystallization heat treatment time (holding time) from reaching the above crystallization heat treatment temperature until rapid cooling is substantially 0.1 seconds or more, and holding for 7 minutes or more is undesirable because it damages the uniform fine metallic structure and leads to a decrease in various magnetic properties. Therefore, the holding time is preferably 0.1 seconds or more and less than 7 minutes, more preferably 0.1 seconds or more and 2 minutes or less, and even more preferably 0.1 seconds or more and 30 seconds or less. When the crystallization heat treatment temperature and crystallization heat treatment time are within the above range, a relatively high crystallization heat treatment temperature and a relatively long crystallization heat treatment time tend to facilitate the formation of a layered structure in the grain boundary region.

[0058] In this flash annealing (crystallization heat treatment), it is preferable to cool the rapidly solidified alloy to 500°C or below at a cooling rate of 2°C / sec or more and 300°C / sec or less. If the cooling rate is less than 2°C / sec, the crystal structure will coarseen, and if it exceeds 300°C / sec, the alloy may become brittle due to thermal stress. Therefore, the cooling rate is preferably 2°C / sec or more and 300°C / sec or less, more preferably 6°C / sec or more and 300°C / sec or less, and even more preferably 6°C / sec or more and 200°C / sec or less. Examples of rapid cooling methods include using a water-cooled cooling retort or using a SiC susceptor with high heat dissipation. As a result of rapid cooling, elemental diffusion due to preheating is suppressed, and the compositions of the phases tend to differ. Consequently, the difference in domain wall energy becomes larger, making magnetic pinning more likely, and the intrinsic coercivity HcJ tends to increase.

[0059] For the flash annealing (crystallization heat treatment) described above, an inert gas atmosphere is preferred to prevent oxidation of the rapidly solidified alloy. As the inert gas, noble gases such as helium and argon or nitrogen can be used, but since nitrogen reacts relatively easily with rare earth elements and iron, noble gases such as helium and argon are preferred, and argon gas is more preferred from a cost standpoint.

[0060] The method for producing the material for the first rare earth bond magnet may further include a step of producing magnet powder by crushing the above-mentioned rapidly solidified alloy or the rapidly solidified alloy that has undergone flash annealing.

[0061] The rapidly solidified alloy obtained through the above process may be roughly cut or crushed into thin strips, for example, 50 mm or less, before flash annealing (crystallization heat treatment). This makes it possible to obtain a thin strip material for first rare earth bond magnets. Furthermore, by crushing the rapidly solidified alloy after flash annealing (crystallization heat treatment) to a suitable average powder particle size in the range of 20 μm to 300 μm, a powdered magnet material for first rare earth bond magnets can be obtained.

[0062] Various magnets can be manufactured using the first rare earth bond magnet material by known processes. The magnet may be a magnet containing the first rare earth bond magnet material and a thermosetting resin. The magnet may be, for example, a resin-bonded permanent magnet (referred to as a plastic magnet or bond magnet). The magnet can be manufactured, for example, as follows: First, prepare the powdered first rare earth bond magnet material manufactured as described above. Next, add a thermosetting resin to the first rare earth bond magnet material, fill it into a molding die, and form a compression molded body by compression molding, then heat treat it at a temperature above the polymerization temperature of the thermosetting resin. Alternatively, after preparing the powdered first rare earth bond magnet material, a thermoplastic resin can be added to the first rare earth bond magnet material to produce an injection molding compound, which can then be injection molded.

[0063] When manufacturing the above magnet, the powdered material for the first rare earth bond magnet is mixed with, for example, epoxy, polyamide, polyphenylene sulfide (PPS), liquid crystal polymer, acrylic, polyether, etc., and molded into the desired shape. In this case, a hybrid magnet powder may be used, for example, by mixing it with permanent magnet powder such as SmFeN-based magnet powder or hard ferrite magnet powder. ２ Fe １４ A permanent magnet powder having a different microstructure from that of the present invention, with a type B compound as the main phase, may be used, which may be mixed with a powdered first rare earth bond magnet material.

[0064] When the above-mentioned powdered material for first rare earth bonded magnets is used for injection-molded bonded magnets, it is preferable to grind it so that the average particle size is 100 μm or less, and more preferably the average crystal grain size of the powder is 20 μm or more and 100 μm or less. When it is used for compression-molded bonded magnets, it is preferable to grind it so that the average particle size is 200 μm or less, and more preferably the average crystal grain size of the powder is 50 μm or more and 180 μm or less. Even more preferably, the particle size distribution has two peaks and the average crystal grain size is 80 μm or more and 130 μm or less.

[0065] By applying surface treatments such as coupling treatment and chemical conversion treatment (including phosphate treatment and glass coating treatment) to the surface of the material for first-order rare-earth bonded magnets, the formability during magnet formation, as well as the corrosion resistance and heat resistance of the resulting magnets, can be improved regardless of the molding method. In addition, if surface treatments such as resin coating, chemical conversion treatment, and plating are applied to the surface of the magnet after molding, the corrosion resistance and heat resistance of the magnets can be improved in the same way as the surface treatment of the magnet alloy powder.

[0066] The method for manufacturing the material for the first rare earth bond magnet is not limited to the one described above. Other manufacturing methods can be used as long as a magnet material having the above-described composition, average crystal grain size, etc., can be produced. For example, if flash annealing is used, RE ２ Fe １４ While it is possible to form a fine metallic structure with type B tetragonal compounds as the main phase, other methods can be employed to form such a fine metallic structure, not just flash annealing. For example, even when using a normal annealing process instead of flash annealing, good magnetic properties can be obtained by adjusting the surface speed of the rotating roll used to rapidly cool the molten alloy, resulting in a homogeneous, fine metallic structure consisting of crystal grains that are 5% to 20% smaller than those of the alloy structure that yields optimal magnetic properties.

[0067] [Second Embodiment] The rare earth bond magnet material according to the second embodiment (hereinafter also referred to as the second rare earth bond magnet material) is RE ２ Fe １４ This is a rare-earth bond magnet material whose main phase is the crystal grains of type B compounds. RE represents at least one rare-earth element. ２ Fe １４The grain boundary regions between the crystal grains of the type B compound have a layered structure in which two or more grain boundary phases are stacked. The grain boundary phase contains at least one rare earth element, at least one transition metal element, and at least one element selected from the group consisting of F, O, and B. The at least one transition metal element includes Fe or Co. The grain boundary phase has a different concentration of F or O compared to the main phase, or at least one of the crystal structure and the concentration of the at least one transition metal element differs from the main phase. The second rare earth bond magnet material may be an isotropic rare earth bond magnet material. Preferably, the second rare earth bond magnet material is an isotropic rare earth bond magnet material. The second embodiment will mainly be described in terms of the differences from the first embodiment.

[0068] In the material for the second rare earth bond magnet, the grain boundary phase contains at least one rare earth element, at least one transition metal element, and at least one element selected from the group consisting of F, O, and B.

[0069] The grain boundary phase may contain at least one element selected from the group consisting of F, O, and B, which may be F, O, and B, which may be O and B, or which may be B. The grain boundary phase may not contain F, or may not contain O.

[0070] The present invention will be described in more detail below with reference to examples.

[0071] <Examples 1-3 and Comparative Examples 1-4> 100 g of raw materials containing Nd, Pr, Fe, and B with a purity of 99.5% or higher to achieve the alloy composition shown in Table 1 were placed in an alumina melting crucible and then set in a work coil inside a vacuum melting furnace. After evacuating the inside of the vacuum melting furnace to 0.02 Pa or less, argon gas was introduced to atmospheric pressure, and the alloy was heated by high-frequency induction heating to produce molten metal. Subsequently, the molten alloy was cast into a water-cooled copper mold to produce the master alloy.

[0072] Next, the obtained master alloy was broken into appropriate sizes, and 40 g was inserted into a transparent quartz nozzle equipped with orifices of varying diameters (0.7 mm or more, 1.2 mm or less) at the bottom to achieve an average pouring rate of 200 g / min or more and less than 2000 g / min. The nozzle was then set into a work coil in a single-roll quenching device. After evacuating the vacuum melting furnace to 0.02 Pa or less, argon gas was introduced until the quenching atmosphere pressure (40-65 kPa) was reached, and the master alloy was remelted by high-frequency induction heating. The molten alloy was then injected from the nozzle orifice at a pressure of 30 kPa onto the surface of a rotating roll rotating at a surface velocity of 20-70 m / s to produce a rapidly solidified alloy. This method is called the melt spinning method. The distance between the nozzle tip and the surface of the rotating roll was set to 0.8 mm. The main component of the rotating roll was Mo.

[0073] The rapidly solidified alloy obtained in the above process was coarsely ground to a few millimeters or less to obtain rapidly solidified alloy powder, which was then flash-annealed using an infrared-heated high-speed heat treatment furnace. The coarse powder of rapidly solidified alloy was heat-treated at the crystallization heat treatment temperature, crystallization heat treatment time, and heating rate shown in Table 1. Furthermore, the material was cooled so that the average cooling rate from the maximum temperature to 500°C was 10°C to 100°C / sec, and the average cooling rate from the maximum temperature to 50°C was 15 to 50°C / min, thereby producing isotropic rare-earth bond magnet material.

[0074] When the constituent phases of the rapidly solidified alloy powder after flash annealing (crystallization heat treatment) were confirmed by powder X-ray diffraction, Nd ２ Fe １４ The presence of phase B was confirmed. The magnetic properties of the rapidly solidified alloy powder after flash annealing (crystallization heat treatment) were measured using VSM. The results are shown in Table 1.

[0075] Furthermore, the rapidly solidified alloy powder of Example 1 was processed using a focused ion beam apparatus, and image observation was performed using TEM, as well as elemental mapping by energy-dispersive X-ray analysis (EDX).

[0076] Figure 5 shows TEM images of the magnetic materials obtained in Example 1 and Comparative Example 1. In Example 1, the presence of a grain boundary phase having a layered structure between the crystal grains constituting the main phase was confirmed. On the other hand, in Comparative Example 1, although a grain boundary phase was present, the presence of a grain boundary region having a layered structure in which multiple grain boundary phases were stacked was not confirmed.

[0077] Figure 6 shows the elemental mapping of Example 1 by EDX. The main phase consisting of crystal grains containing Nd, Pr, Fe, and B was identified. Between the crystal grains, a grain boundary phase was identified that had a layered structure in which a layer containing F, Nd, Pr, Fe, B, and O on the crystal grain side was stacked, and a layer containing O, Nd, Pr, and B at a higher concentration than the first layer was stacked. For example, in the elemental mapping of F, the white areas represent F, and it can be seen that it is distributed along the grain boundary phase.

[0078] Figure 7 shows the results of elemental quantitative analysis by EDX line analysis for Example 1. It was confirmed that the crystal grains constituting the main phase contain Nd, Pr, Fe, B, and O. It was also confirmed that the grain boundary phase located on the crystal grain side (second grain boundary phase) contains F, Nd, Pr, Fe, B, and O. Furthermore, it was confirmed that the grain boundary phase located between the grain boundary phase located on the crystal grain side and the grain boundary phase located on another crystal grain side (first grain boundary phase) contains F, Nd, Pr, and B, and considering the elemental mapping in Figure 6, the concentrations of O and Fe were lower than those of the second grain boundary phase.

[0079] Figure 8 shows a high-magnification TEM observation image of Example 1. The presence of a third grain boundary phase was confirmed between the second grain boundary phase and the main phase.

[0080] As described above, the magnetic material obtained by flash annealing (crystallization heat treatment) was crushed to 250 μm or less using an agate mortar, and then filled into cylindrical plastic capsules with a diameter of 6 mm and a height of 4 mm. Next, it was magnetized in the longitudinal direction using a pulsed magnetic field of 3.2 MA / m. Subsequently, in order to suppress the effect of the demagnetizing field, a sample for magnetic property evaluation was set in the longitudinal direction, and the room-temperature magnetic properties were measured using a vibrating sample magnetometer (VSM). The results are shown in Table 1. In particular, it was found that Examples 1 and 2, which had a low content of B, obtained a higher intrinsic coercivity HcJ compared to the other examples.

[0081]

[0082] Examples 1 and 3 showed improved intrinsic coercivity HcJ compared to Comparative Examples 1 and 2 due to higher processing temperatures. Example 2 also showed improved intrinsic coercivity HcJ due to longer processing times compared to Comparative Example 1. In Comparative Examples 3 and 4, which had relatively high B content, increasing the processing temperature did not improve the intrinsic coercivity HcJ; in fact, it decreased.

[0083] <Examples 4-10> Mixed magnetic materials were prepared by mixing magnetic material 1 and magnetic material 2 shown in Table 2 at the mass mixing ratios shown in Table 2, and the intrinsic coercivity HcJ was measured. The mass mixing ratio is the ratio (%) of the mass of magnetic material 2 to the total mass of magnetic material 1 and magnetic material 2. The results are shown in Table 2.

[0084]

[0085] In Examples 4-7, where the magnetic material of Example 1 was mixed with the magnetic material of Comparative Example 3, an improved intrinsic coercivity HcJ was obtained compared to Comparative Example 3. Similarly, in Examples 8-10, where the magnetic material of Example 1 was mixed with the magnetic material of Comparative Example 1, an improved intrinsic coercivity HcJ was obtained compared to Comparative Example 1. In Comparative Example 5, although the magnetic material of Example 1 was mixed with the magnetic material of Comparative Example 3, an improved intrinsic coercivity HcJ was not obtained because the mass mixing ratio of the magnetic material of Example 1 was too low. It can be seen that the magnetic material of this disclosure exhibits an improved intrinsic coercivity HcJ when used in a predetermined ratio mixed with other magnetic materials.

[0086] In the description of the embodiments described above, the combinable configurations may be combined with each other.

[0087] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope of equivalents of the claims are intended.

[0088] 11 main phase, 12 grain boundary region, 13 first grain boundary phase, 14 second grain boundary phase, 15 third grain boundary phase, G crystal grain.

Claims

1. RE ２ Fe １４ A rare earth bond magnet material having a crystal grain of a type B compound as the main phase, wherein RE represents at least one rare earth element, the grain boundary region existing between the crystal grains has a layered structure in which two or more grain boundary phases are stacked, the grain boundary phase contains at least one rare earth element, at least one transition metal element, and at least one element selected from the group consisting of F and O, the at least one transition metal element includes Fe or Co, and the grain boundary phase has a different concentration of F or O compared to the main phase, or at least one of the crystal structure and the concentration of the at least one transition metal element is different from the main phase, a rare earth bond magnet material.

2. RE ２ Fe １４ A rare earth bond magnet material having a crystal grain of a type B compound as the main phase, wherein RE represents at least one rare earth element, the grain boundary region existing between the crystal grains has a layered structure in which two or more grain boundary phases are stacked, the grain boundary phase contains at least one rare earth element, at least one transition metal element, and at least one element selected from the group consisting of F, O, and B, the at least one transition metal element includes Fe or Co, and the grain boundary phase has a different concentration of F or O compared to the main phase, or at least one of the crystal structure and the concentration of the at least one transition metal element is different from the main phase, a rare earth bond magnet material.

3. The rare earth bond magnet material according to claim 1 or 2, wherein the thickness of the grain boundary region in the stacking direction is 1 nm or more and 50 nm or less.

4. The rare earth bond magnet material according to any one of claims 1 to 3, wherein at least one of the two or more grain boundary phases has a concentration of at least one of the at least one rare earth element, at least one transition metal element, and at least one of F, O, and B that differs by 5 atomic percentages or more compared to at least one of the other grain boundary phases.

5. The material for rare earth bond magnets according to any one of claims 1 to 4, wherein the average grain size of the crystal grains is 10 nm or more and 200 nm or less.

6. The rare earth bond magnet material according to any one of claims 1 to 5, wherein at least one of the two or more grain boundary phases is an amorphous phase.

7. The rare earth bond magnet material according to any one of claims 1 to 6, wherein at least one of the two or more grain boundary phases is a ferromagnetic phase having a different Fe concentration than the main phase and a different Fe concentration than at least one of the other grain boundary phases.

8. The rare earth bonded magnet material according to any one of claims 1 to 7, wherein the volume ratio of the two or more grain boundary phases in the rare earth bonded magnet material is 1 to 50 volume%.

9. The atomic concentration of B is the same as RE ２ Fe １４ A rare earth bond magnet material according to any one of claims 1 to 8, having a stoichiometric composition lower than that of a type B compound.

10. A magnet comprising a rare earth bond magnet material according to any one of claims 1 to 9 and a thermosetting resin.

11. A rare earth bond magnet material and a magnet containing 3% by mass or more of the rare earth bond magnet material described in any one of claims 1 to 9.

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