NEODYMIUM-IRON-BORON MAGNET AND PREPARATION METHOD THEREOF

Abstract

Provided is a neodymium-iron-boron magnet and preparation method thereof. The preparation method includes the following steps: preparing a Fe.sub.aG.sub.b metal sheet, covering the Fe.sub.aG.sub.b metal sheet with a rare earth compound Re.sub.xM.sub.yB.sub.z layer, performing multi-layer stacking on the metal sheet covered with the rare earth compound Re.sub.xM.sub.yB.sub.z layer, and then performing high-temperature diffusion under an extrusion force with certain strength, so as to prepare a neodymium-iron-boron magnet.

Claims

1. A method for preparing a neodymium-iron-boron magnet, comprising the following steps: (S1) preparing a Fe.sub.aG.sub.b metal sheet, and covering at least one side surface of the Fe.sub.aG.sub.b metal sheet with a rare earth compound Re.sub.xM.sub.yB.sub.z coating; (S2) mutually stacking the Fe.sub.aG.sub.b metal sheets covered with the rare earth compound Re.sub.xM.sub.yB.sub.z coatings to a set thickness in a tool, and after stacking, ensuring that there is at least one rare earth compound Re.sub.xM.sub.yB.sub.z coating between the adjacent two Fe.sub.aG.sub.b metal sheets; and (S3) applying an extrusion force to the stacked Fe.sub.aG.sub.b metal sheets, and performing high-temperature diffusion on the metal sheets under a vacuum condition, so as to obtain the neodymium-iron-boron magnet.

2. The method for preparing a neodymium-iron-boron magnet according to claim 1, wherein Fe in the Fe.sub.aG.sub.b metal sheet is an iron element, G is one or more selected from an aluminum element, a titanium element, a copper element, a zinc element, a manganese element, a cobalt element, a nickel element, a niobium element, a molybdenum element, a zirconium element, and a chromium element, and a and b are mass percentages, wherein 75%a100% and 0%b25%.

3. The method for preparing a neodymium-iron-boron magnet according to claim 1, wherein Re in the rare earth compound Re.sub.xM.sub.yB.sub.z coating is one or more selected from a neodymium element, a praseodymium element, a cerium element, a lanthanum element, a terbium element, a dysprosium element, or a holmium element, M is one or more selected from an iron element, an aluminum element, a titanium element, a copper element, a zinc element, a manganese element, a cobalt element, or a gallium element, B is a boron element, and x, y, and z are mass percentages, wherein 70%x95%, 2%z4%, and y=1xz.

4. The method for preparing a neodymium-iron-boron magnet according to claim 2, wherein Re in the rare earth compound Re.sub.xM.sub.yB.sub.z coating is one or more selected from a neodymium element, a praseodymium element, a cerium element, a lanthanum element, a terbium element, a dysprosium element, or a holmium element, M is one or more selected from an iron element, an aluminum element, a titanium element, a copper element, a zinc element, a manganese element, a cobalt element, or a gallium element, B is a boron element, and x, y, and z are mass percentages, wherein 70%x95%, 2%z4%, and y=1xz.

5. The method for preparing a neodymium-iron-boron magnet according to claim 1, wherein a mass of the single Fe.sub.aG.sub.b metal sheet is defined as M.sub.1, and a mass of the rare earth compound Re.sub.xM.sub.yB.sub.z coating on the single Fe.sub.aG.sub.b metal sheet is defined as M.sub.2, wherein 40%M.sub.2/M.sub.180%.

6. The method for preparing a neodymium-iron-boron magnet according to claim 2, wherein a mass of the single Fe.sub.aG.sub.b metal sheet is defined as M.sub.1, and a mass of the rare earth compound Re.sub.xM.sub.yB.sub.z coating on the single Fe.sub.aG.sub.b metal sheet is defined as M.sub.2, wherein 40%M.sub.2/M.sub.180%.

7. The method for preparing a neodymium-iron-boron magnet according to claim 3, wherein a mass of the single Fe.sub.aG.sub.b metal sheet is defined as M.sub.1, and a mass of the rare earth compound Re.sub.xM.sub.yB.sub.z coating on the single Fe.sub.aG.sub.b metal sheet is defined as M.sub.2, wherein 40%M.sub.2/M.sub.180%.

8. The method for preparing a neodymium-iron-boron magnet according to claim 1, wherein a thickness of the single Fe.sub.aG.sub.b metal sheet is defined as h.sub.1, wherein 0.02 mmh.sub.10.5 mm.

9. The method for preparing a neodymium-iron-boron magnet according to claim 2, wherein a thickness of the single Fe.sub.aG.sub.b metal sheet is defined as h.sub.1, wherein 0.02 mmh.sub.10.5 mm.

10. The method for preparing a neodymium-iron-boron magnet according to claim 3, wherein a thickness of the single Fe.sub.aG.sub.b metal sheet is defined as h.sub.1, wherein 0.02 mmh.sub.10.5 mm.

11. The method for preparing a neodymium-iron-boron magnet according to claim 1, wherein a thickness of the stacked Fe.sub.aG.sub.b metal sheets and a thickness of the rare earth compound Re.sub.xM.sub.yB.sub.z coatings are defined as h.sub.2, wherein 0.04 mmh.sub.280 mm.

12. The method for preparing a neodymium-iron-boron magnet according to claim 2, wherein a thickness of the stacked Fe.sub.aG.sub.b metal sheets and a thickness of the rare earth compound Re.sub.xM.sub.yB.sub.z coatings are defined as h.sub.2, wherein 0.04 mmh.sub.280 mm.

13. The method for preparing a neodymium-iron-boron magnet according to claim 3, wherein a thickness of the stacked Fe.sub.aG.sub.b metal sheets and a thickness of the rare earth compound Re.sub.xM.sub.yB.sub.z coatings are defined as h.sub.2, wherein 0.04 mmh.sub.280 mm.

14. The method for preparing a neodymium-iron-boron magnet according to claim 1, wherein covering surface of the Fe.sub.aG.sub.b metal sheet with the rare earth compound Re.sub.xM.sub.yB.sub.z coating comprises vacuum coating, plasma spraying, and thermal spraying.

15. The method for preparing a neodymium-iron-boron magnet according to claim 2, wherein covering surface of the Fe.sub.aG.sub.b metal sheet with the rare earth compound Re.sub.xM.sub.yB.sub.z coating comprises vacuum coating, plasma spraying, and thermal spraying.

16. The method for preparing a neodymium-iron-boron magnet according to claim 3, wherein covering surface of the Fe.sub.aG.sub.b metal sheet with the rare earth compound Re.sub.xM.sub.yB.sub.z coating comprises vacuum coating, plasma spraying, and thermal spraying.

17. The method for preparing a neodymium-iron-boron magnet according to claim 1, wherein the Fe.sub.aG.sub.b metal sheets are mutually stacked to form a square, a tile-like shape, a cylindrical shape, or a ring shape.

18. The method for preparing a neodymium-iron-boron magnet according to claim 2, wherein the Fe.sub.aG.sub.b metal sheets are mutually stacked to form a square, a tile-like shape, a cylindrical shape, or a ring shape.

19. The method for preparing a neodymium-iron-boron magnet according to claim 1, wherein a diffusion temperature in step (S3) is 1000 C. to 1200 C., and a diffusion time is 0.5 h to 10 h.

20. A neodymium-iron-boron magnet, obtained through the method according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG. 1 is a schematic diagram of a Fe.sub.aG.sub.b metal sheet with a surface coated with a layer of rare earth compound Re.sub.xM.sub.yB.sub.z.

[0025] FIG. 2 is a schematic diagram of Fe.sub.aG.sub.b metal sheets covered with rare earth compound Re.sub.xM.sub.yB.sub.z coatings and stacked into a square.

[0026] FIG. 3 is a schematic diagram of Fe.sub.aG.sub.b metal sheets covered with rare earth compound Re.sub.xM.sub.yB.sub.z coatings and stacked into a tile-like shape.

[0027] FIG. 4 is a schematic diagram of Fe.sub.aG.sub.b metal sheets covered with rare earth compound Re.sub.xM.sub.yB.sub.z coatings and stacked into a ring shape.

[0028] FIG. 5 is a schematic diagram of Fe.sub.aG.sub.b metal sheets covered with rare earth compounds Re.sub.xM.sub.yB.sub.z and stacked into a cylindrical shape.

[0029] In the drawings: 1. Fe.sub.aH.sub.b metal sheet; 2. Rare earth compound Re.sub.xM.sub.yB.sub.z; 3. Lower square extrusion tooling mold; 4. Upper square extrusion tooling mold; 5. Lower tile-like-shaped extrusion tooling mold; 6. Upper tile-like-shaped extrusion tooling mold; 7. Ring-shaped extrusion tooling core rod; 8. Upper ring-shaped extrusion tooling mold; 9. Lower ring-shaped extrusion tooling mold; 10. Upper cylindrical extrusion tooling mold; and 11. Lower cylindrical extrusion tooling mold.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] Principles and features of the present disclosure are described with reference to FIG. 1 to FIG. 5. Embodiments are merely for explaining the present disclosure, and are not used to limit scope of the present disclosure.

Embodiment 1

[0031] (S1) A Fe.sub.aG.sub.b metal ingot was smelted, and then extruded into a Fe.sub.aG.sub.b metal sheet through extrusion. In this embodiment, Fe.sub.aG.sub.b was Fe.sub.90Ti.sub.2Ni.sub.3Zr.sub.5, that is, G represented a group of a titanium element, a nickel element, and a zirconium element. a and b were mass percentages, a was 90%, and b was 10%, where a mass percentage of the titanium element was 2%, a mass percentage of the nickel element was 3%, and a mass percentage of the zirconium element was 5%. A rare earth compound Re.sub.xM.sub.yB.sub.z coating 2 was sprayed on an upper surface of the Fe.sub.90Ti.sub.2Ni.sub.2Zr.sub.5 metal sheet through thermal spraying. In this embodiment, Re.sub.xM.sub.yB.sub.z was Nd.sub.70Al.sub.3.8Cu.sub.4Ga.sub.2Ti.sub.2.2Fe.sub.16B.sub.2, that is, Re was a neodymium element, M was a group of an aluminum element, a copper element, a gallium element, a titanium element, and an iron element, and B was a boron element. x, y, and z were mass percentages. In this embodiment, x was 70%, that is, a mass percentage of the neodymium element was 70%; y was 28%, that is, a total mass percentage of the aluminum element, copper element, gallium element, titanium element, and iron element was 28%, where a mass percentage of the aluminum element was 3.8%, a mass percentage of the copper element was 4%, a mass percentage of the gallium element was 2%, a mass percentage of the titanium element was 2.2%, and a mass percentage of the iron element was 16%; and z was 2%, that is, a mass percentage of the boron element was 2%. A mass of the single Fe.sub.aG.sub.b metal sheet 1 was defined as M.sub.1, and a mass of the rare earth compound Re.sub.xM.sub.yB.sub.z coating 2 on the single Fe.sub.aG.sub.b metal sheet 1 was defined as M.sub.2, where M.sub.2/M.sub.1=70%. A thickness of the single Fe.sub.aG.sub.b metal sheet 1 was defined as h.sub.1, and in this embodiment, h.sub.1=0.35 mm. [0032] (S2) A plurality of Fe.sub.90Ti.sub.2Ni.sub.2Zr.sub.5 metal sheets covered with the rare earth compound Nd.sub.70Al.sub.3.8Cu.sub.4Ga.sub.2Ti.sub.2.2Fe.sub.16B.sub.2 coatings were stacked into a cylindrical shape in a cylindrical tool with a length being 20 mm and an inner diameter being 60 mm, a thickness of the stacked Fe.sub.aG.sub.b metal sheets 1 was defined as h.sub.2, and in this embodiment, h.sub.2=30 mm, and a diameter of the cylindrical shape was 60 mm. After stacking, it should ensure that there was at least one rare earth compound Re.sub.xM.sub.yB.sub.z coating 2 between the adjacent two Fe.sub.aG.sub.b metal sheets 1. Referring to FIG. 5 for a specific tool, 10 was an upper cylindrical extrusion tooling mold, 11 was a lower cylindrical extrusion tooling mold, and an arrow represented a force applying direction. [0033] (S3) An extrusion force was applied to the stacked Fe.sub.aG.sub.b metal sheets 1, and was subjected to high-temperature diffusion under a vacuum condition, so as to prepare a neodymium-iron-boron magnet, where a diffusion temperature was 1100 C., and a diffusion time was 5 h; and finally, a cylindrical neodymium-iron-boron magnet with a diameter being 60 mm and a height being 20 mm was obtained.

[0034] The above obtained neodymium-iron-boron magnet was cut into a sample column with a diameter being 10 mm and a height being 10 mm, then a magnetic performance test (temperature being 20 C.3 C.) was performed, and test results were recorded in Table 1.

TABLE-US-00001 TABLE 1 Magnetic performance of sample in Embodiment I Magnet name Br (KGs) Hcj (KOe) Embodiment 1 10.87 10.2

[0035] From the above test results, it might be seen that, Br of the cylindrical magnet prepared in Embodiment 1 was 10.87, and Hcj was 10.2 and had high magnetic performance.

Embodiment 2

[0036] (S1) A Fe.sub.aG.sub.b metal ingot was smelted, and then extruded into a Fe.sub.aG.sub.b metal sheet 1 through extrusion. In this embodiment, Fe.sub.aG.sub.b was Fe.sub.90Cr.sub.9Al.sub.0.5Zn.sub.0.5, that is, G represented a group of a chromium element, an aluminum element, and a zinc element. a and b were mass percentages, a was 90%, and b was 10%, where a mass percentage of the chromium element was 9%, a mass percentage of the aluminum element was 0.5%, and a mass percentage of the zinc element was 0.5%. A rare earth compound Re.sub.xM.sub.yB.sub.z coating 2 was sprayed on an upper surface of the Fe.sub.90Cr.sub.9Al.sub.0.5Zn.sub.0.5 metal sheet through vacuum coating. In this embodiment, Re.sub.xM.sub.yB.sub.z was Nd.sub.72Dy.sub.1Ho.sub.2Cu.sub.3Ti.sub.0.3Zn.sub.0.2Fe.sub.19B.sub.2.5, that is, Re was a group of a neodymium element, a dysprosium element, and a holmium element, M was a group of a copper element, a titanium element, a zinc element, and an iron element, and B was a boron element. x, y, and z were mass percentages. In this embodiment, x was 75%, that is, a mass percentage of the neodymium element was 72%, a mass percentage of the dysprosium element was 1%, and a mass percentage of the holmium element was 2%; y was 22.5%, where a mass percentage of the copper element was 3%, a mass percentage of the titanium element was 0.3%, a mass percentage of the zinc element was 0.2%, and a mass percentage of the iron element was 19%; and z was 2.5%, that is, a mass percentage of the boron element was 2.5%. A mass of the single Fe.sub.aG.sub.b metal sheet 1 was defined as M.sub.1, and a mass of the rare earth compound Re.sub.xM.sub.yB.sub.z coating 2 on the single Fe.sub.aG.sub.b metal sheet 1 was defined as M.sub.2, where M.sub.2/M.sub.1=80%. A thickness of the single Fe.sub.aG.sub.b metal sheet 1 was defined as h.sub.1, and in this embodiment, h.sub.1=0.2 mm. [0037] (S2) A plurality of Fe.sub.90Cr.sub.9Al.sub.0.5Zn.sub.0.5 metal sheets plated with the rare earth compound Nd.sub.72Dy.sub.1Ho.sub.2Cu.sub.3Ti.sub.0.3Zn.sub.0.2Fe.sub.19B.sub.2.5 coatings were stacked into a tile-like shape in a tile-like-shaped tool with a length being 10 mm, a radian being 90 and a height being 15 mm, a thickness of the stacked Fe.sub.aG.sub.b metal sheets 1 was defined as h.sub.2, and in this embodiment, h.sub.2=10 mm. After stacking, it should ensure that there was at least one rare earth compound Re.sub.xM.sub.yB.sub.z coating 2 between the adjacent two Fe.sub.aG.sub.b metal sheets 1. Referring to FIG. 3 for a specific tool, 5 was a lower tile-like-shaped extrusion tooling mold, 6 was an upper tile-like-shaped extrusion tooling mold, and an arrow represented a force applying direction. [0038] (S3) An extrusion force was applied to the stacked Fe.sub.aG.sub.b metal sheets 1, and was subjected to high-temperature diffusion under a vacuum condition, so as to prepare a neodymium-iron-boron magnet, where a diffusion temperature was 1200 C., and a diffusion time was 8 h; and finally, a tile-like-shaped neodymium-iron-boron magnet was obtained.

[0039] The above obtained neodymium-iron-boron magnet was cut into a sample column with a diameter being 10 mm and a height being 10 mm, then a magnetic performance test (temperature being 20 C.3 C.) was performed, and test results were recorded in Table 2.

TABLE-US-00002 TABLE 2 Magnetic performance of sample in Embodiment II Magnet name Br (KGs) Hcj (KOe) Embodiment 2 9.68 10.35

[0040] From the above test results, it might be seen that, Br of the tile-like-shaped magnet with a dimension thickness being 10 mm prepared in Embodiment 2 was 9.68, and Hcj was 10.35 and had high magnetic performance.

Embodiment 3

[0041] (S1) A Fe.sub.aG.sub.b metal ingot was smelted, and then extruded into a Fe.sub.aG.sub.b metal sheet 1 through extrusion. In this embodiment, Fe.sub.aG.sub.b was Fe.sub.75Mn.sub.3Cu.sub.1Ho.sub.2Co.sub.3Zr.sub.10Ni.sub.8, that is, G represented a group of a manganese element, a copper element, a holmium element, a cobalt element, a zirconium element, and a nickel element. a and b were mass percentages, a was 75%, and b was 25%, where a mass percentage of the manganese element was 3%, a mass percentage of the copper element was 1%, a mass percentage of the holmium element was 2%, a mass percentage of the cobalt element was 3%, a mass percentage of the zirconium element was 10%, and a mass percentage of the nickel element was 8%. A rare earth compound Re.sub.xM.sub.yB.sub.z coating 2 was sprayed on an upper surface of the Fe.sub.75Mn.sub.3Cu.sub.1Ho.sub.2Co.sub.3Zr.sub.10Ni.sub.8 metal sheet through plasma spraying. In this embodiment, Re.sub.xM.sub.yB.sub.z was Pr.sub.60Ce.sub.30Cu.sub.1.5Mn.sub.0.5Ga.sub.1Fe.sub.4B.sub.3, that is, Re was a praseodymium element and a cerium element, M was a group of a copper element, a manganese element, a gallium element, and an iron element, and B was a boron element. x, y, and z were mass percentages. In this embodiment, x was 90%, that is, a mass percentage of the praseodymium element was 60%, and a mass percentage of the cerium element was 30%; y was 7%, where a mass percentage of the copper element was 1.5%, a mass percentage of the manganese element was 0.5%, a mass percentage of the gallium element was 1%, and a mass percentage of the iron element was 4%; and z was 3%, that is, a mass percentage of the boron element was 3%. A mass of the single Fe.sub.aG.sub.b metal sheet 1 was defined as M.sub.1, and a mass of the rare earth compound Re.sub.xM.sub.yB.sub.z coating 2 on the single Fe.sub.aG.sub.b metal sheet 1 was defined as M.sub.2, where M.sub.2/M.sub.1=60%. A thickness of the single Fe.sub.aG.sub.b metal sheet 1 was defined as h.sub.1, and in this embodiment, h.sub.1=0.5 mm. [0042] (S2) A plurality of Fe.sub.75Mn.sub.3Cu.sub.1Ho.sub.2Co.sub.3Zr.sub.10Ni.sub.8 metal sheet coated with the rare earth compound Pr.sub.60Ce.sub.30Cu.sub.1.5Mn.sub.0.5Ga.sub.1Fe.sub.4B.sub.3 coatings were stacked into a square in a square tool with a length being 60 mm and a width being 40 mm, a thickness of the stacked Fe.sub.aG.sub.b metal sheets 1 was defined as h.sub.2, and in this embodiment, h.sub.2=80 mm. After stacking, it should ensure that there was at least one rare earth compound Re.sub.xM.sub.yB.sub.z coating 2 between the adjacent two Fe.sub.aG.sub.b metal sheets 1. Referring to FIG. 2 for a specific tool, 3 was a lower square extrusion tooling mold, and 4 was an upper square extrusion tooling mold. [0043] (S3) An extrusion force was applied to the stacked Fe.sub.aG.sub.b metal sheets 1, and was subjected to high-temperature diffusion under a vacuum condition, so as to prepare a neodymium-iron-boron magnet, where a diffusion temperature was 1200 C., and a diffusion time was 10 h; and finally, a square neodymium-iron-boron magnet was obtained.

[0044] The above obtained neodymium-iron-boron magnet was cut into a sample column with a diameter being 10 mm and a height being 10 mm, then a magnetic performance test (temperature being 20 C.3 C.) was performed, and test results were recorded in Table 2.

TABLE-US-00003 TABLE 3 Magnetic performance of sample in Embodiment 3 Magnet name Br (KGs) Hcj (KOe) Embodiment 3 8.23 10.45

[0045] From the above test results, it might be seen that, Br of the square magnet with a dimension thickness being 80 mm prepared in Embodiment 3 was 8.23, and Hcj was 10.45 and had high magnetic performance.

Embodiment 4

[0046] (S1) A Fe.sub.aG.sub.b metal sheet 1 was prepared, and in this embodiment, Fe.sub.aG.sub.b was pure iron, where a and b were mass percentages, that is, a was 100%, and b was 0%. A rare earth compound Re.sub.xM.sub.yB.sub.z coating 2 was plated on an upper surface of the Fe.sub.aG.sub.b metal sheet 1 through vacuum coating. In this embodiment, Re.sub.xM.sub.yB.sub.z was Nd.sub.60Pr.sub.33La.sub.1Tb.sub.0.5Ho.sub.0.5Mn.sub.0.5Ga.sub.0.5B.sub.4, that is, Re was a group of a neodymium element, a spectral element, a lanthanum element, a terbium element, and a holmium element, M was a group of a manganese element and a gallium element, and B was a boron element. x, y, and z were mass percentages. In this embodiment, x was 95%, that is, a mass percentage of the neodymium element was 60%, a mass percentage of the spectral element was 33%, a mass percentage of the lanthanum element was 1%, a mass percentage of the terbium element was 0.5%, and a mass percentage of the holmium element was 0.5%; y was 1%, where a mass percentage of the manganese element was 0.5%, and a mass percentage of the gallium element was 0.5%; and z was 4%, that is, a mass percentage of the boron element was 4%. A mass of the single Fe.sub.aG.sub.b metal sheet was defined as M.sub.1, and a mass of the rare earth compound Re.sub.xM.sub.yB.sub.z coating 2 on the single Fe.sub.aG.sub.b metal sheet 1 was defined as M.sub.2, where M.sub.2/M.sub.1=40%. A thickness of the single Fe.sub.aG.sub.b metal sheet 1 was defined as h.sub.1, and in this embodiment, h.sub.1=0.1 mm. [0047] (S2) A plurality of Fe.sub.aG.sub.b metal sheets 1 plated with the rare earth compound Nd.sub.60Pr.sub.33La.sub.1Tb.sub.0.5Ho.sub.0.5Mn.sub.0.5Ga.sub.0.5B.sub.4 coatings were multi-layer wound on a core rod with a diameter being 56 mm and a height being 30 mm, a thickness of the stacked Fe.sub.aG.sub.b metal sheets 1 was defined as h.sub.2, in this embodiment, h.sub.2=2 mm, and then the core rod was placed in a circular tool with an inner diameter being 60 mm. Referring to FIG. 4 for a specific tool, 7 was a ring-shaped extrusion tooling core rod, and 8 was an upper ring-shaped extrusion tooling mold. [0048] (S3) An extrusion force was applied to the wound Fe.sub.aG.sub.b metal sheets 1, and was subjected to high-temperature diffusion under a vacuum condition, so as to prepare a neodymium-iron-boron magnet, where a diffusion temperature was 1150 C., and a diffusion time was 2 h; and finally, a ring-shaped neodymium-iron-boron magnet with an inner diameter being 60 mm and a wall thickness being 2 mm was obtained.

[0049] The above obtained neodymium-iron-boron magnet was cut into a sample column with a diameter being 10 mm and a height being 2 mm, then a magnetic performance test (temperature being 20 C.3 C.) was performed, and test results were recorded in Table 4.

TABLE-US-00004 TABLE 4 Magnetic performance of sample in Embodiment IV Magnet name Br (KGs) Hcj (KOe) Embodiment 4 10.08 9.58

[0050] From the above test results, it might be seen that, Br of the ring-shaped magnet prepared in Embodiment 4 was 10.08, and Hcj was 9.58 and had high magnetic performance.

Embodiment 5

[0051] (S1) A Fe.sub.aG.sub.b metal ingot was smelted, and then extruded into a Fe.sub.aG.sub.b metal sheet 1 through extrusion. In this embodiment, Fe.sub.aG.sub.b was Fe.sub.95Ni.sub.2Nb.sub.0.5Mo.sub.1.5Co.sub.1, that is, G represented a group of a nickel element, a niobium element, a molybdenum element, and a cobalt element. a and b were mass percentages, in this embodiment, a was 95%, and b was 5%, where a mass percentage of the nickel element was 2%, a mass percentage of the niobium element was 0.5%, a mass percentage of the molybdenum element was 1.5%, and a mass percentage of the cobalt element was 1%. A rare earth compound Re.sub.xM.sub.yB.sub.z coating 2 was sprayed on an upper surface of the Fe.sub.95Ni.sub.2Nb.sub.0.5Mo.sub.1.5Co.sub.1 metal sheet through vacuum coating. In this embodiment, Re.sub.xM.sub.yB.sub.z was Nd.sub.85Al.sub.1Cu.sub.0.5Ga.sub.0.5Fe.sub.10Co.sub.0.5B.sub.2.5, that is, Re was a neodymium element, M was a group of an aluminum element, a copper element, a gallium element, an iron element, and a cobalt element, and B was a boron element. x, y, and z were mass percentages. In this embodiment, x was 85%, that is, a mass percentage of the neodymium element was 80%; y was 12.5%, where a mass percentage of the aluminum element was 1%, a mass percentage of the copper element was 0.5%, a mass percentage of the gallium element was 0.5%, a mass percentage of the iron element was 10%, and a mass percentage of the cobalt element was 0.5%; and z was 2.5%, that is, a mass percentage of the boron element was 2.5%. A mass of the single Fe.sub.aG.sub.b metal sheet 1 was defined as M.sub.1, and a mass of the rare earth compound Re.sub.xM.sub.yB.sub.z coating 2 on the single Fe.sub.aG.sub.b metal sheet 1 was defined as M.sub.2, where M.sub.2/M.sub.1=55%. A thickness of the single Fe.sub.aG.sub.b metal sheet 1 was defined as h.sub.1, and in this embodiment, h.sub.1=0.02 mm. [0052] (S2) A plurality of Fe.sub.95Ni.sub.2Nb.sub.0.5Mo.sub.1.5Co.sub.1 metal sheets plated with the rare earth compound Nd.sub.85Al.sub.1Cu.sub.0.5Ga.sub.0.5Fe.sub.10Co.sub.0.5B.sub.2.5 coatings were stacked in a square tool with a length being 10 mm and a width being 10 mm, a thickness of the stacked Fe.sub.aG.sub.b metal sheets 1 was defined as h.sub.2, and in this embodiment, h.sub.2=0.04 mm. After stacking, it should ensure that there was at least one rare earth compound Re.sub.xM.sub.yB.sub.z coating between the adjacent two Fe.sub.aG.sub.b metal sheets 1. [0053] (S3) An extrusion force was applied to the stacked Fe.sub.aG.sub.b metal sheets 1, and was subjected to high-temperature diffusion under a vacuum condition, so as to prepare a neodymium-iron-boron magnet, where a diffusion temperature was 1000 C., and a diffusion time was 0.5 h; and finally, a square neodymium-iron-boron magnet was obtained.

[0054] The above obtained neodymium-iron-boron magnet was cut into a sample column with a diameter being 10 mm and a height being 0.04 mm, then a magnetic performance test (temperature being 20 C.3 C.) was performed, and test results were recorded in Table 5.

TABLE-US-00005 TABLE 5 Magnetic performance of sample in Embodiment V Magnet name Br (KGs) Hcj (KOe) Embodiment 5 9.65 11.57

[0055] From the above test results, it might be seen that, Br of the square magnet prepared in Embodiment 5 was 9.65, and Hcj was 11.57 and had high magnetic performance.

Embodiment 6

[0056] (S1) A Fe.sub.aG.sub.b metal sheet 1 was prepared, and in this step, Fe.sub.aG.sub.b was pure iron, where a and b were mass percentages, where a was 100%, and b was 0%. A rare earth compound Re.sub.xM.sub.yB.sub.z coating 2 was sprayed on an upper surface of the Fe.sub.aG.sub.b metal sheet 1 through vacuum coating. In this step, Re.sub.xM.sub.yB.sub.z was Nd.sub.60Pr.sub.34Tb.sub.0.5Ho.sub.0.5Mn.sub.0.5Ga.sub.0.5B.sub.4, that is, Re was a group of a neodymium element, a praseodymium element, a terbium element, and a holmium element, M was a group of a manganese element and a gallium element, and B was a boron element. x, y, and z were mass percentages. In this embodiment, x was 95%, that is, a mass percentage of the neodymium element was 60%, a mass percentage of the praseodymium element was 34%, a mass percentage of the terbium element was 0.5%, and a mass percentage of the holmium element was 0.5%; y was 1%, where a mass percentage of the manganese element was 0.5%, and a mass percentage of the gallium element was 0.5%; and z was 4%, that is, a mass percentage of the boron element was 4%. A mass of the single Fe.sub.aG.sub.b metal sheet 1 was defined as M.sub.1, and a mass of the rare earth compound Re.sub.xM.sub.yB.sub.z coating 2 on the single Fe.sub.aG.sub.b metal sheet 1 was defined as M.sub.2, where M.sub.2/M.sub.1=40%. A thickness of the single Fe.sub.aG.sub.b metal sheet 1 was defined as h.sub.1, and in this embodiment, h.sub.1=0.1 mm. [0057] (S2) A plurality of Fe.sub.aG.sub.b metal sheets 1 plated with the rare earth compound Nd.sub.60Pr.sub.34Tb.sub.0.5Mn.sub.0.5Ga.sub.0.5Ho.sub.0.5B.sub.4 coatings in step (S1) were stacked in a square tool with both length and width being 30 mm, and a stacked thickness was 5 mm. [0058] (S3) The Fe.sub.aG.sub.b metal sheet 1 was continuously prepared, in this step, Fe.sub.aG.sub.b was Fe.sub.95Ni.sub.2Nb.sub.0.5Mo.sub.1.5Co.sub.1, where G was a group of a nickel element, a niobium element, a molybdenum element, and a cobalt element. a and b were mass percentages, where a was 95%, and b was 5%. A rare earth compound Re.sub.xM.sub.yB.sub.z coating 2 was plated on an upper surface of the Fe.sub.aG.sub.b metal sheet 1 through vacuum coating. In this step, Re.sub.xM.sub.yB.sub.z was Nd.sub.85Al.sub.1Cu.sub.0.5Ga.sub.0.5Fe.sub.10Co.sub.0.5B.sub.2.5, that is, Re was a group of a neodymium element, M was a group of an aluminum element, a copper element, a gallium element, an iron element, and a cobalt element, and B was a boron element. x, y, and z were mass percentages. In this embodiment, x was 85%, that is, a mass percentage of the neodymium element was 85%; y was 12.5%, where a mass percentage of the aluminum element was 1%, a mass percentage of the copper element was 0.5%, a mass percentage of the gallium element was 0.5%, a mass percentage of the iron element was 10%, and a mass percentage of the cobalt element was 2.5%; and z was 2.5%, that is, a mass percentage of the boron element was 2.5%. A mass of the single Fe.sub.aG.sub.b metal sheet was defined as M.sub.1, and the mass of the rare earth compound Re.sub.xM.sub.yB.sub.z coating 2 on the single Fe.sub.aG.sub.b metal sheet was defined as M.sub.2, where M.sub.2/M.sub.1=55%. A thickness of the single Fe.sub.aG.sub.b metal sheet was defined as h.sub.1, and in this embodiment, h.sub.1=0.02 mm. [0059] (S4) The Fe.sub.95Ni.sub.2Nb.sub.0.5Mo.sub.1.5Co.sub.1 metal sheet plated with the rare earth compound Nd.sub.85Al.sub.1Cu.sub.0.5Ga.sub.0.5Fe.sub.10Co.sub.0.5B.sub.2.5 coating in step (S3) was placed in the square tool in step (S2), multi-layer stacking was continuously performed on the stacked product, and a final stacking thickness was defined as h.sub.2, where h.sub.2=10 mm. [0060] (S5) An extrusion force was applied to the stacked Fe.sub.aG.sub.b metal sheets, and was subjected to high-temperature diffusion under a vacuum condition, so as to prepare a neodymium-iron-boron magnet, where a diffusion temperature was 1050 C., and a diffusion time was 5 h; and finally, a square neodymium-iron-boron magnet was obtained.

[0061] The above obtained neodymium-iron-boron magnet was cut into a sample column with a diameter being 10 mm and a height being 15 mm, then a magnetic performance test (temperature being 20 C.3 C.) was performed; and then the sample was partitioned into a cut sample column 1, cut sample column 2, and cut sample column 3 with diameters being 10 mm and heights being 5 mm, and all test results were recorded in Table 6.

TABLE-US-00006 TABLE 6 Magnetic performance of sample in Embodiment VI Magnet name Br (KGs) Hcj (KOe) Sample column 9.8 11.2 Cut sample column 1 10.05 9.63 Cut sample column 2 9.57 11.48 Cut sample column 3 9.71 11.57

[0062] From the above test results, it might be seen that, the square magnet prepared in Embodiment 6 had overall performance of Br=9.65 and Hcj=11.57, and had high magnetic performance, and the test results after cutting showed that the magnet had different properties within different thickness ranges, and thus belonged to magnets with gradient variation in property.

[0063] The foregoing descriptions were merely preferred examples of the present disclosure, and were not intended to limit the present disclosure. Any modification, equivalent replacement and improvement made within the spirit and principle of the present disclosure should be included in the protection scope of the present disclosure.