NdFeB Magnet Materials of Composite Main Phase System and Preparation Method Thereof

Abstract

The present invention discloses a composite main-phase Nd-Fe-B magnet material and a preparation method thereof. The raw material composition of the composite main-phase Nd-Fe-B magnet material of the present invention includes a first type of alloy raw material and a second type of alloy raw material, wherein the mass percentage of the second type of alloy raw material in the raw material composition of the composite main-phase Nd-Fe-B magnet material is 2.0 to 15.0 mas%. The composite main-phase Nd-Fe-B magnet material prepared by using this raw material composition has improved coercivity while ensuring high remanence, and its preparation method can be applied in engineering.

Description

Technical Field

[0001] The present invention relates to a composite main-phase Nd-Fe-B material and a preparation method thereof. Background Art

[0002] Neodymium iron boron (Nd-Fe-B) has attracted much attention as the permanent magnet with the largest remanence coercivity at room temperature, and is widely used in fields such as traction motors, servo motors, main drive motors of new energy vehicles, magnetic components, and wind turbines. However, the demagnetization resistance of commercial magnets is only 1 / 4 of the theoretical value (about 71 kOe). The demagnetization resistance of Nd-Fe-B is generally characterized by coercivity. The magnitude of coercivity is greatly affected by the microstructure of Nd-Fe-B, and is simultaneously controlled by two mechanisms, namely nucleation field and pinning field, with the nucleation field being the dominant one. The way to increase HcJ by the nucleation field is to eliminate the nucleation points of reverse domains. From a microscopic perspective, there are generally three ways to increase coercivity:

[0003] 1) Improve the demagnetization coupling ability of the grain boundary phase between the main phases. Specifically, the method is to absorb Fe in the grain boundary by the main phase containing Nd6Fe 13 X, so that the grain boundary phase transforms into a non-magnetic phase or an antiferromagnetic phase, and at the same time widen the grain boundary; or increase the total rare earth content to increase the volume of the grain boundary phase; by adding grain boundary elements such as Cu, Ga, Co, Al, etc., improve the fluidity of the Nd-rich phase, optimize the boundaries of the main phase particles, thereby repair the defects of the main phase, reduce the formation of reverse domains, and increase HcJ. The HcJ improved by such methods is limited, and it is difficult to increase HcJ to more than 25 kOe.

[0004] 2) Reduce the reverse domain nucleation points of the main phase particles by refining the grains. The closer to the single-domain size, the more difficult it is to form reverse domains; or form grain boundary phases such as Nd6Fe 13 X to melt the sharp corners of the main phase particles, make the grain boundaries of the main phase smooth, and reduce the reverse nucleation points. Such methods have a strong effect on improving HcJ. The HcJ of the magnet prepared by the thin film method can reach 29 kOe, but it is difficult to be applied in engineering.

[0005] 3) By adding heavy rare earths, increase the anisotropy field of the main phase. However, the reserves of heavy rare earth resources are small and the price is high, which severely restricts the application of Nd-Fe-B magnets in various industries. Usually, the double alloy or diffusion method is used to distribute the heavy rare earths in the outer layer of the main phase to improve the utilization rate of heavy rare earths. However, the diffusion method cannot be applied to magnets with a large thickness (>15 mm), and the improvement effect of the existing double alloy method is limited (the HcJ can be increased by 1-1.5 kOe). Summary of the Invention

[0006] In order to solve the defect that the coercivity of the Nd-Fe-B magnet prepared by the double alloy method in the prior art is relatively low, the present invention provides a composite main-phase Nd-Fe-B magnet material and a preparation method thereof. The composite main-phase Nd-Fe-B magnet material of the present invention has a relatively high coercivity, and its preparation method can be applied in engineering.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] The present invention provides a raw material composition for a composite main phase system neodymium iron boron magnet material, which includes a first type of alloy raw material and a second type of alloy raw material; wherein,

[0009] The first type of alloy raw material includes the following components: light rare earth element LR, 10.0 - 33.0 mas%; LR is selected from one or more of Y, La, Ce, Pr, and Nd; heavy rare earth element HR, 0 - 20.0 mas%; HR is selected from one or more of Gd, Dy, Tb, and Ho; M, 0.1 - 5.0 mas%; M is selected from one or more of Co, Cu, Al, and Ga; X, 0.05 - 0.7 mas%; X is selected from one or more of Zr, Ti, and Nb; B, 0.90 - 1.1 mas%; the balance is Fe; wherein, mas% refers to the mass percentage of the component in the first type of alloy raw material;

[0010] The second type of alloy raw material includes the following components: light rare earth element LR, 10.0 - 30.0 mas%; LR includes Nd and / or Pr; heavy rare earth element HR, 5.0 - 40.0 mas%; HR is Dy and / or Tb; M, 0.1 - 5.0 mas%; M is selected from one or more of Co, Cu, Al, and Ga; X, 0.1 - 4.5 mas%; X is selected from one or more of Ti, Zr, Hf, Nb, W, and Ta; B, 0.85 - 0.93 mas%; the balance is Fe; wherein, mas% refers to the mass percentage of the component in the second type of alloy raw material;

[0011] The mass percentage of the second type of alloy raw material in the raw material composition of the composite main phase system neodymium iron boron magnet material is 2.0 - 15.0 mas%.

[0012] In the present invention, preferably, the total rare earth content TRE in the first type of alloy raw material is 28.0 - 35.0 mas%, such as 30.35 mas%, 31.0 mas%, or 31.05 mas%.

[0013] In the present invention, in the first type of alloy raw material, the content of the LR is preferably 26.0 - 30.0 mas%, such as 26.7 mas%, 28.4 mas%, or 29.0 mas%, and mas% refers to the mass percentage of the component in the first type of alloy raw material.

[0014] In the present invention, in the first type of alloy raw material, when the LR contains Nd, the content of Nd is preferably 20.0-23.0 mas%, such as 20.96 mas%, 22.5 mas% or 22.72 mas%, where mas% refers to the mass percentage of the component in the first type of alloy raw material.

[0015] In the present invention, in the first type of alloy raw material, when the LR contains Pr, the content of Pr is preferably 5.0-7.5 mas%, such as 5.24 mas% or 5.68 mas%, where mas% refers to the mass percentage of the component in the first type of alloy raw material.

[0016] Preferably, in the first type of alloy raw material, the LR contains Nd and Pr. More preferably, the content of Nd is 20.96 mas% and the content of Pr is 5.24 mas%; or the content of Nd is 22.5 mas% and the content of Pr is 7.5 mas%; or the content of Nd is 22.72 mas% and the content of Pr is 5.68 mas%; where mas% refers to the mass percentage of the component in the first type of alloy raw material.

[0017] In the present invention, in the first type of alloy raw material, the content of the HR is preferably 1.0-4.5 mas%, such as 1.35 mas%, 2.6 mas% or 4.35 mas%, where mas% refers to the mass percentage of the component in the first type of alloy raw material.

[0018] In the present invention, in the first type of alloy raw material, when the HR contains Dy, the content of Dy is preferably 2.0-4.5 mas%, such as 2.6 mas% or 4.35 mas%, where mas% refers to the mass percentage of the component in the first type of alloy raw material.

[0019] In the present invention, in the first type of alloy raw material, when the HR contains Gd, the content of Gd is preferably 1.0-2.0 mas%, such as 1.35 mas%, where mas% refers to the mass percentage of the component in the first type of alloy raw material.

[0020] In the present invention, in the first type of alloy raw material, the content of M is preferably 1.0-2.5 mas%, such as 1.4 mas%, 1.84 mas% or 2.1 mas%, where mas% refers to the mass percentage of the component in the first type of alloy raw material.

[0021] In the present invention, in the first type of alloy raw material, when M contains Ga, the content of Ga is preferably 0.1 to 0.25 mas%, for example 0.14 mas%, where mas% refers to the mass percentage of the component in the first type of alloy raw material.

[0022] In the present invention, in the first type of alloy raw material, when M contains Al, the content of Al is preferably 0.5 to 1.0 mas%, for example 0.7 mas%, where mas% refers to the mass percentage of the component in the first type of alloy raw material.

[0023] In the present invention, in the first type of alloy raw material, when M contains Cu, the content of Cu is preferably 0.1 to 0.25 mas%, for example 0.15 mas%, where mas% refers to the mass percentage of the component in the first type of alloy raw material.

[0024] In the present invention, in the first type of alloy raw material, when M contains Co, the content of Co is preferably 1.0 to 2.0 mas%, for example 1.55 mas%, where mas% refers to the mass percentage of the component in the first type of alloy raw material.

[0025] Preferably, in the first type of alloy raw material, M is Ga, Al, Cu and Co; wherein, the content of Ga is preferably 0.25 mas%, the content of Al is preferably 0.7 mas%, the content of Cu is preferably 0.15 mas%, and the content of Co is preferably 1.0 mas%. Wherein, mas% refers to the mass percentage of the component in the first type of alloy raw material.

[0026] Preferably, in the first type of alloy raw material, M is Ga, Cu and Co; wherein, the content of Ga is preferably 0.14 mas%, the content of Cu is preferably 0.15 mas%, and the content of Co is preferably 0.15 mas%. Wherein, mas% refers to the mass percentage of the component in the first type of alloy raw material.

[0027] In the present invention, in the first type of alloy raw material, the content of X is preferably 0.3 to 0.5 mas%, for example 0.32 mas%, where mas% refers to the mass percentage of the component in the first type of alloy raw material.

[0028] In the present invention, in the first type of alloy raw material, when M contains Zr, the content of Zr is preferably 0.1 to 0.3 mas%, for example 0.12 mas%, where mas% refers to the mass percentage of the component in the first type of alloy raw material.

[0029] In the present invention, in the first type of alloy raw materials, when M includes Ti, the content of Ti is preferably 0.1 to 0.3 mas%, for example, 0.2 mas%, and mas% refers to the mass percentage of the component in the first type of alloy raw materials.

[0030] Preferably, in the first type of alloy raw materials, X is Zr; the content of Zr is preferably 0.3 mas%.

[0031] Preferably, in the first type of alloy raw materials, X is Zr and Ti; the content of Zr is preferably 0.1 mas% or 0.12 mas%, and the content of Ti is preferably 0.2 mas%.

[0032] In the present invention, in the first type of alloy raw materials, the content of B is preferably 0.94 to 0.99 mas%, for example, 0.97 mas% or 0.98 mas%, and mas% refers to the mass percentage of the component in the first type of alloy raw materials.

[0033] In a preferred embodiment, the first type of alloy raw materials includes the following components: Nd, 20.96 mas%; Pr, 5.24 mas%; Dy, 4.35 mas%; Ga, 0.14 mas%; Cu, 0.15 mas%; Co, 1.55 mas%; Zr, 0.3 mas%; B, 0.97 mas%; the balance is Fe; wherein, mas% refers to the mass percentage of the component in the first type of alloy raw materials.

[0034] In a preferred embodiment, the first type of alloy raw materials includes the following components: Nd, 22.5 mas%; Pr, 7.5 mas%; Gd, 1.35 mas%; Ga, 0.25 mas%; Al, 0.7 mas%; Cu, 0.15 mas%; Co, 1.0 mas%; Zr, 0.12 mas%; Ti, 0.2 mas%; B, 0.98 mas%; the balance is Fe; wherein, mas% refers to the mass percentage of the component in the first type of alloy raw materials.

[0035] In a preferred embodiment, the first type of alloy raw materials includes the following components: Nd, 22.72 mas%; Pr, 5.68 mas%; Dy, 2.6 mas%; Ga, 0.25 mas%; Cu, 0.15 mas%; Co, 1.0 mas%; Zr, 0.1 mas%; Ti, 0.2 mas%; B, 0.97 mas%; the balance is Fe; wherein, mas% refers to the mass percentage of the component in the first type of alloy raw materials.

[0036] In the present invention, preferably, the total rare earth content TRE in the second type of alloy raw material is 31.5 - 45.0 mass%, for example 33.0 mass%.

[0037] In the present invention, in the second type of alloy raw material, the content of the LR is preferably 10.0 - 15.0 mas%, for example 13.0 mas%, and mas% refers to the mass percentage of the component in the second type of alloy raw material.

[0038] In the present invention, in the second type of alloy raw material, when the LR contains Nd, the content of the Nd is preferably 9.0 - 10.0 mas%, for example 9.75 mas%, and mas% refers to the mass percentage of the component in the second type of alloy raw material.

[0039] In the present invention, in the second type of alloy raw material, when the LR contains Pr, the content of the Pr is preferably 1.0 - 5.0 mas%, for example 3.25 mas%, and mas% refers to the mass percentage of the component in the second type of alloy raw material.

[0040] Preferably, in the second type of alloy raw material, the LR is Nd and Pr, the content of the Nd is preferably 9.75 mas%, and the content of the Pr is preferably 3.25 mas%; mas% refers to the mass percentage of the component in the second type of alloy raw material.

[0041] In the present invention, in the second type of alloy raw material, the content of the HR is preferably 15.0 - 25.0 mas%, for example 20.0 mas%, and mas% refers to the mass percentage of the component in the second type of alloy raw material.

[0042] Preferably, in the second type of alloy raw material, the HR is Tb, and the content of the Tb is 20.0 mas%, and mas% refers to the mass percentage of the component in the second type of alloy raw material.

[0043] Preferably, in the second type of alloy raw material, the HR is Dy, and the content of the Dy is 20.0 mas%, and mas% refers to the mass percentage of the component in the second type of alloy raw material.

[0044] In the present invention, in the second type of alloy raw material, the content of the M is preferably 2.0 - 3.0 mas%, for example 2.75 mas%, and mas% refers to the mass percentage of the component in the second type of alloy raw material.

[0045] In the present invention, in the second type of alloy raw material, when M includes Ga, the content of Ga is preferably 0.1 to 0.3 mas%, for example 0.25 mas%, and mas% refers to the mass percentage of the component in the second type of alloy raw material.

[0046] In the present invention, in the second type of alloy raw material, when M includes Co, the content of Co is preferably 2.0 to 3.0 mas%, for example 2.5 mas%, and mas% refers to the mass percentage of the component in the second type of alloy raw material.

[0047] Preferably, in the second type of alloy raw material, M is Ga and Co; wherein, the content of Ga is preferably 0.25 mas%, and the content of Co is preferably 2.5 mas%, and mas% refers to the mass percentage of the component in the second type of alloy raw material.

[0048] In the present invention, in the second type of alloy raw material, the content of X is preferably 0.1 to 0.5 mas%, for example 0.3 mas%, and mas% refers to the mass percentage of the component in the second type of alloy raw material. Preferably, in the second type of alloy raw material, X is Zr.

[0049] In the present invention, in the second type of alloy raw material, the content of B is preferably 0.88 to 0.91 mas%, for example 0.9 mas%, and mas% refers to the mass percentage of the component in the second type of alloy raw material.

[0050] In a preferred embodiment, the second type of alloy raw material includes the following components: Nd, 9.75 mas%; Pr, 3.25 mas%; Tb, 20.0 mas%; Ga, 0.25 mas%; Co, 2.5 mas%; Zr, 0.3 mas%; B, 0.9 mas%; the balance is Fe; wherein, mas% refers to the mass percentage of the component in the second type of alloy raw material.

[0051] In a preferred embodiment, the second type of alloy raw material includes the following components: Nd, 9.75 mas%; Pr, 3.25 mas%; Dy, 20.0 mas%; Ga, 0.25 mas%; Co, 2.5 mas%; Zr, 0.3 mas%; B, 0.9 mas%; the balance is Fe; wherein, mas% refers to the mass percentage of the component in the second type of alloy raw material.

[0052] In the present invention, the mass percentage of the second type of alloy raw material in the raw material composition of the composite main phase Nd-Fe-B magnet material is preferably 2.5 to 10.0 mas%, for example 7.5 mas%.

[0053] In the present invention, the content of HR in the second type of alloy raw material is preferably more than 3 times, more preferably 4 to 15 times, the content of HR in the first type of alloy raw material. This can ensure that there is enough HR in the neodymium-rich phase to form a shell layer.

[0054] In the present invention, preferably, the content of B in the second type of alloy raw material is lower than that in the first type of alloy raw material, and the total rare earth content TRE in the second type of alloy raw material is greater than that in the first type of alloy raw material. This can form more neodymium-rich phases, thereby providing a channel for the diffusion of HR to the main phase epitaxial layer during the sintering process.

[0055] In a more preferred embodiment, the raw material composition of the composite main phase Nd-Fe-B magnet material comprises a first type of alloy raw material and a second type of alloy raw material; wherein, the first type of alloy raw material comprises the following components: Nd, 20.96 mas%; Pr, 5.24 mas%; Dy, 4.35 mas%; Ga, 0.14 mas%; Cu, 0.15 mas%; Co, 1.55 mas%; Zr, 0.3 mas%; B, 0.97 mas%; the balance is Fe; wherein, mas% refers to the mass percentage of the component in the first type of alloy raw material; the second type of alloy raw material comprises the following components: Nd, 9.75 mas%; Pr, 3.25 mas%; Tb, 20.0 mas%; Ga, 0.25 mas%; Co, 2.5 mas%; Zr, 0.3 mas%; B, 0.9 mas%; the balance is Fe; wherein, mas% refers to the mass percentage of the component in the second type of alloy raw material; the mass percentage of the second type of alloy raw material in the raw material composition of the composite main phase Nd-Fe-B magnet material is 2.5 mas%.

[0056] In a more preferred embodiment, the raw material composition of the composite main-phase Nd-Fe-B magnet material comprises a first type of alloy raw material and a second type of alloy raw material; wherein, the first type of alloy raw material comprises the following components: Nd, 22.5 mas%; Pr, 7.5 mas%; Gd, 1.35 mas%; Ga, 0.25 mas%; Al, 0.7 mas%; Cu, 0.15 mas%; Co, 1.0 mas%; Zr, 0.12 mas%; Ti, 0.2 mas%; B, 0.98 mas%; the balance is Fe; wherein, mas% refers to the mass percentage of the component in the first type of alloy raw material; the second type of alloy raw material comprises the following components: Nd, 9.75 mas%; Pr, 3.25 mas%; Dy, 20.0 mas%; Ga, 0.25 mas%; Co, 2.5 mas%; Zr, 0.3 mas%; B, 0.9 mas%; the balance is Fe; wherein, mas% refers to the mass percentage of the component in the second type of alloy raw material; the mass percentage of the second type of alloy raw material in the raw material composition of the composite main-phase Nd-Fe-B magnet material is 7.5 mas%.

[0057] In a more preferred embodiment, the raw material composition of the composite main-phase Nd-Fe-B magnet material comprises a first type of alloy raw material and a second type of alloy raw material; wherein, the first type of alloy raw material comprises the following components: Nd, 22.72 mas%; Pr, 5.68 mas%; Dy, 2.6 mas%; Ga, 0.25 mas%; Cu, 0.15 mas%; Co, 1.0 mas%; Zr, 0.1 mas%; Ti, 0.2 mas%; B, 0.97 mas%; the balance is Fe; wherein, mas% refers to the mass percentage of the component in the first type of alloy raw material; the second type of alloy raw material comprises the following components: Nd, 9.75 mas%; Pr, 3.25 mas%; Dy, 20.0 mas%; Ga, 0.25 mas%; Co, 2.5 mas%; Zr, 0.3 mas%; B, 0.9 mas%; the balance is Fe; wherein, mas% refers to the mass percentage of the component in the second type of alloy raw material; the mass percentage of the second type of alloy raw material in the raw material composition of the composite main-phase Nd-Fe-B magnet material is 10.0 mas%.

[0058] The present invention also provides a preparation method of a composite main-phase Nd-Fe-B magnet material, which comprises the following steps:

[0059] S1. Melting and casting the first type of alloy raw material and the second type of alloy raw material in the raw material composition of the composite main-phase Nd-Fe-B magnet material respectively to obtain a first type of alloy and a second type of alloy;

[0060] S2. Hydrogenate and micro-crush the first type of alloy and the second type of alloy respectively, and then mix them, followed by shaping and sintering to obtain the composite main-phase Nd-Fe-B magnet material.

[0061] In the present invention, the melting, casting, hydrogenation crushing, micro-crushing, shaping, and sintering are all conventional operation methods and conditions in the art.

[0062] In the present invention, the melting can be carried out according to the conventional melting in the art. For example, it can be melted in a melting furnace. The vacuum degree of the melting furnace is about 5×10 -2 Pa. The melting temperature can be 1300°C to 1600°C, preferably 1500°C to 1550°C.

[0063] In the present invention, the casting process can be a conventional casting process in the art, such as strip continuous casting, ingot casting, centrifugal casting, or rapid quenching.

[0064] In the present invention, the hydrogenation crushing process can be a conventional process in the art. The dehydrogenation temperature of the hydrogenation crushing can be 400°C to 650°C, such as 500 to 620°C. The dehydrogenation time of the hydrogenation crushing can be 3 to 10 hours.

[0065] In the present invention, the micro-crushing process can be a conventional micro-crushing process in the art. The micro-crushing is preferably carried out in a jet mill. The micro-crushing is preferably carried out in an oxygen-containing atmosphere; the oxygen content in the oxygen-containing atmosphere can be 80 ppm or less, preferably 50 ppm or less. The particle size D50 of the powder after micro-crushing can be 1 to 20 μm, preferably 1 to 10 μm, such as 3.0 to 5.3 μm.

[0066] In the present invention, the shaping conditions can be conventional in the art. For example, it can be pressed into a green body in a press. The magnetic field strength of the press is preferably 0.5 T to 3.0 T, such as 1.0 to 2.0 T. The pressing pressure can be 200 to 300 MPa, such as 260 MPa. The pressing time can be conventional in the art, which can be 3 to 30 s, such as 15 s.

[0067] In the present invention, the sintering conditions can be conventional in the art. The sintering temperature can be 1000°C to 1150°C, preferably 1050 to 1085°C. The sintering time can be 4 to 20 hours. The sintering atmosphere is preferably a vacuum or argon atmosphere.

[0068] The present invention also provides a composite main-phase Nd-Fe-B magnet material, which is prepared according to the preparation method of the composite main-phase Nd-Fe-B magnet material.

[0069] In the present invention, the composite matrix Nd-Fe-B magnet material includes a first matrix phase, a second matrix phase and a grain boundary phase; wherein, the first matrix phase has a core-shell structure, the core is LR2T 14 B, and the shell is HR2T 14 B; the second matrix phase is HR2T 14 B; the grain boundary phase includes a neodymium-rich phase, an XB2 phase and an R2T 14 phase;

[0070] wherein, R is LR and / or HR;

[0071] LR is selected from one or more of Y, La, Ce, Pr and Nd;

[0072] HR is selected from one or more of Gd, Dy, Tb and Ho;

[0073] X is selected from one or more of Ti, Zr, Hf, Nb, W and Ta;

[0074] T is selected from Fe, Ga, Cu and Co.

[0075] Preferably, in the composite matrix Nd-Fe-B magnet material, LR is Pr and Nd; HR is Dy and Tb; X is Zr; T is Fe, Ga, Cu and Co.

[0076] Preferably, in the composite matrix Nd-Fe-B magnet material, LR is Pr and Nd; HR is Dy and Gd; X is Zr and Ti; T is Fe, Ga, Cu and Co.

[0077] Preferably, in the composite matrix Nd-Fe-B magnet material, LR is Pr and Nd; HR is Dy; X is Zr and Ti; T is Fe, Ga, Cu and Co.

[0078] In the present invention, the first type of alloy provides the first matrix phase LR2Fe 14 B, and the second type of alloy provides the second matrix phase HR2Fe 14 B. On the one hand, since both the first type of alloy and the second type of alloy form the matrix phase R2Fe 14 B, their melting points are close, which is beneficial to the migration of HR near the sintering temperature, that is, part of HR in the second type of alloy acts as a diffusion source and diffuses through the molten neodymium-rich phase to the surface layer of the first matrix phase particles during sintering, replacing LR therein, so as to form a heavy rare earth shell layer HR2Fe 14 B on the surface layer of the first matrix phase. On the other hand, there is a high HR2Fe 14 B phase in the second type of alloy, and the anisotropy field is high, pinning the magnetic domain structure in the surrounding area. This high HR2Fe 14The mass distribution of B in the magnet makes the movement of the overall magnetic domain wall difficult, thereby enhancing the demagnetization resistance of the magnet. The composite main-phase NdFeB magnet material maintains a high proportion of the main phase (i.e., a high Br) through high B, and at the same time eliminates the excess B content at the grain boundaries through the high-temperature element X. At high temperatures, the X element in the Nd-rich phase combines with B to form a precipitate XB2, and B is basically enriched in the high-X element region, enabling elements such as Ga / Cu at the grain boundaries to flow more strongly and fully wrap the grain boundaries, thereby increasing HcJ. In the present invention, the grain boundary elements of the second alloy are the same as those of the first alloy, reducing the risk of uneven mixing distribution and improving the performance consistency.

[0079] Based on the common knowledge in the art, the above preferred conditions can be combined arbitrarily to obtain various preferred examples of the present invention.

[0080] The reagents and raw materials used in the present invention are all commercially available.

[0081] The positive and progressive effects of the present invention are as follows:

[0082] The present invention constructs a composite main-phase combination method and combines specific raw material ratios. In the NdFeB main-phase particles LR2T 14 B forms a shell of heavy rare earths; at the same time, through the main-phase particles HR2T 14 The dispersion distribution of B in the magnet improves the overall demagnetization resistance; and through the purification effect of the high-temperature element X on the grain boundaries, the fluidity of the rare-earth-rich phase is improved. The demagnetization resistance of the NdFeB magnet is comprehensively improved from three aspects, thereby improving the intrinsic coercivity (HcJ) of the magnet while ensuring a high remanence (Br). BRIEF DESCRIPTION OF THE DRAWINGS

[0083] Figure 1 It is an elemental analysis diagram of the composite main-phase NdFeB magnet material of Example 1 of the present invention.

[0084] Figure 2 It is an elemental analysis diagram of the composite main-phase NdFeB magnet material of Example 2 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0085] The present invention will be further described below by way of examples, but the present invention is not limited to the scope of the described examples. The experimental methods without specific conditions in the following examples are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0086] Examples 1 to 3

[0087] (1) Casting process: According to the ratios shown in Examples 1 to 3 in Table 1 below, the first alloy raw material and the second alloy raw material in the raw material composition of the composite main-phase NdFeB magnet material are respectively placed in a vacuum melting furnace at about 5×10-2 In a vacuum of Pa, vacuum melting is carried out at a temperature of 1500 - 1550 °C respectively; then, the molten liquid obtained by melting is cast respectively by strip continuous casting method to obtain the first type of alloy and the second type of alloy.

[0088] (2) Hydrogen crushing process: At room temperature, the first type of alloy and the second type of alloy in step (1) are respectively hydrogenated, and vacuum dehydrogenation treatment is carried out at 550 °C for 3 - 10 hours to obtain coarse crushed powder.

[0089] (3) Fine crushing treatment: The coarse crushed powder in step (2) is finely crushed in a fluid energy mill under an atmosphere with an oxidation gas content of 50 ppm or less to obtain finely crushed powder with an average particle size D50 of 4 μm.

[0090] (4) Forming process: It is pressed into a green body in a press with a magnetic field strength of 2.0 T, and then kept at a pressure of 260 MPa for 15 s to obtain a formed body.

[0091] (5) Sintering process: The formed body is sintered at a temperature of 1075 °C for 6 hours, and the sintering atmosphere is a vacuum or argon atmosphere to obtain a composite main phase system neodymium iron boron magnet material.

[0092] Table 1 Components and contents (mas%) of the raw material composition of the composite main phase system neodymium iron boron magnet material

[0093]

[0094] Among them, " / " means that this component is not contained.

[0095] Effect examples

[0096] (1) Magnetic property test: The composite main phase system neodymium iron boron magnet materials prepared in Examples 1 - 3 are respectively taken, and the magnetic properties are detected by using the PFM14.CN type super high coercivity permanent magnet measuring instrument of the National Institute of Metrology of China.

[0097] Table 2 Magnetic properties of the composite main phase system neodymium iron boron magnet material

[0098] Number Example 1 Example 2 Example 3 Br (kGs) 13.3 12.75 13.0 HcJ (kOe) 27.2 22.5 27.0

[0099] "B r " refers to the remanence; after the permanent magnet material is saturated magnetized, the magnetism that can be maintained after removing the external magnetic field is called the remanence. The magnetic polarization intensity coercivity H cJ (intrinsic coercivity).

[0100] (2) FE - EPMA detection:

[0101] The composite main phase system neodymium iron boron magnet materials prepared in Examples 1 and 2 are respectively taken, and element analysis diagrams are formed by FE - EPMA surface scanning. The results are shown inFigure 1 and Figure 2 。

[0102] As can be seen from the attached drawings, there is an obvious heavy rare earth shell layer on the outer edge layer of the main phase; at the same time, the dispersed distribution of the main phase particles with high heavy rare earth content in the magnet hinders the further growth of reverse domains; as a result, the HcJ of the whole magnet is greatly improved. And through the absorption of non-metallic elements such as B by high-temperature element Zr, etc., the grain boundaries are purified, further improving HcJ.

Claims

1. A raw material composition of a composite main phase Nd-Fe-B magnet material, characterized in that, The raw material composition of the composite main phase Nd-Fe-B magnet material includes a first type of alloy raw material and a second type of alloy raw material; wherein, The first type of alloy raw material includes the following components: light rare earth element LR, 10.0 - 33.0 mas%; LR is selected from one or more of Y, La, Ce, Pr, and Nd; heavy rare earth element HR, 2.6 - 4.5 mas%; HR is selected from one or more of Gd, Dy, Tb, and Ho; M, 1.4 - 1.84 mas%; M is selected from one or more of Co, Cu, and Ga; X, 0.05 - 0.7 mas%; X is selected from one or more of Zr, Ti, and Nb; B, 0.90 - 1.1 mas%; the balance is Fe; wherein, mas% refers to the mass percentage of the component in the first type of alloy raw material; The second type of alloy raw material includes the following components: light rare earth element LR, 10.0 - 30.0 mas%; LR includes Nd and / or Pr; heavy rare earth element HR, 5.0 - 40.0 mas%; HR is Dy and / or Tb; M, 0.1 - 5.0 mas%; M is selected from one or more of Co, Cu, and Ga; X, 0.1 - 4.5 mas%; X is selected from one or more of Ti, Zr, Hf, Nb, W, and Ta; B, 0.85 - 0.93 mas%; the balance is Fe; wherein, mas% refers to the mass percentage of the component in the second type of alloy raw material; The mass percentage of the second type of alloy raw material in the raw material composition of the composite main phase Nd-Fe-B magnet material is 2.0 - 15.0 mas%; The content of B in the second type of alloy raw material is lower than the content of B in the first type of alloy raw material, and the total rare earth content TRE in the second type of alloy raw material is greater than the total rare earth content TRE in the first type of alloy raw material.

2. The raw material composition of the composite main phase Nd-Fe-B magnet material according to claim 1, characterized in that, The total rare earth content TRE in the first type of alloy raw material is 28.0 - 35.0 mas%, and mas% refers to the mass percentage of the component in the first type of alloy raw material; And / or, in the first type of alloy raw material, the content of the LR is 26.0 - 30.0 mas%, and mas% refers to the mass percentage of the component in the first type of alloy raw material; And / or, in the first type of alloy raw material, when the LR contains Nd, the content of the Nd is 20.0 - 23.0 mas%; when the LR contains Pr, the content of the Pr is 5.0 - 7.5 mas%; wherein, mas% refers to the mass percentage of the component in the first type of alloy raw material; And / or, in the first type of alloy raw material, the LR contains Nd and Pr; wherein, the content of the Nd is 20.96 mas%, and the content of the Pr is 5.24 mas%; or, the content of the Nd is 22.5 mas%, and the content of the Pr is 7.5 mas%; or, the content of the Nd is 22.72 mas%, and the content of the Pr is 5.68 mas%; mas% refers to the mass percentage of the component in the first type of alloy raw material; And / or, in the first type of alloy raw materials, the content of HR is 4.35 - 4.5 mas%, where mas% refers to the mass percentage of the component in the first type of alloy raw materials; And / or, in the first type of alloy raw materials, when HR contains Dy, the content of Dy is 2.0 - 4.5 mas%; when HR contains Gd, the content of Gd is 1.0 - 2.0 mas%; where mas% refers to the mass percentage of the component in the first type of alloy raw materials; And / or, in the first type of alloy raw materials, when M contains Ga, the content of Ga is 0.1 - 0.25 mas%; when M contains Cu, the content of Cu is 0.1 - 0.25 mas%; when M contains Co, the content of Co is 1.0 - 1.55 mas%; where mas% refers to the mass percentage of the component in the first type of alloy raw materials; And / or, in the first type of alloy raw materials, the content of X is 0.3 - 0.5 mas%, where mas% refers to the mass percentage of the component in the first type of alloy raw materials; And / or, in the first type of alloy raw materials, when X contains Zr, the content of Zr is 0.1 - 0.3 mas%; when X contains Ti, the content of Ti is 0.1 - 0.3 mas%; where mas% refers to the mass percentage of the component in the first type of alloy raw materials; And / or, in the first type of alloy raw materials, X is Zr; the content of Zr is 0.3 mas%, where mas% refers to the mass percentage of the component in the first type of alloy raw materials; And / or, in the first type of alloy raw materials, X is Zr and Ti; the content of Zr is 0.1 mas% or 0.12 mas%, and the content of Ti is 0.2 mas%, where mas% refers to the mass percentage of the component in the first type of alloy raw materials; And / or, in the first type of alloy raw materials, the content of B is 0.94 - 0.99 mas%, where mas% refers to the mass percentage of the component in the first type of alloy raw materials.

3. The raw material composition of the composite main phase Nd-Fe-B magnet material according to claim 2, characterized in that, The total rare earth content TRE in the first type of alloy raw materials is 30.35 mas%, 31.0 mas% or 31.05 mas%, where mas% refers to the mass percentage of the component in the first type of alloy raw materials; And / or, in the first type of alloy raw materials, the content of LR is 26.7 mas%, 28.4 mas% or 29.0 mas%, where mas% refers to the mass percentage of the component in the first type of alloy raw materials; And / or, in the first type of alloy raw materials, when LR contains Nd, the content of Nd is 20.96 mas%, 22.5 mas% or 22.72 mas%; when LR contains Pr, the content of Pr is 5.24 mas% or 5.68 mas%; where mas% refers to the mass percentage of the component in the first type of alloy raw materials; And / or, in the first type of alloy raw materials, when the HR contains Dy, the content of Dy is 2.6 mas% or 4.35 mas%; when the HR contains Gd, the content of Gd is 1.35 mas%; wherein, mas% refers to the mass percentage of the component in the first type of alloy raw materials; And / or, in the first type of alloy raw materials, when the M contains Ga, the content of Ga is 0.14 mas%; when the M contains Cu, the content of Cu is 0.15 mas%; when the M contains Co, the content of Co is 1.55 mas%; wherein, mas% refers to the mass percentage of the component in the first type of alloy raw materials; And / or, in the first type of alloy raw materials, the content of X is 0.32 mas%, and mas% refers to the mass percentage of the component in the first type of alloy raw materials; And / or, in the first type of alloy raw materials, when the X contains Zr, the content of Zr is 0.12 mas%; when the X contains Ti, the content of Ti is 0.2 mas%; wherein, mas% refers to the mass percentage of the component in the first type of alloy raw materials; And / or, in the first type of alloy raw materials, the content of B is 0.97 mas% or 0.98 mas%, and mas% refers to the mass percentage of the component in the first type of alloy raw materials.

4. The raw material composition of the composite main phase Nd-Fe-B magnet material according to claim 1, characterized in that, The first type of alloy raw materials includes the following components: Nd, 20.96 mas%; Pr, 5.24 mas%; Dy, 4.35 mas%; Ga, 0.14 mas%; Cu, 0.15 mas%; Co, 1.55 mas%; Zr, 0.3 mas%; B, 0.97 mas%; the balance is Fe; wherein, mas% refers to the mass percentage of the component in the first type of alloy raw materials; Or, the first type of alloy raw materials includes the following components: Nd, 22.72 mas%; Pr, 5.68 mas%; Dy, 2.6 mas%; Ga, 0.25 mas%; Cu, 0.15 mas%; Co, 1.0 mas%; Zr, 0.1 mas%; Ti, 0.2 mas%; B, 0.97 mas%; the balance is Fe; wherein, mas% refers to the mass percentage of the component in the first type of alloy raw materials.

5. The raw material composition of the composite main phase Nd-Fe-B magnet material according to claim 1, characterized in that, In the second type of alloy raw materials, the total rare earth content TRE is 31.5 - 45.0 mass%, and mas% refers to the mass percentage of the component in the second type of alloy raw materials; And / or, in the second type of alloy raw materials, the content of LR is 10.0 - 15.0 mas%, and mas% refers to the mass percentage of the component in the second type of alloy raw materials; And / or, in the second type of alloy raw materials, when the LR contains Nd, the content of Nd is 9.0 - 10.0 mas%; when the LR contains Pr, the content of Pr is 1.0 - 5.0 mas%; wherein, mas% refers to the mass percentage of the component in the second type of alloy raw materials; And / or, in the second type of alloy raw material, the LR is Nd and Pr, the content of Nd is 9.75 mas%, and the content of Pr is 3.25 mas%; mas% refers to the mass percentage of the component in the second type of alloy raw material; And / or, in the second type of alloy raw material, the content of HR is 15.0 - 25.0 mas%; mas% refers to the mass percentage of the component in the second type of alloy raw material; And / or, in the second type of alloy raw material, the HR is Tb, the content of Tb is 20.0 mas%, and mas% refers to the mass percentage of the component in the second type of alloy raw material; And / or, in the second type of alloy raw material, the HR is Dy, the content of Dy is 20.0 mas%, and mas% refers to the mass percentage of the component in the second type of alloy raw material; And / or, in the second type of alloy raw material, the content of M is 2.0 - 3.0 mas%; mas% refers to the mass percentage of the component in the second type of alloy raw material; And / or, in the second type of alloy raw material, when M contains Ga, the content of Ga is 0.1 - 0.3 mas%; when M contains Co, the content of Co is 2.0 - 3.0 mas%; where mas% refers to the mass percentage of the component in the second type of alloy raw material; And / or, in the second type of alloy raw material, M is Ga and Co; where the content of Ga is 0.25 mas% and the content of Co is 2.5 mas%, and mas% refers to the mass percentage of the component in the second type of alloy raw material; And / or, in the second type of alloy raw material, the content of X is 0.1 - 0.5 mas%; mas% refers to the mass percentage of the component in the second type of alloy raw material; in the second type of alloy raw material, X is Zr; And / or, in the second type of alloy raw material, the content of B is 0.88 - 0.91 mas%; mas% refers to the mass percentage of the component in the second type of alloy raw material; And / or, the mass percentage of the second type of alloy raw material in the raw material composition of the composite main - phase Nd - Fe - B magnet material is 2.5 - 10.0 mas%; And / or, the content of HR in the second type of alloy raw material is more than 3 times the content of HR in the first type of alloy raw material.

6. The raw material composition of the composite main phase Nd-Fe-B magnet material according to claim 5, characterized in that, The total rare - earth content TRE in the second type of alloy raw material is 33.0 mass%, and mas% refers to the mass percentage of the component in the second type of alloy raw material; And / or, in the second type of alloy raw material, the content of LR is 13.0 mas%, and mas% refers to the mass percentage of the component in the second type of alloy raw material; And / or, in the second type of alloy raw material, when LR contains Nd, the content of Nd is 9.75 mas%; when LR contains Pr, the content of Pr is 3.25 mas%; where mas% refers to the mass percentage of the component in the second type of alloy raw material; And / or, in the second type of alloy raw material, the content of HR is 20.0 mas%, where mas% refers to the mass percentage of the component in the second type of alloy raw material; And / or, in the second type of alloy raw material, the content of M is 2.75 mas%, where mas% refers to the mass percentage of the component in the second type of alloy raw material; And / or, in the second type of alloy raw material, when M contains Ga, the content of Ga is 0.25 mas%; when M contains Co, the content of Co is 2.5 mas%; where mas% refers to the mass percentage of the component in the second type of alloy raw material; And / or, in the second type of alloy raw material, the content of X is 0.3 mas%, where mas% refers to the mass percentage of the component in the second type of alloy raw material; in the second type of alloy raw material, X is Zr; And / or, in the second type of alloy raw material, the content of B is 0.9 mas%, where mas% refers to the mass percentage of the component in the second type of alloy raw material; And / or, the mass percentage of the second type of alloy raw material in the raw material composition of the composite main phase NdFeB magnet material is 7.5 mas%; And / or, the content of HR in the second type of alloy raw material is 4 to 15 times the content of HR in the first type of alloy raw material.

7. The raw material composition of the composite main-phase Nd-Fe-B magnet material according to claim 1, characterized in that, The second type of alloy raw material includes the following components: Nd, 9.75 mas%; Pr, 3.25 mas%; Tb, 20.0 mas%; Ga, 0.25 mas%; Co, 2.5 mas%; Zr, 0.3 mas%; B, 0.9 mas%; the balance is Fe; where mas% refers to the mass percentage of the component in the second type of alloy raw material; Or, the second type of alloy raw material includes the following components: Nd, 9.75 mas%; Pr, 3.25 mas%; Dy, 20.0 mas%; Ga, 0.25 mas%; Co, 2.5 mas%; Zr, 0.3 mas%; B, 0.9 mas%; the balance is Fe; where mas% refers to the mass percentage of the component in the second type of alloy raw material.

8. The raw material composition of the composite main phase Nd-Fe-B magnet material according to claim 1, characterized in that The raw material composition of the composite main-phase Nd-Fe-B magnet material includes a first type of alloy raw material and a second type of alloy raw material; wherein, the first type of alloy raw material includes the following components: Nd, 20.96 mas%; Pr, 5.24 mas%; Dy, 4.35 mas%; Ga, 0.14 mas%; Cu, 0.15 mas%; Co, 1.55 mas%; Zr, 0.3 mas%; B, 0.97 mas%; the balance is Fe; wherein, mas% refers to the mass percentage of the component in the first type of alloy raw material; the second type of alloy raw material includes the following components: Nd, 9.75 mas%; Pr, 3.25 mas%; Tb, 20.0 mas%; Ga, 0.25 mas%; Co, 2.5 mas%; Zr, 0.3 mas%; B, 0.9 mas%; the balance is Fe; wherein, mas% refers to the mass percentage of the component in the second type of alloy raw material; the mass percentage of the second type of alloy raw material in the raw material composition of the composite main-phase Nd-Fe-B magnet material is 2.5 mas%; Alternatively, the raw material composition of the composite main-phase Nd-Fe-B magnet material includes a first type of alloy raw material and a second type of alloy raw material; wherein, the first type of alloy raw material includes the following components: Nd, 22.72 mas%; Pr, 5.68 mas%; Dy, 2.6 mas%; Ga, 0.25 mas%; Cu, 0.15 mas%; Co, 1.0 mas%; Zr, 0.1 mas%; Ti, 0.2 mas%; B, 0.97 mas%; the balance is Fe; wherein, mas% refers to the mass percentage of the component in the first type of alloy raw material; the second type of alloy raw material includes the following components: Nd, 9.75 mas%; Pr, 3.25 mas%; Dy, 20.0 mas%; Ga, 0.25 mas%; Co, 2.5 mas%; Zr, 0.3 mas%; B, 0.9 mas%; the balance is Fe; wherein, mas% refers to the mass percentage of the component in the second type of alloy raw material; the mass percentage of the second type of alloy raw material in the raw material composition of the composite main-phase Nd-Fe-B magnet material is 10.0 mas%.

9. A method for preparing a composite main-phase Nd-Fe-B magnet material, comprising the following steps: S1. Melting and casting the first type of alloy raw material and the second type of alloy raw material in the raw material composition of the composite main-phase Nd-Fe-B magnet material according to any one of claims 1-8 respectively to obtain a first type of alloy and a second type of alloy; S2. Hydrogenating and micro-pulverizing the first type of alloy and the second type of alloy respectively, then mixing them, and performing shaping and sintering treatments to obtain the composite main-phase Nd-Fe-B magnet material.

10. The preparation method of the composite main phase Nd-Fe-B magnet material according to claim 9, characterized in that, The melting is carried out in a smelting furnace, and the vacuum degree of the smelting furnace is 5×10 -2 Pa, and the temperature of the melting is 1300°C to 1600°C; And / or, the casting process is strip continuous casting, ingot casting, centrifugal casting or rapid quenching; And / or, the dehydrogenation temperature of the hydrogenation and crushing is 400°C to 650°C; the dehydrogenation time of the hydrogenation and crushing is 3 to 10 hours; And / or, the micro-pulverization is carried out in a jet mill; And / or, the micronization is carried out in an oxygen-containing atmosphere; And / or, the particle size D50 of the micronized powder is 1 - 20 μm; And / or, the forming is to press into a green compact in a press; And / or, the sintering temperature is 1000 °C - 1150 °C; And / or, the sintering time is 4 - 20 hours; And / or, the sintering atmosphere is a vacuum or argon atmosphere.

11. The preparation method of the composite main phase Nd-Fe-B magnet material according to claim 10, characterized in that, The melting temperature is 1500 °C - 1550 °C; And / or, the dehydrogenation temperature of the hydrogen decrepitation is 500 - 620 °C; And / or, the oxygen content in the oxygen-containing atmosphere is 80 ppm or less; And / or, the particle size D50 of the micronized powder is 1 - 10 μm; And / or, the magnetic field strength of the press is 0.5 T - 3.0 T; the pressing pressure is 200 - 300 MPa; the pressing time is 3 - 30 s; And / or, the sintering temperature is 1050 - 1085 °C.

12. The preparation method of the composite main-phase Nd-Fe-B magnet material according to claim 11, wherein The oxygen content in the oxygen-containing atmosphere is 50 ppm or less; And / or, the particle size D50 of the micronized powder is 3.0 - 5.3 μm; And / or, the magnetic field strength of the press is 1.0 - 2.0 T; the pressing pressure is 260 MPa; the pressing time is 15 s.

13. A composite main phase NdFeB magnet material, which is prepared by the preparation method of the composite main phase NdFeB magnet material according to any one of claims 9 - 12.

14. The composite main-phase Nd-Fe-B magnet material according to claim 13, characterized in that, The composite main-phase Nd-Fe-B magnet material includes a first main phase, a second main phase, and a grain boundary phase; wherein, the first main phase has a core-shell structure, the core is LR2T 14 B, and the shell is HR2T 14 B; the second main phase is HR2T 14 B; the grain boundary phase includes a neodymium-rich phase, an XB2 phase, and an R2T 14 phase; Wherein, R is LR and / or HR; LR is selected from one or more of Y, La, Ce, Pr and Nd; HR is selected from one or more of Gd, Dy, Tb and Ho; X is selected from one or more of Ti, Zr, Hf, Nb, W and Ta; T is Fe, Ga, Cu and Co.

15. The composite main-phase Nd-Fe-B magnet material according to claim 14, characterized in that, In the composite main phase NdFeB magnet material, LR is Pr and Nd; HR is Dy and Tb; X is Zr; And / or, in the composite main phase NdFeB magnet material, LR is Pr and Nd; HR is Dy and Gd; X is Zr and Ti; And / or, in the composite main phase NdFeB magnet material, LR is Pr and Nd; HR is Dy; X is Zr and Ti.

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