Neodymium iron boron rare earth permanent magnets, their preparation methods and applications

Abstract

This invention discloses a neodymium iron boron rare earth permanent magnet, its preparation method, and its applications. The microstructure of this neodymium iron boron rare earth permanent magnet includes a main phase M, a grain boundary phase A, and a grain boundary phase B; the main phase M is R2(Fe,Co). 14 B, wherein the main phase has a volume percentage of 90–94.5%; the grain boundary phase A is R(Fe,Co)₂, and the volume percentage of grain boundary phase A is 4.5–8%; the grain boundary phase B is R₄(Fe,Co)₃, and the volume percentage of grain boundary phase B is 0.5–2%. This invention achieves high Co content (12–20 wt%) while selecting 0 ≤ Pr < 14 wt%, and suppresses R₂Co by controlling the temperature and cooling rate during the preparation process. 17 The formation of the phase can reduce the temperature coefficient while improving remanence, coercivity, magnetic energy product, and mechanical properties.

Description

Technical Field

[0001] This invention relates to a neodymium iron boron rare earth permanent magnet, its preparation method, and its application. Background Technology

[0002] Traditional neodymium iron boron (NdFeB) rare-earth permanent magnets have a remanence temperature coefficient (α) of approximately -0.1% / ℃ to -0.12% / ℃ and a coercivity temperature coefficient (β) of approximately -0.6% / ℃ to -0.8% / ℃. Therefore, their magnetic properties decay rapidly with increasing temperature, and their typical operating temperature does not exceed 200℃, limiting their application in high-temperature fields. While samarium cobalt (SMC) permanent magnets have low temperature coefficients (approximately -0.035% / ℃ for remanence temperature coefficient (α) and -0.25% / ℃ for coercivity temperature coefficient (β), they suffer from higher brittleness, poor bending strength, and lower energy product, making it difficult to meet the increasingly stringent mechanical reliability and energy efficiency requirements of permanent magnet motors.

[0003] Chinese patent application CN1067134A discloses a method for preparing neodymium iron boron with a low temperature coefficient. By adding elements such as Co, Mo, Al and Dy2O3, a rare earth permanent magnet with a low temperature coefficient is prepared. However, the magnet prepared by this method has low remanence and magnetic energy product, poor coercivity, low Co addition amount, and limited improvement in temperature coefficient.

[0004] Chinese patent application CN1308344A discloses a heat-resistant low temperature coefficient magnet containing elements such as Co and Ga, with an operating temperature of up to 150℃. However, it also suffers from the problems of low Co content, low Curie temperature, and limited improvement in remanence temperature coefficient. Furthermore, the presence of a Co-containing soft magnetic phase after adding Co results in low remanence and poor coercivity. Even with the addition of large amounts of high coercivity elements such as Dy and Tb, its coercivity is still less than 2000 kA / m.

[0005] Chinese patent application CN1696324A discloses a high-coercivity magnet with added Co, Cu, Al and Nb that is resistant to high temperatures. However, its magnetic energy product is low, the improvement of temperature coefficient is limited, and the sintered magnet needs to be rapidly cooled during its preparation process to avoid the precipitation of soft magnetic phase. The preparation process is complex and not suitable for large-scale production.

[0006] Chinese patent CN101364465B discloses a Co-containing rare earth permanent magnet with added nano-TiO2, ZrO2, MgO, and ZnO nanocrystals. Although the coercivity of the magnet is improved by adding a large amount of Dy, Tb, Pr, etc., thereby improving its irreversible magnetic flux loss, the amount of Co added is low and the improvement in temperature coefficient is not obvious.

[0007] In summary, the existing technologies currently suffer from defects such as low Co addition, low Curie temperature, insignificant improvement in remanence temperature coefficient, and low coercivity. In order to avoid the precipitation of soft magnetic phase during the manufacturing process after adding Co and to ensure the coercivity of the magnet, a large amount of heavy rare earth elements and special processes such as rapid cooling are required during manufacturing, which makes the manufacturing process difficult and costly. Summary of the Invention

[0008] This invention addresses the shortcomings of existing NdFeB rare-earth permanent magnets, such as low Co content, low Curie temperature, insignificant improvement in remanence temperature coefficient, and low coercivity. It provides a NdFeB rare-earth permanent magnet, its preparation method, and its applications. This invention achieves high Co content (12–20 wt%) while selecting 0 ≤ Pr < 14 wt%. By controlling the temperature and cooling rate during the preparation process, R₂Co is suppressed. 17 The formation of the phase can reduce the temperature coefficient while improving remanence, coercivity, magnetic energy product, and mechanical properties.

[0009] To achieve the above objectives, the present invention adopts the following technical solution.

[0010] This invention provides a neodymium iron boron rare earth permanent magnet, which comprises the following components:

[0011] R: 28.5~33.7wt%, R is a rare earth element, R includes light rare earth element RL and heavy rare earth element RH, wherein RL includes Nd and Pr, 0≤Pr<14wt%; RH includes one or more of Dy, Tb, Gd and Ho;

[0012] X: 0.3–1.5 wt%, where X is one or more of Cu, Ga, Bi, Sn, Nb, Zr, and Ti;

[0013] Al: 0.5–1.5 wt%;

[0014] Co: 12-20 wt%;

[0015] B: 0.88–1.1 wt%;

[0016] The balance is Fe;

[0017] Where wt% represents the mass percentage of the neodymium iron boron rare earth permanent magnet, and the total of all components is 100wt%; the balance is Fe, meaning that in addition to the above-mentioned elements and other possible elements, the balance is Fe.

[0018] The microstructure of the neodymium iron boron rare earth permanent magnet includes a main phase M, a grain boundary phase A, and a grain boundary phase B; the main phase M is R2(Fe, Co). 14B, wherein the main phase has a volume percentage of 90-94.5%; the grain boundary phase A is R(Fe,Co)2, and the volume percentage of the grain boundary phase A is 4.5-8%; the grain boundary phase B is R4(Fe,Co)3, and the volume percentage of the grain boundary phase B is 0.5-2%.

[0019] In this invention, the Nd content is preferably 14wt% to 25wt%, for example 14.1wt%, 14.6wt%, 15.1wt%, 15.9wt%, 16.1wt%, 16.5wt%, 17.2wt%, 17.3wt%, 18.5wt%, 19.7wt%, 22.8wt%, or 25wt%.

[0020] In this invention, the content of Pr is preferably 2wt% to 13wt%, for example 2.6wt%, 3.8wt%, 6.9wt%, 7.1wt%, 7.4wt%, 7.5wt%, 7.8wt%, 8.5wt%, 9.9wt%, 10.7wt%, or 13wt%.

[0021] Preferably, the RH includes Dy, and the content of Dy is 1wt% to 5wt%, for example 1.5wt%, 1.6wt%, 1.7wt%, 2.4wt%, 2.6wt%, 2.7wt%, 3wt%, 3.1wt%, 3.4wt%, 3.7wt%, 4.1wt%, or 4.7wt%.

[0022] Preferably, the RH includes Tb, and the content of Tb is 0.5wt% to 5wt%, for example 0.6wt%, 1.3wt%, 2wt%, 2.4wt%, 2.6wt%, 3.3wt%, 3.7wt%, 3.8wt%, 3.9wt%, 4wt%, 4.3wt%, 4.8wt%, or 4.9wt%.

[0023] Preferably, the RH includes Gd, and the content of Gd is 0.4wt% to 1.5wt%, for example 0.4wt%, 0.7wt%, 0.8wt% or 1.3wt%.

[0024] Preferably, the RH includes Ho, and the content of Ho is 0.1wt% to 1wt%, for example 0.1wt%, 0.5wt% or 0.8wt%.

[0025] Preferably, the RH comprises Dy and Tb, wherein the content of Dy is 1.7wt% to 4.1wt% and the content of Tb is 0.6wt% to 4.9wt%.

[0026] Preferably, the RH comprises Dy, Tb and Gd, wherein the content of Dy is 2.7wt% to 3.1wt%, the content of Tb is 2wt% to 2.6wt%, and the content of Gd is 0.4wt% to 0.8wt%.

[0027] Preferably, the RH comprises Dy, Tb and Ho, wherein the content of Dy is 1.6wt% to 4.7wt%, the content of Tb is 1.3wt% to 4.3wt%, and the content of Ho is 0.8wt%.

[0028] Preferably, the RH comprises Tb, Gd and Ho, wherein the Tb content is 3.7 wt%, the Gd content is 0.7 wt%, and the Ho content is 0.1 wt%.

[0029] Preferably, X comprises Cu, and the Cu content is 0.1 wt% to 0.2 wt%, for example 0.1 wt% or 0.2 wt%.

[0030] Preferably, X comprises Ga, and the content of Ga is 0.1wt% to 0.3wt%, for example 0.1wt%, 0.2wt% or 0.3wt%.

[0031] Preferably, X comprises Bi, and the content of Bi is 0.2wt% to 0.4wt%, for example 0.3wt%.

[0032] Preferably, X comprises Sn, and the content of Sn is 0.1wt% to 0.2wt%, for example 0.1wt% or 0.2wt%.

[0033] Preferably, X includes Nb, and the content of Nb is 0.2wt% to 0.3wt%, for example 0.2wt% or 0.3wt%.

[0034] Preferably, X comprises Zr, and the Zr content is 0.1wt% to 0.3wt%, for example 0.1wt%, 0.2wt% or 0.3wt%.

[0035] Preferably, X comprises Ti, and the content of Ti is 0.1 wt% to 0.2 wt%, for example 0.1 wt% or 0.2 wt%.

[0036] Preferably, X comprises Cu and Zr, wherein the content of Cu is 0.1 wt% and the content of Zr is 0.3 wt%.

[0037] Preferably, X comprises Ga and Nb, wherein the content of Ga is 0.2 wt% and the content of Nd is 0.3 wt%.

[0038] Preferably, X comprises Cu, Ga, and Ti, wherein the content of Cu is 0.2 wt%, the content of Ga is 0.1 wt%, and the content of Ti is 0.2 wt%.

[0039] Preferably, X comprises Cu, Sn, and Zr, wherein the content of Cu is 0.1 wt%, the content of Sn is 0.1 wt%, and the content of Zr is 0.2 wt%.

[0040] Preferably, X comprises Cu, Bi, and Ti, wherein the content of Cu is 0.1 wt%, the content of Bi is 0.3 wt%, and the content of Ti is 0.2 wt%.

[0041] Preferably, X comprises Cu, Ga, and Zr, wherein the content of Cu is 0.1 wt%, the content of Ga is 0.2 wt%, and the content of Zr is 0.2 wt%.

[0042] Preferably, X comprises Cu, Ga, Zr and Ti, wherein the content of Cu is 0.1 wt%, the content of Ga is 0.1 wt%, the content of Zr is 0.1 wt%, and the content of Ti is 0.2 wt%.

[0043] Preferably, X comprises Cu, Bi, Sn and Ti, wherein the content of Cu is 0.1 wt%, the content of Bi is 0.3 wt%, the content of Sn is 0.2 wt%, and the content of Ti is 0.2 wt%.

[0044] Preferably, X comprises Cu, Ga, Nb and Ti, wherein the content of Cu is 0.1wt% to 0.2wt%, the content of Ga is 0.1wt% to 0.3wt%, the content of Nb is 0.2wt%, and the content of Ti is 0.1wt% to 0.2wt%.

[0045] Preferably, X comprises Cu, Ga, Zr and Ti, wherein the content of Cu is 0.1 wt%, the content of Ga is 0.1 wt%, the content of Zr is 0.1 wt%, and the content of Ti is 0.2 wt%.

[0046] In this invention, the content of Al is, for example, 0.5 wt%, 0.6 wt%, 0.7 wt%, 1 wt%, 1.2 wt%, or 1.5 wt%.

[0047] In this invention, the content of Co is, for example, 12.5 wt%, 13.4 wt%, 13.9 wt%, 15.3 wt%, 15.4 wt%, 16.2 wt%, 16.3 wt%, 17.2 wt%, 18.2 wt%, 18.3 wt%, 19.2 wt%, or 20%.

[0048] In this invention, the content of B is, for example, 0.9 wt%, 1 wt%, or 1.1 wt%.

[0049] In this invention, the Fe content is preferably 44.7 wt% to 54.5 wt%, for example 44.7 wt%, 45.09 wt%, 46.7 wt%, 47.2 wt%, 49.1 wt%, 49.8 wt%, 50.2 wt%, 50.5 wt%, 51.1 wt%, 51.2 wt%, 51.9 wt%, 53.4 wt%, or 54.5 wt%.

[0050] In this invention, preferably, the main phase M comprises the following components in the following amounts:

[0051] R: 27.73wt%~30.04wt%; of which, Pr: 0~12wt%, Nd: 12.06wt%~22.57wt%, RH: 2.27wt%~8.59wt%;

[0052] Al: 0.47wt%~1.6wt%;

[0053] Co: 12.4wt%~20wt%;

[0054] B: 0.84wt%~1.01wt%;

[0055] Fe: 47.46wt%~56.45wt%;

[0056] Wherein, wt% represents the mass percentage of the main phase M, and the total of all components is 100wt%.

[0057] Preferably, the main phase M further includes one or more of Cu, Ga, Bi, Sn, Nb, Zr, Ti, and O.

[0058] In this invention, the grain boundary phase A is an RT2-based phase with a MgCu2-type structure and is paramagnetic at room temperature. The grain boundary phase A is a Nd and Co-rich but Fe-poor grain boundary phase.

[0059] Preferably, the grain boundary phase A comprises the following components in varying amounts:

[0060] R: 54.78wt%~68.54wt%; of which, Pr: 0~31.4wt%, Nd: 30.25wt%~52.13wt%, RH: 2.29wt%~9.95wt%;

[0061] Al: 0.15wt%~0.57wt%;

[0062] Co: 15.41wt%~24.06wt%;

[0063] B: 3.01wt%~5.01wt%;

[0064] Fe: 1.6wt%~22.03wt%;

[0065] Wherein, wt% represents the mass percentage of the grain boundary phase A, and the total of all components is 100wt%.

[0066] Preferably, the grain boundary phase A further includes one or more of Cu, Ga, Bi, Sn, Nb, Zr, Ti, and O.

[0067] In this invention, the grain boundary phase B is an R4T3 system phase with an Nd4Co3 structure. Grain boundary phase B is "Nd-rich and Co and Fe-poor". Grain boundary phase B is similar to the Nd-rich phase in traditional low-Co formulation systems, and its composition is mainly rare earth metals and their oxides or R-(T,X) alloy phases, where T is Fe or Co, and X is one or more of the aforementioned Cu, Ga, Bi, Sn, Nb, Zr, and Ti. It mainly functions to demagnetize the grains and improve coercivity.

[0068] Preferably, the grain boundary phase B comprises the following components in varying amounts:

[0069] R: 71.27wt%~88.31wt%; of which, Pr: 0~42.1wt%, Nd: 43.35wt%~79.1wt%, RH: 0.29wt%~0.99wt%;

[0070] Al: 0.01wt%~0.09wt%;

[0071] Co: 6.25wt%~10.07wt%;

[0072] Fe: 2.28wt%~9.76wt%;

[0073] O: 0.54–1.47 wt%;

[0074] Wherein, wt% represents the mass percentage of the grain boundary phase B, and the total of all components is 100wt%.

[0075] Preferably, the Co content c(A) in the grain boundary phase A is greater than the Co content c(M) in the main phase M, and c(A) - c(M) > 3wt%. This ensures that the grain boundary phase A has sufficient Co elements to form an RT2-system paramagnetic phase, which is beneficial to improving the coercivity of the magnet.

[0076] Preferably, the RH content in the grain boundary phase A is higher than that in the main phase M and also higher than that in the grain boundary phase B. RH is concentrated in the grain boundary phase A, which improves the magnetic properties of the Co-rich grain boundaries and avoids the deterioration of the coercivity of the magnet.

[0077] Preferably, the RH content in the grain boundary phase B is lower than that in the main phase M and also lower than that in the grain boundary phase A. A lower RH content in the grain boundary phase B means that more RH can be obtained in the grain boundary phase A or the main phase M, which is beneficial for improving the magnet's coercivity.

[0078] Preferably, the content of X (especially Cu and Ga) in the grain boundary phase B is higher than that in the main phase M and also higher than that in the grain boundary phase A. When X is distributed in the main phase, it reduces the remanence of the main phase, while when it is distributed in the grain boundary phase B, it has no effect on the remanence and can form an RX grain boundary alloy phase, increasing the demagnetizing coupling between grains and improving the coercivity of the magnet.

[0079] In this invention, the neodymium iron boron rare earth permanent magnet may also include impurity phases, such as rare earth oxide phase RO or ZrB2 / TiB2 phase.

[0080] In this invention, the volume percentage of the impurity phase is preferably 0.1% to 0.3%, for example, 0.15%, 0.18%, 0.19%, 0.2%, 0.21%, 0.22%, 0.23%, or 0.25%.

[0081] In this invention, the volume percentage of the main phase M is, for example, 90.15%, 90.4%, 91.45%, 91.88%, 92.18%, 92.21%, 92.55%, 92.81%, 93.22%, 93.34%, 93.35%, 93.76%, or 94.5%.

[0082] In this invention, the volume percentage of the grain boundary phase A is, for example, 4.5%, 5.33%, 5.54%, 5.65%, 5.79%, 6.35%, 6.42%, 6.45%, 6.65%, 6.86%, 7.18%, 7.7%, or 7.8%.

[0083] In this invention, the volume percentage of the grain boundary phase B is, for example, 0.62%, 0.68%, 0.72%, 0.78%, 0.81%, 0.82%, 0.88%, 0.92%, 1.12%, 1.55%, 1.6%, or 1.9%.

[0084] In one specific embodiment, the microstructure of the neodymium iron boron rare earth permanent magnet comprises 94.5% main phase M, 4.5% grain boundary phase A, 0.82% grain boundary phase B, and 0.18% impurity phase.

[0085] In one specific embodiment, the microstructure of the neodymium iron boron rare earth permanent magnet comprises 90.4% main phase M, 7.8% grain boundary phase A, 1.6% grain boundary phase B, and 0.2% impurity phase.

[0086] In one specific embodiment, the microstructure of the neodymium iron boron rare earth permanent magnet comprises 90.15% main phase M, 7.7% grain boundary phase A, 1.9% grain boundary phase B, and 0.25% impurity phase.

[0087] In one specific embodiment, the microstructure of the NdFeB rare earth permanent magnet comprises 91.88% main phase M, 6.42% grain boundary phase A, 1.55% grain boundary phase B, and 0.15% impurity phase.

[0088] In one specific embodiment, the microstructure of the neodymium iron boron rare earth permanent magnet comprises 92.55% main phase M, 6.45% grain boundary phase A, 0.81% grain boundary phase B, and 0.19% impurity phase.

[0089] In one specific embodiment, the microstructure of the neodymium iron boron rare earth permanent magnet comprises 92.18% main phase M, 6.65% grain boundary phase A, 0.92% grain boundary phase B, and 0.25% impurity phase.

[0090] In one specific embodiment, the microstructure of the neodymium iron boron rare earth permanent magnet comprises 93.76% main phase M, 5.33% grain boundary phase A, 0.68% grain boundary phase B, and 0.23% impurity phase.

[0091] In one specific embodiment, the microstructure of the neodymium iron boron rare earth permanent magnet comprises 93.35% main phase M, 5.54% grain boundary phase A, 0.88% grain boundary phase B, and 0.23% impurity phase.

[0092] In one specific embodiment, the microstructure of the neodymium iron boron rare earth permanent magnet comprises 92.81% main phase M, 6.35% grain boundary phase A, 0.62% grain boundary phase B, and 0.22% impurity phase.

[0093] In one specific embodiment, the microstructure of the neodymium iron boron rare earth permanent magnet comprises 93.34% main phase M, 5.65% grain boundary phase A, 0.78% grain boundary phase B, and 0.23% impurity phase.

[0094] In one specific embodiment, the microstructure of the NdFeB rare earth permanent magnet comprises 93.22% main phase M, 5.79% grain boundary phase A, 0.81% grain boundary phase B, and 0.18% impurity phase.

[0095] In one specific embodiment, the microstructure of the neodymium iron boron rare earth permanent magnet comprises 91.45% main phase M, 7.18% grain boundary phase A, 1.12% grain boundary phase B, and 0.25% impurity phase.

[0096] In one specific embodiment, the microstructure of the neodymium iron boron rare earth permanent magnet comprises 92.21% main phase M, 6.86% grain boundary phase A, 0.72% grain boundary phase B, and 0.21% impurity phase.

[0097] In one specific embodiment, the Nd content is 15.1 wt%, the Pr content is 9.9 wt%, the Tb content is 3.7 wt%, the Gd content is 0.7 wt%, the Ho content is 0.1 wt%, the Cu content is 0.2 wt%, the Ga content is 0.1 wt%, the Ti content is 0.2 wt%, the Al content is 0.7 wt%, the Co content is 13.9 wt%, the B content is 0.9 wt%, and the Fe content is 54.5 wt%. The microstructure of the NdFeB rare earth permanent magnet comprises 94.5% main phase M, 4.5% grain boundary phase A, 0.82% grain boundary phase B, and 0.18% impurity phase.

[0098] In one specific embodiment, the Nd content is 14.6 wt%, the Pr content is 14 wt%, the Dy content is 2.7 wt%, the Tb content is 2 wt%, the Gd content is 0.4 wt%, the Cu content is 0.1 wt%, the Zr content is 0.3 wt%, the Al content is 0.6 wt%, the Co content is 19.2 wt%, the B content is 1 wt%, and the Fe content is 45.09 wt%. The microstructure of the NdFeB rare earth permanent magnet comprises 90.4% main phase M, 7.8% grain boundary phase A, 1.6% grain boundary phase B, and 0.2% impurity phase.

[0099] In one specific embodiment, the Nd content is 14.1 wt%, the Pr content is 13 wt%, the Dy content is 3.1 wt%, the Tb content is 2.6 wt%, the Gd content is 0.8 wt%, the Cu content is 0.1 wt%, the Sn content is 0.1 wt%, the Zr content is 0.2 wt%, the Al content is 0.5 wt%, the Co content is 12.5 wt%, the B content is 1.1 wt%, and the Fe content is 51.9 wt%. The microstructure of the NdFeB rare earth permanent magnet comprises 90.15% main phase M, 7.7% grain boundary phase A, 1.9% grain boundary phase B, and 0.25% impurity phase.

[0100] In one specific embodiment, the Nd content is 16.5 wt%, the Pr content is 7.4 wt%, the Dy content is 3.7 wt%, the Tb content is 4 wt%, the Ho content is 0.8 wt%, the Ga content is 0.2 wt%, the Nb content is 0.3 wt%, the Al content is 0.5 wt%, the Co content is 15.4 wt%, the B content is 1 wt%, and the Fe content is 50.2 wt%. The microstructure of the NdFeB rare earth permanent magnet comprises 91.88% main phase M, 6.42% grain boundary phase A, 1.55% grain boundary phase B, and 0.15% impurity phase.

[0101] In one specific embodiment, the Nd content is 16.1 wt%, the Pr content is 7.8 wt%, the Dy content is 3 wt%, the Tb content is 4.9 wt%, the Cu content is 0.1 wt%, the Ga content is 0.1 wt%, the Zr content is 0.1 wt%, the Ti content is 0.2 wt%, the Al content is 0.5 wt%, the Co content is 17.2 wt%, the B content is 0.9 wt%, and the Fe content is 49.1 wt%. The microstructure of the NdFeB rare earth permanent magnet comprises 92.55% main phase M, 6.45% grain boundary phase A, 0.81% grain boundary phase B, and 0.19% impurity phase.

[0102] In one specific embodiment, the Nd content is 16.5 wt%, the Pr content is 7.5 wt%, the Dy content is 2.6 wt%, the Tb content is 3.8 wt%, the Gd content is 0.8 wt%, the Ho content is 0.8 wt%, the Cu content is 0.1 wt%, the Bi content is 0.3 wt%, the Sn content is 0.2 wt%, the Ti content is 0.2 wt%, the Al content is 1.5 wt%, the Co content is 20 wt%, the B content is 1 wt%, and the Fe content is 44.7 wt%. The microstructure of the NdFeB rare earth permanent magnet comprises 92.18% main phase M, 6.65% grain boundary phase A, 0.92% grain boundary phase B, and 0.25% impurity phase.

[0103] In one specific embodiment, the Nd content is 15.9 wt%, the Pr content is 8.5 wt%, the Dy content is 1.6 wt%, the Tb content is 4.3 wt%, the Ho content is 0.8 wt%, the Cu content is 0.1 wt%, the Ga content is 0.3 wt%, the Nb content is 0.2 wt%, the Ti content is 0.1 wt%, the Al content is 0.5 wt%, the Co content is 13.4 wt%, the B content is 0.9 wt%, and the Fe content is 53.4 wt%. The microstructure of the NdFeB rare earth permanent magnet comprises 93.76% main phase M, 5.33% grain boundary phase A, 0.68% grain boundary phase B, and 0.23% impurity phase.

[0104] In one specific embodiment, the Nd content is 18.5 wt%, the Pr content is 10.7 wt%, the Dy content is 1.7 wt%, the Tb content is 0.6 wt%, the Cu content is 0.1 wt%, the Ga content is 0.1 wt%, the Zr content is 0.1 wt%, the Ti content is 0.2 wt%, the Al content is 0.5 wt%, the Co content is 15.3 wt%, the B content is 1 wt%, and the Fe content is 51.2 wt%. The microstructure of the NdFeB rare earth permanent magnet comprises 93.35% main phase M, 5.54% grain boundary phase A, 0.88% grain boundary phase B, and 0.23% impurity phase.

[0105] In one specific embodiment, the Nd content is 17.3 wt%, the Pr content is 7.1 wt%, the Dy content is 1.5 wt%, the Tb content is 3.9 wt%, the Gd content is 0.8 wt%, the Ho content is 0.8 wt%, the Cu content is 0.1 wt%, the Ga content is 0.1 wt%, the Nb content is 0.2 wt%, the Ti content is 0.2 wt%, the Al content is 0.5 wt%, the Co content is 15.4 wt%, the B content is 1 wt%, and the Fe content is 51.1 wt%. The microstructure of the NdFeB rare earth permanent magnet comprises 92.81% main phase M, 6.35% grain boundary phase A, 0.62% grain boundary phase B, and 0.22% impurity phase.

[0106] In one specific embodiment, the Nd content is 17.2 wt%, the Pr content is 6.9 wt%, the Dy content is 3.4 wt%, the Tb content is 2.4 wt%, the Gd content is 1.3 wt%, the Ho content is 0.5 wt%, the Cu content is 0.2 wt%, the Ga content is 0.2 wt%, the Nb content is 0.2 wt%, the Ti content is 0.2 wt%, the Al content is 0.5 wt%, the Co content is 16.2 wt%, the B content is 1 wt%, and the Fe content is 49.8 wt%. The microstructure of the NdFeB rare earth permanent magnet comprises 93.34% main phase M, 5.65% grain boundary phase A, 0.78% grain boundary phase B, and 0.23% impurity phase.

[0107] In one specific embodiment, the Nd content is 19.7 wt%, the Pr content is 3.8 wt%, the Dy content is 4.1 wt%, the Tb content is 3.3 wt%, the Cu content is 0.1 wt%, the Bi content is 0.3 wt%, the Ti content is 0.2 wt%, the Al content is 0.7 wt%, the Co content is 16.3 wt%, the B content is 1 wt%, and the Fe content is 50.5 wt%. The microstructure of the NdFeB rare earth permanent magnet comprises 93.22% main phase M, 5.79% grain boundary phase A, 0.81% grain boundary phase B, and 0.18% impurity phase.

[0108] In one specific embodiment, the Nd content is 22.8 wt%, the Pr content is 2.6 wt%, the Dy content is 2.4 wt%, the Tb content is 4.8 wt%, the Cu content is 0.1 wt%, the Ga content is 0.2 wt%, the Zr content is 0.2 wt%, the Al content is 1 wt%, the Co content is 18.2 wt%, the B content is 1 wt%, and the Fe content is 46.7 wt%. The microstructure of the NdFeB rare earth permanent magnet comprises 91.45% main phase M, 7.18% grain boundary phase A, 1.12% grain boundary phase B, and 0.25% impurity phase.

[0109] In one specific embodiment, the Nd content is 25wt%, the Dy content is 4.7wt%, the Tb content is 1.3wt%, the Ho content is 0.8wt%, the Cu content is 0.1wt%, the Ga content is 0.2wt%, the Zr content is 0.2wt%, the Al content is 1.2wt%, the Co content is 18.3wt%, the B content is 1wt%, and the Fe content is 47.2wt%. The microstructure of the NdFeB rare earth permanent magnet comprises 92.21% main phase M, 6.86% grain boundary phase A, 0.72% grain boundary phase B, and 0.21% impurity phase.

[0110] This invention also provides a method for preparing neodymium iron boron rare earth permanent magnets, which includes the following steps:

[0111] S1. The raw material composition of the neodymium iron boron rare earth permanent magnet is sequentially smelted, cast, hydrogenated, and shaped to obtain a shaped body;

[0112] S2. The molded body is subjected to preheating, sintering, and aging treatment; wherein...

[0113] The preheating temperature T1 is 300-600℃, the sintering temperature T2 is 1040-1090℃, the heating rate from T1 to T2 is not less than 10℃ / min, and the average cooling rate from T2 to 600℃ is 80℃ / min-120℃ / min.

[0114] The aging process includes a primary aging process and a secondary aging process. The temperature T3 of the primary aging process is 850–950°C, and the temperature T4 of the secondary aging process is 430–600°C. Before the primary aging process, the temperature rise rate from 600°C to T3 is not less than 10°C / min. After the primary aging process, the average cooling rate from T3 to 600°C is 80°C / min–120°C / min.

[0115] In step S1, the melting can be carried out by conventional methods in the art, such as melting in a high-frequency vacuum induction furnace.

[0116] The smelting can be carried out in an alumina crucible; a portion of Al is introduced into the NdFeB rare earth permanent magnet in the alumina crucible.

[0117] The vacuum degree of the high-frequency vacuum induction melting furnace can be 5×10⁻⁶. -2 Pa; the melting temperature can be below 1600℃.

[0118] In step S1, the casting process can be a conventional casting process in the art, such as cooling the molten liquid obtained by melting in an Ar atmosphere by passing it through rotating rollers.

[0119] Preferably, the pressure of the Ar atmosphere is 5.5 × 10⁻⁶. 4 Pa.

[0120] The cooling rate is preferably 10. 2 ℃ / second ~10 4 ℃ / second. The cooling is achieved by circulating cooling water through the rollers. Preferably, the inlet temperature of the cooling water is ≤25℃.

[0121] In step S1, the hydrogen destruction process can be a conventional hydrogen destruction process in the art, such as hydrogen absorption, dehydrogenation, and cooling treatment.

[0122] The hydrogen absorption can be carried out under a hydrogen pressure of 0.15 MPa. The dehydrogenation can be carried out under conditions of simultaneous vacuuming and heating.

[0123] The hydrogen-induced breakdown process can be followed by further pulverization using conventional methods in the art. The pulverization process can be a conventional pulverization process in the art, such as air jet milling.

[0124] The air jet milling process can be carried out under a nitrogen atmosphere with an oxidizing gas content of less than 100 ppm. The oxidizing gas refers to oxygen and / or moisture.

[0125] The pressure in the grinding chamber of the air jet mill can be 0.58 MPa.

[0126] The grinding time of the air jet mill can be 3 hours.

[0127] Preferably, the particle size of the pulverized powder is 3.5-4.5 μm.

[0128] After pulverization, a lubricant, such as zinc stearate, can be added to the powder using conventional methods in the art. The amount of lubricant added can be 0.10–0.15% of the weight of the mixed powder, for example, 0.12%.

[0129] In step S1, the molding process can be a conventional molding process in the art, such as magnetic field orientation molding.

[0130] When using the magnetic field orientation molding method, the orientation pressing pressure is greater than 80MPa, the orientation magnetic field is 1.6T, and the holding time is 4-6s.

[0131] After the magnetic field orientation is formed, the magnet can be further densified by cold isostatic pressing, with the pressure of the cold isostatic pressing being 150-160 MPa.

[0132] In step S2, the preheating time can be 1 to 2 hours. Preferably, the preheating is performed at temperatures of 300°C and 600°C for 1 hour each. The preheating time refers to the time spent holding the material at the preheating temperature T1.

[0133] In step S2, the sintering time can be 4 to 6 hours, for example, 4 hours. The sintering time refers to the time spent holding the sintering temperature T2.

[0134] In step S2, the heating rate from T1 to T2 is preferably 10 to 25 °C / min, for example 16 °C / min.

[0135] In this invention, the average cooling rate refers to the average cooling rate within a temperature range, that is, the ratio of the cooling temperature range to the cooling time. Generally, the cooling rate is faster in the high-temperature range (e.g., 120°C / min) and slower in the lower-temperature range (e.g., 80°C / min).

[0136] In step S2, after sintering, the average cooling rate from T2 to 600°C is preferably 90°C / min.

[0137] In step S2, the sintering is preferably performed under vacuum conditions, such as 5 × 10⁻⁶. -3 Pa.

[0138] In step S2, before cooling after sintering, Ar gas can be introduced to make the pressure reach 0.05-0.1 MPa.

[0139] In step S2, after cooling from the sintering temperature T2 to 600°C, a conventional cooling rate can be used to cool to room temperature. In this invention, the conventional cooling rate refers to an average cooling rate of less than 80°C / min, preferably 10-20°C / min, for example, 15°C / min.

[0140] In step S2, the preferred temperature T3 for the first-stage aging treatment is 900℃.

[0141] In step S2, before the first-stage aging treatment, the heating rate from 600℃ to T3 is preferably 10-25℃ / min, for example 15℃ / min.

[0142] In step S2, after the first-stage aging treatment, the average cooling rate from T3 to 600°C is preferably 90°C / min.

[0143] In step S2, the duration of the first-stage aging treatment can be 3 hours. The duration of the first-stage aging treatment refers to the time spent holding the material at the temperature T3 during the first-stage aging treatment.

[0144] In step S2, after cooling from the temperature T3 of the first-stage aging treatment to 600°C, a rapid cooling rate (average cooling rate of 80°C / min to 120°C / min) or a conventional cooling rate (average cooling rate less than 80°C / min) can be used to cool to room temperature. Preferably, after cooling from the temperature T3 of the first-stage aging treatment to 600°C, an average cooling rate of 10 to 20°C / min is used to cool to room temperature.

[0145] In step S2, the preferred temperature T4 for the secondary aging treatment is 600℃.

[0146] In step S2, before the secondary aging treatment, the heating rate to T4 is preferably 3-5℃ / min, and the starting point for the heating is preferably room temperature. In this invention, the room temperature is 25℃±5℃.

[0147] In step S2, the duration of the secondary aging treatment can be 3 hours. The duration of the secondary aging treatment refers to the time spent holding the material at the temperature T4 during the secondary aging treatment.

[0148] In a preferred embodiment of the present invention, step S2 specifically includes:

[0149] In 5×10 -3Under vacuum conditions of Pa, the molded body was preheated at 300°C and 600°C for 1 hour each; then, it was heated from 600°C to 1040°C at a heating rate of 16°C / min and sintered for 4 hours, with Ar gas introduced to achieve a pressure of 0.1 MPa beforehand. It was then cooled to 600°C at an average cooling rate of 90°C / min, and then cooled to room temperature at an average cooling rate of 15°C / min. Next, it was heated from room temperature to 600°C at a heating rate of 5°C / min, and then heated to 900°C at a rate of 15°C / min and held for 3 hours. It was then cooled to 600°C at an average cooling rate of 90°C / min, and then cooled to room temperature at an average cooling rate of 15°C / min. Finally, it was heated from room temperature to 600°C at a heating rate of 5°C / min and held for 3 hours.

[0150] The present invention also provides an application of the neodymium iron boron rare earth permanent magnet in electronic components.

[0151] The electronic components mentioned therein can be conventional in the art, such as electronic components in a motor.

[0152] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0153] The reagents and raw materials used in this invention are all commercially available.

[0154] The positive and progressive effects of this invention are as follows:

[0155] The neodymium iron boron rare earth permanent magnet of the present invention, with the addition of high Co content and low Pr content, forms uniformly distributed low-melting-point grain boundary phases of RT2 and R4T3 structures by controlling the heating rate before sintering, the cooling rate after sintering, the heating rate before first-stage aging treatment, and the cooling rate after first-stage aging treatment, thereby avoiding the R2Co that is easily formed in traditional high Co magnets. 17 The soft magnetic phase leads to a significant reduction in coercivity. The magnet of this invention has high remanence Br (11.55~13.54kGs), coercivity Hcj (24.5~31.05kOe), and squareness (95%~99%), low remanence temperature coefficient (0.048% / ℃ < |α| < 0.056% / ℃, 20~100℃) and coercivity temperature coefficient (0.463% / ℃ < |β| < 0.522% / ℃, 20~100℃), high Curie temperature (Tc > 460℃), and excellent heat resistance. Attached Figure Description

[0156] Figure 1 The images show electron backscattered images (SEM-BSE) of different phases of the neodymium iron boron rare earth permanent magnet in Example 1. Detailed Implementation

[0157] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0158] Examples 1-13 and Comparative Examples 1-7

[0159] The raw material composition formulations of NdFeB rare earth permanent magnets in Examples 1-13 and Comparative Examples 1-7 are shown in Table 1. The materials were proportioned according to the raw material composition formulations of NdFeB rare earth permanent magnets in Table 1, and the following steps were performed sequentially:

[0160] S1. The raw material composition of neodymium iron boron rare earth permanent magnets is sequentially smelted, cast, hydrogenated, and shaped to obtain a shaped body, specifically:

[0161] (1) Melting process: According to the formula shown in Table 1, take the prepared raw materials and put them into an alumina crucible. Melt the raw materials in a high-frequency vacuum induction furnace at 5×10⁻⁶ ℃. -2 Vacuum melting is carried out in a vacuum at a temperature below 1600°C.

[0162] (2) Casting process: at 5.5×10 4 In an Ar atmosphere with a pressure of Pa, the molten liquid after vacuum melting is passed through rotating rollers for casting. Cooling water (inlet water temperature ≤25℃) is then introduced into the rollers at a pressure of 10... 2 ℃ / second ~10 4 Cooling is performed at a cooling rate of ℃ / second.

[0163] (3) Hydrogen crushing process: At room temperature, hydrogen gas with a purity of 99.9% is introduced into the hydrogen crushing furnace and the hydrogen pressure is maintained at 0.15 MPa. After the hydrogen is fully absorbed, the furnace is evacuated and heated to fully dehydrogenate the hydrogen. Then the furnace is cooled and the powder after hydrogen crushing is taken out.

[0164] (4) Air jet milling: The powder after hydrogen pulverization was subjected to air jet milling for 3 hours under a nitrogen atmosphere with an oxidizing gas content of less than 100 ppm and a pulverizing chamber pressure of 0.58 MPa to obtain fine powder. Oxidizing gas refers to oxygen and / or moisture.

[0165] (5) Add zinc stearate to the powder after air jet milling. The amount of zinc stearate added is 0.12% of the weight of the mixed powder. Then mix thoroughly with a V-type mixer.

[0166] (6) Magnetic field forming process: Using a right-angle orientation magnetic field forming machine, in an orientation magnetic field of 1.6T, under a forming pressure of more than 80MPa, the above-mentioned powder with added zinc stearate is held for 4-6s; then, using an isostatic pressing machine, under a pressure of 150-160MPa, the magnet is further densified to obtain the formed body.

[0167] S2. The molded body is preheated, sintered, and aged. Specifically:

[0168] (7) Preheating and sintering process: Transfer each molded body to the sintering furnace and heat it at 5×10 -3 Under a vacuum of Pa, the material was preheated at 300℃ and 600℃ for 1 hour each, then heated to 1040℃ at a heating rate of 16℃ / min, and sintered at 1040℃ for 4 hours. After that, Ar gas was introduced to bring the pressure to 0.1MPa, and then cooled to 600℃ at an average cooling rate of 90℃ / min, and then cooled to room temperature at an average cooling rate of 15℃ / min to obtain the sintered body.

[0169] (8) Aging process: The sintered body is heated from room temperature to 600℃ in high-purity Ar gas at a heating rate of 5℃ / min, and then heated to 900℃ at a rate of 15℃ / min for 3 hours of heat treatment (first-level aging). It is then cooled to 600℃ at an average cooling rate of 90℃ / min, and then cooled to room temperature at an average cooling rate of 15℃ / min. Finally, it is heated from room temperature to 600℃ at a heating rate of 5℃ / min and held for 3 hours (second-level aging) to obtain neodymium iron boron rare earth permanent magnet.

[0170] Table 1. Raw material composition formula (wt%) for NdFeB rare earth permanent magnets

[0171]

[0172]

[0173] Among them, the magnet formulations of Comparative Examples 5-7 were the same as those of Example 10, but their sintering and heat treatment heating and cooling rates were different, resulting in an increased proportion of soft magnetic impurities in the magnets and lower magnet performance. The sintering and first-stage aging treatment heating and cooling processes of the comparative examples are shown in Table 2.

[0174] Table 2 shows the sintering and first-stage aging heating and cooling processes for Comparative Examples 5-7.

[0175]

[0176] Example 1: Phase composition and component analysis of neodymium iron boron rare earth permanent magnets

[0177] Electron backscattering images (SEM-BSE) of different phases of the neodymium iron boron rare earth permanent magnet in Example 1 are shown below. Figure 1 As shown, Figure 1 The diagram shows the main phase M, crystalline phase A, and crystalline phase B.

[0178] The volume percentages of each phase in the neodymium iron boron rare earth permanent magnets in the examples and comparative examples are shown in Table 3, and the composition of each phase is shown in Table 4.

[0179] Table 3 Phase composition of NdFeB rare earth permanent magnets

[0180]

[0181]

[0182] The percentages in Table 3 are volume percentages, estimated according to the stereochemical Delesse Law, i.e., V V (Component volume percentage) = A A (Area percentage of cross-section components) The area percentage of a component on a random cross-section is equal to its volume percentage.

[0183] Table 4. Composition of each phase in neodymium iron boron rare earth permanent magnets

[0184]

[0185]

[0186]

[0187]

[0188] Example 2: Performance Testing of Magnets

[0189] The magnetic properties of the neodymium iron boron rare earth permanent magnets were tested using the PFM-14 pulse magnetic property measuring instrument from the National Institute of Metrology, China. Table 5 shows the results of the magnetic property testing.

[0190] Table 5 Magnetic Properties of Neodymium Iron Boron Rare Earth Permanent Magnets

[0191]

[0192]

[0193] As shown in Table 5, the permanent magnets of the embodiments of the present invention have high remanence, coercivity and squareness, and have low remanence temperature coefficient and coercivity temperature coefficient, as well as high magnet Curie temperature and excellent heat resistance.

[0194] As can be seen from Comparative Example 1, when the Co content in the magnet is low, the remanence temperature coefficient of the magnet is poor, and the performance decays quickly at high temperatures. Furthermore, when the Pr content in the magnet is high, the mechanical properties of the magnet will be reduced due to the different composition and content of the grain boundary phase when the rapid cooling method of this scheme is adopted.

[0195] As shown in Comparative Example 2, when the Co content in the magnet is too high, R2Co 17 The formation of soft magnetic impurities will be unavoidable, the coercivity of the magnet will be greatly reduced, and the remanence and temperature coefficient of coercivity will be significantly reduced.

[0196] As can be seen from Comparative Examples 3 and 4, the absence of Al in the magnet will increase the amount of soft magnetic phase precipitation and reduce the coercivity. On the other hand, excessive Al content will cause the remanence of the magnet to drop rapidly. Although it has good coercivity, the magnetic energy product of the magnet is very low, and its practical value is poor.

[0197] Comparative Examples 5-7 show that the heating and cooling rates during magnet sintering and first-stage aging processes affect the R2Co content in the magnet. 17 The content of soft magnetic phase has a significant impact. Insufficient heating or cooling rates will increase the soft magnetic phase in the magnet, reduce the coercivity of the magnet, and worsen the temperature coefficient.

Claims

1. A neodymium iron boron rare earth permanent magnet, characterized in that, It includes the following components in the following amounts: R: 28.5~33.7wt%, R is a rare earth element, including light rare earth element RL and heavy rare earth element RH. Among them, RL includes Nd and Pr, 2wt%≤Pr<14wt%; RH includes Gd, and one or more of Dy, Tb and Ho, with the content of Gd being 0.4wt%~1.5wt%. X: 0.3wt%~1.5wt%, where X is one or more of Cu, Ga, Bi, Sn, Nb, Zr, and Ti; Al: 0.6wt%~1.5wt%; Co: 12wt%~20wt%; B: 0.88wt%~1.1wt%; The balance is Fe; Where wt% represents the mass percentage of the neodymium iron boron rare earth permanent magnet, and the total of all components is 100wt%; the balance being Fe indicates that the balance is Fe in addition to the above-mentioned elements and other possible elements. The microstructure of the neodymium iron boron rare earth permanent magnet includes a main phase M, a grain boundary phase A, and a grain boundary phase B; the main phase M is R2(Fe, Co). 14 B, wherein the main phase has a volume percentage of 90-94.5%; wherein the grain boundary phase A is R(Fe,Co)2, and the volume percentage of grain boundary phase A is 4.5-8%; wherein the grain boundary phase B is R4(Fe,Co)3, and the volume percentage of grain boundary phase B is 0.5-2%. The Co content c(A) in the grain boundary phase A is greater than the Co content c(M) in the main phase M, and c(A) - c(M) > 3wt%; The RH content in the grain boundary phase A is higher than that in the main phase M and also higher than that in the grain boundary phase B.

2. The neodymium iron boron rare earth permanent magnet according to claim 1, characterized in that, The Nd content is 14wt%~25wt%; And / or, the content of Pr is 2wt%~13wt%; And / or, the RH includes Dy, and the content of Dy is 1wt%~5wt%; And / or, the RH includes Tb, and the content of the Tb is 0.5wt%~5wt%; And / or, the Gd content is 0.7wt%, 0.8wt%, or 1.3wt%; And / or, the RH includes Ho, and the content of Ho is 0.1wt%~1wt%; And / or, the RH comprises Dy, Tb, and Gd, wherein the content of Dy is 2.7wt%~3.1wt%, the content of Tb is 2wt%~2.6wt%, and the content of Gd is 0.4wt%~0.8wt%; And / or, the RH comprises Tb, Gd, and Ho, wherein the Tb content is 3.7 wt%, the Gd content is 0.7 wt%, and the Ho content is 0.1 wt%; And / or, the X comprises Cu, wherein the Cu content is 0.1wt%~0.2wt%; And / or, the X comprises Ga, wherein the Ga content is 0.1wt%~0.3wt%; And / or, the X comprises Bi, wherein the Bi content is 0.2wt%~0.4wt%; And / or, the X includes Sn, with a Sn content of 0.1wt%~0.2wt%; And / or, the X includes Nb, the content of which is 0.2wt%~0.3wt%; And / or, the X includes Zr, with a Zr content of 0.1wt% to 0.3wt%; And / or, the X comprises Ti, wherein the Ti content is 0.1wt%~0.2wt%; And / or, the X comprises Cu and Zr, wherein the content of Cu is 0.1 wt% and the content of Zr is 0.3 wt%; And / or, the X comprises Ga and Nb, wherein the content of Ga is 0.2 wt% and the content of Nd is 0.3 wt%; And / or, the X comprises Cu, Ga, and Ti, wherein the content of Cu is 0.2 wt%, the content of Ga is 0.1 wt%, and the content of Ti is 0.2 wt%; And / or, the X comprises Cu, Sn, and Zr, wherein the content of Cu is 0.1 wt%, the content of Sn is 0.1 wt%, and the content of Zr is 0.2 wt%; And / or, the X comprises Cu, Bi, and Ti, wherein the content of Cu is 0.1 wt%, the content of Bi is 0.3 wt%, and the content of Ti is 0.2 wt%; And / or, the X comprises Cu, Ga, and Zr, wherein the content of Cu is 0.1 wt%, the content of Ga is 0.2 wt%, and the content of Zr is 0.2 wt%; And / or, the X comprises Cu, Ga, Zr and Ti, wherein the content of Cu is 0.1 wt%, the content of Ga is 0.1 wt%, the content of Zr is 0.1 wt%, and the content of Ti is 0.2 wt%; And / or, the X comprises Cu, Bi, Sn and Ti, wherein the content of Cu is 0.1 wt%, the content of Bi is 0.3 wt%, the content of Sn is 0.2 wt%, and the content of Ti is 0.2 wt%; And / or, the X comprises Cu, Ga, Nb and Ti, wherein the content of Cu is 0.1wt%~0.2wt%, the content of Ga is 0.1wt%~0.3wt%, the content of Nb is 0.2wt%, and the content of Ti is 0.1~0.2wt%; And / or, the X comprises Cu, Ga, Zr and Ti, wherein the content of Cu is 0.1 wt%, the content of Ga is 0.1 wt%, the content of Zr is 0.1 wt%, and the content of Ti is 0.2 wt%; And / or, the Al content is 0.5wt%, 0.6wt%, 0.7wt%, 1wt%, 1.2wt%, or 1.5wt%; And / or, the content of Co is 12.5wt%, 13.4wt%, 13.9wt%, 15.3wt%, 15.4wt%, 16.2wt%, 16.3wt%, 17.2wt%, 18.2wt%, 18.3wt%, 19.2wt%, or 20%; And / or, the content of B is 0.9wt%, 1wt%, or 1.1wt%; And / or, the Fe content is 44.7wt%~54.5wt%.

3. The neodymium iron boron rare earth permanent magnet according to claim 2, characterized in that, The Nd content is 14.1 wt%, 14.6 wt%, 15.1 wt%, 15.9 wt%, 16.1 wt%, 16.5 wt%, 17.2 wt%, 17.3 wt%, 18.5 wt%, 19.7 wt%, 22.8 wt%, or 25 wt%. And / or, the content of Pr is 2.6wt%, 3.8wt%, 6.9wt%, 7.1wt%, 7.4wt%, 7.5wt%, 7.8wt%, 8.5wt%, 9.9wt%, 10.7wt%, or 13wt%; And / or, the RH comprises Dy, the content of which is 1.5wt%, 1.6wt%, 1.7wt%, 2.4wt%, 2.6wt%, 2.7wt%, 3wt%, 3.1wt%, 3.4wt%, 3.7wt%, 4.1wt%, or 4.7wt%; And / or, the RH includes Tb, and the content of the Tb is 0.6wt%, 1.3wt%, 2wt%, 2.4wt%, 2.6wt%, 3.3wt%, 3.7wt%, 3.8wt%, 3.9wt%, 4wt%, 4.3wt%, 4.8wt%, or 4.9wt%; And / or, the RH comprises Ho, wherein the content of Ho is 0.1wt%, 0.5wt%, or 0.8wt%; And / or, the X comprises Cu, wherein the Cu content is 0.1 wt% or 0.2 wt%; And / or, the X comprises Ga, wherein the Ga content is 0.1 wt%, 0.2 wt%, or 0.3 wt%; And / or, the X comprises Bi, wherein the content of Bi is 0.3 wt%; And / or, the X includes Sn, with a Sn content of 0.1 wt% or 0.2 wt%; And / or, the X includes Nb, wherein the Nb content is 0.2 wt% or 0.3 wt%; And / or, the X includes Zr, wherein the Zr content is 0.1wt%, 0.2wt%, or 0.3wt%; And / or, the X comprises Ti, wherein the content of Ti is 0.1 wt% or 0.2 wt%; And / or, the Fe content is 44.7wt%, 45.09wt%, 46.7wt%, 47.2wt%, 49.1wt%, 49.8wt%, 50.2wt%, 50.5wt%, 51.1wt%, 51.2wt%, 51.9wt%, 53.4wt%, or 54.5wt%.

4. The neodymium iron boron rare earth permanent magnet according to claim 1, characterized in that, The main phase M comprises the following components in the following amounts: R: 27.73wt%~30.04wt%; of which, Pr: 0~12wt%, Nd: 12.06wt%~22.57wt%, RH: 2.27wt%~8.59wt%; Al: 0.47wt%~1.6wt%; Co: 12.4wt%~20wt%; B: 0.84wt%~1.01wt%; Fe: 47.46wt%~56.45wt%; Wherein, wt% represents the mass percentage of the main phase M, and the total of all components is 100 wt%; And / or, the grain boundary phase A comprises the following components in varying amounts: R: 54.78wt%~68.54wt%; of which, Pr: 0~31.4wt%, Nd: 30.25wt%~52.13wt%, RH: 2.29wt%~9.95wt%; Al: 0.15wt%~0.57wt%; Co: 15.41wt%~24.06wt%; B: 3.01wt%~5.01wt%; Fe: 1.6wt%~22.03wt%; Wherein, wt% represents the mass percentage of the grain boundary phase A, and the total of all components is 100 wt%; And / or, the grain boundary phase B comprises the following components in varying amounts: R: 71.27wt%~88.31wt%; of which, Pr: 0~42.1wt%, Nd: 43.35wt%~79.1wt%, RH: 0.29wt%~0.99wt%; Al: 0.01wt%~0.09wt%; Co: 6.25wt%~10.07wt%; Fe: 2.28wt%~9.76wt%; O: 0.54~1.47wt% Wherein, wt% represents the mass percentage of the grain boundary phase B, and the total of all components is 100wt%.

5. The neodymium iron boron rare earth permanent magnet according to claim 4, characterized in that, The main phase M also includes one or more of Cu, Ga, Bi, Sn, Nb, Zr, Ti, and O.

6. The neodymium iron boron rare earth permanent magnet according to claim 1, characterized in that, The content of X in the grain boundary phase B is higher than that in the main phase M and also higher than that in the grain boundary phase A.

7. The neodymium iron boron rare earth permanent magnet according to claim 1, characterized in that, The neodymium iron boron rare earth permanent magnet also includes an impurity phase; wherein the volume percentage of the impurity phase is 0.1% to 0.3%. And / or, the volume percentage of the main phase M is 90.15%, 90.4%, 91.45%, 91.88%, 92.18%, 92.21%, 92.55%, 92.81%, 93.22%, 93.34%, 93.35%, 93.76%, or 94.5%; And / or, the volume percentage of the grain boundary phase A is 4.5%, 5.33%, 5.54%, 5.65%, 5.79%, 6.35%, 6.42%, 6.45%, 6.65%, 6.86%, 7.18%, 7.7%, or 7.8%; And / or, the volume percentage of the grain boundary phase B is 0.62%, 0.68%, 0.72%, 0.78%, 0.81%, 0.82%, 0.88%, 0.92%, 1.12%, 1.55%, 1.6% or 1.9%.

8. The neodymium iron boron rare earth permanent magnet according to claim 7, characterized in that, The impurity phase is a rare earth oxide phase RO or a ZrB2 / TiB2 phase; And / or, the volume percentage of the impurity phase is 0.15%, 0.18%, 0.19%, 0.2%, 0.21%, 0.22%, 0.23%, or 0.25%.

9. The neodymium iron boron rare earth permanent magnet according to claim 1, characterized in that, The microstructure of the neodymium iron boron rare earth permanent magnet comprises 94.5% main phase M, 4.5% grain boundary phase A, 0.82% grain boundary phase B, and 0.18% impurity phase; Alternatively, the microstructure of the neodymium iron boron rare earth permanent magnet comprises 90.4% main phase M, 7.8% grain boundary phase A, 1.6% grain boundary phase B, and 0.2% impurity phase; Alternatively, the microstructure of the neodymium iron boron rare earth permanent magnet comprises 90.15% main phase M, 7.7% grain boundary phase A, 1.9% grain boundary phase B, and 0.25% impurity phase; Alternatively, the microstructure of the neodymium iron boron rare earth permanent magnet comprises 91.88% main phase M, 6.42% grain boundary phase A, 1.55% grain boundary phase B, and 0.15% impurity phase; Alternatively, the microstructure of the neodymium iron boron rare earth permanent magnet comprises 92.55% main phase M, 6.45% grain boundary phase A, 0.81% grain boundary phase B, and 0.19% impurity phase; Alternatively, the microstructure of the neodymium iron boron rare earth permanent magnet comprises 92.18% main phase M, 6.65% grain boundary phase A, 0.92% grain boundary phase B, and 0.25% impurity phase; Alternatively, the microstructure of the neodymium iron boron rare earth permanent magnet comprises 93.76% main phase M, 5.33% grain boundary phase A, 0.68% grain boundary phase B, and 0.23% impurity phase; Alternatively, the microstructure of the neodymium iron boron rare earth permanent magnet comprises 93.35% main phase M, 5.54% grain boundary phase A, 0.88% grain boundary phase B, and 0.23% impurity phase; Alternatively, the microstructure of the neodymium iron boron rare earth permanent magnet comprises 92.81% main phase M, 6.35% grain boundary phase A, 0.62% grain boundary phase B, and 0.22% impurity phase; Alternatively, the microstructure of the neodymium iron boron rare earth permanent magnet comprises 93.34% main phase M, 5.65% grain boundary phase A, 0.78% grain boundary phase B, and 0.23% impurity phase; Alternatively, the microstructure of the neodymium iron boron rare earth permanent magnet comprises 93.22% main phase M, 5.79% grain boundary phase A, 0.81% grain boundary phase B, and 0.18% impurity phase; Alternatively, the microstructure of the neodymium iron boron rare earth permanent magnet comprises 91.45% main phase M, 7.18% grain boundary phase A, 1.12% grain boundary phase B, and 0.25% impurity phase; Alternatively, the microstructure of the neodymium iron boron rare earth permanent magnet comprises 92.21% main phase M, 6.86% grain boundary phase A, 0.72% grain boundary phase B, and 0.21% impurity phase.

10. A method for preparing a neodymium iron boron rare earth permanent magnet as described in any one of claims 1 to 9, characterized in that, It includes the following steps: S1. The raw material composition of the neodymium iron boron rare earth permanent magnet is sequentially smelted, cast, hydrogenated, and shaped to obtain a shaped body; S2. The molded body is subjected to preheating, sintering, and aging treatment; wherein... The preheating temperature T1 is 300~600℃, the sintering temperature T2 is 1040~1090℃, the heating rate from T1 to T2 is not less than 10℃ / min, and the average cooling rate from T2 to 600℃ is 80℃ / min~120℃ / min. The aging process includes a primary aging process and a secondary aging process. The temperature T3 of the primary aging process is 850~950℃, and the temperature T4 of the secondary aging process is 430~600℃. Before the primary aging process, the temperature rise rate from 600℃ to T3 is not less than 10℃ / min. After the primary aging process, the average cooling rate from T3 to 600℃ is 80℃ / min~120℃ / min.

11. The method for preparing a neodymium iron boron rare earth permanent magnet according to claim 10, characterized in that, In step S2, the preheating time is 1~2 hours; And / or, the sintering time is 4~6 hours; And / or, the heating rate from T1 to T2 is 10~25℃ / min; And / or, the sintering is performed under vacuum conditions; And / or, before cooling is performed after sintering, Ar gas is introduced to bring the pressure to 0.05-0.1 MPa; And / or, after sintering, the average cooling rate from T2 to 600°C is 90°C / min; And / or, after cooling from the sintering temperature T2 to 600°C, the average cooling rate to room temperature is less than 80°C / min; And / or, the temperature T3 of the first-stage aging treatment is 900°C; And / or, before the first-stage aging treatment, the temperature is increased from 600℃ to temperature T3 at a rate of 10~25℃ / min. And / or, after the first-stage aging treatment, the average cooling rate from T3 to 600°C is 90°C / min; And / or, the time for the first-level time-sensitive processing is 3 hours; And / or, after cooling from the temperature T3 of the first-stage aging treatment to 600°C, the average cooling rate to room temperature is less than 80°C / min; And / or, the temperature T4 of the secondary aging treatment is 600°C; And / or, before the secondary aging treatment, the temperature rise rate to T4 is 3~5℃ / min; And / or, the duration of the secondary aging process is 3 hours.

12. The method for preparing a neodymium iron boron rare earth permanent magnet according to claim 11, characterized in that, In step S2, the preheating is performed at 300°C and 600°C for 1 hour each. And / or, the heating rate from T1 to T2 is 16℃ / min; And / or, the vacuum condition is 5 × 10⁻⁶. -3 Pa; And / or, after cooling from the sintering temperature T2 to 600°C, the average cooling rate to room temperature is 10~20°C / min; And / or, before the first-stage aging treatment, the temperature is increased from 600℃ to temperature T3 at a rate of 15℃ / min. And / or, after cooling from the temperature T3 of the first-stage aging treatment to 600°C, the average cooling rate to room temperature is 10~20°C / min.

13. The method for preparing a neodymium iron boron rare earth permanent magnet according to claim 12, characterized in that, And / or, after cooling from the sintering temperature T2 to 600°C, the average cooling rate to room temperature is 15°C / min; And / or, after cooling from the temperature T3 of the first-stage aging treatment to 600°C, the average cooling rate to room temperature is 15°C / min.

14. The method for preparing a neodymium iron boron rare earth permanent magnet according to any one of claims 11 to 13, characterized in that, The specific operations of step S2 include: In 5×10 -3 Under vacuum conditions of Pa, the molded body was preheated at 300°C and 600°C for 1 hour each; then, it was heated from 600°C to 1040°C at a heating rate of 16°C / min and sintered for 4 hours, with Ar gas introduced to achieve a pressure of 0.1 MPa beforehand. It was then cooled to 600°C at an average cooling rate of 90°C / min, and then cooled to room temperature at a cooling rate of 15°C / min. Next, it was heated from room temperature to 600°C at a heating rate of 5°C / min, and then heated to 900°C at a rate of 15°C / min and held for 3 hours. It was then cooled to 600°C at an average cooling rate of 90°C / min, and then cooled to room temperature at an average cooling rate of 15°C / min. Finally, it was heated from room temperature to 600°C at a heating rate of 5°C / min and held for 3 hours.

15. The application of a neodymium iron boron rare earth permanent magnet as described in any one of claims 1 to 9 in electronic components.

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