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CN-115798852-B - High lanthanum cerium neodymium iron boron sintered permanent magnet and preparation method thereof

CN115798852BCN 115798852 BCN115798852 BCN 115798852BCN-115798852-B

Abstract

The invention belongs to the technical field of permanent magnet materials, and particularly relates to a high-lanthanum cerium neodymium iron boron sintered permanent magnet and a preparation method thereof. The raw materials for preparing the high lanthanum cerium neodymium iron boron sintered permanent magnet comprise alloy one and alloy two, wherein the chemical molecular formula of the alloy one component is [(PrNd) 1‑x (RL) x ] a (TM) b (HM) c B d Fe 100‑a‑b‑c‑d ,0.3≤x＜1,29.5≤a≤32.5,0＜b≤5,0＜c≤0.8,0.85≤d≤1.1,, the chemical molecular formula of the alloy two component is (PrNd) a1 Ga b1 Fe 100‑a1‑b1 , a1 is more than or equal to 70 and less than or equal to 90, and b1 is more than or equal to 0 and less than or equal to 20. The high lanthanum cerium neodymium iron boron sintered permanent magnet is obtained through compounding of the alloy I and the alloy II and combining of proper sintering and aging processes, and surface magnetic hardening of high-content lanthanum cerium main phase grains is achieved.

Inventors

  • CHEN KAN
  • ZHAO HONGLIANG
  • FAN FENGCHUN
  • SHI LONGYAN
  • ZHENG XIWEN
  • XIE DINGFU

Assignees

  • 宁波同创强磁材料有限公司

Dates

Publication Date
20260508
Application Date
20221116

Claims (6)

  1. 1. The high lanthanum cerium neodymium iron boron sintered permanent magnet is characterized in that the preparation raw materials comprise alloy one and alloy two, wherein the chemical molecular formula of the alloy one component is [(PrNd) 1-x (RL) x ] a (TM) b (HM) c B d Fe 100-a-b-c-d ,0.3≤x＜1,29.5≤a≤32.5,0＜b≤5,0＜c≤0.8,0.85≤d≤1.1,, RL is one or two of La and Ce, TM is one or more of Al, cu, ga, co, mn, and HM is one or more of Nb, zr, hf, ti, V; The chemical molecular formula of the alloy II is (PrNd) a1 Ga b1 Fe 100-a1-b1 , a1 is more than or equal to 70 and less than or equal to 90, b1 is more than or equal to 0 and less than or equal to 20, and the mass percentages of the alloy I and the alloy II are 95.0-99.9% and 0.1-5.0% respectively; the preparation method of the Gao Lanshi neodymium iron boron sintered permanent magnet comprises the following steps: (1) Casting after rapid hardening smelting to obtain an alloy sheet; (2) Casting after metal smelting to obtain an alloy two cast ingot; (3) Crushing alloy I and alloy II into coarse powder respectively, carrying out dehydrogenation treatment on the coarse powder of the alloy I, uniformly mixing the coarse powder of the alloy I with the coarse powder of the alloy II, wherein the hydrogen content of the dehydrogenation treatment of the coarse powder of the alloy I is less than or equal to 1300ppm, adding an antioxidant, grinding by adopting a twice air-flow grinding process to obtain air-flow grinding magnetic powder, carrying out the first air-flow grinding to obtain powder with the average granularity of 4.0-4.5 mu m, and carrying out the second air-flow grinding to obtain powder with the average granularity of 2.5-3.2 mu m; (4) Carrying out orientation molding on the air flow grinding powder obtained in the step (3), and carrying out isostatic pressing treatment after vacuum packaging; (5) And sintering the magnet obtained by isostatic pressing treatment, and performing effective treatment.
  2. 2. A method for preparing the high lanthanum cerium neodymium iron boron sintered permanent magnet according to claim 1, which is characterized by comprising the following steps: (1) Casting after rapid hardening smelting to obtain an alloy sheet; (2) Casting after metal smelting to obtain an alloy two cast ingot; (3) Crushing alloy I and alloy II into coarse powder respectively, carrying out dehydrogenation treatment on the coarse powder of the alloy I, uniformly mixing the coarse powder of the alloy I with the coarse powder of the alloy II, wherein the hydrogen content of the dehydrogenation treatment of the coarse powder of the alloy I is less than or equal to 1300ppm, adding an antioxidant, grinding by adopting a twice air-flow grinding process to obtain air-flow grinding magnetic powder, carrying out the first air-flow grinding to obtain powder with the average granularity of 4.0-4.5 mu m, and carrying out the second air-flow grinding to obtain powder with the average granularity of 2.5-3.2 mu m; (4) Carrying out orientation molding on the air flow grinding powder obtained in the step (3), and carrying out isostatic pressing treatment after vacuum packaging; (5) And sintering the magnet obtained by isostatic pressing treatment, and performing effective treatment.
  3. 3. The method for producing a sintered permanent magnet of high lanthanum, cerium, neodymium, iron and boron according to claim 2, wherein in the step (3), alloy one and alloy two are hydrogen crushed into coarse powder with particle size of 20-50 μm, respectively.
  4. 4. The method for preparing a sintered permanent magnet of high lanthanum, cerium, neodymium and iron boron according to claim 2, wherein the addition amount of the antioxidant in the step (3) is 0.05-0.1% of the sum of the mass of the alloy I and the mass of the alloy II.
  5. 5. The method for preparing the high lanthanum cerium neodymium iron boron sintered permanent magnet according to claim 2, wherein the vacuum degree in the sintering in the step (5) is 0.2-0.5 MPa, the sintering temperature is 1010-1040 ℃, and the sintering time is 4-6 h.
  6. 6. The method for preparing the high-lanthanum cerium neodymium iron boron sintered permanent magnet according to claim 2, wherein in the step (5), the aging treatment is carried out in a second stage, the aging treatment temperature is 600-860 ℃ in the first stage, the time is 2-4 h, the aging treatment temperature is 360-600 ℃ in the second stage, and the time is 3-6 h.

Description

High lanthanum cerium neodymium iron boron sintered permanent magnet and preparation method thereof Technical Field The invention belongs to the technical field of permanent magnet materials, and particularly relates to a high-lanthanum cerium neodymium iron boron sintered permanent magnet and a preparation method thereof. Background The neodymium-iron-boron magnet is a tetragonal crystal formed by rare earth neodymium, iron and boron, the magnetic energy product is larger than that of a samarium-cobalt magnet, is the substance with the largest magnetic energy product at present, is known as a 'magnetic king' because of excellent comprehensive magnetic performance, is an indispensable component in traditional industries such as an air conditioner compressor, a permanent magnet traction machine, a magnetic chuck and the like, and has wide application in new energy driving motors, wind power generation and the like, and carbon neutralization and carbon emission reduction and inseparable emerging industries. Along with the changes of market supply and demand and international situation, the price of rare earth raw materials is continuously high, the cost of a downstream customer to a magnet becomes more sensitive, so that how to realize the efficient utilization of rare earth is particularly important, and the rare earth is used as the most abundant and cheapest rare earth element in the crust, and the effective use of lanthanum and cerium is particularly necessary. The rare earth permanent magnet material prepared by replacing praseodymium and neodymium with traditional lanthanum and cerium has low intrinsic magnetic property and poor microstructure, and the magnetic property can not well meet the market demand. Disclosure of Invention Aiming at the problems, the invention provides a high-lanthanum cerium neodymium iron boron sintered permanent magnet which has higher magnetic property, so that the application of high-abundance rare earth lanthanum cerium in the neodymium iron boron magnet is widened. According to the technical scheme, the high-lanthanum cerium neodymium iron boron sintered permanent magnet is prepared from alloy one and alloy two, wherein the chemical molecular formula of the alloy one component is [(PrNd)1-x(RL)x]a(TM)b(HM)cBdFe100-a-b-c-d,0.3≤x＜1,29.5≤a≤32.5,0＜b≤5,0＜c≤0.8,0.85≤d≤1.1,, RL is one or two of La and Ce, TM is one or more of Al, cu, ga, co, mn, and HM is one or more of Nb, zr, hf, ti, V. Further, the chemical formula of the alloy two components is (PrNd) a1Gab1Fe100-a1-b1, a1 is more than or equal to 70 90,0< b1 is less than or equal to 20. The alloy I improves the proportion of high abundance rare earth lanthanum cerium to the greatest extent, and realizes the surface magnetic hardening of high-content lanthanum cerium main phase crystal grains through the compounding with alloy II, wherein the epitaxial layer (PrNd)/RE of the main phase crystal grain in the high-lanthanum cerium neodymium iron boron sintered permanent magnet is more than or equal to 0.6, and RE 6(Fe,TM)14 compound is formed at the crystal boundary of the magnet, and meanwhile, the regulation and control of the rare earth component of the crystal grain shell and the crystal boundary phase component are realized, so that higher magnetic performance is obtained. Further, the mass percentages of the alloy I and the alloy II are 95.0-99.9% and 0.1-5.0% respectively. The invention also provides a preparation method of the Gao Lanshi neodymium iron boron sintered permanent magnet, which comprises the following steps: (1) Casting after rapid hardening smelting to obtain an alloy sheet; (2) Casting after metal smelting to obtain an alloy two cast ingot; (3) Hydrogen crushing alloy one and alloy two into coarse powder, dehydrogenating alloy one coarse powder, mixing with alloy two coarse powder, adding antioxidant, and grinding with twice air flow grinding process to obtain air flow grinding powder; (4) Carrying out orientation molding on the air flow grinding powder obtained in the step (3), and carrying out isostatic pressing treatment after vacuum packaging; (5) And sintering the magnet obtained by isostatic pressing treatment, and performing effective treatment. A small amount of hydrogen element is reserved in the permanent magnet, the coercive force is promoted to a certain extent, and if the hydrogen content is too high, the product can be cracked. Through proper sintering and aging processes, two tissue structures which promote the improvement of coercive force, namely a thin region grain boundary which is uniformly distributed and a non-ferromagnetic 6:14 phase, are formed at the grain boundary, so that the improvement of the comprehensive magnetic performance in the high lanthanum cerium magnet is realized. Further, in the step (1), the smelting temperature is 1465-1485 ℃ and the casting temperature is 1405-1425 ℃. Further, the thickness of the alloy sheet in the step (1) is 0.30-0.80 mm. Further, in the step