US 12,293,869 B2
Manufacturing method for anisotropic bonded magnet
Yongan Dong, Taiyuan (CN)
Assigned to Taiyuan Kalyuan Intelligent Equipment Co., Ltd., Taiyuan (CN); and Ganzhou Kaiyuan Intelligent Equipment Co., Ltd., Ganzhou (CN)
Appl. No. 17/413,415
Filed by Taiyuan Kaiyuan Intelligent Equipment Co., Ltd., Shanxi (CN)
PCT Filed Nov. 22, 2019, PCT No. PCT/CN2019/120344
§ 371(c)(1), (2) Date Jun. 11, 2021,
PCT Pub. No. WO2020/147424, PCT Pub. Date Jul. 23, 2020.
Claims priority of application No. 201910030332.7 (CN), filed on Jan. 14, 2019.
Prior Publication US 2022/0059286 A1, Feb. 24, 2022
Int. Cl. H01F 41/02 (2006.01); B22F 1/102 (2022.01); B22F 3/02 (2006.01); B22F 3/24 (2006.01)
CPC H01F 41/0273 (2013.01) [B22F 1/102 (2022.01); B22F 3/02 (2013.01); B22F 3/24 (2013.01); H01F 41/0266 (2013.01); B22F 2003/248 (2013.01); B22F 2201/02 (2013.01); B22F 2202/05 (2013.01)] 5 Claims
 
1. A manufacturing method for an anisotropic bonded magnet, comprising the following steps:
1) manufacturing a thermosetting binder into powder to obtain thermosetting binder powder, and mixing anisotropic magnetic powder and the thermosetting binder powder to obtain a mixture;
2) Adding the mixture of the step 1) to a mould cavity, performing pressure forming under an orientated magnetic field, and performing demagnetization, so as to obtain a green body;
step (2a) a hot pressing step is added after step 2), that is, the green body obtained in the step 2) is preheated in a vacuum furnace before thermal curing; the green body after preheating is taken out from the vacuum furnace and immediately put into a hot-pressing mould with the same preheating temperature for hot pressing to obtain a hot pressed green body, and the hot pressing process is completed in a protective atmosphere of nitrogen; and
3) loading the hot pressed green body of the step 2a) into a vacuum furnace for thermal curing, so as to obtain an anisotropic bonded magnet, wherein during the pressure forming under an oriented magnetic field in a cold state or at room temperature, the thermosetting binder is in a non-melted state, ensuring that each magnetic powder particle is independent, and the magnetic powder particles are not bonded to each other;
wherein, before the step 1), the anisotropic magnetic powder is treated as follows: a coupling agent, a surfactant and a lubricant are diluted with absolute ethanol or acetone in an amount that is 5 to 20 times of the total weight of the coupling agent, the surfactant and the lubricant to obtain a diluted solution, and the diluted solution in an amount that is 0.3% to 1.5% of the weight of the anisotropic magnetic powder is added to the anisotropic magnetic powder and then mixed uniformly; and the amount of each of the coupling agent; the surfactant and the lubricant is 1% to 4.5% of the weight of the anisotropic magnetic powder; the surfactant is one of nonylphenol polyoxyethylene ether and triethylene glycol; the coupling agent is one of silane coupling agent, titanate, aluminate, phosphate, zirconate and stannate; and the lubricant is ethyl stearate.