Sintered NdFeB permanent magnet based on particle combination adjustment and production method of sintered NdFeB permanent magnet

Abstract

The invention discloses a sintered NdFeB permanent magnet based on particle combination adjustment and a production method of the sintered NdFeB permanent magnet. The permanent magnet comprises a composite principal phase in which a principal phase with high heavy rare earth RH content surrounds a principal phase with low heavy rare earth RH content. Continuous grain boundary phase does not exist in the composite principal phase. The content of heavy rare earth RH on the periphery of the composite principal phase is higher than the content of heavy rare earth RH at the center of the composite principal phase. The average grain size of the composite principal phase is 6-14 micrometers. The heavy rare earth RH contains one or more of Dy (dysprosium), Tb (terbium), Ho (holmium), Gd (gadolinium) and Y (yttrium). The production method includes the processes of preparation of first alloyed powder, preparation of second alloyed powder, mixing of the alloyed powder, forming of magnetic fields, and vacuum sintering and aging. The first alloyed powder contains Pr (praseodymium) and Nd (neodymium). The second alloyed powder contains the heavy rare earth RH. The average grain size of the second alloyed powder is 1.1-2.9 micrometers.

Description

technical field [0001] The invention belongs to the field of permanent magnet devices, and in particular relates to a sintered NdFeB permanent magnet and a manufacturing method for controlling particle combination. Background technique [0002] Corrosion-resistant high-performance permanent magnet is a basic electronic component and electrical component widely used in the world today, mainly used in computers, mobile phones, televisions, automobiles, communications, toys, audio, automation equipment, nuclear magnetic resonance imaging, etc. With the requirements of energy saving and low-carbon economy, high-performance permanent magnets have begun to be applied in energy-saving household appliances, hybrid electric vehicles, wind power generation and other fields. [0003] U.S. Patent No. 7,258,751 authorized on August 21, 2007 and U.S. Patent No. 7,867,343 authorized on January 11, 2011 disclose heat treatment of quick-setting alloy sheets at 400-800°C for 5 minutes to 12 h...

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Problems solved by technology

[0003] U.S. Patent No. 7,258,751 authorized on August 21, 2007 and U.S. Patent No. 7,867,343 authorized on January 11, 2011 disclose heat treatment of quick-setting alloy sheets at 400-800°C for 5 minutes to 12 hours. Make the RH element move from the grain boundary phase to the main phase, thereby increasing the coercive force of the rare earth magnet; US Patent No. 7,585,378 authorized on October 8, 2009 discloses a method for manufacturing an alloy for R-T-Q series rare earth magnets. It consists in rapidly cooling the alloy melt to a range of 700-1000°C to form a quick-setting alloy, and then keeping the quick-setting alloy at a temperature of 700-900°C for 15-600 seconds; State-bed airflow milling powder technology, using cyclone collector to collect powder; the disadvantage of fluidized bed is that the bottom material of tens of kg is always kept in the mill, and the powder-making speed is controlled by controlling the weight of the bottom material, which affects the powder-making Particle size, carry large particles, need to take out the bottom material when changing the brand, the bottom material is easy to oxidize; the disadvantage of the cyclone collector is that the fine powder with a particle size of less than 1 μm will be discharged with the exhaust airflow, affecting the product yield and particle size distribution

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