A kind of sintered NdFeB permanent magnet based on grain recombination and its manufacturing method

Abstract

The invention discloses a sintered NdFeB permanent magnet based on grain recombination and a manufacturing method thereof. The permanent magnet has a composite main phase in which a main phase with a high heavy rare earth RH content is distributed around a main phase with a low heavy rare earth RH content. There is no continuous grain boundary phase inside the main phase; the average heavy rare earth RH content in the periphery of the composite main phase is higher than that in the center of the composite main phase, and the average grain size of the composite main phase is 6‑14 μm; the heavy rare earth RH contains Dy , Tb, Ho, Gd, and Y elements are more than one; the manufacturing method includes melting the first alloy process, melting the second alloy process, hydrogen crushing process, alloy flake mixing process, jet mill powder process, magnetic field forming process, vacuum sintering and The aging process; the first alloy melting process includes the process of preparing the first alloy sheet containing Pr and Nd elements; the second alloy melting process includes the process of preparing the second alloy sheet containing heavy rare earth RH elements.

Description

technical field [0001] The invention belongs to the field of permanent magnet devices, in particular to a sintered NdFeB permanent magnet based on grain recombination and a manufacturing method thereof. 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 hours. Make ...

AI Technical Summary

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

Images