Multi-main phase Ho-containing NdFeB (neodymium iron boron) permanent magnet and manufacturing method thereof

Abstract

The invention discloses a multi-main phase Ho-containing NdFeB (neodymium iron boron) permanent magnet and a manufacturing method thereof. The permanent magnet contains multiple main phases with different rare earth element contents. Oxide phases exist among the main phases. Oxygen contents of the oxide phases are higher than those of the main phases. The main phases with the high Ho content exist. Crystal grains composed of the main phases are isolated by grain boundaries. Average grain size is 6-14 um. The manufacturing method includes smelting a first alloy, smelting a second alloy, smelting a third alloy, performing hydrogen decrepitation, mixing the alloys, performing grinding powder, pressing under magnetic field, performing vacuum sintering, performing aging and the like. The method smelting the first alloy includes preparing the first alloy containing La element, Ce element, Pr element and Nd element. The method smelting the second alloy includes preparing the second alloy containing the element Pr, the element Nd, the element Dy and the element Ho. The method smelting the third alloy includes preparing the third alloy containing the element Pr, the element Nd, the element Dy and the element Gd.

Description

technical field [0001] The invention belongs to the field of permanent magnet devices, in particular to a Ho-containing multi-main phase NdFeB permanent magnet and a manufacturing method. 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 the RH element ...

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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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