Double-hard magnetic main phase mixed rare-earth permanent magnet and preparation method thereof

Abstract

The invention relates to a double-hard magnetic main phase mixed rare-earth permanent magnet and a preparation method thereof. The permanent magnet comprises double hard magnetic main phases and a rear-earth-rich phase, wherein the double hard magnetic main phases are MM<2>Fe<14>B and (PrNd)<2>Fe<14>B respectively; the permanent magnet is prepared from the following chemical component in percentage by mass: [MM<x1>(PrNd)<1-x1>]<x>Fe<100-x-y-z>B<y>TM<z>; x is smaller than or equal to 31 and greater than or equal to 27; x1 is smaller than or equal to 1 and greater than or equal to 0; y is smaller than or equal to 1 and greater than or equal to 0.9; z is smaller than or equal to 1.5 and greater than 0; TM is a composition of more of the elements Al, Cu, Co, Nb, Ga, Tb and Zr; and MM is a mixed rare-earth alloy which is directly separated from raw ore and contains La, Ce, Pr and Nd. The anisotropic sintered mixed rare-earth permanent magnet with high cost performance within a range of 10-48MGOe can be prepared by adjusting the content of PrNd. A basic rare-earth raw material used by the permanent magnet is cheap mixed rare earth, so that a separation and purification technology for the rare earth can be reduced, efficient utilization of lanthanum-cerium rare earth is achieved and the double-hard magnetic main phase mixed rare-earth permanent magnet meets the requirements of low carbon economy on green production technology innovation of a rare-earth permanent magnet product.

Description

technical field [0001] The invention belongs to the technical field of mixed rare earth permanent magnet materials, and in particular relates to a sintered mixed rare earth permanent magnet with dual hard magnetic main phases and a preparation method thereof. Background technique [0002] In 2014, China's demand for sintered NdFeB was about 120,000 tons, with an annual growth rate of 19%. The demand for rare earth Nd also increased accordingly, making strategic rare earth resources with low abundance even more scarce. However, most of the sintered NdFeB magnets are currently used in speakers, voice coil motors, generators and electric motors. Most of the products are of low and medium grade performance, resulting in overkill for sintered NdFeB magnets. From the aspects of preparation cost, magnetic performance and comprehensive utilization of resources, the anisotropic sintered permanent magnet, referred to as S-MMFeB, is prepared by using Misch-metal with large reserves and...

AI Technical Summary

Problems solved by technology

In 2015, the patent document CN104637643A continued to apply to report that the low-cost magnet was made of mixed rare earth with Baiyun Obo co-associated raw ore, and its magnetic energy product can be freely adjusted within 20-40MGOe. The thermal deformation process was realized. In the same year, CN104700973A patent application adopted the same powder metallurgy and rapid quenching hot-pressing thermal deformation process, and replaced PrNd with cheap MM. The control range of the magnetic energy product was within 25-45MGOe. In the same year, the alloy composition used in the patent document CN104715876A application was MM x M1 z1 co u1 BB v1 Fe (100-x1-z1-u1-v1) It is mixed with alloys containing Nd as the rare earth raw material, but the mixed rare earth elements are decomposed into individual elements and then formed into R 2 Fe 14 B main phase, so that most of the rare earth elements in the mixed rare earths should be simultaneously formed into R 2 Fe 14 The B main phase, coexisting in the magnet, will bring greater technical difficulty to the later thermal process, because multiple R 2 Fe 14 The synthesis temperature conditions of the B main phase are quite different

Patent CN102800454A reports the preparation method of dual main phase Ce-containing permanent magnets, which is different from the raw material (MM) of this technology, and the technical control is also quite different. The key point of this technology is to use mixed rare earth (MM) raw materials as the first choice; at the same time, during sintering During the tempering and tempering process, the uniformity of the furnace temperature can be regulated by controlling the constant change of the Ar atmosphere in the range of 0.03-0.3MPa; finally, the excess lanthanum, cerium or mixed rare earths are controlled at the grain boundaries and corners of the grains, that is, the increase The magnetic performance reduces the cost again, which is an effect that cannot be achieved by using the technology at this stage

[0004] Increasing the amount of PrNd alloy in the sintered mixed rare earth permanent magnet to improve the magnetic performance will inevitably lead to another increase in cost

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