Double-main-phase Nd2Fe14B-Ce2Fe14B composite permanent magnet and preparation method thereof

Abstract

The invention discloses a double-main-phase Nd2Fe14B-Ce2Fe14B composite permanent magnet. Mass fractions of Nd2Fe14B and Ce2Fe14B are 80%-90% and 10%-20% respectively. A preparation method includes: (1) weighing substances according to requirements, and smelting in a vacuum arc smelting furnace to obtain two alloys uniform in component; (2) putting the alloys into vacuum glass tubes respectively, putting into an annealing furnace, keeping the temperature at 700-800 DEG C for 10-12 days, and quenching in ice water; (3) making strip-casting flakes; (4) subjecting the strip-casting flakes to a hydrogen explosion process to obtain powder; (5) mixing the powder with a magnetic powder protection agent to obtain powder; (6) pressing; (7) sintering; (8) annealing. The preparation method is simple, the magnet is high in coercivity, and balance use of rare earth resources can be promoted.

Description

technical field [0001] The invention belongs to the technical field of rare earth permanent magnet materials, in particular to a dual main phase Nd 2 Fe 14 B-Ce 2 Fe 14 B composite permanent magnet and its preparation method. Background technique [0002] The third-generation rare earth permanent magnet material NdFeB has a high magnetic energy product (BH) unmatched by other permanent magnets m , high coercive force Hcj and high remanence Br and other characteristics, so it is known as the "king of permanent magnets", and has been widely used in many fields such as electronics, automobiles, computers, electric power, machinery, energy, environmental protection, national defense, medical equipment, etc. application. However, with the development of science and technology, there are higher requirements for the technical indicators of the material, especially for the intrinsic coercive force, because the intrinsic coercive force is an important indicator for judging the e...

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Problems solved by technology

The market requires the coercive force of Nd-Fe-B rare earth permanent magnet materials to exceed 1.7T, but researchers failed to meet this requirement through composition optimization and process adjustment

On the other hand, due to the relatively large amount of sintered Nd-Fe-B rare earth permanent magnet materials, it is found through investigation that at least 90g of Nd-Fe-B materials are needed in the engine of each car, and now there are about 100 million Nd-Fe-B materials in the world every year. This has led to a great reduction in the content of rare earth Nd, while for other light rare earths, such as rare earth Ce, which is relatively low in cost and whose content accounts for more than 30% of the total amount of rare earths, it has not been effectively developed and utilized. Seriously unbalanced use of resources

Rare earth Ce and Fe-B alloys are relatively easy to form Ce by melting 2 Fe 14 B, the phase and Nd 2 Fe 14 B has a similar crystal structure, however due to Ce 2 Fe 14 The magnetocrystalline anisotropy of B single-phase alloy is relatively low, which cannot meet the market demand, so it is not well utilized

[0003] At present, in order to improve the comprehensive performance of Nd-Fe-B rare earth permanent magnet materials, they are directly added to the Nd-Fe-B alloy by smelting in a single alloy method, which makes other weaker light rare earths directly enter the Nd 2 Fe 14 B main phase, which will eventually lead to a serious decline in the performance of the magnet

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