Method for reducing oxygen content of sintered neodymium iron boron material, and additive

Abstract

The invention relates to the technical field of permanent magnet materials, and discloses a method for reducing oxygen content of a sintered neodymium iron boron material, and an additive. According to the method disclosed by the invention, magnetic powder is subjected to anti-oxidation protection by adopting a two-step method before grinding and after grinding, and different formulas (II type andII type) are adopted for the additive before grinding and after grinding, wherein the I-type additive comprises BTA, 200# solvent oil, isopropanol and cyclohexanone; and the II-type additive comprises stearate and 120# solvent oil, oleamide, terpilenol, petroleum ether and stadis (R) 450. The additive is added into the neodymium iron boron powder in a continuous spraying manner, so that the particle surfaces of the neodymium iron boron powder are uniformly coated, and the antioxidant effect of the neodymium iron boron powder is improved; the chain section of the I type additive is slightly longer, and the new section caused by airflow grinding is conveniently coated; the chain segment of the type II additive is slightly short and contains a lubricant and a polar group component, so that the static magnetic effect between the powder particles can be weakened, agglomeration between powder particles is reduced, and the orientation degree is improved.

Description

Technical field

[0001] The invention relates to the technical field of permanent magnet materials, in particular to a method and additives for reducing the oxygen content of sintered NdFeB materials. Background technique

[0002] Sintered neodymium iron boron (NdFeB) permanent magnet materials are mainly made of rare earth metals, neodymium praseodymium, iron, boron and some additional metals such as Co, Cu, Al, Ga and other elements through powder metallurgy. Since the invention of neodymium iron boron permanent magnet materials, due to its high magnetic energy product, high coercivity, light weight and other characteristics, magnetic devices have developed in the direction of high efficiency, miniaturization and light weight. However, there are still the following problems in the manufacturing process of sintered NdFeB permanent magnet materials: First, NdFeB powder needs nitrogen protection, and it is easy to be oxidized and damp when exposed to air, stored or transferred, whi...

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