Target airflow mill and method for preparing economical sintered neodymium iron boron blank

Abstract

The invention discloses a target airflow mill, comprising: a housing vertically arranged, the lower part of the side wall of the housing being provided with a downward inclined feed opening and at least one horizontal dispersed nitrogen flow inlet, and the center of the bottom of the housing being provided with a pulverized nitrogen flow inlet; and an impact path pipe coaxially fixed in the housing, the impact path pipe comprising a thick pipe section and a thin pipe section integrally formed and connected from top to bottom, and an alloy target being coaxially fixed in the thick pipe section.Also provided is a method for preparing an economical sintered neodymium iron boron blank, comprising the steps of: crushing a neodymium iron boron alloy casting piece to obtain coarse powder; feeding the coarse powder into the housing, introducing dispersed nitrogen and crushed nitrogen, and crushing and screening the coarse powder to obtain target powder; and preparing a blank from the target powder. The method can prepare small-sized and uniform neodymium iron boron powder and a blank with good magnetic properties, and can save raw materials and reduce the production cost.

Description

technical field [0001] The invention relates to a jet mill and a method for preparing NdFeB blanks. More specifically, the present invention relates to a target jet mill and a method for preparing economical sintered NdFeB blanks. Background technique [0002] In order to obtain high-performance sintered NdFeB magnets, it is required that the crystal grains of the magnets be as small and uniform as possible, and that the peripheries of the crystal grains be evenly wrapped with a layer of neodymium-rich phase as thin as possible. The powder preparation technology is mainly realized by the method of fluidized bed jet mill pulverization. This pulverization method requires a large amount of powders to collide with each other. Under certain conditions, the number of powders is proportional to the probability of collision. Therefore, after pulverization The relationship between the particle size of the powder and the quantity of the powder is very significant. However, in the lat...

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Problems solved by technology

[0002] In order to obtain high-performance sintered NdFeB magnets, it is required that the crystal grains of the magnets be as small and uniform as possible, and that the peripheries of the crystal grains be evenly wrapped with a layer of neodymium-rich phase as thin as possible. The powder preparation technology is mainly realized by the method of fluidized bed jet mill pulverization. This pulverization method requires a large amount of powders to collide with each other. Under certain conditions, the number of powders is proportional to the probability of collision. Therefore, after pulverization The relationship between the particle size of the powder and the quantity of the powder is very significant. However, in the later stage of crushing, the quantity of powder decreases, and it is bound to produce powder with large particle size fluctuations. This part of the powder with large particle size deviation cannot be directly used. Especially when preparing high-performance sintered NdFeB permanent magnets, they cannot be used directly. In the end, the accumulation of this part of raw materials will cause inevitable waste and greatly increase the production cost.

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