Method for preparing high-performance R-Fe-B system sintering magnetic body

Abstract

The invention relates to a method for preparing a high-performance R-Fe-B system sintering magnetic body. According to the method for preparing the high-performance R-Fe-B system sintering magnetic body, due to the fact that heavy rare earth powder R<2> or R<2>X is added to powder composed of R<1>-Fe-B-M alloy, the purpose of enrichment of a heavy rare earth element on grain boundaries is achieved, after forming of the powder is accomplished in a pressed mode, pressure is exerted on the powder to enable the powder to reach a preset density through a pressure sintering device in a state with a temperature smaller than a normal sintering temperature, and the added heavy rare earth elements is made to scatter on the areas of the grain boundaries. The method for preparing the high-performance R-Fe-B system sintering magnetic body has the advantages that due to the fact that the heavy rare earth element of a small amount is added, coercive force of the magnetic body is obviously improved under the premise that reduction of remanence is small, production efficiency is high, and the method for preparing the high-performance R-Fe-B system sintering body is not limited by the size of the magnetic body.

Description

technical field [0001] The invention relates to a method for preparing a high-performance R-Fe-B series sintered magnet, which belongs to the field of rare earth permanent magnet materials. Background technique [0002] Nd-Fe-B magnets are widely used due to their superior performance, especially due to the demand for energy-saving motors in automotive and electronic applications, the market application of sintered NdFeB will be further expanded. The improvement of remanence and coercivity of NdFeB materials is conducive to its rapid growth in the motor market, but the improvement of coercivity in traditional processes is always at the expense of remanence, and a larger proportion must be used to increase coercivity The heavy rare earth element Dy / Tb causes a sharp increase in the cost of the magnet. In order to reduce the amount of heavy rare earths such as Dy / Tb and achieve high temperature resistance, the recently developed low-dysprosium high-coercivity magnets mainly u...

AI Technical Summary

Problems solved by technology

At present, the surface coating and burying methods used to improve the performance of R-Fe-B magnets are limited by the size of the magnets. The thickness of the magnets can only be less than 7mm. At the same time, factors such as coating thickness and density during the coating and burying process can vary Poor controllability, resulting in a high defect rate in the mass production process

However, in the process of high-temperature sintering using the traditional process of two-alloying, the Dy-rich and Tb-rich alloys on the grain boundaries do not play the role of optimizing the microstructure of the grain boundaries because most of the heavy rare earth elements enter the main phase during the heat treatment process, which affects the performance of the magnet. The effect of improvement is not obvious

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