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Tempering method for sintering Nd-Fe-B permanent magnet

A permanent magnet and NdFeB technology, which is applied in the field of tempering of sintered NdFeB permanent magnet materials, can solve the problems of uneven cooling speed, inability to effectively increase the intrinsic coercivity of magnets, etc.

Inactive Publication Date: 2011-04-20
ZHEJIANG SHENGHUA MAGNETIC MATERIALS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the tempering method in the prior art, although the cooling rate is relatively fast, causes uneven cooling rate at the same time, cannot effectively increase the intrinsic coercive force of the magnet, and fails to achieve an excellent consistency of the intrinsic coercive force

Method used

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  • Tempering method for sintering Nd-Fe-B permanent magnet
  • Tempering method for sintering Nd-Fe-B permanent magnet
  • Tempering method for sintering Nd-Fe-B permanent magnet

Examples

Experimental program
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Effect test

Embodiment 1

[0014] Select a sintered NdFeB magnet with the same alloy composition, and conduct tempering tests with different tempering processes, that is, after sintering and cooling a batch of NdFeB magnets, half of the blanks are subjected to secondary tempering according to the existing technology. Fire treatment, that is: the sintered and cooled permanent magnet billet is first heated to the first-stage tempering temperature in the vacuum furnace heating chamber, and after the heat preservation is completed, it is filled with inert gas to quench and cool, and then the billet is heated to the second-stage tempering temperature. After the heat preservation is over, the billet is still filled with an inert gas for gas quenching and cooling; the other half of the billet is cooled according to the process of the present invention, that is, the sintered and cooled permanent magnet billet is heated to the same tempering temperature in the vacuum furnace heating chamber, and the heat preservat...

Embodiment 2

[0016] Select another sintered NdFeB magnet with the same alloy composition, and conduct tempering tests with different tempering processes, that is, after sintering and cooling a batch of NdFeB magnets, half of the blanks are subjected to secondary processing according to the existing technology. Tempering treatment, that is: the sintered and cooled permanent magnet billet is first heated to the first-stage tempering temperature in the heating chamber of the vacuum furnace. After the heat preservation is completed, the billet is filled with inert gas to quench and cool, and then the billet is sent to the heating chamber. Raise the temperature to the second-stage tempering temperature, and after the heat preservation is completed, the billet is still filled with inert gas for gas quenching and cooling; the other half of the billet is cooled according to the process of the present invention, and the cooled permanent magnet billet is about to be sintered and heated to the same tem...

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Abstract

The invention relates to a tempering method for sintering a Nd-Fe-B permanent magnet, comprising the following steps: temperature of permanent magnet blanks after sintering and cooling firstly rises to a first-stage tempering temperature in a heating chamber of a vacuum furnace, inert gas with the volume increased by 1.5 to 3 times compared with the prior inert gas is filled into the vacuum furnace after heat insulation to be taken as cooling carrier gas, and the blanks are uniformly cooled to 300 DEG C to 500 DEG C after natural cooling; and the permanent magnet blanks are heated to a second-stage tempering temperature, the inert gas with the volume increased by 1.5 to 3 times compared with the prior inert gas is filled into the vacuum furnace as the cooling carrier gas after the heat insulation, and the blanks are uniformly cooled to room temperature after the natural cooling. The cooling mode improves the uniformity of a cooling speed to enable an Nd-rich phase to be uniformly distributed so as to improve the crystal boundary morphology and optimize boundary components, thereby the flatness and the smoothness of an interface are ensured, a stray magnetic field is lowered, and the intrinsic coercivity and the consistency thereof are fully enhanced.

Description

technical field [0001] The invention relates to a tempering method for sintered NdFeB permanent magnet materials. Background technique [0002] NdFeB permanent magnet materials are called "Magnetic King" because of their high magnetic energy product and high coercive force, and have been widely used in many fields such as electronics, computers, automobiles, machinery, energy, and medical equipment. The manufacturing process of sintered Nd-Fe-B permanent magnet materials is as follows: raw material preparation → smelting → ingot casting → crushing powder making → magnetic field orientation, pressing → sintering → tempering → machining, surface treatment → testing. [0003] The magnetic properties of sintered Nd-Fe-B permanent magnet alloys are very sensitive to process factors. Due to different sintering and tempering methods, the magnetic properties of alloys with the same composition can vary several times, dozens of times, or even hundreds of times. It is very important ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21D1/76C21D1/18
Inventor 王胜华魏方允
Owner ZHEJIANG SHENGHUA MAGNETIC MATERIALS