Unlock instant, AI-driven research and patent intelligence for your innovation.

Process for producing sintered NdFeB permanent magnetic material with high corrosion resistance

A permanent magnet material and production process technology, applied in the direction of magnetic materials, magnetic objects, electrical components, etc., can solve the problems of inability to play a pinning role, poor corrosion resistance of NdFeB permanent magnet materials, uneven magnets, etc., to achieve Reduce the probability of transgranular fracture, reduce the probability of formation, and improve the effect of corrosion resistance

Inactive Publication Date: 2012-03-21
宁波永久磁业有限公司
View PDF1 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, the current production process of NdFeB permanent magnet materials is to avoid the contact between the alloy and oxygen as much as possible, but it is inevitably oxidized, and most of the oxidation occurs on the surface of the magnet, which is extremely uneven for the entire magnet. Yes, unable to play a pinning role
Therefore, the NdFeB permanent magnet material produced by the current process has poor corrosion resistance. Under the environment of PCT temperature of 130 ° C and pressure of 0.27 MPa, the weight loss rate of 240 hours is ≥ 100 mg / cm 2

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 3

[0046] Embodiment three, the production process of the high corrosion resistance sintered NdFeB permanent magnet material of this embodiment includes the following process steps in turn:

[0047] a. Melting the prepared materials in a melting furnace with a temperature of 1450°C;

[0048] b. The material after smelting is made into strip or ingot with a thickness of 0.5mm;

[0049] c. Then the belt or ingot is crushed by hydrogen to make a powder with a particle size of 3.5um;

[0050] d. Put the powder into the jet mill with an oxygen content of 300ppm for further powder making;

[0051] e. After powder making, the powder is subjected to magnetic field orientation pressing in the mold;

[0052] f. Sintering the magnets pressed into magnetic blocks in a vacuum sintering furnace;

[0053] g. The sintered magnet is tempered once every 2.2 hours in a tempering furnace at a temperature of 900°C;

[0054] h. Then, the magnet after primary tempering is subjected to secondary tem...

Embodiment 4

[0057] Embodiment 4, the production process of the high corrosion resistance sintered NdFeB permanent magnet material of this embodiment includes the following process steps in sequence:

[0058] a. Melting the prepared materials in a melting furnace with a temperature of 1450°C;

[0059] b. The material after smelting is made into strip or ingot with a thickness of 0.5mm;

[0060] c. Then the belt or ingot is crushed by hydrogen to make a powder with a particle size of 3.5um;

[0061] d. Put the powder into a jet mill with an oxygen content of 500ppm for further pulverization;

[0062] e. After powder making, the powder is subjected to magnetic field orientation pressing in the mold;

[0063] f. Sintering the magnets pressed into magnetic blocks in a vacuum sintering furnace;

[0064] g. Then temper the sintered magnet in a tempering furnace at a temperature of 900°C for 2.2 hours;

[0065] h. Finally, it is finished by machining and surface treatment.

[0066] The steps...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention discloses a process for producing a sintered NdFeB permanent magnetic material with high corrosion resistance, which is characterized by sequentially comprising the following process steps: smelting prepared materials in a smelting furnace; producing the smelt material into a throwing belt or a cast ingot with the thickness of 0.3-0.5 mm; producing the throwing belt or the cast ingotinto a powder shape with the granularity of 2.5-3.5 microns through hydrogen decrepitation; allowing the powder to enter a gas stream mill containing oxygen with the concentration of 200-500ppm to make the powder; performing magnetic orientation press molding to the powder in a mould after the powder is made; sintering the magnet pressed into a magnetic block in a vacuum sintering furnace; and performing backfire, mechanical processing, surface processing, and the like to obtain a finished product. The invention has the advantages of adjusting the technical parameters of the throwing belt cast by smelting and reducing the probability of the occurrence of transcrystalline rupture from a source; changing the prior mechanical disruption way of an NdFeB permanent magnetic alloy and reducing the proportion of the transcrystalline rupture through selective absorption of the hydrogen among different phases of the alloy; and intentionally introducing 200-500ppm of micro-oxygen in the powder-making process of the gas stream mill to increase the content of the oxide in the alloy powder with even distribution.

Description

technical field [0001] The invention relates to a production process of high corrosion resistance sintered NdFeB permanent magnet material. Background technique [0002] NdFeB permanent magnet materials have been widely used in many fields such as electronics, computers, automobiles, machinery, energy, and medical equipment due to their high magnetic energy, high coercive force, and high operating temperature. However, due to the influence of the environment and various conditions during its use, the rare earth elements in the magnet with relatively active chemical properties will be corroded to varying degrees, affecting the performance of its magnetic properties, and seriously causing the entire equipment to be scrapped. Therefore, the research and development of permanent magnet materials with low weight loss and high corrosion resistance sintered NdFeB has become a subject, especially for permanent magnet material equipment used in harsh environments. [0003] The exist...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Patents(China)
IPC IPC(8): H01F1/057B22F3/12
Inventor 任春德宋小明周鸿波任荷芬何国平张应海
Owner 宁波永久磁业有限公司