Sintered NdfeB magnet

Made by powder metallurgy

Chemical composition: Nd2Fe14B

High remanence, high coercivity, high magnetic energy product, high cost performance


Sintered ndfeb permanent magnet is an alloy magnet composed of metal neodymium, iron, boron and other trace elements (Dy,Al,Nb,Mo,Co, etc.). Its made by powder metallurgy process after melting alloy ingot made in the magnetic field orientation and powder molding, forming the embryo of the body in an inert gas or vacuum sintering densification, so sintered ndfeb has a very high magnetic energy product and coercive force, and cost-effective, and have good mechanical. It is the best magnetic material in modern society.

 

Sintered ndfeb production process


1. Raw materials are prepared according to Nd2Fe14.

2. Put the prepared raw materials into the vacuum melting furnace (or flaking furnace) and conduct high temperature smelting to form alloy ingot (or flaking plate).

3. Alloy ingot (or slabs) is ground into magnetic powder particles only a few microns in size by air flow.

4. Press magnetic powder in magnetic field according to actual requirement.

5. After molding of billet in high temperature above 1000 vacuum sintering, and then to aging treatment in order to achieve the corresponding magnetic.

6. Magnetic performance testing.

7. Perform mechanical processing and surface treatment according to the size and shape required.

8. Visual inspection.

 

Low temperature coefficient high corrosion resistance magnetic products


Ndfeb in equal neodymium iron and rich corrosion resistance is very poor, so it must be used after plating.With the expanding of the elevator motor application fields, the users'  needs of resistance to corrosion of ndfeb put forward higher request. Some has put forward usage without plating. According to this situation the company developed low weightlessness ndfeb products, through continuous innovation. Under the situation of 2 atmospheric pressure, 120 , 100% humidity, 168 hours weightlessness below 5 mg/cm2 (usually in 1-2 mg/cm2). And domestic enterprises’ need is more than 50 mg/cm2. Because of the low gravity, good corrosion resistance, therefore, to satisfy the operation of the motor and other high-end field corrosion resistance requirements, mainly used in the field of elevator, radar, such as wind turbines.

 

High temperature good stability magnetic products


It is well known that neodymium-iron-boron products have poorer temperature stability than AlNiCo, SmCo and other permanent magnet materials, directly restricting the use of neodymium-iron-boron in general and special fields. The temperature coefficient of conventional neodymium-iron-boron is -0.6%/°C or more, and the company developed product is above -0.5%°C and has good temperature stability.