What is alnico permanent magnet?

What is alnico permanent magnet?

Alnico Magnet is an alloy made of aluminum, nickel, cobalt, copper, iron and other materials.

Aluminum nickel cobalt (Alnico Magnet) permanent magnet material was successfully developed in the 1930s. It is the first permanent magnetic material developed in history. It is an alloy composed of aluminum, nickel, cobalt, iron and other trace metal elements. Before the discovery of rare earth permanent magnet materials in 1970s, Alnico Magnet alloy was the strongest permanent magnet material. However, with the advent of ferrite permanent magnet and rare earth permanent magnet, Alnico Magnet permanent magnet was gradually replaced in many applications, and its proportion was declining.

Classification of Alnico Magnet

Because of its low mechanical strength, high hardness, brittleness and poor machinability, Alnico Magnet permanent magnet can not be designed as structural parts. Only a small amount of grinding or EDM can be carried out during machining, and forging and other machining can not be used. Alnico Magnet is mainly produced by casting method. In addition, sintered magnets corresponding to cast magnets can also be made by powder metallurgy, but the properties are slightly lower.

Performance parameter of Alnico Magnet

American Standard

Magnetic properties of cast Alnico magnets

Chinese standard

Note: customers have special requirements, according to customer requirements. Curie temperature and temperature coefficient are only for reference, not for judgment.

Performance Curve of Alnico Magnet

Processing technology of Alnico Magnet

According to the different processing technology, it can be divided into casting Alnico magnet and sintering Alnico magnet.

• The production process of cast Alnico Magnet: batching → smelting → casting → heat treatment → performance testing → machining → inspection → packaging
• The production process of sintered Alnico Magnet is as follows: batching → pulverizing → pressing → sintering → heat treatment → performance testing → machining → inspection → packaging

Casting Alnico Magnet can be processed into different sizes and shapes; sintered Alnico Magnet is mainly small-sized products, and the dimensional tolerance of the blank produced by sintered Alnico Magnet is better than that of the casting product, and the magnetic property is slightly lower than that of the casting product, but the machinability is better.

Properties and applications of Alnico Magnets

The advantages of Alnico Magnets are high remanence (up to 1.35t), but the disadvantages are very low coercivity (usually less than 160kA / M) and nonlinear demagnetization curve. Therefore, Alnico magnet is easy to be magnetized and demagnetized easily. Special attention should be paid to its particularity when designing and manufacturing the magnetic circuit of the device, and the magnet must be stabilized in advance. It is strictly forbidden to use it in any way Contact with ferromagnetic materials to avoid local irreversible demagnetization or distortion of magnetic flux density distribution.
In permanent magnet materials, cast Alnico Magnet permanent magnet has the lowest reversible temperature coefficient. It is suitable for the manufacture of mechanical, electrical and magnetic devices.