There are many types of permanent magnets, and different types have different characteristics and applications. This article will introduce you to the five types of permanent magnets. You can find out which one is right for you and what kind of permanent magnet product your company needs.

What is a Permanent Magnet

Permanent magnets refer to magnets that can maintain their magnetic properties for a long time, that is, general magnets used in daily life. Such as natural magnets (magnetite) and artificial magnets (such as Al-Ni-Co alloys with alloying elements such as aluminum, nickel, and cobalt added to iron).

In addition to permanent magnets, there are also electromagnets that need to be energized to be magnetic. Permanent magnets are also called hard magnets, which are not easy to lose their magnetism and are not easy to be magnetized. However, if the permanent magnet is heated above the Curie temperature, or is placed in an environment with a high magnetic field strength in the opposite direction, its magnetism will also decrease or disappear.

What is a Permanent Magnet

Neodymium Iron Boron (NdFeB)
Samarium Cobalt (SmCo)
Alnico (AlNiCo)
Ceramic
Flexible Rubber Magnets

1. Neodymium Iron Boron (NdFeB)

A neodymium magnet (also known as NdFeB, NIB or Neo magnet) is the most widely used type of rare-earth magnet. It is a permanent magnet made from an alloy of neodymium, iron, and boron to form the Nd2Fe14B tetragonal crystalline structure.

This material has similar properties to samarium cobalt, except that it oxidizes more easily and generally does not have the same temperature resistance.

Neodymium magnet materials are expensive and are often used in very selective applications for cost reasons. Costs are also driven by the existing intellectual property rights of developers of such magnets. Their high-energy products fit into compact designs, enabling innovative applications and lowering manufacturing costs.

Main Feature:

Neodymium magnets are far less subject to cracking & chipping and less costly than other rare-earth magnetic materials such as samarium cobalt, in a wide variety of shapes, sizes, and grades.

Application:

Neodymium magnets are used for a wide variety of applications and are well-suited for small parts and components. Common applications range from crafts and model making projects to high-performance motors, medical instruments, audio components, POP displays, science projects, home improvement projects, hanging artwork & much more.

Due to their high magnetic strength and relatively low cost, they are the first choice for many consumer, commercial, industrial and technical applications.

2. Samarium Cobalt (SmCo)

A samarium–cobalt (SmCo) magnet, a type of rare-earth magnet, is a strong permanent magnet made of two basic elements: samarium and cobalt.

Samarium cobalt permanent magnets are very resistant to oxidation, higher magnetic strength and temperature resistance than alnico or ceramic materials, and it can withstand temperatures up to 300 degrees Celsius.

These magnets have the temperature characteristics of all rare earth magnets and can withstand temperatures up to 300°C. Sintered samarium cobalt magnets are brittle, prone to chipping and cracking, and may break when subjected to thermal shock. Due to the high cost of the material samarium,

Samarium cobalt magnets are extremely resistant to different temperatures and maintain their strength. Many companies use samarium cobalt magnets for magnetic separation in a variety of industries including pharmaceutical, automotive, aerospace, manufacturing, and more.

In other words, samarium cobalt magnets are among the most powerful and versatile industrial magnets on the market today.

Main Feature:

SmCo magnets offer excellent temperature and thermal stability, their magnetic properties stay within a very narrow range up to about 300° C (570° F). They exhibit excellent corrosion resistance and do not require any surface treatments. In addition, sintered samarium cobalt magnets offer very high resistance to demagnetization.

Application:

They are well suited for technical applications where high-performance and magnetic strength are required in very high or low-temperature environments. SmCo magnets are widely used in the automotive, aerospace, medical, military, industrial manufacturing, semiconductor, wind, power, oil, and energy industry.

3. Alnico (AlNiCo)

Alnico is a family of iron alloys which in addition to iron are composed primarily of aluminium (Al), nickel (Ni), and cobalt (Co), hence the acronym al-ni-co. They also include copper, and sometimes titanium. Alnico alloys are ferromagnetic, and are used to make permanent magnets.

AlNiCo magnets have good temperature stability and good shock resistance to demagnetization, but are easy to demagnetize.

If your company processes materials at different temperatures, Alnico magnets may be the choice for you. The reason is that they are stable at various temperatures while maintaining strength. There are two common types of Alnico magnets: cast and sintered.

They can be produced by sintering or casting, each process yielding different magnet properties. Sintering produces enhanced mechanical properties. Casting produces higher energy products and enables magnets to achieve more complex design features.

Main Feature:

Alnico magnets offer high magnetic strength, and energies but low coercivities. They are less brittle than Rare Earth magnets, are highly resistant to corrosion, have excellent temperature stability, and can be used at very high temperatures. Manufactured through either a casting or sintering process, they can be made into complex shapes (such as horseshoe shapes) that are not possible with other magnet materials.

Application:

Instrumentation, meters, microwave devices, actuators, holding devices, and sensors, are among the most common applications for Alnico magnets.

4. Ceramic

Ceramic, also known as Ferrite, magnets are made of a composite of iron oxide and barium or strontium carbonate. In most cases, you will probably use a ceramic magnet as it is the most commonly used material for making permanent magnets. While not comparable to rare earth magnets in terms of strength, ferrite magnets are inexpensive, giving them a good balance between strength and price.

Ceramic magnets have a good balance of magnetic strength, anti-demagnetization and economy. They are the most widely used magnets today.

Ceramic magnets are made by pressing and sintering. These magnets are brittle, and if grinding is required, a diamond wheel is required. These magnets also come in different grades.

Main Feature:

Ceramic magnets have gained widespread acceptance due to their resistance to corrosion and demagnetization, as well as their low price per pound.

Application:

Commonly used for crafts, holding latches, toys, motors and more.

5. Flexible Rubber Magnets

Flexible magnets are one of a family of ferrite magnetic materials. It is a flexible, elastic and twistable magnet made of ferrite magnetic powder and synthetic rubber through extrusion, calendering, injection molding and other processes.

These magnets have low magnetic strength and are very flexible, depending on the material mixed with the magnetic powder. Flexible magnets are much weaker than similarly sized solid magnets, but flexible magnets with large surface areas can be very effective.

Generally, its magnetic energy product is 0.60-1.50 MGOe. Flexible magnets can be processed into various complex shapes such as strips, rolls, sheets, blocks, and rings.

Main Feature:

Flexible magnets are easy to use, easy to manipulate, low cost, and extremely versatile. They can easily be cut, bent, twisted, slit, or coiled and adhere to multiple items and surfaces.

Application:

Automotive signage, Warehouse labeling, O.P. & tradeshow displays, Arts and crafts, Control charts, Menu boards, Air-tight seals on windows & doors, Social distancing barriers & partitions.

Conclusion

I hope you have an understanding of the types of permanent magnets through this article. If you need to know more about permanent magnets, you can visit our webpage!