Varieties of the Permanent Magnet

In terms of the industrial magnet, there are six main varieties of the permanent kind. These six include ceramic, alnico, samarium cobalt and neodymium iron boron (rare earth magnets), injection molded and flexible magnets.

Ceramic magnets are just as commonly referred to as ferrite, and are desirable because of their lower cost. This is because the materials which form them are easier to access than other types of permanent varieties. The method which is used to produce ceramic types is called pressing and sintering, which is a common process used in the manufacturing process. Some other benefits of ceramic types include their high coercive force and their resistance to corrosion. However, two mitigating factors are their brittleness and therefore low level of strength and durability for mechanical applications.

Alnico magnets have high mechanical strength and a high level of non-corrosiveness. The only varieties stronger than alnico are rare earth magnets. They are also stable in the face of high temperatures, making them valuable in the fields of aviation, military technology and space flights. However alnico is actually more expensive than ceramic magnets and has a lower coercive force and is more easily demagnetized. Composed primarily of aluminum, nickel and cobalt, hence al-ni-co, Alnico is produced either through casting or sintering processes. Sintering produces better mechanical abilities in the final product. Cast Alnico’s, however, may be manufactured in unique and intricate shapes. This is beneficial as it allows for more freedom in how the magnet is applied and used.

Samarium cobalt is one type of rare earth magnet with a higher overall strength and ability to withstand high temperatures than both alnico and ceramic varieties. When rare earth magnets were first developed in the 1970′s, they were exclusively made from samarium cobalt. Now, however, they are commonly supplanted by neodymium iron boron. Samarium cobalt is brittle and costly, but has a higher capacity to withstand high temperatures than neodymium and is still valued for this reason.

Neodymium Iron Boron are a more recent invention that samarium cobalt but have become more commonly used for their reputation as the strongest type of rare earth magnet. Like samarium cobalt, because of their costliness, they are used selectively. They are also highly corrosive when uncoated, which is why it has become commonplace to see nickel-plated rare earth magnets, for instance. Neodymium magnets are produced through two main routes: powder metallurgy or sintered magnetic process or through a rapid solidification process.

Injection-molded permanent magnets are valued because they are uniquely and highly shapeable. Made via an injection-molding process, they can be manufactured in more complex shapes with a high level of corrosion resistance. These magnets are usually a lot lower in magnetic strength, however.

Finally, flexible magnets are popular for the unique application that their shape provides. They are molded via injection as well, but are formed into flat sheet-like shapes. This makes them flexible but also of lower energy production (lower strength). Flexible magnets are low in cost and have a high resistance to corrosion. The flexible magnet is most commonly used for labeling, holding, door gaskets, and signs.

You can find out more about permanent magnets by contacting a retailer. You can also look online to buy permanent magnets. If you want to order custom magnets, it is recommended that you be in touch via phone with the supplier, in order for clarifications about your specific magnet application to be made.


Post time: 06-15-2017