Engineered Magnets

Ceramic magnets, or ferrite magnets, are low-cost, lightweight, moderate-energy permanent magnets capable of withstanding operating temperatures of up to 249°C (480°F). They are highly corrosion-resistant and perform well in high-volume applications. These qualities make them a popular choice in manufacturing and consumer products such as speaker magnets, DC motors, reed switches, sweepers, and automotive sensors.

Alnico magnets are alloys comprised of aluminum, nickel, iron, and cobalt. They have the highest operating temperature and temperature stability of any permanent magnetic material. They retain approximately 85% of room-temperature magnetization at temperatures of up to 538°C (1,000°F). They possess high residual induction as well as relatively high energy products. Alnico magnets naturally possess an excellent corrosion resistance. This makes surface treatment unnecessary, although they may still be easily plated if desired. Alnico magnets may be produced by either casting or sintering.

Samarium cobalt magnets are rare earth magnets that offer high maximum energy products and can operate in high temperature environments. They are extremely strong and typically allow for smaller size magnet profiles. Though not as strong as neodymium magnets, samarium cobalt magnets present three significant advantages. They work over a wider temperature range, have superior temperature coefficients, and have a greater resistance to corrosion. Special coatings are available for specific marine and automotive applications.

Neodymium magnets are a type of rare earth magnet and are the most common rare earth permanent magnets in the world. They are composed of Neodymium (Nd), Iron (Fe) and Boron (B), and exhibit the highest maximum energy product of any permanent magnet material. However, these magnets are vulnerable to corrosion. To protect the magnet from corrosion, the magnet is usually coated with nickel. Other coating options are aluminum, zinc, tin, copper, epoxy, silver and gold.

Injection molded magnets are available in both neodymium and hard ferrite materials and are often used in large quantities for various applications. What makes these especially useful is that they provide seemingly endless shapes and sizes while maintaining magnetic strength. They are made by mixing magnetic materials with a polymer binder, like nylon or polyphenylene sulfide.

Compression molded magnets are generally used in applications that require the highest magnetic performance for a bonded magnet. They are often produced in very high quantities. Compression molded magnets are more cost-effective than injection molded magnets, but are limited to simple shapes like rings, cylinders, and rectangles.

Bonded magnets are a highly versatile material with multiple processing options. They have good mechanical properties and higher electrical resistivity than sintered magnets. Bonded magnets are available in complex shapes and have excellent geometric tolerances. Bonded magnets consist of two components: a hard magnetic powder and a non-magnetic polymer or rubber binder.