Types of magnets
Apr 1, 1999 12:00 PM, SOUND & VIDEO CONTRACTOR STAFF
Alnico magnets: The Alnico magnet is composed of aluminum, nickel andcobalt, and consequently, it is relatively strong and stable. Alnico isbeneficial for high-heat applications, but it is susceptible todemagnetization. Cobalt became expensive in the '70s due to a limited worldsupply, which is what prompted many manufacturers to switch to ceramicmaterials.
Ceramic Magnets: The Ceramic magnet is rigid and brittle, but it doesprovide good performance and economy. Ceramic magnets are resistant todemagnetization, making them useful in high-power applications.
Rare earth magnetsNeodymium and samarium cobalt magnets offer the highest energy magneticfields available in permanent magnets. These are ideal for applicationsthat require high energy but are space limited. These magnets offer aweight savings in the design process, but due to their lack of mass, theycan be difficult to cool.
Neodymium iron boron (NeFeB): This material is extremely strong, has a highresistance to demagnetization, and although it is relatively expensive, itshigh energy output makes it extremely cost effective. These are used inmany demanding assembly and industrial applications where price is aconcern.
Samarium cobalt (SmCo): Samarium cobalt is also extremely strong and hashigh resistance to demagnetization, but the material is more stable thanneodymium and therefore more useful in high temperature applications(250degrees Celsius to 300degrees Celcius). Samarium cobalt is ideal forapplications where temperature fluctuates over a wide range.