Disc Magnets Are A Type Of Very Strong Magnet.

Disc magnets are a type of very strong magnet produced by using natural elements in a process that makes alloys from them. Most often, these magnets are made from rare earth metals, otherwise known as rare earth elements and most commonly from neodymium. They are called rare earth metals because they are part of a class from the table of elements, which are classified as ?rare.? Nevertheless, most of these ?rare elements? are found quite abundantly in the Earth when mining. Other forms of the magnets include ?ceramic? magnets, which are made by combining iron (ferrite) with ceramic and alnico, which is made by combining nickel, copper, cobalt, iron, aluminum and, in some cases, titanium. However, because it takes a large size of these magnets to produce the same strength and magnetic force as a rare earth magnet, manufacturers rarely sue them in commercial applications anymore.



Neodymium disc magnets are more powerful than any other magnet type. A neodymium magnet just a millimeter in diameter has enough force to erase a hard disk drive and other magnetic media. However powerful these magnets are, they are brittle as well. Two neodymium magnets clashing together hold enough force for them to shatter, possibly causing severe injury from the shards. Additionally, they have enough force to sprain or even break a finger if the user loses his grip on one or both of them. Originally manufactured by General Motors Corporation, the neodymium is combined with iron and boron in a process called stinting. In a process called bonding, the same elements are combined to produce a different form of the permanent magnets. Another type of magnet is the SmCo magnet, which is made from combining cobalt and samarium. These are typically much more expensive to make than typical Ne-Fe-B magnets.

Commercial uses for rare earth discs have increased over the years. The disc shaped neodymium magnets have slowly replaced other types, such as ferrite and alnico magnets, because of their small, but powerful sizes. For example, in modern technology, the requirement for manufacturers to produce more powerful speakers and, most notably, hard drives, among similar electronics, requires the use of very small but very powerful magnets. For instance, the thin plate inside of a hard disk drive, usually located on the opposite of the read-write spin disks, contains a neodymium-iron-boron disc magnet (neo magnet). Underneath the plate and the magnet is a coil attached to an actuator that contains another of the neodymium-iron-boron disc magnets underneath. While most modern hard disk drives contain two magnets, some contain only one and are not as powerful in computing applications. To achieve the same force from a ferrite or alnico magnet, the disk drive would need to use one at least 10 times the size of the neo-magnets.