Rare earth disc magnets have been of considerable technological value since their development approximately four decades ago. They have been utilized in many products the great and the small and they are commonly purchased and used alone, even for novelty’s sake, because of their sheer magnetic strength. It is the unique combination of components (combined with economy) that have made these magnets so popular.
Neodymium and samarium-cobalt are the two types. Due to the corrosiveness and eventual tendency toward cracking or splitting of both types, they are commonly plated for protection. Neodymium alloy is the later developed, stronger and more affordable of the two, and is composed of neodymium, boron, and iron. The result is supposedly the strongest permanent magnet made, with a magnetic field sometimes in excess of 1.4 teslas, which is almost triple that of alnico or ferrite, so smaller magnets become a space-saving option. Nonetheless, samarium-cobalt retains its place due to its resistance to oxidation and its higher Curie temperature that accommodates equipment of a higher operating temperature.
These rare earth disc magnets have many practical uses. They are vital in computer hard drives as well as headphones and speakers. They are used in fishing reels and bicycles, and even on roller coasters. More recently, they have been made popular as magnetic toys. Regardless of whatever use is applied, there are noteworthy cautions to heed:
Magnets particularly an inch or more in diameter have such strength that they are capable of pinching the skin to the extent of visible injury. There have been documented medical cases of children having swallowed multiple magnets and pinched the digestive tract, necessitating surgery. They have also been known to cause fracture or breakage of bones. Stronger magnetic fields also have the ability to erase data from credit cards and other such devices.
Despite the potential hazards, neodymium and similar magnets continue to serve great and interesting purposes and receive rave reviews online (particularly the larger ones). It is reported that a three-quarter inch magnet can hold up to 22 pounds of weight. They have been used behind drywall (held by another metal source) to hold items on the visible side of the wall. They can also be epoxy-glued to surfaces to lend an impressive weight-bearing capacity. Varied testimonials online are worth investigating by people who enjoy finding clever ways to manipulate gadgetry.
There is no doubt that rare earth disc magnets have enhanced living in electronic, mechanical and other fields. They are versatile, very affordable and available online in myriad sizes and packs of multiples for convenient shopping. The magnetic neodymium alloy could very well be the toy of the future for children, and a gateway to unfathomable possibilities in the fields of engineering and design.
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.
