Rare earth magnets are similar to regular magnets, but much stronger. They are currently the strongest magnets available. From an industrial standpoint, they symbolize high performance.
There is a lot of misconception surrounding the “rare earth” terminology.
Periodic table elements classified as rare earths are derived from the scandium, yttrium, and lanthanide families; they are actually quite abundant on Earth. Neodymium is almost as plentiful as copper and in greater abundance than gold. The U.S., Australia, Afghanistan, and Japan all have significant reserves of rare earths. However, it is difficult to find them in concentrated amounts and are typically found along with other elements. These elements are then used by magnet manufacturers. Rare earth magnets are formed by these alloys.
Why Are They Called Rare Earths?
Rare earths attained their name as a result of two different factors. The first is because they were initially perceived to be scarce. The second is because of the difficulty and level of skill required to separate the element from the mineral ore. The mining and refining processes (which were done by the process of crystallization), was difficult. Thus, the term “rare” was given to these elements.
Two Types Of Rare Earth Magnets
Generally, neodymium and samarium cobalt magnets are the two primary rare earth magnet types used today. They are both have different grades available with different properties.
The strongest is Neodymium alloy which contains neodymium, boron, and iron and with praseodymium and dysprosium in varying degrees. These magnets are typically coated or plated by manufacturers since they tend to corrode easily due to their brittleness. This helps to prevent chipping and breaking.
Samarium cobalt is the oldest of the rare earth magnet types. Made from alloy that contains samarium, cobalt, copper, iron, zirconium, hafnium, and praseodymium. Samarian cobalt can be a challenge to demagnetize. These magnets operate at high temperatures and are highly resistant to corrosion.
Neodymium Common Applications
- Medical Devices
- Magnetic Separators
- Microphone Assemblies
- DC Motors
- Servo Motors
- Computer Disc Drives, Speakers, and Printers
Samarium Cobalt Common Applications
- Computer Sensors and Disc Drives
- Satellite Systems
- Linear Actuators
- Motors Requiring Temperature Stability
Because these magnets are high-energy, they are perfect for various miniaturized applications. Highly resistant to demagnetization, it is recommended that they are used for applications under 180°F (82°C).
Rare earth magnets sold in raw form have the appearance of dull metallic. When grinding these magnets, use extreme caution to avoid crushing the material. The dust particles from cutting or grinding are flammable.
Raw magnet materials can be purchased in various strengths and types, as well as different shapes and sizes. Common shapes include square, rectangular, round ring, and round disc.
Consider the following specifications when ordering magnetic materials for a particular task:
- Magnetic Orientation
- Type of Material Desired
Custom magnets in bulk can generally be purchased with discounted pricing for distributors.
History of Rare Earth Supply
China currently supplies the majority (90%) of primary elements used in manufacturing neodymium magnets. However, additional resources were recently discovered off of Japan’s coast, in the mud at the sea bottom. This discovery could possibly mean an additional source of neodymium and other elements. An estimated amount of more than 15 million tons sea bottom mud may contain massive stores of quite valuable minerals.
The United States was the world’s primary supplier of the rarest earth elements throughout the 1960s, 70s, and 80s. Mountain Pass mine in California was the source for that material. By the ‘90s, however, China became a contender in the rare elements market. Prices were driven down and the Mountain Pass operation became unprofitable. It eventually closed for business in 2002 and China became the market’s leading supplier.
The supply in Japan could serve as a lifeline for supply of rare earths but more research must be conducted. The method of extracting the elements on a continual basis must still be developed. Several entities and research facilities in Japan are conducting feasibility tests to uncover an appropriate solution.