What is Special About Rare Earth Magnets?

Special About Rare Earth Magnets

There is an odd little section at the bottom of the Periodic Table filled with long, unpronounceable elements that look like they shouldn’t even be there. It’s called the “rare earth” group and contains metals that are more magnetic than almost anything else on the planet. Rare earth magnets derive their strength from two of these metals—samarium and neodymium—and that’s what makes them so special.

Rare earth magnets use the fact that their atoms contain many unpaired electrons to hold a charge and generate magnetic fields. These magnets are also far more compact than traditional permanent magnets, meaning they can pack more magnetism into a smaller space. And, unlike some other types of permanent magnets, rare earth magnets don’t easily lose their magnetic properties. They can resist demagnetization from heat, poor storage and physical trauma.

Because of this, rare earth magnets are used in a variety of applications from electric motors to speakers to computer hard disk drives. They’re also used in medical equipment and even cars. In fact, you probably have a small neodymium magnet inside your mobile phone that makes the “vibrate” mode work by redirecting electrons to the screen.

The two most popular types of rare earth magnets are neodymium and samarium-cobalt. Neodymium magnets are made from an alloy of neodymium, iron and boron (Nd2Fe14B) and account for the majority of rare earth permanent magnet production. Samarium-cobalt magnets are less common but have an advantage over neodymium in that they can withstand higher temperatures and are less prone to oxidation.

What is Special About Rare Earth Magnets?

Both kinds of magnets are produced in the same way—by isostatic pressing in rubber moulds. They’re then coated to protect them from the elements and other contaminants that could cause them to degrade over time. Most of the coatings are made from nickel, zinc or tin, but there are other choices available depending on the specific application.

China currently mines and refines the majority of the world’s rare earth element supply. This dominance is under threat from the US and other countries that are stepping up their research efforts on alternatives to rare earths.

In the future, there may be other ways to make strong permanent magnets that don’t require the use of rare earth metals. Ceramic magnets, for example, are a good alternative and have similar properties to rare earth magnets. But, while they do have some limitations and can’t replace the power of rare earth magnets, they offer a cost benefit and are an excellent option for a wide range of applications. In addition, there are no environmental concerns associated with ceramic magnets because they don’t require any mining, refining or processing. The main disadvantage is that they’re not nearly as strong or as durable as neodymium and samarium-cobalt magnets. The other big issue is that they’re very difficult to recycle, so they need to be disposed of carefully.

Samarium-cobalt magnets, developed earlier in the 1960s, are less powerful than neodymium magnets but offer higher temperature stability and greater resistance to corrosion. This makes them suitable for applications in harsh environments, such as aerospace, military, and high-temperature industrial processes.