Toyota Motor Corp. says it has developed a neodymium-reduced, heat-resistant magnet. Similar magnets are used in motors such as the high-output motors found in electrified vehicles. Toyota says its new magnet uses less neodymium, a rare-earth element, and can be used in high-temperature conditions.

The newly developed magnet uses no terbium (Tb) or dysprosium (Dy), which are rare earths that are also categorized as critical materials necessary for highly heat-resistant neodymium magnets. A portion of the neodymium has been replaced with lanthanum (La) and cerium (Ce), which are low-cost rare earths.

Production volumes of neodymium are relatively high among rare earths, but concerns exist that shortages will develop as electrified vehicles, including hybrid and battery electric vehicles, become increasingly popular.

The automaker says that neodymium plays a role in maintaining high coercivity (the ability to maintain magnetization) and heat resistance. Merely reducing the amount of neodymium and replacing it with lanthanum and cerium can result in a decline in motor performance, Toyota says.

To counter this, researchers adopted new technologies that suppress the deterioration of coercivity and heat resistance, even when neodymium is replaced with lanthanum and cerium, and developed a magnet that has equivalent levels of heat resistance as earlier neodymium magnets. The effect is to reduce the amount of neodymium used by up to 50 percent.

This new type of magnet is expected to be useful in expanding use of motors in various areas such as automobiles and robotics. Toyota says it will work to further enhance performance and evaluate application in products while accelerating the development of mass production technologies, with the aim of achieving early adoption in motors used for various applications, including in automobiles and robotics.

Despite this, little effort has been made to address neodymium use.

To overcome these issues, Toyota successfully undertook development of technologies that can both eliminate the use of terbium and dysprosium and reduce the amount of neodymium used. Through substitution of neodymium with lanthanum and cerium, which are abundant and low-cost rare earths, high heat resistance can be maintained and loss of coercivity minimized.