Toyota develops the World’s first Nd-reduced, heat resistant magnet

Toyota is working on a new type of magnet that reduces the use of some of the rarest materials on earth. Their ultimate effort is to maintain a balance between the supply and demand of valuable rare earth resources.

Toyota Motor Corporation (Toyota) has announced the world's first neodymium-reduced, heat-resistant magnet. Neodymium magnets are used in various types of motors such as the high-output motors found in electrified vehicles, use of which is expected to increase rapidly in the future. The new magnet uses significantly less neodymium, a rare-earth element ("rare earth"), and can be used in high-temperature conditions. This new magnet also skips on the use of other rare earths, such as Terbium (Tb) or Dysprosium (Dy) that are essential in the preparation of highly heat-resistant neodymium magnets and replaced a portion of the neodymium in the magnet with Lanthanum (La) and Cerium (Ce). The latter are both low-cost rare earths, subsequently reducing the amount of neodymium used in the magnet.

Magnets used in automotive motors and other applications have high coercivity even at high temperatures and for this, approximately 30 percent of the elements used in magnets are rare earths.

With the rising popularity of electrified vehicles in the near future, shortages of neodymium are bound to develop and after considering the gravitas of this grave situation, Toyota had undertaken the development of this technology.

Toyota has demonstrated that merely reducing the amount of neodymium and replacing it with lanthanum and cerium leads to a lower motor performance. Hence, to maintain high coercivity (the ability to maintain magnetization) and heat resistance, Toyota adopted the following three new technologies:

Grain refinement of magnet

Size of magnet grain is less than one-tenth of the conventional ones along with enlarged grain boundary area

Two-layered high-performance grain surface 

Increasing the neodymium concentration on the surface of the magnet grains and decreasing the concentration in the grain core

Specific alloying ratio of lanthanum and cerium

A specific ratio at which lanthanum and cerium can be alloyed to suppress the deterioration properties

The new Nd-reduced, heat-resistant magnet developed at this time not only eliminates the use of terbium and dysprosium, rare earths necessary for neodymium magnets that require high heat resistance, but it also reduces the amount of neodymium used. This new magnet is expected to have a wide range of applications in motors that require relatively high output such as those required for electrified vehicle drive motors and generators, electric power steering, robots, and various household appliances. It will also contribute to reducing the risks of a disruption in supply and demand of rare earths and price increases.

It is expected to see the application of these magnets in the motors of electric power steering for automobiles and other applications in the first half of the 2020s. Furthermore, the company will undertake development with the aim of practical application in high-performance electric motors within the next 10 years.