The electrification of automobiles and aircrafts is moving forward rapidly due to the global trend toward carbon neutrality. Magnets, a component of motors, also need to have high heat resistance since the motors used in these applications are exposed to high temperatures of 100°C or higher. Neodymium sintered magnets are suitable for increasing torque and downsizing motors, given their high magnetic properties. To improve heat resistance, it is necessary to add heavy rare earths.^*3 However, there are fewer reserves of heavy rare earths than there are of light rare earths, creating the following challenges at a time of rising demand: Volatile prices of heavy rare earths and high resource depletion risk. Accordingly, the need to reduce or avoid the use of heavy rare earths (heavy-rare-earth-free) is increasing with each year.

Proterial has been developing and mass producing heavy-rare-earth-free neodymium sintered magnets, which feature increased heat resistance without the use of heavy rare earths. To meet growing needs, Proterial has successfully developed NMX™-F1SH-HF and NMX-G1NH-HF materials. These high-performance, heavy-rare-earth-free neodymium sintered magnets can be used for electric vehicle driving motors, with dramatic gains in residual magnetic flux density (B_r) and coercive force (H_cJ) through its unique textural and compositional control technology.

The NMX-F1SH-HF material has magnetic properties that permit applications for driving motors as well as electric power steering and compressors with B_r = 1.40 T and H_cJ ≥ 1671 kA/m. Proterial's mass production plant has already started providing pre-production samples.

The NMX-G1NH-HF material is a heavy-rare-earth-free material that can be used even for driving motors requiring high torque and heat resistance. Research facilities have achieved magnetic properties that enable use in a hot environment of 100°C or above with B_r = 1.42 T and H_cJ ≥ 1830 kA/m. Proterial will verify mass production potential. In April 2026, the mass-production plant will be ready to respond to requests for pre-production samples.

As the leader in the neodymium sintered magnet field, Proterial has obtained over 600 patents relating to neodymium sintered magnets around the world and has built a portfolio of more than 200 patents in Japan as a result of long-term research and development, manufacturing and distributing the neodymium sintered magnet NEOMAX^®. Particularly determined to bring to the world the most powerful neodymium sintered magnet free from heavy rare earth, Proterial has bolstered its portfolio of patents, concentrating on heavy-rare-earth-free technology development and patent applications while developing heavy-rare-earth-saving technology.

Figure shows a magnetic property map for Proterial's high-performance, heavy-rare-earth-free neodymium sintered magnet. The NMX-F1SH-HF material and the NMX-G1NH-HF material, that is, the new high-performance, heavy-rare-earth-free magnets, have been successfully developed with H_cJ and B_r dramatically improved from the first-generation NMX-S49F material by controlling impurities and optimizing the composition and process using Proterial's original manufacturing methods.

The NMX-F1SH-HF material has magnetic properties with B_r = 1.40 T and H_cJ ≥ 1671 kA/m, permitting applications for driving motors as well as electric power steering and compressors. Furthermore, for the NMX-G1NH-HF material, the research facilities achieved magnetic properties with B_r = 1.42T and H_cJ ≥ 1830 kA/m to satisfy the strong need for the development of a heavy-rare-earth-free material that can be used for driving motors requiring high torque and heat resistance.

In addition to neodymium magnets, Proterial manufactures and sells Ferrite Magnets NMF™ excelling in cost-effectiveness and having a comparatively small resource risk. Proterial is a comprehensive motor material manufacturer, offering amorphous metal for cores (iron cores), enameled wire, magnetic wedges, and other materials for elevating the performance and efficiency of motors. Proterial will continue to supply varied motor materials to address the motor-related issues of customers.