ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2023 29 The 44th Honda Prize is being awarded to Dr. John J. Croat, FASM, former president of John Croat Consulting Inc., and Dr. Masato Sagawa, an advisor to Daido Steel Co. Ltd. and president of NDFEB Corp. Both men simultaneously invented the world’s most powerful permanent magnet—the neodymium (NdFeB) magnet—and established two different manufacturing methods to produce it. When Croat and Sagawa began their research, the most powerful magnet was the samarium-cobalt type, developed in 1969. In their independent research projects, both scientists pursued the potential of magnetic materials using iron because it is more abundant and has a greater magnetic moment than cobalt. They added neodymium in place of samarium along with a small amount of boron to the iron-based magnet, thereby creating the NdFeB permanent magnet. In 1982—at roughly the same time—Croat presented a paper on the rapid solidification process while Sagawa presented one on sintering, detailing their respective magnet manufacturing methods (Figs. 1 and 2). The advent of the NdFeB permanent magnet, which shows a high coercivity even with a piece measuring just a few millimeters, enabled a significant size reduction in motors and hard disk drives, thus advancing the field of information technology. The neodymium magnet now accounts for 95% of the permanent magnet market for motors used in wind turbines and electric and hybrid vehicles, thereby supporting electrification efforts, improving motor efficiency, and contributing to reduced CO2 emissions worldwide. The awards ceremony was held at the Imperial Hotel in Tokyo on November 16. In addition to prize medals and diplomas, the laureates were awarded a total of 10 million yen. This article highlights each inventor’s research contributions. MAKING MAGNETS: RAPID SOLIDIFICATION In 1972, John Croat joined the Magnetic Materials Group of General Motors Research Laboratories, whose mission was to develop high performance, low-cost permanent magnets for use in automotive components. The global economy was confronted with the 1973 OPEC oil embargo, which significantly increased gasoline prices worldwide and greatly stimulated the INVENTOR SPOTLIGHT 2023 HONDA PRIZE HONORS NEODYMIUM MAGNET INVENTORS With this year’s prestigious Honda Prize, the Honda Foundation is recognizing John J. Croat, FASM, and Masato Sagawa for simultaneously inventing the neodymium magnet. Fig. 1 – Bonded neodymium magnets produced via rapid solidification. Image courtesy of Daido Electronics Co. Ltd. Fig. 2 – Neodymium magnets produced via sintering. Image courtesy of Daido Electronics Co. Ltd.
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