September 15, 2016 12:00 pm JST

Magnet makers fight for supremacy in the coming electric-car era

This motor, developed jointly by Honda Motor and Daido Electronics, incorporates magnets containing no rare earths.

TOKYO Honda Motor and Daido Electronics have developed a new way to make high-performance magnets -- used in everything from electric cars to wind turbines to air conditioners -- that eliminates the need for rare-earth metals imported from China.

The new technology has helped Honda secure a stable supply of a vital component for electric motors, which, in turn, are key to hybrid and electric vehicles. Daido Electronics, a unit of Daido Steel, says it has received inquiries from about 20 companies in the auto industry about the magnets. It plans to build a new plant to make them in the U.S. in three years at a cost of about 10 billion yen ($97.3 million). The company hopes to expand in North America, where sales of environment-friendly vehicles are expected to rise.

Long dominated by the Japanese trio of Hitachi Metals, Shin-Etsu Chemical and TDK, the market for high-performance magnets is expected to grow 60% in volume terms over the next five years. Until now, heavy rare-earth metals have been considered essential to increasing the power and heat-resistance of such magnets. However, deposits of one of the metals, dysprosium, are heavily concentrated in China, making supplies vulnerable to political tensions.

The new magnet developed by Honda and Daido Electronics uses another element, neodymium, and contains no heavy rare-earth metals. Honda and Daido Electronics began working on the magnet around 2010, when tensions were rising between Japan and China over disputed islands in the East China Sea. The Chinese government cut exports of rare-earth metals and prices shot up, with dysprosium becoming especially costly. Prices dropped in 2012, but the risk of wild swings in raw material prices worried automakers and magnet manufacturers.

Honda and Daido Electronics also developed a motor that takes full advantage of the properties of its neodymium magnet. To keep a lid on its technology, Daido Electronics built its own production equipment at its main plant.

Honda, meanwhile, set up a production line at its Suzuka factory in Mie Prefecture, in western Japan, to turn out motors for its new hybrid Freed minivan, which hit showrooms in September. The motors incorporate the new magnets.

Daido Electronics' leapfrogging of its competitors points to a major transition in the market. Last year, 25,000 tons of high-performance magnets were used globally, according to Showa Denko, which produces magnetic alloys. Of that amount, 3,300 tons were used in eco-friendly vehicles such as hybrids and electric vehicles, not including power steering components. Demand for automotive magnets is growing rapidly and is expected to reach around 10,000 tons by 2020.

U.S. electric car manufacturer Tesla Motors uses coils rather than magnets in its motors. What's more, said an official with a Japanese competitor, "It is essential to use high-performance magnets to make electric vehicles lighter."

Japan's three leading magnet makers are not sitting on their hands. Hitachi Metals plans to start producing neodymium magnets in China in March, now that China's antitrust authorities have completed the approval process. After three months' delay, the project will finally get off the ground, said an official at Hitachi Metals' magnetic materials unit.

Hitachi Metals hopes local production will eliminate procurement risks and cut costs compared with production in Japan. Annual output at the Chinese plant will start at around 1,000 tons in fiscal 2017. The company is aiming for sales of 10 billion yen in fiscal 2018.

TDK began producing neodymium magnets at a factory in the Chinese province of Guangdong in fiscal 2016.

Shin-Etsu Chemical has been hesitant to produce neodymium magnets in China. Instead, the company has upgraded its Vietnamese factory, which it decided to build in 2014.

HOLDING IT TOGETHER Neodymium magnets were invented in 1982 by Masato Sagawa, a former Fujitsu researcher who later moved to a company called Neomax. The magnets are widely used in small motors for inverter air conditioners and hard disk drives, wind turbines, power steering for cars, industrial robots and more.

Although they are ubiquitous, they are not easy to make. That is especially true of the magnets used in the motors of cars, which must operate at temperatures of 150 to 180 C. "The magnetic properties diminish as the temperature rises," explained an official at TDK.

The tried and true recipe for maintaining magnetic performance at high temperatures is to add the heavy rare earths dysprosium and terbium to the mix. Unfortunately, as their name implies, they are not readily available in large quantities.

Through trial and error, the magnet makers have developed ways to significantly reduce the use of dysprosium by adding the rare earth to just the surface of the crystals that comprise the magnetic material. The neodymium magnets now being used in electric car motors contain just a few percent of heavy rare earths. The ultimate goal is to eliminate their use altogether.

Easier said than done. High-performance magnets are typically made by sintering, that is, heating a powdered magnetic alloy to make it solidify. The grains of the powder measure 3 to 5 microns in diameter.

Ideally, the powder should be much finer, but if the grains are crushed any smaller, the material oxidizes too easily due to the greater surface area exposed to the air. It seemed that solving this conundrum was a long way off.

Daido's new magnet was thus a game-changer. Instead of sintering, Daido employs a method known as hot working, in which a press fashions the magnet from a solid alloy at high temperatures. Daido licensed hot working technology from U.S. carmaker General Motors in 1988. The method dispenses with powders altogether. Instead, the molten magnetic material is cooled rapidly to create tiny clumps of crystals. When the clumps are pressed flat, the crystals naturally align in the same direction.

Hot working produces crystals measuring just 0.2 micron in diameter, a tenth the size of the powdered granules used in sintering. This improves the heat-resistance of the magnet, according to Daido's President Yoshio Inagaki.

THE RIGHT STUFF Other projects are underway in Japan to make magnets that outperform neodymium magnets, which are reaching their theoretical limits.

Formed in 2012 by the National Institute of Advanced Industrial Science and Technology and a group of private companies that includes Toyota Motor and Denso, the Technology Research Association of Magnetic Materials for High-Efficiency Motors (MagHEM) is working on the next generation of high-performance magnets.

One of the fruits of their labor is a new magnet developed by the Shizuoka Institute of Science and Technology. Composed mainly of samarium, iron, titanium and cobalt, the magnet contains no heavy rare earths. The key is the use of zirconium, which stabilizes the magnet.

"We believe we will eventually be able to formulate magnets that are 20-30% more powerful than neodymium magnets at temperatures of around 200 C," said professor Kurima Kobayashi.

The National Institute of Advanced Industrial Science and Technology is also working on a new magnet made from samarium, iron, and nitrogen.

TDK is developing "nanocomposite magnets" which require nanometer-level manipulation of materials. And Hitachi plans to develop magnets at a research facility slated to open in April 2017.

China is the biggest challenge to Japan when it comes to magnets, since no leading manufacturers are based in the U.S. or Europe. Because China is backing electric vehicles, the country has become a global center for the development of electric vehicle technology. The motors that drive these cars require powerful magnets, which is spurring their development in China. European automakers are rumored to be using Chinese magnets in their electric cars.

(Nikkei)

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