Magnetic materials are ancient and very versatile functional materials. The magnetic properties of substances were recognized and applied as early as 3000 years ago, for example, natural magnets were used as compasses in ancient China. In recent times, with the development of industry and technology, a large number of new magnetic materials have been discovered, which are roughly divided into three generations according to their main applications: the first generation of AlNiCo, the second generation of ferrite, and the third generation of rare earth permanent magnets. The following is a brief history of the development of magnetic materials.
1st century B.C. Sima Qian’s “The Records of the Grand Historian” describes that the Yellow Emperor used a compass in battle.
In 1086, Shen Kuo’s book of “Mengxi Pen-talk” of the Song Dynasty recorded the manufacturing method of the compass, etc.
1119 The compass was used for navigation as recorded in Zhu or Pingzhou Kezhuan of the Song Dynasty.
1600 William Gibert of England, the earliest work “De Magnete Magnet”.
1820 H.C. Oersted, Denmark, first discovered that electric currents could produce magnetic fields.
1822 Lussac, France, invented the electromagnet, i.e. an electric current passing through a wound wire could magnetize an intermediate iron.
1826 France’s Ampere discovered Abe’s law, the right-hand spiral rule.
1831 Faraday demonstrated the phenomenon of electromagnetic induction and revealed the relationship between electromagnetism.
1832 A.H. Pixey, France, invented the permanent magnet rotating alternator made of natural magnets.
19th century to 20th century New types of DC and AC motors/generators were inundated in Europe.
1931 Japanese Tokushichi Mishima invented AlNiCo AlNiCo magnets. before the discovery of rare earth magnets in the 1970s, AlNiCo alloys were the strongest permanent magnet material. (First generation magnetic material)
1933 Japanese Kato and Takei discovered Fe2O3, a ferrite containing Co. By weight, ferrite is still the most widely used magnetic material in the world today. (Second generation magnetic material)
1935 Snoek of Holland invented soft magnetic ferrite
1965 Mader and Nowick prepared CoP ferromagnetic amorphous alloy
1967 Discovery of 1:5 SmCo by Strnat, USA, marking the era of rare earth permanent magnets (third generation magnetic materials)
1977 Ojima, Japan discovered 2:17 type SmCo with small amounts of Cu and Zr.
1983 Japan Sagawa discovered Nd2Fe14B, NdFeB was called the king of contemporary magnetism.
1983 NdFe14B was discovered by General Motors of USA and Japan, and each of them had a patent.
1984 NdFeB with magnetic energy product over 35MGOe was developed by China Iron and Steel Research Institute.
In 1992, some domestic companies bought the patent of Nd-Fe-B from Sumitomo in Japan.
In 2002, the annual output of Nd-Fe-B in China reached 8,000 tons, surpassing Japan to become the first in the world.
In 2008, the annual output of Nd-Fe-B reached 46,000 tons with more than 100 Nd-Fe-B manufacturers in China.
In 2011, the price of rare earth skyrocketed, and the downstream customers were affected, so the replacement and reduction of dysprosium became the trend. At the same time, the lobbying capital was flooded in the rare earth industry, causing a serious overcapacity in the whole industry chain, including NdFeB.
In 2013, the industry predicts that the domestic NdFeB production capacity has reached 335,000 tons, multiplied by 0.8 factor about 270,000 tons, while the actual annual demand is only 110,000 tons, so the production capacity is seriously overcapacity, especially the middle and low-end products.
In 2014, except for Hitachi Metals, Shin-Etsu Chemical, TDK and VAC in Germany, and a small amount of production by Molybdenum in USA, all other NdFeB factories are in China, and the annual output of NdFeB in China is more than 80% of the world, but the output value only accounts for more than half.
From the above development history, we can find some interesting phenomena.
First, China was the first to pay attention to magnetic materials, and the application of compass changed the world’s maritime history. But there was a gap in the middle, and finally, by the reform and opening up, it became the biggest manufacturing base of magnetic materials in the world. However, the grade of Chinese NdFeB products is quite low, and the gap between the added value and Japanese enterprises is large.
Secondly, in the 19th century, Europe developed science and technology, and the pioneering theories and practices of modern electromagnetism, engines and generators were initiated by Europeans.
Third, since the 1930s, the locomotive of the world’s magnetic material research and development has changed to Japan and the United States. Especially, Japan has been the world leader in magnetic material R&D before the war, so we have to admire the achievement of Japanese in the field of material science, which is worthy of Chinese people to learn.
Since the birth of Nd-Fe-B in laboratory, it has been more than 30 years. Due to the expensive price of rare earths, especially due to the lack of heavy rare earths of dysprosium and terbium, countries all over the world are competing to develop new generation of magnetic materials, such as samarium-iron-nitrogen permanent magnets, nano-composite rare earth permanent magnets, etc. However, the effect is still unsatisfactory, and the position of Nd-Fe-B is still unshakable in the next one or two decades. We will wait and see how the magnetic materials will develop in the future.