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The Neodymium magnet, also referred to as the NdFeB magnet, is a tetragonal crystal system composed of neodymium, iron, and boron (Nd2Fe14B). It was first discovered in 1982 by Mr. Sagawa of Sumitomo Special Metals. The magnetic energy product (BHmax) of this magnet surpasses that of samarium cobalt magnets. At the time of its discovery, it held the record for the highest BHmax in the world. Subsequently, Sumitomo Special Metals successfully developed the powder metallurgy process for producing NdFeB magnets. General motors later achieved success in developing the melt-spinning process, which enabled mass production of NdFeB magnets.
NdFeB magnets are the second most powerful permanent magnets available today, following holmium absolute zero magnets. They are widely used as rare-earth magnets in various electronic devices, including hard disks, cell phones, headphones, and battery-powered tools. Their exceptional magnetic properties make them highly desirable for applications requiring strong and compact magnets. The widespread utilization of NdFeB magnets underscores their importance in modern electronic products and technological advancements.
Depending on the manufacturing process used, NdFeB magnets are categorized as sintered or bonded. They have replaced other types of magnets in many applications of modern products that require strong permanent magnets, such as electric motors in cordless tools, hard disk drives and magnetic fasteners.
The U.S. Department of Energy (DOE) has recognized the necessity of seeking alternatives to rare earth metals in permanent magnet technology and has allocated funding for research in this area. The Rare Earth Alternatives in Critical Technologies (REACT) program, sponsored by the Advanced Research Projects Agency for Energy (ARPA-E), was established to develop substitute materials. In 2011, ARPA-E granted $31.6 million in funding for the Rare Earth Alternatives program.
Given its role in permanent magnets for wind turbines, it has been suggested that neodymium will be a primary target in geopolitical competition in a renewable energy-based world. However, this perspective has been criticized for overlooking the fact that most wind turbines do not utilize permanent magnets and for underestimating the influence of economic incentives on production expansion.
Due to its exceptional magnetic properties and cost-effectiveness, NdFeB permanent magnet material has rapidly emerged as the predominant player in the rare earth permanent magnet market since its inception. Its output value accounts for 90% of the global rare earth permanent magnet material output value. Furthermore, with ongoing enhancements in the preparation process and production technology, its performance continues to improve, and its application fields are gradually expanding. Therefore, the extent of NdFeB permanent magnet material applications serves as an indicator of modernization levels. NdFeB permanent magnet material remains a burgeoning sector in the rare earth material industry.
What is permanent magnet material
Permanent magnetic material is a functional material that is magnetized to saturation under the action of an external magnetic field and retains its magnetic properties after the external magnetic field is removed. It is also known as hard magnetic material. As early as the Warring States period in China, the invention of “Sinan” (the prototype of the compass) is to use the role of the magnet guide to identify the direction.
Although mankind has known about magnetic materials for more than 2,000 years, man-made permanent magnets began with the invention of magnetized steel needles in China in the tenth century. Significant progress in the development and application of magnetic materials began in the late nineteenth and early twentieth centuries. At the beginning of the twentieth century, people mainly use tungsten steel, carbon steel, chromium steel and cobalt steel as permanent magnet materials. At the end of the 1930s, Alnico permanent magnetic materials were successfully developed, and then permanent magnetic materials began to be applied on a large scale. In the 1950s, barium ferrite appeared. The cost of permanent magnets was lowered, and at the same time, the range of applications of permanent magnet materials was broadened to high frequency. In the sixties, rare earth cobalt permanent magnets were successfully developed. The application of permanent magnets entered a new era. In 1967, the University of Dayton in the United States successfully made SmCo5 permanent magnets, which marked the arrival of the rare earth permanent magnet era. So far, rare earth permanent magnet materials have been developed from the first generation of 1:5 type SmCo5, the second generation of precipitation hardening type Sm2Co17, to the third generation of Nd-Fe-B permanent magnet materials.
In addition, Cu-Ni-Fe, Fe-Co-V, Fe-Co-Mo, A1MnC, MnBi alloys have historically been used as permanent magnet materials. These alloys are seldom used in most occasions due to their poor performance and low cost performance.FeCrCo, AlNiCo, PtCo and other alloys are still used in some special occasions. Ba, Sr ferrite is still the largest amount of permanent magnet materials, but it is gradually being replaced by Nd-Fe-B materials in many application areas. Currently, the output value of rare earth permanent magnet materials has far exceeded that of ferrite permanent magnet materials, and the production of rare earth permanent magnet materials has developed into a large industry.Nd-Fe-B has become the most widely used rare earth permanent magnet material. Nd-Fe-B has become the most widely used rare-earth permanent magnet material. It is also the strongest magnetic permanent magnet material so far.
Introduction of NdFeB
NdFeB is a rare earth permanent magnetic compound composed of the rare earth metal neodymium, the metal element iron, the non-metallic element boron and a small amount of added elements such as praseodymium, dysprosium, niobium, aluminum, gallium, copper and other elements. NdFeB permanent magnets have excellent magnetic properties, light weight and low price, and a wide range of applications. It is known as the “king of magnets” and is by far the most cost-effective magnet material.
NdFeB powerful magnets have large magnetocrystalline anisotropy field and high intensity magnetic polarization. Its theoretical magnetic energy product is 64MGOe. Its magnetic property is more than 100 times higher than that of the magnet steel used by people in the 19th century. It is 10 times higher than usual ferrite and alnico. Its coercivity and energy density is very high, greatly reducing the size of magnetic material parts. This also promotes the miniaturization, lightweight, thinning and high efficiency of equipment such as instrumentation, electro-acoustic motors, computers and cell phones. These characteristics improve the performance of products, and promote the generation of certain special devices. NdFeB has good mechanical properties and is easy to be cut and processed. Its preparation technology is relatively mature, the Curie temperature of this magnet is about 580K, the use of temperature up to 150 degrees Celcius.
NdFeB does not contain strategic elements Co and Ni, and is rich in raw materials. Its high cost-effectiveness makes it since 1983 NdFeB was introduced, to 2006, the output soared to 55,540 tons. By 2015, it surged even more to around 130,000 tons. Sintered NdFeB permanent magnetic materials have excellent magnetic properties. They are widely used in electronics, electric machinery, medical equipment, toys, packaging, hardware machinery, aerospace and aviation.
