Rare earth permanent magnet material: a metal structural material belonging to new energy materials
This article mainly introduces the rare earth permanent magnet material from the aspects of performance, principle, classification, application and development prospects, which is a kind of metal structural material belonging to new energy materials. Rare earth permanent magnet materials have been widely used in the fields of communications, transportation, medical, aerospace and other fields due to their excellent comprehensive magnetic properties such as high remanence, high coercivity, and high magnetic energy product. They have also been used in wind power generation as new energy materials. , Electric vehicles, industrial energy-saving motors and other new energy applications. Among the various fields of application of rare earths, rare earth permanent magnet materials are the fastest growing. It not only brings a huge impetus to the development of the rare earth industry, but also has a profound impact on many related industries.
Introduction
Rare-earth permanent magnet materials are currently known as a permanent magnet material with the highest comprehensive performance. It is more than 100 times higher than the magnetic steel used in the nineteenth century. It is much superior to ferrite and AlNiCo. The magnetic properties of expensive platinum-cobalt alloys are also twice as high. Because the use of rare earth permanent magnetic materials not only promotes the miniaturization of permanent magnetic devices, improves the performance of products, but also promotes the production of certain special devices. Therefore, the emergence of rare earth permanent magnetic materials immediately attracted great attention from all countries. The development is extremely rapid. The properties of various rare earth permanent magnet materials developed and produced in my country have approached or reached the international advanced level.
Now rare earth permanent magnet materials have become important materials in electronic technology communications. They are used in traveling wave tubes, circulators in artificial satellites, radars, etc., as well as micro-motors, micro-recorders, aviation instruments, electronic watches, seismographs and other electronics. On the instrument. At present, the application of rare earth permanent magnets has penetrated into automobiles, household appliances, electronic instruments, nuclear magnetic resonance imagers, audio equipment, micro motors, mobile phones, etc. In terms of medical treatment, the use of rare earth permanent magnet materials for “magnetic acupuncture therapy” has greatly improved the curative effect and promoted the rapid promotion of “magnetic acupuncture therapy”. Among the various fields of application of rare earths, rare earth permanent magnet materials are the fastest growing. It not only brings a huge impetus to the development of the rare earth industry, but also has a profound impact on many related industries.
Rare earth permanent magnet materials
Definition of rare earth permanent magnet materials
The so-called rare earth permanent magnet materials refer to permanent magnet materials made of alloys of rare earth metals (such as neodymium, samarium, etc.) and transition metals (such as iron, cobalt, etc.) through a certain process.
Rare earth elements refer to the lanthanide elements in the periodic table of chemical elements-lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu) ), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), and 15 elements in the lanthanide series Two closely related elements, scandium (Sc) and yttrium (Y), consist of 17 elements with special properties. Rare earth element atoms have more unpaired spin electrons than iron, cobalt, and nickel. The magnetic moment generated by the electron spin and the magnetic moment generated by the orbital motion of the electrons add up to make the rare earth atoms have a high atomic magnetic moment . After these rare earth elements are made into magnetic materials by a certain process, rare earth atoms can also form countless small areas in the crystal. Under the condition of an external magnetic field, in these small areas, the atoms are arranged in the direction of the magnetic moment to form magnetic domains. . This makes the rare earth permanent magnet materials have strong magnetism, which is of greater value for human use and a wider range of applications.
The principle of rare earth permanent magnet materials
The magnetic types of substances mainly include paramagnetism, diamagnetism and ferromagnetism. When the substance molecule contains unpaired electrons, it is paramagnetic, and the paramagnetic substance can generate an additional magnetic field in the external magnetic field, showing strong magnetism, such as potassium ferricyanide (red blood salt) [K3Fe(CN)6] , Ferrous sulfate (FeSO4·H2O), etc. And some substances that do not contain unpaired electrons, under the action of an external magnetic field, produce a small magnetic moment opposite to the external magnetic field, so they are called diamagnetic, such as salt (NaCl), calcium oxide (CaO), potassium ferrocyanide (Yellow blood salt) [K4Fe(CN)6] and so on. There is also a class of substances, which are usually metals or alloys, which are ferromagnetic substances. Under the action of a magnetic field, the magnetic moments of the atoms tend to be aligned in parallel with ferromagnetic substances, which produces a large magnetic moment, forming a strong magnetic field inside the substance. Such substances are called ferromagnetic substances. The most familiar examples are iron, cobalt, nickel and their alloys.
Permanent magnet materials refer to materials that have long-term retention of magnetism after being magnetized. Cobalt ferrite, barium ferrite, and strontium ferrite discovered in 1932 were the first permanent magnet materials used. They are composite oxides with iron oxide as the main component.
(MFe2O4, M=CO2+, Ba2+, Sr2+, Mg2+), these ferrites do not show magnetism when there is no external magnetic field, but when a magnetic field is applied, the ferrite is magnetized and produces strong magnetism. After the magnetic field, the magnetism can still be retained, so it is called a permanent magnet, such as Co0.75Fe2.25O4. Rare earth atoms have more unpaired spin electrons than iron, cobalt, and nickel. The magnetic moment generated by the electron spin and the magnetic moment generated by the orbital motion of the electrons add up to make the rare earth atoms have a very high atomic magnetic moment. Magnets can also form countless small areas in the crystal. Under the action of an external magnetic field, atoms in these small areas are arranged in the direction of the magnetic moment to form magnetic domains. This greatly enhances the magnetic properties of rare earth alloy materials.
Rare earth permanent magnetic material is a kind of magnetic material made by alloy composed of samarium, neodymium mixed rare earth metal and transition metal (such as cobalt, iron, etc.), pressed and sintered by powder metallurgy method, and magnetized by magnetic field.
Classification of rare earth permanent magnet materials
Rare earth cobalt permanent magnet material
Including rare earth cobalt (1-5 type) permanent magnet material SmCo5 and rare earth cobalt (2-17 type) permanent magnet material Sm2Co17. Although samarium-cobalt magnets have the advantages of high magnetic energy product and high Curie temperature (727°C), samarium is a rare earth element that is relatively scarce, and there is no reliable guarantee for the supply of raw materials.
Rare earth neodymium permanent magnet material
NdFeB permanent magnetic materials, such as neodymium iron boron (Nd2Fe14B) magnetic materials, are magnetic materials with a higher magnetic energy product than samarium cobalt. For example, the unit of maximum magnetic energy product is megagauge, the ferrite is 3.7, the samarium cobalt is 21.0, and the rated value of sintered Nd2Fe14B is 37.0 (the data obtained in the laboratory is 50.6); and the tensile sum of Nd2Fe14B is The bending strength is twice that of samarium cobalt magnets; at the same time, the price of raw materials is higher than ferrite, but lower than samarium cobalt, so it has the title of “ferromagnetic king”.
Rare earth iron nitrogen (RE-Fe-N series) or rare earth iron carbon (RE-Fe-C series) permanent magnet materials
The maximum magnetic energy product (BH) max of this kind of magnetic material is higher than NdFeB magnetic powder, about 2 times, so the technical advantage is stronger. Moreover, the cost of the material is lower than that of NdFeB, because the content of rare earth in the magnetic powder is relatively small, and there is no need to dope with expensive metals such as cobalt. In addition, the rare earth component in the material can be neodymium or samarium, and the price of samarium in the market is much lower than neodymium.
Classification of rare earth permanent magnet materials
Rare earth cobalt permanent magnet material
Including rare earth cobalt (1-5 type) permanent magnet material SmCo5 and rare earth cobalt (2-17 type) permanent magnet material Sm2Co17. Although samarium-cobalt magnets have the advantages of high magnetic energy product and high Curie temperature (727°C), samarium is a rare earth element that is relatively scarce, and there is no reliable guarantee for the supply of raw materials.
Rare earth neodymium permanent magnet material
NdFeB permanent magnetic materials, such as neodymium iron boron (Nd2Fe14B) magnetic materials, are magnetic materials with a higher magnetic energy product than samarium cobalt. For example, the unit of maximum magnetic energy product is megagauge, the ferrite is 3.7, the samarium cobalt is 21.0, and the rated value of sintered Nd2Fe14B is 37.0 (the data obtained in the laboratory is 50.6); and the tensile sum of Nd2Fe14B is The bending strength is twice that of samarium cobalt magnets; at the same time, the price of raw materials is higher than ferrite, but lower than samarium cobalt, so it has the title of “ferromagnetic king”.
Rare earth iron nitrogen (RE-Fe-N series) or rare earth iron carbon (RE-Fe-C series) permanent magnet materials.
The maximum magnetic energy product (BH) max of this kind of magnetic material is higher than NdFeB magnetic powder, about 2 times, so the technical advantage is stronger. Moreover, the cost of the material is lower than that of NdFeB, because the content of rare earth in the magnetic powder is relatively small, and there is no need to dope with expensive metals such as cobalt. In addition, the rare earth component in the material can be neodymium or samarium, and the price of samarium in the market is much lower than neodymium.
Rare earth permanent magnet material production process
Over the years, the production technology and equipment level of my country’s rare earth permanent magnet materials have been rapidly improved and perfected. The quality and magnetic properties of permanent magnets have been improved rapidly, which has promoted the development of applications and promoted the rapid development of the permanent magnet industry.
Sintering NaFeB originally used the sintering method (sintering method) to produce sintered NaFeB. The magnetic properties are not as high as (HB)m<35MGOe. It is only used for general devices (such as audio magnetic therapy, magnetic separators and magnetized wax protectors, etc.). Later, the improved low-oxygen production process used fibrous melt-cast ingots and oxygen explosion method to replace fine grinding powder, only (HB)m increased to 50MGOe, which broadened the application fields of the product (such as VCM, etc.). In recent years, my country has been able to use advanced quick-setting sheet technology and one-step molding technology to greatly improve the production level, improve the performance of permanent magnets to high-end grades, and reduce the consumption of raw materials sharply, and the production cost has dropped by 40%-50% . Because the original backward process must be mechanically processed, the yield is only about 70%. For example, after the one-step process (direct compression molding process can produce tile-shaped, ring-shaped and sector-shaped magnets), the process is simple and the magnetic billet density is high. It is 5.59g/cm3, the product yield is very high (above 90%), and the product cost is reduced by half. As mentioned above, the rapid advancement of NdFeB production technology and equipment by the above-mentioned firing method has not only sharply increased the output, but also improved the magnetic performance, which strongly promotes the development of the magnetic industry.
Bonded NdFeB
Magnetic powder prepared by melt rapid quenching method can produce isotropic bonded NdFeB permanent magnet (MQI), (BH) m=140KJ/m3 (17.5MGOe). To prepare isotropic hot-pressed permanent magnet (MQZ), (BH) m=119KJ/m3 (15MGOe). Their processes and equipment have reached the level of industrial production. In recent years, the use of hot extrusion technology can produce anisotropic radial magnetic ring NdFeB magnets, and obtain a high magnetic energy product (BH) m=400KJ/m3 (50MGOe), which is conducive to development and application development.
After making powder by the HDDR method, isotropic and anisotropic bonded NdFeB permanent magnets can be produced, and it has reached the level of industrialized production. For example, the magnetic energy product (BH) of the anisotropic bonded NdFeB permanent magnet (MFP13) obtained by pressing and injection molding the magnetic powder is m=310KJ/m3 (38MGOe) and (MFP14) (BH) m=253KJ/m3 (33MGOe) ), the improvement of the above process technology has pushed the bonded NdFeB permanent magnet to a new stage of development. The improvement of my country’s technology and service equipment in this area has strongly promoted the new development of bonded NdFeB magnets in my country.
SmCo5 permanent magnet
Before 2000, my country used the reduction diffusion method (sintering method) to produce SmCo5 permanent magnets, (BH) m=250-279KJ/m3 (31-35MGQe), while Sm2Co17 permanent magnets (BH) m=223-263KJ/m3 ( 28-33MGOe), and can also produce Sm (Co, Cu, Fe, ZR) Z (BH) m=264KJ/m3 (33MGOe). The above-mentioned permanent magnets have reached the level of industrial production in my country, which has promoted the application demand of the industrial sector. In addition, my country has successfully developed a bonding method to prepare SmCo5 permanent magnets. This new technology is: fast cooling thick strip technology to produce bonded SmCo5 magnets. At present, it has reached the level of industrialization. The (BH) m=239-269KJ/m3 (30-35MGoe) of the bonded SmCo5 product is obtained, which can open up new application areas of SmCo5 products and facilitate the development of this magnet.
SmFeN permanent magnets have two main intermetallic compounds in SmFeN: Sm2Fe7Nx and SmFe7Nx. Because they are easily decomposed at higher temperatures, sintering cannot be used to prepare such magnets. Only the bonding method can be used to produce SmFeN magnets. At present, the isotropic Sm2Fe7Nx magnetic powder is produced by the melt rapid quenching method and the HDDR method, and the bonded Sm2Fe7Nx magnetic powder can be obtained by the compression molding technology, (BH) m=123KJ/m3 (15MGOe). Anisotropic Sm2FenNx magnetic powder can be made by ingot crushing method and reduction diffusion method, and anisotropic bonded Sm2FenNx permanent magnet can be made by compression molding process, (BH) m=100-160KJ/m3 (12-20MGOe) is also available Extrusion and injection molding technology produces this magnet. The former (BH) m=50-68KJ/m3 (6.2-8.5MGOe), and the latter (BH) m=84-103KJ/m3 (10.4-13MGOe). At present, my country has built a production line for the production of bonded SmFeN and realized industrialized production. It has been ahead of foreigners. The production technology and equipment are gradually in the stage of perfection. This provides an example of independent property rights for my country to develop new product applications. ! Also promoted the new development of my country’s permanent magnet industry.
Nanocrystalline composite permanent magnet
In recent years, my country has been able to develop nanocrystalline composite permanent magnets, which have high coercivity and can be industrialized. This kind of magnet is made of hard magnetic Nd2Fe14B phase and soft magnetic γ-Fe phase as raw materials, and its crystal grains are 20nm made by rapid quenching method, with high remanence and high coercivity, (BH) m=203KJ/m3 ( 25MGOe), Br=0.95-1.2T (9.5-12KOe), 10-20% higher than the rapid quenching single-phase SmFeN, but the coercivity of Nd2Fe14B/γ-Fe is extremely high as Hcj=8000KA/m (100KOe). Therefore, the magnetic performance of the magnet is better, the cost is lower, users love to use it, and the market has a broad market. It is mainly suitable for making small motors. This new magnet technology and equipment have enriched the field of my country’s permanent magnet industry and promoted the development of the entire permanent magnet material.
Surface treatment technology of permanent magnet
Due to the uneven surface and many pores of sintered NdFeB, it is easy to be oxidized and chemically unstable. It is easy to be oxidized and corroded when used in moist air and aqueous solution. For many years, electroplating, electrophoresis, and ion (molecular) coating have been used for surface treatment techniques, but the effect is not ideal. In recent years, a new composite surface treatment technology called “SEN” has been studied, and the effect is very good in practice. This method is to use various elements of metal and non-metal to make a solution, then raise the temperature and adjust the process parameters. Immerse the NdFeB component in the solution to form a layer of alloy coating (protective film) on the surface of the component to prevent the surface of the component from being corroded. Its technical and economic effects are good, and it has been promoted. In recent years, my country has developed a new ultrasonic chemical coating protection technology for permanent magnet surface treatment. According to the characteristics of multi-phase porous on the surface of NdFeB permanent magnet, the permanent magnet is pretreated by ultrasonic degreasing and surface sealing under vacuum conditions to improve the surface properties of the magnetic matrix. Then the ultrasonic chemical coating method is used to form a strong bond between the magnetic substrate and the coating, which prevents the pores on the magnetic surface and plays a protective role. This technology has the world’s advanced level of originality, which improves the international competitiveness of products. At present, the technology has achieved good technical and economic effects in the application of industrialization.
New type of binder
The binder for bonding permanent magnets is one of the important components of magnets and also the continuous phase of magnets. It can improve particle fluidity, binding force, mechanical properties and corrosion resistance in the magnet. Therefore, it is extremely important to develop new binders. In recent years, my country has developed a new type of binder for magnet-specific resin BM-2C, which plays an extremely important role and conditions for producing better bonded NdFeB magnets. The binder is suitable for wet and dry mixing and bonding of permanent magnetic powder. It has been used in batch production in some permanent magnet factories. It has good technical and economic effects and improves the competitiveness of magnetic products.
Application of rare earth permanent magnet materials in the field of new energy
Wind power
Wind energy is a clean and sustainable energy. Compared with traditional energy, wind power does not rely on fossil energy, has no fuel price risk, stable power generation costs, and does not include environmental costs such as carbon emissions. In addition, the available wind energy is widely distributed globally. It is precisely because of these unique advantages that wind power has gradually become an important part of the sustainable development strategy of many countries and has developed rapidly. According to statistics from the Global Wind Energy Council, the global wind power industry is growing at an alarming rate, with an average annual growth rate of 28% in the past 10 years, and the total installed capacity worldwide has reached 93.85 million kilowatts (10,000 kW).
The Chinese government regards wind power as one of the main alternative energy technologies to improve the energy structure, cope with climate change and energy security issues, and has given strong support. Policies related to the localization of wind power equipment have been formulated, supplemented by measures such as “wind power concession bidding” to promote technological innovation, market cultivation and industrialization. In 2007, China’s wind power installed capacity increased by 3,304 million kilowatts, an increase of 147%, and the cumulative installed capacity reached 5,912 million kilowatts, an increase of 127%, both hit a record high, and achieved the National Development and Reform Commission’s 2010 planning goal three years ahead of schedule. From 1997 to 2007, the installed capacity of China’s wind power industry increased from 145,700 kilowatts to 59,12 million kilowatts, an increase of nearly 37 times. The average annual growth rate in the past three years was 70%, much higher than that of major developed countries in the world. Both are 30% average.
At present, among the three main technical types of wind turbines, “direct drive permanent magnet wind turbines” is an advanced technology developed in recent years. It has a series of advantages such as high efficiency, long life, high stability, and simple structure. It is the future The development direction of wind power technology. However, direct drive permanent magnet wind turbines require a large amount of neodymium iron boron permanent magnet materials. According to the development plan of the National Development and Reform Commission, China’s installed wind power capacity will reach 30-40 million kW in 2020.
As one of the 2008 “Green Olympics” projects, 33 giant windmills in the first phase of “Beijing Guanting Wind Farm” using Goldwind’s 1.5MW permanent magnet direct-drive wind turbines have been put into operation. Since the overall grid-connected power generation on March 10, it has maintained a high operating efficiency. As of June 30, a total of 34.87 million kWh has been generated. In June 2008, on the basis of the first phase of the Guanting Wind Farm, 10 1.5MW units were expanded in the second phase. In order to achieve better unit performance, the impeller diameter of the unit was increased from 77 meters to 82 meters. 9 units have been installed. According to wind power experts, in 2007, the world’s new installed capacity of wind power was about 20 million kW, of which the proportion of direct-drive permanent magnet wind turbines was still relatively small. No more than 2 million kW, accounting for about 10% of the world’s new installed wind power capacity. In 2008, China plans to add about 4 million kW of installed wind power capacity, of which the installed capacity of direct-drive permanent magnet wind turbines is about 1.5 million kW, accounting for about 40%, and it needs to use about 1,500 tons of sintered NdFeB. Among the newly added direct-drive permanent magnet wind turbines, Goldwind, a leading domestic wind power company, has an installed capacity plan of over 1 million kW, accounting for more than 60%.
Electric cars and bicycles
With the sharp rise in oil prices, the development enthusiasm of various auto companies for electric vehicles has also been increasing. In the global market. The production and sales of hybrid models are already on a large scale. Faced with this situation, automakers have been developing electric vehicles, but these models are too expensive or the technology is not yet mature enough to produce. Therefore, the most ideal solution at present is a hybrid model. It has been 11 years since the world’s first mass-produced hybrid model came out; in contrast, the technology is very mature.
Although the sales ratio of hybrid vehicles in the global automotive market is only about 1% so far, KPMG, a well-known information company in the United States, has released a survey report on auto company executives, showing that 83% of respondents It is believed that the most popular cars in the next 5 years will be hybrid models.
Domestic policies have also been introduced to encourage the production of environmentally friendly and energy-saving vehicles. New energy vehicles formally entered the catalog of encouraged industries of the National Development and Reform Commission, including electric vehicles such as hybrid vehicles. The state will provide support to these industries in terms of consumption, production, taxation policies, preferential policies, and approvals. For the current stage, hybrid models are ideal energy-saving and emission-reducing models. According to the latest domestic media reports, relevant state ministries and commissions will take the lead in introducing a policy of exempting purchase tax on hybrid vehicles in the second half of this year. Further promote the development of the hybrid electric vehicle market.
In order to realize the three concepts of “Green Olympics, Humanistic Olympics, and High-tech Olympics” for the 2008 Beijing Olympics, the Ministry of Science and Technology and Beijing Municipal Government jointly launched the “Olympic Technology (2008) Action Plan” after Beijing’s successful bid for the Olympics in 2001. Among them, the large-scale application of energy-saving and new energy vehicles independently developed and produced by China to provide green transportation services for Beijing Olympic transportation is an important part of the plan. During the Beijing Olympics and Paralympics, 500 new energy vehicles will be put into use. Including 25 hybrid electric buses developed and produced by Dongfeng Motor Company and FAW Group to operate on the Olympic bus line; 75 hybrid electric cars developed and produced by Chery, Changan, FAW Group and other companies are incorporated into the taxi fleet for operation; There will also be more than 320 pure electric field vehicles between the venues.
The generators of hybrid vehicles use permanent magnet synchronous motors, and each motor needs to use 2-3 kilograms of sintered NdFeB magnets. In 2007, the world output of hybrid vehicles was less than 1 million. The ratio of less than 1 million hybrid electric vehicles to the traditional automobile industry’s annual output of more than 70 million is insignificant. The future development space for hybrid electric vehicles and other electric vehicles is undoubtedly huge, so the demand for neodymium iron boron magnets in the future It is undoubtedly huge.
Bicycles are one of China’s traditional pillar industries. With the improvement of people’s living standards and the enhancement of environmental protection awareness, the demand for electric bicycles has increased in recent years. According to incomplete statistics from the China Moped Professional Committee. China’s electric bicycles have been developed and put on the market in small batches in 1997, and their production and sales have been increasing year by year. The output in 1998 was 54 thousand and 500, and the output in 2006 has exceeded 10 million. On average, each electric bicycle needs O. Calculated with 3 kg of sintered NdFeB magnets, 3,000 tons of magnets are needed per year (about 6,000 tons of blanks).
Industrial energy-saving motors
Industrial motor is a kind of high energy-consuming power equipment with large application volume and wide range of use. According to statistics, China’s industrial motor power consumption accounts for about 60%-70% of the total industrial power consumption. In practical applications, the overall operating conditions of Chinese motors are far behind foreign countries. The unit efficiency is about 75%, which is about 10% lower than foreign countries; the system operating efficiency is 30%-40%, which is 20% lower than the international advanced level- 30%. As a large-volume and wide-ranging energy-consuming device, the motor can bring huge energy savings even if the motor efficiency is increased by a small margin. Therefore, China’s motor applications have great potential for energy saving, and it is imperative to promote motor energy saving.
Over the past 20 years of reform and opening up, China has achieved “quadruple GDP and only double energy consumption” in energy utilization. However, compared with developed countries, China’s power energy utilization efficiency is still low, especially the high power consumption of industrial power equipment and serious waste. A large number of industrial equipment mostly use AC motor constant speed transmission scheme, which leads to low efficiency of AC motor. Fans, pumps and other equipment also use the method of adjusting dampers and valves to adjust the flow. Although this adjustment method is simple and easy to implement, it is at the cost of large energy consumption; in industrial sewing machines and mechanical processing equipment, clutches, The friction plate adjusts the speed, causing a lot of standby loss and braking energy consumption.
China is actively preparing for the implementation of electric motor energy efficiency standards, and regulates the electric motor market with a mandatory energy efficiency standard management system and voluntary product certification. Rare earth permanent magnets have excellent magnetic properties such as high remanence, high coercivity, and high energy product. They are used to make various motor products. They have the characteristics of high performance, light weight, high efficiency and energy saving, and have the potential to be applied in the field of energy saving motors. huge. In recent years, China has promoted rare-earth permanent magnet energy-saving motors in some fields, such as the motors used in “kowtow machines” in oil fields, and large motors in steel companies. With the improvement of performance, the improvement of drive and control systems, and the reduction of costs, rare earth permanent magnet energy-saving motors will increasingly replace traditional industrial motors, and their application prospects are very promising.
Micro Motor
In developed countries such as the United States, Japan and Western Europe, the application of rare earth permanent magnet materials in motors has accounted for more than 60% of the total sales of rare earth permanent magnets. Moreover, the national conditions of each country are different, and the application of rare earth permanent magnets in motors is not the same. Japan accounts for about 50% of rare earth permanent magnets in motors, while the United States uses the largest amount of motors in aviation, aerospace, military, automobiles, and machine tools, and Europe uses most CNC machine tools.
There are many types of micromotors, including motors for information processing equipment, motors for audio-visual equipment, motors for household appliances, motors for vehicles, motors for robots, motors for game machines, motors for beauty appliances, motors for health appliances, and kitchen appliances In addition to the above-mentioned application fields, micro-motors are also widely used in children’s toys, old-age toys, industrial automation, agricultural modernization, and military equipment modernization. The demand is also quite large. It can be predicted that the micro-motor market will show a continuous and stable development trend in the future, the application fields of micro-motors will become wider and wider, and the demand for micro-motors will increase.
In 2006, China produced more than 37 million rare earth permanent magnet motors, including 50,000 large and medium-sized energy-saving motors.
Energy-saving and environmentally friendly home appliances
In today’s increasingly tense energy, energy conservation and emission reduction have become an issue of great concern to the world. The State Council has made energy conservation and emission reduction the focus of macro-control in recent years and listed it as the performance evaluation in the national environmental protection “Eleventh Five-Year Plan”. Important content, the energy consumption of home appliances has therefore been referred to an important position in the development of the industry.
At present, in the field of home appliances, new energy efficiency standards for air conditioners, refrigerators, and freezers with higher energy efficiency requirements have been introduced or are being revised, and new energy-saving and environmentally-friendly home appliances are also getting more and more attention. More and more home appliances have entered the catalog of energy efficiency management products, and energy conservation has become the eternal pursuit of home appliances.
For example, the air conditioner is one of the main equipment for household electricity consumption. The traditional “fixed frequency air conditioner” is gradually being adopted by a new generation of “inverter air conditioners” with a series of advantages such as energy saving, stable temperature adjustment and low operating noise due to its low operating efficiency. “Replaced. The frequency converter controls the speed of the compressor and fan motor by the way of outputting the power frequency in this century to achieve the purpose of adjusting the cooling capacity. Therefore, the inverter air conditioner does not control the room temperature by frequently turning on and off, but operating at a constant temperature and low frequency for a long time to keep the room temperature constant. In 2007, the number of air conditioners produced and sold worldwide was nearly 90 million, of which about 15% used permanent magnet inverter compressors. Japan accounted for 90% of inverter motors, Europe and the United States accounted for 25%, and China less than 10%. With the increasing popularity of inverter air conditioners , The use of related permanent magnet DC motors and rubidium iron boron magnets will increase and the market capacity is huge. If it is estimated that the proportion of inverter air conditioners in the total air conditioners will increase to 30%-50% in the next 3-5 years, about 3000-5000 tons of rubidium-iron-boron magnets of this type will be used each year, and the sales will exceed 1 to 1.5 billion yuan.
After the introduction of inverter air conditioners, “inverter washing machines” appeared on the market, which have the advantages of water and electricity saving, healthy washing, and quietness. In addition, the “inverter refrigerator” has also been listed.
Magnetic Levitation System
Another important application field of rare earth permanent magnets is magnetic levitation systems. Magnetic suspension bearings have been successfully applied to ultra-high-speed rotating devices and watt-hour meter bearings. A huge potential application field is the magnetic suspension train transportation system.
The new technology of suspended high-speed train has the characteristics of fast train speed, large number of people, large investment, low cost, good efficiency, no noise, and easy operation, and realizes the unification of high speed, large capacity and intelligence. Such projects are only carried out in a few developed countries with strong economic power and high technological level. Therefore, it has the development potential as a new technology transportation, and it has become a symbol of the advanced and modern transportation of a country. The amount of sintered rubidium iron boron material in this aspect is also considerable. If the maglev train is put into commercial operation, it will greatly promote the higher-speed development of the rare earth permanent magnet industry.
The growth rate of China’s demand for rare earth permanent magnets continues to be around 20%. During the “Tenth Five-Year Plan” period, China’s total output of sintered rubidium-iron-boron magnets reached about 50,000 tons, with a total sales of 15 billion yuan. By 2010, China’s output of sintered rubidium-iron-boron magnets will reach 70,000 tons, accounting for 75% of the world, with sales of 26 billion yuan. In the next 10 years, China will become the world’s manufacturing center for rare earth permanent magnet materials.
Electroacoustic components
Speakers and earphones are traditional applications of permanent magnets. After the emergence of rare earth permanent magnet materials, under the same output power and sound quality, rubidium iron boron permanent magnets are used to reduce the size and improve performance. At present, rare earth permanent magnet speakers and headphones have been applied to advanced walkman and other fields. As the technological innovation of electro-acoustic equipment develops towards high fidelity and miniaturization, higher performance magnets are required. In this field, rubidium iron boron permanent magnet materials have begun to be widely used.
Modern medical equipment
Permanent magnet type MRI—CT MRI equipment used ferrite permanent magnets in the past, and the weight of the magnet is up to 50 tons. Now it uses the latest neodymium iron boron permanent magnet material, its magnetic field strength has doubled, and the image clarity has been greatly improved. , And save a lot of raw materials. Each MRI machine needs 0.5’3 tons of neodymium iron boron permanent magnets, which is calculated according to the world market’s annual demand of 1,000 units. The annual demand for magnets is 500’3000 tons. At present, General Electric of the United States and Siemens of Germany have nuclear magnetic resonance imaging equipment production bases in China.
Conclusion
Continue to strengthen the development of high-grade rare earth permanent magnet materials and open up new application fields. It is the rare earth permanent magnet materials that play an increasingly important role in energy conservation and environmental protection. Continue to strengthen the improvement of rare earth permanent magnetic materials technology, reduce costs, and maintain sustainable development. While strengthening their own integration and continuously improving their management and technical levels, Chinese rare earth permanent magnet enterprises have strengthened their cooperation with foreign advanced permanent magnet enterprises to achieve better development during the transfer of the international rare earth industry to China.
Source: China Rare Earth Permanent Magnet Manufacturer – www.rizinia.com
