Rare earth new materials and their applications in high-tech fields

The unique physicochemical properties of rare earth elements determine their extremely versatile use. Rare earth elements have a unique 4f electronic structure, large atomic magnetic distance, strong spin-orbital coupling characteristics, etc. When forming rare earth complexes with other elements, the coordination number can vary between 3 and 12, and rare earth compounds The crystal structure is also diverse. In the field of new materials, the rich optical, electrical and magnetic properties of rare earth elements have been widely used. In the high-tech field, rare earth new materials play an important role. Rare earth new materials mainly include rare earth permanent magnet materials, rare earth luminescent materials, rare earth hydrogen storage materials, rare earth catalyst materials, rare earth ceramic materials and other rare earth new materials such as rare earth giant magnetostrictive materials, giant magnetoresistance materials, magnetic refrigeration materials, and light. Refrigeration materials, magneto-optical storage materials, and the like.

First, rare earth permanent magnet materials

Rare earth permanent magnet materials because of different alloy composition, the current can be divided into three categories:

1. Rare earth-drilling permanent magnet materials: SmCo ₅ and Sm ₂ Co _l7 ;

2. Rare earth- iron permanent magnet material: Nd2Fel4B;

3. Rare-earth iron-nitrogen (RE-Fe-N) or rare earth iron (RE-Fe-C) permanent magnet materials.

According to the time sequence of development and application, it can be divided into the first generation (1:5 type SmCo ₅ ), the second generation ( ₂ :7 type Sm ₂ Co ₁₇ ), and the third generation (NdFeB). Currently, it is actively developing to find the fourth generation. Rare earth permanent magnets. Shortly after the first generation of SmCo ₅ rare earth permanent magnets appeared, in order to improve the magnetic energy product of the permanent magnet alloy, a second generation Sm ₂ Co ₁₇ rare earth permanent magnet was developed. Sm ₂ Co ₁₇ has high magnetic properties and stability and is widely used. In the 1980s, Nd ₂ Fe ₁₄ B type rare earth permanent magnets were introduced. Due to their excellent performance and low price, Sm ₂ Co ₁₇ rare earth permanent magnets were quickly replaced in many fields, and industrial production was quickly realized. Its performance is still improving, and Japan has developed a Nd ₂ Fe ₁₄ B type rare earth permanent magnet with a magnetic energy product of 55.8 MGOe. NdFeB permanent magnets have been widely used in energy, transportation, machinery, medical, computer, home appliances and other fields. China's NdFeB production accounted for 38% of the world's total production in 1998, with a total of 3,850 tons. However, China's NdFeB industry has not yet formed a large-scale operation, most of which are medium and low-end products. The magnetic energy product is generally less than 45MGOe, and most of them are below 40MGOe. Therefore, it is mostly used in low-end fields such as audio equipment, magnetizers and magnetic separators; and Japan NdFeB Production is concentrated in only a few large factories, and its products are mostly 40MGOe or above, and are mostly used in high-tech fields such as computer VCM, new motors, and MRI. Only by realizing scale, industrial grouping, and high-quality product quality, China's NdFeB industry can stand in an invincible position in international competition and drive the development of the rare earth industry.

Second, rare earth luminescence and laser materials

The luminescence and laser properties of rare earths are all due to the transition of the rare earth 4f electrons between different energy levels. Due to its rich energy level and 4f electronic transition characteristics, rare earth ions make rare earths a treasure trove of light, providing high-performance luminescent materials for high-tech fields, especially information and communication.

The rare earth luminescent material has the advantages of strong absorption capacity, high conversion rate, emission of ultraviolet to infrared spectrum, strong emission capability in the visible light region, and stable physical and chemical properties. Rare earth luminescent materials can be divided into rare earth cathode ray luminescent materials, rare earth photo luminescent materials, X-ray rare earth luminescent materials, rare earth scintillators, rare earth upconversion luminescent materials and other rare earth functional luminescent materials due to their different excitation modes. At present, rare earth luminescent materials are mainly used in color TV tubes, computer monitors, lighting, medical equipment and the like. The largest amount of rare earth luminescent materials is color TV tubes, computer monitors, rare earth trichromatic energy-saving lamps, PDP plasma display.

The rare earth luminescent materials used in color TV tubes and computer monitors are cathode ray luminescent materials. Pink CPT present in commonly used are sulfur europium-activated yttrium oxide Y ₂ O ₂ S:Eu phosphors, size 6 ~ 8μm, computer display requires a light emitting material provides high brightness, high contrast and sharpness, which is also used Pink Y ₂ O ₂ S: Eu, but the content of Eu is higher, the green powder is Tb ³⁺ activated rare earth sulfur oxide Y ₂ O ₂ S: Tb, Dy and Gd ₂ O ₂ S: Tb, Dy high-efficiency green phosphor The particle size is 4-6 um. It is reported that blue powder will also replace zinc and antimony sulfide powder by rare earth luminescent materials. Pink large-screen projection TV is also Y ₂ O ₂ S: Eu, Tb-activated green powder as a light emitting material such as rare earth aluminum garnet Ji YAG: Tb (P ₅₃₎ and yttrium aluminum gallium garnet YAGG: Tb, large-screen projection TV requires high current density excitation, high external screen temperature, requires high energy conversion efficiency of luminescent materials, good temperature quenching characteristics, linear relationship between brightness and current, good current saturation characteristics, and stable performance. Phosphors for projection TVs can consume several tons of rare earth oxides per year. The rare earth luminescent materials in the PDP plasma display are electroluminescent materials, red is ZnSiNdF ₃ , Zn—SiSmF ₃ and ZnSiEuF ₃ thin films, green is ZnSiTbF ₃ , Zn-SiErF ₃ and ZnSiHoF ₃ thin films, due to the blue luminescent material Zn— The SiTmF _{3 has a} very low brightness, so a rare earth-free ZnSiAg is used. PDP is a flat panel display technology. As the market demand for PDP TV increases, the consumption of rare earths will further expand.

Another important application of rare earth luminescent materials is rare earth trichromatic energy-saving lamps. The rare earth trichromatic phosphors used are photoluminescent materials, and the main component is red powder Y ₂ O ₃ :Eu ³⁺ , accounting for 60%-70. % (mass fraction), green powder is Ce0.67Mg0.33Al11019: Tb ³⁺ (~30%) (mass fraction), and blue powder is BaMgAl ₁₆ O ₂₇ :Eu ²⁺ (small amount). Rare earth energy-saving lamps have high luminous efficiency and save electricity, and their development and application have been valued by countries all over the world. Compared with foreign countries, there are still some problems in the quality of China's lamp powder. The light decay is relatively large and the brightness is low. It needs to be improved in the control method of lamp powder particle size and raw material purity.

In addition, there is a rare earth upconversion luminescent material. The energy of the photoconductor emitted by the upconverting luminescent material is greater than the energy of absorbing photons. It is widely used for infrared detection. Some upconversion rare earth luminescent materials such as BaYF5:Yb, Er can convert infrared rays into visible light. This material is used in night vision goggles, and some materials such as Ho3 ⁺ doped SrF ₂ crystal can achieve up-conversion of laser output. Under red laser excitation, Ho ³⁺ can realize blue color in SrF ₂ crystal. Upconverting illumination.

Rare earth laser materials were born at the same time as lasers. Rare earths are very important elements in laser working materials, and 90% of laser materials are related to rare earths. Rare earth laser materials can be divided into three categories: solid, liquid and gas. Rare earth solid laser materials are the most widely used. Rare earth solid laser materials can be further divided into crystal, glass, optical fiber and stoichiometric laser materials. Rare earth laser materials are widely used in communications, medical, information storage, cutting and soldering.

The rare earth crystal laser material is mainly an oxygen-containing compound and a fluorine-containing compound. Among them, the rare earth garnet system is the most active research, development and application system. For example, Y ₃ Al ₅ O ₁₂ Nd (YAG: Nd) has been widely used due to its excellent performance, and more efficient doping of Nd and Cr. gadolinium scandium marry garnet GSGG: Nd, Cr and the like and GSGG _{(Gd, Ca) 3 (Ga} , Mg, Zr) 5 O 12: Nd, Cr. Neodymium-doped yttrium vanadate (YVO _4: Nd) and YLiF _4, a continuous wave solid-state diode-pumped green laser is suitable for extensive application of laser technology, medical, scientific research and other fields. Rare earth glass laser materials use trivalent ions such as Nd ^{3 +} , Er ^{3 +} and Tm ^{3 +} as rare earth activators, which are less than crystals, easy to prepare, flexible than crystals, and can be made into different shapes and sizes as needed. The disadvantage is that the thermal conductivity is lower than that of the crystal and therefore cannot be used for continuous laser operation and high repetition rate operation. The rare earth glass laser has large output pulse energy and high output power, and can be used for thermonuclear fusion research, and can also be used for punching and welding.

Rare earth fiber laser materials play an important role in the development of modern optical fiber communication. The construction and development of modern information highways puts forward higher requirements on transmission capacity, quality and speed of transmitted signals. The optical signal direct amplification technique was developed to compensate for light attenuation during long-distance transmission. The development and application of erbium-doped fiber amplifiers (EDFAs) and other high-tech developments have made great progress in modern fiber-optic communications. In the EDFA, Er ^{3 +} is excited by light with a wavelength of 980 nm and 1480 nm, and its energy level transitions from the ground state to a high energy state. When the high energy state Er ³⁺ re-transition returns to the ground state, it emits 1550 nm light, which is up-conversion luminescence. Played a role in light amplification. In addition to the EDFA there praseodymium-doped fluoride fiber amplifiers, they have the same principle, which is an excitation wavelength of 1017nm. Rare earths are used in small amounts in optical fibers, and the total world consumption is only kilograms, but the role played is decisive.

Third, rare earth hydrogen storage materials

Hydrogen storage materials are new functional materials developed in the 1970s, and its development has made it possible to use hydrogen as an energy source. Today, with the shortage of energy and environmental pollution, the development and application of hydrogen storage materials has naturally become a research hotspot. Hydrogen storage alloys are alloys of two specific metals, one of which can absorb a large amount of hydrogen to form a stable hydride, while the other metal has a small affinity with hydrogen, and hydrogen easily moves therein. The intermetallic compound MMNi ₅ (MM is a mixed rare earth metal) of rare earth and transition group elements and LaNi ₅ are excellent hydrogen absorbing materials. It can be used for purification, separation and recovery of hydrogen because it can selectively absorb hydrogen and can be released under normal pressure. Another important application of rare earth hydrogen storage materials is that it can be used as a cathode material for Ni/MH batteries. Compared with traditional nickel- cadmium batteries, nickel-metal hydride batteries are twice as energy-efficient and non-polluting, so they are called green energy. Ni/MH batteries are widely used, such as notebook computers, computers, video cameras, radio cassette recorders, digital cameras, communication equipment, etc., and one potentially important use is electric vehicles. Japan's production of nickel-hydrogen batteries in 1996, 1997 and 1998 was 350 million, 580 million, and 640 million, respectively. The growth is rapid, showing that its market prospects are positive. The performance of nickel-metal hydride batteries produced in China is still far from that of foreign countries. This is due to the backwardness of process equipment and poor material properties. The consistency and stability of batteries are four.

Rare earth catalyst materials have been widely used in petroleum cracking, synthetic rubber, petrochemical and automobile exhaust gas purification. At present, due to China's emphasis on environmental protection, the strengthening of air pollution control measures has stimulated the market demand for automobile exhaust gas purifiers, and the development and application of automobile exhaust catalyst materials have received further attention. High activity catalyst such as platinum and rhodium noble metal, a good purification effect, but expensive, and rare earth autocatalyst its low price and good thermal and chemical stability, high activity, long life, anti-Pb, S poisoning, Extremely valued. The main pollutants in automobile exhaust are CO, HC, and NOx. The survey shows that the main source of urban pollution is automobile exhaust, and effective control of vehicle exhaust pollutant content is the main way to improve air quality. The principle of catalytic purification is to use the catalyst to oxidize the HC and CO emitted from the exhaust gas, and to reduce the NOx to achieve the purpose of purification. The main function of the automobile exhaust gas purifier is to increase the speed of the following catalytic reactions.

CO+l/2O ₂ →CO ₂

*CH ₄ +2O ₂ →CO ₂ +2H ₂ O

*NOx+xCO→1/2N ₂ +xCO ₂

(*represents multicomponent hydrocarbons and nitrogen oxides, respectively)

The compound of La and Ce is used in the rare earth catalyst. Ce has an oxygen storage function and can stabilize the dispersibility of platinum and rhodium on the surface of the catalyst, and La can replace the rhodium in the platinum-based catalyst, thereby reducing the cost. Under certain conditions, the noble metal catalyst and the rare earth catalyst can simultaneously carry out the above three reactions, thereby achieving the purpose of simultaneously purifying CO, HC and NOx. In addition, the addition of rare earth elements such as La, Ce, Y to the catalyst carrier can also improve the high energy and high temperature oxidation resistance of the carrier. The consumption of automotive catalysts in the United States is considerable. In 1995, consumption of rare earths accounted for 44% of the total rare earth consumption in that year, reaching 11,000 tons. In 1997, rare earths in various catalysts accounted for 65% of total consumption (automobile exhaust and petroleum cracking). , reaching 12045 tons. China's demand for rare earth automobile exhaust gas purification catalysts has not yet formed a scale, but with the country's emphasis on environmental pollution control and the formulation of relevant policies, rare earth automobile exhaust gas catalytic materials will be widely used and become another important field of rare earth application in China. , thus driving the development of the rare earth industry.

Fourth, rare earth functional ceramics and high temperature structural ceramics

Rare earth elements in rare earth ceramic materials appear in the form of doping. A small amount of rare earth doping can greatly change the sintering properties, microstructure, density, phase composition and physical and mechanical properties of ceramic materials.

Rare earth functional ceramics include insulating materials (electricity, heat), capacitor dielectric materials, ferroelectric and piezoelectric materials, semiconductor materials, superconducting materials, electro-optic ceramic materials, thermoelectric ceramic materials, chemical adsorption materials, and solid electrolyte materials. Doping rare earth oxides such as Y ₂ O ₃ , La ₂ O ₃ , Sm ₂ O ₃ , CeO ₂ , Nd ₂ O _{3 ,} etc. in conventional piezoelectric ceramic materials such as PbTiO ₃ and PbZrxTi1-xO ₃ (PZT) Greatly improve the dielectric and piezoelectric properties of these materials, making them more suitable for practical needs. Now PZT piezoelectric ceramics have been widely used in electroacoustic, hydroacoustic, ultrasonic devices, signal processing, infrared technology, ignition detonation, micro Motor and other aspects. Sensors made of piezoelectric ceramics have been successfully used in automotive airbag protection systems. A BaTiO ₃ capacitor dielectric material doped with La or Nd stabilizes the dielectric constant, is unaffected over a wide temperature range, and increases the service life. A large number of multilayer ceramic capacitors are used in mobile phones and computers, and rare earth elements such as La, Ce, and Nd play an important role therein. The research on rare earth semiconductor ceramics is active. This material mainly contains BaTiO ₃ -based rare earth and SrTiO ₃ -based doped rare earth. Its room temperature resistivity is 10-2 - 103 Ω · cm, when the temperature rises to the Curie temperature Tc When it is nearby, the resistivity rises sharply. This phenomenon is called PTC effect. Rare earth doping plays a key role in this effect. PTC thermal semiconductor materials can be used as overheat protection elements, temperature compensators, and temperature. Sensors, delay elements, degaussing elements, etc.

Rare earth high temperature superconducting materials are also a hot research topic in the world. Due to the discovery of the rare earth oxide La-Ba-Cu-O superconductor and its subsequent research, the Curie temperature Tc of the superconducting material has been greatly improved. China is in the leading position in the research of high temperature superconductivity. The preparation technology, application technology and application basic research of Y-Ba-Cu-O system have made different progress. The Tc of RE-Ba-Cu-O superconductor is 80~. 90K, in addition, China has also synthesized alkali-based rare earth doped superconductors such as (Sr, Nd) CuO ₂ and Sr1-xYxCuO ₂ . It has been found that YBCO ceramic samples made by replacing rare earth ions such as Ho with Y have different critical current densities Jc (Y1-xHoxBa ₂ Cu ₂ O7-(HBCO)). Superconducting materials are widely used as superconducting magnets for maglev trains, and can be used in generators, engines, power transmission, microwaves, etc. In addition, recently, Japan has developed an oxide thermoelectric material for semiconductor diodes, a P-type semiconductor is Na:Co oxide, and an n-type is Nd-Cu oxide (doped with Zr). It can convert thermal energy into electric energy. When the temperature difference between p-n is 200 °C, it can generate 280mV. The potential use of this equipment is to generate electricity by the heat generated in industrial production and waste incineration. The applicable temperature is 400-800. °C. There is also a moisture sensitive material such as a La ³⁺ doped BaTiO ₃ material which is used as a humidity sensor by determining the ambient humidity by measuring its electrical conductivity. More important is the rare earth doped ZrO ₂ solid electrolyte material, in which the rare earth acts as a stabilizer, and the Y ₂ O ₃ stabilized ZrO ₂ material has the advantages of compact structure, low electrical resistance and good thermal shock resistance. Can be used for oxygen sensors and high temperature fuel cells. Recently, Japan has developed a new La-Ga oxide solid electrolyte material with an operating temperature of 600 ° C and a power of 0.4 W/m 2 , which is sufficient for practical applications, while Y ₂ O ₃ stabilized ZrO ₂ at 1000 ° C. Only 0.2 W/m 2 of power can be generated, since the La-Ga oxide solid electrolyte contains La, and the electrolyte can allow more oxygen ions to flow.

Rare earth high-temperature structural ceramics mainly refer to rare earth-doped Si ₃ N ₄ , SiC, ZrO ₂ and other high temperature resistant, high strength, high toughness ceramics, and are engineering ceramics. The rare earth (La, Y) doped Si ₃ N ₄ ceramics and composite materials thereof can be used in high-tech fields such as high-temperature gas turbines, ceramic engines, high-temperature bearings, etc., and the working temperature is up to 1650 ° C, and the rare earth plays a flux therein. Improve the role of grain boundaries. Recently, Japan has developed a new silicon nitride ceramic with a strength of 484 MPa at 1500 °C. Silicon nitride ceramic bearings can be used in some special environments such as electromagnetic fields. The temperature range is from -40 ° C to +200 ° C and can be used in unlubricated environments. Rare earth doped ZrO ₂ toughened ceramics can be used as wear resistant materials such as internal combustion engine parts, inserts, mold inserts, computer drive components, seals and ceramic bearings. In this material, Y ₂ O ₃ or CeO ₂ acts as a stabilizer to prevent ceramic cracking of ZrO ₂ due to crystal transformation and volume expansion during cooling. It can also be used as a fine grinding media because of the oxidized toughened zirconia + sub-wear.

5. Other rare earth new materials

The rare earth new material family has many members and it is difficult to elaborate. In addition to the above-mentioned several types of rare earth new materials, there are some rare earth new materials for different uses, such as rare earth giant magnetostrictive materials, magnetic refrigeration materials, rare earth magneto-optical storage materials, giant magnetoresistance materials, and photo-cooling. Materials, rare earth heating materials, etc.

A magnetostrictive material is a material that undergoes mechanical deformation of the same frequency under the action of a bias magnetic field and an alternating magnetic field. The rare earth giant magnetostrictive material is a kind of magnetostrictive material which is 100 to 1000 times larger than the magnetostrictive value of the conventional magnetostrictive materials such as Fe, Co, Ni, etc., such as Pr ₂ Co ₁₇ , SmFe ₂ , Tb (CoFe). ₂ , Tb _0.27 Dy _0.73 : Fe ₂ and the like. It is characterized by accurate length changes with changes in the magnetic field. Research on rare earth giant magnetostrictive materials is concentrated in Terfenol-D, ie Tb _x Dy _{l -x} Fe ₂ . This material is extremely versatile, such as sonar systems, aircraft fuel systems, hydraulic systems, seismic detection systems, active vibration control systems, etc. The most typical application is the transducer of a sonar sensor in underwater communication.

Magnetic refrigerating materials are substances having a magnetocaloric effect for a refrigeration system. When a magnetic field is applied to the magnetic refrigerating material, the magnetic moment is arranged in the direction of the magnetic field, the magnetic entropy becomes small, and after the magnetic field is removed, the direction of the magnetic moment becomes disordered, the magnetic entropy becomes large, and the magnetic refrigerating material absorbs heat from the environment, and the ambient temperature Reduce and achieve the purpose of cooling. This material is Gd ₃ Ga ₅ O ₁₂ (GGG) garnet, (GGG can also be used as a magnetic bubble memory crystal material) Dy: Al ₅ O ₁₂ (DAG) garnet or the like. Other materials are Dy ₂ Ti ₂ O ₇ , Gd ₃ Al ₅ O ₁₂ , Gd(OH) ₃ , Gd ₂ (PO ₃ ) ₃ and DyPO ₄ and the like. At present, a new type of magnetic refrigeration material Gd ₅ Si ₄ Ge ₂ has been developed, which has the advantage that the magnetocaloric effect is large, and the use temperature can be adjusted from about 30K to 290K. The United States has successfully developed the first room temperature magnetic refrigeration prototype. Replacing traditional refrigerants with magnetic refrigerants not only reduces environmental pollution, but also saves energy, and the refrigerating materials can be reused. In addition, in superconductivity research, liquid helium is required to cool the superconductor, which is expensive, and the magnetic refrigerator can be used for liquefaction and evaporation of liquid helium to reduce the loss of helium. Perhaps one day, magnetic refrigerators will also be used in refrigerators and air conditioners.

The rare earth magneto-optical memory material is an amorphous thin film RE-TM of rare earth and transition metal (RE=Gd, Dy, TM=Fe, Co); the RE-TM amorphous thin film perpendicular magnetization film has large anisotropy and is stored. High density; due to amorphous state, uniform reflection, high signal-to-noise ratio, good signal quality; room temperature coercive force (10kOe), signal is not easy to damage, high reliability; Curie temperature can be adjusted to about 100 °C, writing temperature low. This material is used as a magneto-optical disk MO, which can read and write information at random, with a large capacity (up to 2.6GB) and fast reading and writing speed. Magneto-optical storage materials play an important role in the information age.

The research of giant magnetoresistance materials has aroused great interest in recent years. Magnetoresistance is the change in resistivity of a material after it is applied to a magnetic field. Giant magnetoresistive materials have a resistivity change greater than 10% compared to conventional magnetoresistive materials. This material has an ABO ₃ type perovskite structure doped with rare earth manganese oxide and has a composition of RE1-xAxMnO ₃ (A is an alkali metal ion) such as La _0.67 Ca _0.33 MnO ₃ . Studies have shown that the appropriate amount of Sc element doping these materials can further enhance the magnetoresistance effect. The giant magnetoresistive material can be used as a magnetic field sensor, a head position sensor in a disk drive, or the like.

It has also been reported that rare earth doped photo-refrigerated materials have been reported. Yb ³⁺ doped zirconium fluoride glass has been proven to have photo-cooling function. Los Alamas National Laboratory uses lasers to cool this material from 298K in vacuum to 282K, the lowest can reach 16K. The cooling mechanism is that the Yb ³⁺ ion has two excited energy levels, and a three-level photo-cooling mode is generated. In the process of being excited by the excitation level, the energy of the Yb atom radiating outward in the form of photons is greater than Yb. The energy absorbed by the atom, the thermal energy of the system is reduced, and the temperature is lowered. The development direction is to manufacture a solid-solid photocooler or an all-solid cryogenic cooler for cooling electronic components, cooling high Tc oxide superconductors, infrared detectors, and the like.

Conclusion

New rare earth new materials are widely used, and with the further development of research and development, new rare earth new materials will continue to emerge. The rare earth family is indeed a set of magical elements. They play an important role in many new materials and are closely related to the development of modern high technology. New rare earth materials play an irreplaceable role in many fields such as energy, environment and information. However, in general, China's development and application of rare earth new materials is still quite different from that of developed countries such as Japan and the United States. The research and development of many materials are in the state of tracking and imitating. In terms of application, in terms of transforming scientific research results into productivity, our speed cannot keep up with Japan. For example, the development and application of Sm-Fe-N gap-type rare earth permanent magnets discovered by Professor Yang Yingchang of Peking University in China, the Japanese have come to the forefront, Japan TDK Corporation It has been announced that the SmFeN bonded magnets will be mass-produced before the end of 1999. Although China has patents, it cannot produce products. Rare earth elements are the elements of strategic position in the second and first century. The research and development and application of rare earth new materials is one of the most intense and lively areas of international competition. From a certain perspective, the research and development level of rare earth new materials marks a country's high-tech development level and is also a symbol of comprehensive national strength. Compared with developed countries such as the United States, Japan, and France, although China has a certain gap in the research, development, and application of rare earth new materials, under the care of the party and the government, the development of China's rare earth industry is very fast in recent years. The research and development of rare earths has also made great progress, the application level is gradually improving, and basic research is being strengthened. China is the country with the most abundant rare earth resources. Our goal is to transform resource advantages into economic advantages. To achieve this goal, the fundamental way out is to improve the high-tech application level of China's rare earth industry, improve the quality of rare earth products, and further develop the application technology of rare earth new materials in high-tech fields. The rare earth industry is a promising industry. With the industrialization of rare earth high-tech, China's rare earth industry will have a better tomorrow.

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