新闻资讯

News Center

current position: Home > News Center > Industry Information

Application of rare earth in glass ceramic industry

2016-07-25 15:54:09
times

The application of rare earth in China's glass and ceramic industry has increased at an average rate of 25% since 1988, reaching about 1600 tons in 1998. Rare earth glass ceramics are not only the traditional basic materials for Industry and life, but also the main members in the high-tech field. From the perspective of global rare earth consumption, glass-ceramic accounted for 25.6%, while China only accounted for 10% in 1999. Therefore, there is a great space for the application and development of rare earth in glass and ceramics in China.



一、 Rare earth glass and polishing materials

The manufacturing of glass has a history of more than 5000 years, and the production of optical glass has a history of nearly 200 years. However, the application of rare earth elements in glass manufacturing is only a matter of nearly 100 years. At the end of the 19th century, cerium oxide was used as a decolorizing agent for glass. In the 1920s, rare earth borate glass was studied. In the 1930s, lanthanum containing optical glass with high refractive index and low dispersion was manufactured.

Glass ceramic industry is an important traditional field of rare earth application, accounting for about 33% of the total consumption of rare earth in foreign countries. Rare earth is used as clarifier, additive, decolorizer, colorant and polishing powder in glass industry, playing an irreplaceable role in other elements. Taking advantage of the high refraction and low dispersion characteristics of some rare earth elements, optical glasses can be produced, which can be used to manufacture lenses of advanced optical instruments such as advanced cameras, video cameras, telescopes {todayhot}; The anti radiation glass can be produced by using the anti radiation properties of some rare earth elements. A variety of ceramic pigments produced by rare earth elements are favored by users because of their low price, pure color, gorgeous and high temperature resistance.


1. Laser glass

Neodymium glass is a kind of laser glass with high output pulse energy and high output power. Its large laser is used for thermonuclear fusion and so on. The double doped Nd 3 + Yb3 + laser glass sensitizes Yb3 + by Nd 3 +, which makes Yb3 + gain 1.06 μ m at room temperature μ M laser, with simple energy level, high energy storage efficiency, long fluorescence life (three times that of neodymium glass), low second-order nonlinear coefficient, a strong absorption peak near 970nm, which can be directly pumped by lngaas semiconductor laser, good thermal stability, certain stimulated emission cross-section, wide absorption band and high doping concentration. It is used in optical communication and high-energy laser weapons (it can destroy large targets such as missiles, satellites and aircraft). Erbium doped phosphate laser glass can achieve 1.5 μ M U.M low threshold laser with strong transmission ability in the atmosphere. The continuous laser operation of holmium doped fluorozirconate glass at 543nm wavelength; Adding a certain amount of ytterbium into the glass can transfer the energy absorbed by Yb3 + to Ho3 +, which is very promising in the miniaturization and improvement of lasers.


2. Smart glass

Photochromic glass is a kind of glass that can change color under the excitation of light. It can adjust the light transmission performance by itself. It can be used as glasses, high-grade automobile windshield, window glass, holographic materials, writing, image storage, optical memory display, erasable light modulation elements, etc. Photosensitive glass ceramics can form a variety of complex patterns by means of photosensitive chemical etching. It is widely used in printing, circuit boards, jet components, charge storage tubes, opto electric booster fluorescent screens and so on. Optical fibers doped with rare earth elements such as nd, er, Dy, TB, Ho, CE, EU, Yb and PR in glass have temperature sensitive characteristics, and can be used for distributed sensing {hottag} devices, fiber lasers, active gain media of super brightness light sources and other nonlinear devices.


3. Long afterglow luminescent glass

The long afterglow luminescent glass uses the sunlight, fluorescent lamp or incandescent lamp and other light sources to store energy and emit visible light in the dark. The luminescent brightness is high. The main excitation wavelength is at 320nm and 360nm, and the main emission wavelength is at 520nm. The luminescent time is at the visible brightness level of human eyes (0.32mcd / m2) and can last for more than 8h. Thus, solar energy can be used to realize people's dream of "city without night". The paper or the like printed with information such as characters and images is placed on the transparent glass, and then irradiated with high-energy electromagnetic waves such as short wave ultraviolet rays, the glass automatically memorizes the information on the paper or the like. When the paper or the like is irradiated by a long light source such as sunlight in a dark background, the information (characters, images, etc.) originally stored on the glass is reproduced.


4. Rare earth optically active glass

Faraday magneto-optical glass can be prepared by adding 20% ~ 30% CeO2, Eu2O3, Tb4O7, Dy2O3 and so on into the glass based on aluminum barium borosilicate. Paramagnetic and diamagnetic glasses can be further prepared by adjusting the glass composition. The addition of Er2O3, Dy2O3 and Tb4O7 to the glass makes the glass have a high Felder constant. The feld constant of the glass developed by Xi'an Institute of Optics and mechanics in China can reach 0.38 dB / Oster · cm at 632.8 nm and room temperature, which is 52% higher than that of FR-5 in Japan. The glass can be used as various magneto-optical functional devices, and can be used to pull magneto-optical polarization maintaining optical fibers (which can improve the quality of optical fiber communication, information processing, laser technology and automatic measurement in the power industry, such as magneto-optical current transformers). It is used to make isolators for isolating reverse excitation light in high-power laser nuclear fusion devices, and as optical isolators for holographic photoelastics, ring laser magnetometers, and optical communication systems.


5. Lanthanide optical glass

Lanthanide optical glass has high refractive index and low chromatic dispersion, which can simplify the lens of optical instruments, eliminate spherical aberration, chromatic aberration and image quality distortion, expand the field of view angle and improve the image quality; It is widely used in aerial cameras, high-end cameras, high-end telescopes, high-power microscopes, copiers, scanners, zoom lenses, wide-angle lenses, etc. Japan, France and other countries have recently begun to give up 2 / 3 of their domestic and international markets to China. They say that "optoelectronic materials in the 21st century are China's century". Since July 1999, Chengdu Guangming equipment factory alone has received 225 tons of foreign orders (previously, China's exports were zero). Taking the world's lanthanum glass as an example, the annual demand is about 4000 tons, and there is an upward trend. 50% - 70% of lanthanum oxide is required for each ton of lanthanum glass, that is, at least 2000 tons of lanthanum oxide are used for lanthanum glass every year. The upper limit price of lanthanum oxide per ton (99.95%) is 60000 yuan / ton (in August 2002, the lanthanum oxide was 99% - 99.9% of 17000-21000 yuan / ton). The average sales price of lanthanum glass is 200000 yuan / ton, and the annual profits and taxes are at least more than 100 million yuan; At the same time, the problem of surplus lanthanum in rare earths in China can be solved sustainably. The finished product rate of Chengdu auger Optical Glass Co., Ltd. is more than 90%, which is mainly sold abroad.


6. Radiation resistant glass

Adding a certain amount of cerium oxide into the glass can improve the stability of the glass under irradiation. According to the development needs of national nuclear energy technology, Chengdu Guangming equipment factory has researched and produced more than 70 products of this glass, including 53 No. 500, 13 No. 600, 4 No. 700 and 2 No. 800, which meet the needs of the atomic energy industry, aerospace industry, nuclear power and other industries.


7. Rare earth color glass and special glasses glass

Due to the migration of electrons in 4f layer, rare earth ions are colorless except for La3 +, Gd3 +, Y3 +, Lu3 + electrons which are difficult to excite. Other rare earth ions have different degrees of absorption 380-780nm spectral characteristics, and show their own colors. When used alone or in combination, they can make glass show various colors, and can be used as decorations, instruments, photographic lens filters, signal lamps Special glasses (UC film, x, Kesai, anti fatigue, laser protection, ultra-thin lens, etc.).


8. Full color discolored glass

The color change and lightness of the panchromatic glass vary with the temperature and time of the treatment.


9. Infrared glass

Infrared glass is used for infrared photography, night fighting, etc.


10. Rare earth optical fiber glass

Rare earth optical fiber glass is used in communication, night vision devices, optical fiber amplifiers, and has been applied in data storage, printing and display, medicine and other fields.


11. Rare earth polishing powder

Rare earth polishing powder is mainly used for polishing TV glass shell, cathode ray tube, display screen, glass optical instrument, integrated circuit board, spectacle lens and photomask. Its larger traditional market is color TV cathode ray tube. In recent years, with the continuous development of liquid crystal flat display technology and electronic optical industry, high-performance rare earth polishing powder has been widely used in flat display products such as liquid crystal displays, flat right angle large screen color TVs, computers, word processors, automobile navigation systems, photomask, automobile industry, etc., especially in developed countries and regions such as Europe, America, Japan, South Korea, etc The demand for high-performance rare earth polishing powder for photomask increases. Although the market demand for polishing powder continues to increase, the demand direction is changing significantly, requiring higher product quality, better uniformity and better performance. The quality of polishing powder produced by domestic traditional processes can no longer meet the requirements. Therefore, it is of great strategic significance to give play to the advantages of China's rare earth resources and adopt advanced technology and equipment to carry out technological transformation of the production line, so as to lead the development of China's rare earth products such as polishing powder in the high-tech field and change the passive situation of large countries with rare earth resources importing large quantities of high-quality rare earth products for a long time. Rare earth polishing powder is one of the important extension products of rare earth products. It has a long history of development and utilization, good performance, wide application and good prospects. In the 1950s, China began to develop rare earth polishing powder and produced it in small quantities. At the end of 1960s, rare earth polishing powder began to be industrialized.


Since 1990, due to the increasing demand for rare earth polishing powder in domestic and foreign markets, China's rare earth polishing powder industry has made great progress in production capacity, output, production technology and market development. Especially in 1997, Baotou Iron and steel (Group) Co., Ltd., Japan Qingmei Chemical Co., Ltd. and Japan Mitsubishi Corporation Co., Ltd. jointly invested in the establishment of Baotou Tianjiao Qingmei rare earth polishing powder Co., Ltd., which greatly improved the production capacity and output of rare earth polishing powder in China. At present, there are more than 30 enterprises producing rare earth polishing powder in China and 4 enterprises with a scale of more than 1000 tons. In 2003, the production capacity of rare earth polishing powder in China was 8000 tons, 10.7 times that of 700 tons in 1995 and 20 times that of 400 tons in 1990. The actual output in 2003 was 4800 tons, an increase of 6.2 times over 670 tons in 1995 and 19.7 times over 232 tons in 1990. At present, China can produce 14 varieties and 24 specifications of cerium based polishing powders in three categories: high, medium and low. At present, the production capacity and output of rare earth polishing powder in China rank first in the world.


Due to the increase in the output of various optical glass devices, TV picture tubes, optical lenses, oscilloscopes, flat glass, semiconducting wafers, metal precision instruments, crystal resonators, optical discs and advanced optical glass, the application of rare earth polishing powder is becoming more and more popular, and the production capacity and output of rare earth polishing powder in China are constantly expanding. In 2003, China's consumption of rare earth polishing powder was about 3500 tons, and the world's consumption of rare earth polishing powder has reached 15000 tons. It is predicted that the global consumption of rare earth polishing powder will reach 20000 tons in 2005. With the rapid development of China's electronic information industry, China will become a big country in the production, export and consumption of rare earth polishing powder in the world. At present, Baotou Tianjiao Qingmei rare earth polishing powder Co., Ltd. has a production capacity of 2200 tons, and a new te-500 rare earth polishing powder production line with an annual output of 820 tons has been completed and put into production. The production line of high-quality rare earth polishing powder with an annual output of 500 tons of China rare earth Holding Co., Ltd. has been commissioned in December 2003. In the face of market changes, Gansu rare earth group has successfully developed and built a high-performance rare earth polishing powder production line with high equipment level by making use of its own rare earth production scale advantage and years of technology and experience in producing polishing powder, introducing advanced foreign equipment on the basis of the existing technology and process of a rare earth polishing powder production line in China, and absorbing the advantages and advantages of polishing powder production lines in Japan, South Korea and Australia, The new and old (300 t / a) systems of the company have formed a production capacity of 1500 T / a rare earth polishing powder, which has officially entered the mass production stage in the second half of 2003. The products are mainly used for polishing the cathode ray tubes and photomasks of LCD screens, large screen high-definition color TVs. At present, there are more than 20 enterprises producing rare earth polishing powder in China. There are 4 enterprises with an annual production capacity of more than 1000 tons, 5 enterprises with an annual production capacity of 500-1000 tons, more than 10 enterprises with an annual production capacity of 100-500 tons, and more than 10 enterprises with an actual output of more than 100 tons.


二、 Rare earth ceramics

Ceramics is one of the scientific, technological and cultural products with a long history in China, and has become synonymous with "porcelain" and "China" in the world. The application of rare earth in ceramic materials is the earliest in the application of ceramic pigments (colored pottery was developed in the Yangshao culture period).


1. Nanoceramics

Although there are still many key technologies to be solved, in the microstructure of nano ceramics, the grain size, grain boundary and their combination are at the nano level. The refinement of grain size and the large increase in the number of grain boundaries have greatly improved the mechanical properties, bending strength and fracture toughness at room temperature and high temperature. They are widely used in cutting tools, bearings and automobile engine parts; And plays an irreplaceable role in the harsh environment of ultra-high temperature and strong corrosion; It also has an important impact on the electrical, thermal, magnetic and optical properties of ceramics, and opens up a new field for the utilization of ceramics.


2. Superplastic ceramics

The superplasticity study of fine-grained Y-TZP ceramics by Shanghai Institute of silicates shows that when the grain size is 300nm and the temperature is 1400 ℃, the initial strain rate is 1 × 10-2 · s-1, and the compressive strain reaches 350%; When the grain size is reduced to 150nm and the temperature is 1250 ℃, the initial strain rate is 3 × 10-2 · S-1 and the compressive strain is 380%. Like metal, ceramics can be directly made into precision ceramic parts by forging, extrusion, stretching, bending and pneumatic expansion. Superplastic ceramics can be divided into phase transformation superplastic ceramics and structural superplastic ceramics.


3. Intelligent ceramics

Ceramics are easy to realize intelligence. Before the concept of intelligent materials was proposed, some ceramics have become intelligent. For example, multifunctional ceramics can not only sense magnetism, temperature and gas, but also have executive functions like dielectric elements; Ceramics can not only perceive the objective world like living things like human's five senses, but also work externally, emit sound waves, radiate electromagnetic waves or heat energy, promote chemical reactions and change colors, and make intelligent reactions similar to living things. After the intelligent materials were proposed, the integration method was adopted to feed back the signals sensed by the ceramics to the ceramic devices through electrical processing, and then the special functions of the ceramics were used to respond to the outside. Among the developed sensors and drivers, ceramic materials account for a large part: such as piezoelectric, electroacoustic, optoelectronic, thermoelectric, magnetocaloric, electrostrictive or magnetostrictive, phase change, biological, Thermoelectric Ceramics and so on.


4. Superhard ceramics

Ceramics include daily-use ceramics, building ceramics, decorative ceramics and structural ceramics. According to the performance of structural ceramics, they can be divided into superhard, high-strength and high-temperature ceramics.

Ceramics have much higher hardness than ordinary materials. Superhard ceramics refer to diamond and boron nitride, or a composite of both. In addition, cemented carbide cermets such as WC and tic are widely used as superhard tool materials. Superhard ceramics can be used for cutting and grinding stone, glass, concrete, various crystal forms and new structural materials (high hard metal, high hard ceramic Si3N4, SiC, etc.), and also for geological drilling and precision cutting (lead, copper, stainless steel, carbon fiber and boron fiber composite materials, etc.). It can also be used as ball point pen, golf boot nail, watch shell, small aperture wire drawing die, etc.


5. High strength ceramics

The high-strength mechanical properties of ceramics are better than those of metals, but brittle fracture is easy to occur due to the complexity and non-uniformity of ceramic composition, process and microstructure. In recent years, the research and application of high strength and high toughness ceramics with rare earth additions have been widely carried out. Typical high-strength ceramics are Si3N4, SiC and partially stabilized ZrO2, which are mainly used in military and aerospace applications.


6. High temperature ceramics

High temperature ceramics have the following characteristics: (1) they have high strength under the high temperature and harsh environmental conditions that the existing metals can not bear; (2) Toughness does not decrease at high temperature; (3) High creep resistance; (4) Excellent corrosion resistance; (5) High thermal shock resistance; (6) Good abrasion resistance, etc. High temperature ceramics are used in rockets, missiles, jet engine throats, shell parts, end caps, leading edge of recycled artificial satellites, aircraft shell skins, heat-resistant tiles, turbine blades, aircraft high-temperature bearings, melting metal crucibles, valve pumps, transmission pipes, high-temperature electrodes, high-temperature heating elements, power generation and energy, thermocouple protection tubes, molds, etc. High temperature ceramics can be divided into two categories according to composition: (1) oxide system: such as Al2O3, MgO, BeO, ZnO, etc; (2) Non oxide system: such as Si3N4, SiC, BN, AlN, etc. Rare earth is an additive in the above materials.


7. Electronic ceramics

Ceramics have already entered many fields of modern electronic industry: (1) piezoelectric ferroelectric ceramics are used for force, sound, position and speed sensors, infrared sensors, electro-optic sensitive elements, various piezoelectric vibrators and transducers; (2) Microwave dielectric ceramics (microwave communication and satellite communication), capacitor ceramics; (3) Fast ion conductor (solid electrolyte): zirconia oxygen sensor, LaF3 gas sensor, for energy storage and conversion; (4) Application of thermal properties: including insulating ceramics with various thermal properties, temperature sensitive resistance ceramics, forsterite type ceramics with thermal expansion coefficient close to metal, electrode materials for magneto-hydraulic generators, ceramics for thermal power generation elements and electronic cooling elements, photoelectric ceramics and electro-optical ceramics (PLZT), etc.


8. Superconducting ceramics

In the past, the exploration of superconducting materials was mainly carried out in the metal Kingdom, and gradually developed from metals and alloys to intermediate metal compounds (carbides, nitrides) and metal interchanges, with an upper limit of TC = 23.2k. Among metals, there are also NbTi, Nb3Sn, v3si, etc. explorers have turned to inorganic compounds and organic substances such as oxides and sulfides; At present, the TC value of some organic substances is also very low. In the 12 years from 1973 to 1985, the superconducting critical temperature Tc did not increase by 1K. Subsequently, in a short period of more than one year, four high-temperature superconducting systems were discovered, with a total of dozens of different superconducting phases, and TC increased from 30K to 290k. These high-temperature superconductors are all evolved from perovskite structures. According to the different coordination numbers of copper, superconductors are divided into three categories: (1) la2-xmxcuo4 (lanthanide high-temperature superconducting ceramics), M = B, SR or Ca; (2) Yba2cu3o5 (123 phase, yttrium based high-temperature superconducting ceramic), including compounds formed by trivalent elements La, Nd, SM, Gd, Dy, Ho, er, TM, Yb and Lu completely, partially or even mixed with y; (3) Ba, La substituted solid solution compound La1 xyxbacu2oy, etc.


9. Semiconductor ceramics

It has unique electrical properties, excellent mechanical properties, thermal properties and good chemical stability. Y. Rare earth elements such as La, CE, PR, Nd, SM, Gd, TB, etc. can make BaTiO3 ceramics semiconductor.


10. Optical ceramics

The propagation speed of photons is much faster than that of electrons, and light will play an increasingly important role in future technology. Optical ceramics include: (1) transparent ceramics; (2) Infrared optical ceramics; (3) Photochromic ceramics; (4) Fluorescent glass-ceramic is a composite of glass and microcrystalline, and has the advantages of glass, crystal and ceramic. It is a good luminescent matrix material. It has the characteristics of high quantum efficiency, wide absorption and emission range, long fluorescent life, easy molding, low cost, stable chemical performance, large temperature range, good mechanical and thermal properties, and is expected to be used in laser, solar energy utilization, photomask, electronics, display Widely used in decoration and other fields; (5) Luminescent ceramics: Al2O3 ∶ Eu3 +, Tb3 + luminescent ceramic powders and luminescent ceramics were synthesized by sol-gel method using aluminum isopropoxide as raw material; Al2O3-SiO2 ∶ Ln3 + luminescent ceramics were synthesized by sol-gel method; SrAl2O4 ∶ Eu2 + long afterglow luminescent ceramics were prepared by arc method; (6) Photochromic ceramics change color during light irradiation, reversibly recover the primary color after stopping irradiation, and PLZT transparent ceramics show their own color change when exposed to light; (7) Rare earth ceramic color glaze uses rare earth as colorant or color aid to produce various ceramic pigments and color glazes.


11. Ferroelectric ceramics and antiferroelectric ceramics

The piezoelectric constant d31 of lanthanum and bismuth doped PBSZT relaxor ferroelectric ceramics can be controlled by an applied DC bias voltage. Under the induction of a certain electric field, La doped Pb (Zr, Sn, Ti) O3 antiferroelectric ceramics have pyroelectric effect. By controlling the bias electric field, the pyroelectric current can be switched and regulated, which can be used in pyroelectric detectors; Its electric hysteresis loop is thin and narrow, and the forced phase transition is gradually completed in a relatively wide range of field strength. The resulting electrostrain is small and the dielectric loss is low. It is suitable for making energy storage capacitors with high voltage, high energy storage density and long service life.


12. Other applications of rare earth in ceramics

Magnetic ceramics (divided into polycrystalline magnetic ceramics and amorphous magnetic ceramics), bioceramics, sensitive ceramics, high thermal conductivity ceramics, coating ceramics, porous ceramics, ceramic based composites (inorganic, organic, nano metal), etc. 

(source: CNBM)


Tags

Recently Viewed:

Related products

news.related_news