The application amount 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 of industry and life, but also the main members of high-tech field. From the perspective of rare earth consumption, glass ceramics accounted for 25.6%, and China only accounted for 10% in 1999. Therefore, there is a large space for the application and development of rare earth in glass and ceramics in China. In 2003, China's application in the field of glass ceramics doubled. The amount of rare earth application is more than 6000 tons, accounting for 20.3% of the total amount of rare earth application in China.
1、 The manufacture of rare earth glass and polishing material
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. In the late 19th century, cerium oxide was used as decolorizer, rare earth borate glass was studied in 1920s, and lanthanum optical glass with high refractive index and low dispersion was made in 1930s.
Glass ceramic industry is an important traditional field of rare earth application, accounting for 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, and plays an irreplaceable role in other elements. By using the characteristics of high refraction and low dispersion of some rare earth elements, optical glass can be produced, which can be used to make good lenses of cameras, cameras, telescopes and other good optical instruments; by using the anti radiation characteristics of some rare earth elements, anti radiation glass can be produced. A variety of ceramic pigments produced by rare earth elements have the characteristics of low price, positive color, gorgeous and high temperature resistance, and are favored by users.
1. Laser glass neodymium glass is the laser glass with high output pulse energy and high output power. Its large-scale laser is used in thermonuclear fusion and so on. The double doped Nd3 ± Yb3 + laser glass is sensitized to Yb3 + by Nd3 +, which makes Yb3 + obtain 1.06 μ m laser at room temperature. The energy level is simple, the energy storage efficiency is high, the fluorescence lifetime is long (3 times of that of neodymium glass), the second-order nonlinear coefficient is low, there is a strong absorption peak near 970nm, which can be directly pumped by lngaas semiconducting laser. It has good thermal stability, certain stimulated emission cross section, wide absorption band, and doping High impurity concentration, used in optical communication, high-energy laser weapons (can destroy missiles, satellites, aircraft and other large-scale targets). Erbium-doped phosphate laser glass can realize 1.5 μ m low threshold laser and has strong transmission ability in the atmosphere. The glass doped with ytterbium can transfer the energy absorbed by Yb3 + to Ho3 +, which has a bright future in laser miniaturization and improvement.
2. Intelligent glass
photochromic glass is a kind of glass that can change color under the excitation of light. It can adjust the light transmittance by itself, and can be used as glasses, good windshield, window glass, holographic material, making text, image storage light memory display, erasable light adjusting element, etc. Photosensitive microcrystalline glass can form various complex patterns by using photosensitive chemical etching method, which is widely used in printing, circuit board, fluidic element, charge storage tube, photoelectric tube screen, etc. The optical fiber doped with Nd, er, Dy, TB, Ho, CE, EU, Yb, PR and other rare earth elements in the glass has temperature sensitive characteristics, which can be used in distributed sensors, fiber lasers, active gain media of super bright light sources and other nonlinear devices.
3, Long afterglow glass
long afterglow glass uses sunlight, fluorescent lamp or incandescent lamp and other light sources to store energy after a short time of irradiation. It emits visible light in the dark with high luminosity. The main excitation wavelength is at 320nm and 360nm, the main emission wavelength is at 520nm, and the luminosity time is at the level of human visual visible brightness (0.32mcd / m2), which can last for more than 8h. Therefore, it can be utilized Solar energy realizes people's dream of "no night city". Put the paper printed with text, image and other information on the transparent glass, and then irradiate it with high-energy electromagnetic wave such as short wave ultraviolet, the glass will automatically memorize the information on the paper, etc. when it is irradiated by long light source such as sunlight in the dark background, the information (text, image, etc.) originally stored on the glass will be reproduced.
4. Faraday magneto-optical glass can be prepared by adding 20% - 30% CeO2, Eu2O3, Tb4O7, Dy2O3, etc. into the glass based on aluminum barium borosilicate. The paramagnetic and diamagnetic glasses can be further prepared by adjusting the glass composition. Adding Er2O3, Dy2O3 and Tb4O7 to the glass makes the glass have high feld constant.
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, and improve the imaging quality; it is widely used in aerial cameras, good cameras, good telescopes, high-power microscopes, copiers, scanners, zoom lenses, wide-angle lenses, etc. Japan, France and other countries have recently begun to give 2/3 of their domestic and foreign markets to China, saying that "the twenty-first Century is the century of China for photoelectric materials.". At present, taking the world's lanthanum glass as an example, the annual demand is about 4000 tons, and there is a rising trend. Lanthanum oxide is required for 50% - 70% of each ton of lanthanum glass, that is, at least 2000 tons of lanthanum oxide are used for lanthanum glass every year. The high price of lanthanum oxide per ton (99.95%) is 60000 yuan / ton (99% - 99.9% 17000-21000 yuan / ton in August 2002). The average selling price of lanthanum glass is 200000 yuan / ton, and at least 100 million yuan of profits and taxes are paid every year At the same time, it can solve the problem of excess lanthanum in domestic rare earth.
6. The stability of the irradiated glass can be improved by adding ceria to the glass.
7 , rare earth color glass and special glasses glass
rare earth ions are colorless due to electron migration in 4f layer, except La3 +, Gd3 +, Y3 +, Lu3 + electrons are hard to excite, other rare earth ions have spectral characteristics of 380-780nm in varying degrees, and show their own characteristics of color. Single or combined use can make glass show various colors, which can be used as decoration, instrument and camera lens filter Film, signal lamp, special glasses (UC film, x, Kesai, anti fatigue, laser protection, ultra thin lens, etc.).
8. Panchromatic glass
the change of color and lightness of panchromatic glass changes with the temperature and time.
9 infrared glass
infrared glass is used for infrared photography, night battle, etc.
10. Rare earth optical fiber glass
rare earth optical fiber glass is used in communication, night vision devices, optical fiber amplifiers, data storage, printing and display, medicine and other fields.
11. Rare earth polishing powder
rare earth polishing powder is mainly used in the polishing of 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 LCD plane display technology and electronic optical industry, high-performance rare earth polishing powder has been widely used in plane display products such as LCD, plane right angle large screen color TV, computer, word processor, automobile navigation system, 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 LCD, large screen HDTV and photomask is increasing. Although the market demand for polishing powder is increasing, but the direction of demand is changing significantly. The quality of products is required to be higher, the uniformity is better, and the performance is better. The quality of polishing powder produced by traditional domestic technology can not meet the requirements. Therefore, giving full play to the advantages of China's rare earth resources and adopting advanced technology and equipment to carry out technical transformation of the production line are of great strategic significance 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 rare earth resources importing 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 prospect. In the 1950s, China began to develop rare earth polishing powder, and a small amount of production. At the end of 1960s, rare earth polishing powder began to be industrialized.
2、 Rare earth ceramics is one of the products with a long history of science, technology and culture in China. The application of rare earth in ceramic materials is earlier because of its application in ceramic pigments (colored pottery was developed in Yangshao culture period).
1 , nano ceramics
nano ceramics although there are many key technologies to be solved, but in the microstructure, the grains, grain boundaries and their combination are all at the nano level. The refinement of grains and the number of grain boundaries increase greatly, which greatly improves the room temperature and high-temperature mechanical properties, bending strength, fracture toughness, etc. there are many in cutting tools, bearings, automobile engine parts, etc It is widely used; it plays an irreplaceable role in other materials under 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, opening up a new field for the utilization of ceramics.
2. Superplastic ceramics the superplastic study of fine-grained Y-TZP ceramics by Shanghai Silicate Research Institute shows that when the grain size is 300nm and the temperature is 1400 ℃, the initial strain rate is 1 × 10-2 · s-1, the compressive strain is 350%; when the grain size is reduced to 150nm and the temperature is 1250 ℃, the initial strain rate is 3 × 10-2 · s-1, the compressive strain is 380%. Like metal, ceramics can be directly made into precision size ceramic parts by forging, extrusion, stretching, bending and air pressure expansion. Superplastic ceramics can be divided into phase-change superplastic ceramics and structural superplastic ceramics.
3, Intelligent ceramics
ceramics are easy to realize intelligence. Before the concept of intelligent materials was put forward, some ceramics have become intelligent, such as multifunctional ceramics, which can not only sense magnetism, temperature and gas, but also have executive functions like dielectric components; ceramics can sense the objective world like living things, such as human five senses, and can work outside, emitting sound waves, radiating electromagnetic waves or heat energy To promote chemical reaction, change color and other external intelligent reactions similar to living substances. After the intelligent materials are proposed, the signals sensed by ceramics are then fed back to ceramic devices through electrical processing, and then the special functions inherent in ceramics are used to respond to the outside world. In the developed sensors and actuators, ceramic materials occupy a large part: piezoelectric, electroacoustic, photoelectric, thermoelectric, magnetothermal, electrostrictive or magnetostrictive, phase change, biological, thermoelectric ceramics, etc.
4. Superhard ceramics, including household ceramics, architectural ceramics, decorative ceramics and structural ceramics, can be divided into superhard, high-strength and high-temperature ceramics according to the performance of structural ceramics.
Ceramics have much higher hardness than general materials. Superhard ceramics refer to diamond and boron nitride, or both of them. In addition, sintered carbide cermets such as WC and tic are widely used as superhard tool materials. Superhard ceramics can be used to cut and grind stone, glass, concrete, various crystal forms and new structural materials (high hard metal, high hard ceramics Si3N4, SiC, etc.), as well as 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, golf boot nail, watch shell, small hole tap die, etc.
5. High strength ceramics
ceramics have better mechanical properties than metals, but because of the complexity of composition, technology and microstructure of ceramics
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