The application of rare earth in glass ceramics industry

The application of rare earth in glass ceramics industry

Of rare earth are glass and ceramics industry in China since 1988, the average growth rate is 25%, has reached about 1998, 1600 tons of rare earth glass ceramic is not only the traditional base of industry and living materials, is the main member of high-tech fields. In terms of global rare earth consumption, glass ceramics account for 25.6%, and in 1999 China accounted for only 10%, so there is a lot of room for the application of rare earths in glass and ceramics. In 2003, China's application of glass ceramics in China increased by a factor of over 6000 tons, accounting for 20.3% of China's rare earth application.

1. Rare earth glass and polishing materials

The manufacture of glass is about five thousand years old, and the production of optical glass is nearly 200 years old, but the application of rare earth elements to glass is only a hundred years old. At the end of the 19th century, it began to use cerium oxide as a glass decolorizer and began to study the rare earth borate glass in the 1920s, which produced the lanthanum optical glass with high refractive index and low dispersion in the 1930s.

Glass ceramic industry is an important traditional field of rare earth application, accounting for 33% of the total consumption of rare earth. Rare earth is used as a clarifier, additive, decolorizer, colorant and polishing powder in the glass industry, which plays an irreplaceable role in other elements. Using the high refractive and low dispersion properties of some rare earth elements, it can produce optical glass, which can be used to make the lens of advanced optical instruments such as advanced camera, camera and telescope.

The radiation protection of some rare earth elements can be used to produce radiation-proof glass. A variety of ceramic pigments produced by rare earth elements have high price, purity, showiness and high temperature resistance, which are favored by users.

1. laser glass
Neodymium glass is the largest laser output pulse energy, the highest output power laser glass, its large laser for thermal fusion and so on. Double Nd3 + Yb3 + doped laser glass is by Nd3 + Yb3 + sensitization, Yb3 + at room temperature was 1.06 mu m laser, simple level, energy storage of high efficiency and long fluorescent life (3 times that of neodymium glass), second order nonlinear coefficient is low, there is a strong absorption peak near 970 nm, can directly use LnGaAs semiconductor laser pump, better thermal stability, cross section to determine stimulated emission of radiation, absorption band is wide, doping concentration is higher, used in optical communication, high energy laser weapon (can destroy missiles, satellites, aircraft and other large targets).

Erbium-doped phosphate laser glass can realize 1.5 mu m low threshold laser, which can transmit power in the atmosphere. Holmium fluorozirconic acid glass is continuously operated by laser at 543nm wavelength. A certain amount of ytterbium in the glass can transfer the energy absorbed by Yb3+ to the Ho3 +, which has a promising future in the miniaturization of the laser.

2. Smart glass
Photochromic glass can occur under the excitation of light color reaction of glass, it is the ability to adjust themselves pervious to light performance, can make the glasses, senior automotive gear wind glass, glass, holographic photographic materials, production of text, image storage memory display, erasable light modulation components etc. Photosensitive glass-ceramic photosensitive chemical etching method can be used to make this kind of glass form all sorts of complicated design, in the printing, circuit board, fluidic element, charge storage tube, optical telecommunications tube screen, etc, have a wide range of applications.

In the glass with Nd, Er, Dy, Tb, Ho and Ce, Eu, Yb and Pr optical fiber temperature sensitive characteristics of rare earth elements, can be used in distributed sensor, optical fiber laser and ultra brightness light source of the active gain medium and other nonlinear devices.

3. long afterglow glass
Long afterglow luminescence glass USES sunlight, fluorescent, or incandescent light source such as after a short period of time after irradiation, stored energy, and emit visible light from the darkness, high luminous intensity, the main excitation wavelength is located at 320 nm and 360 nm, the main emission wavelength at 520 nm, luminous time in human visible brightness level (0.32 MCD/m2), sustainable amounted to more than 8 h, to utilize solar energy, realize the dream of people "the city that never sleeps".

The paper with the information such as text, images, etc on the transparent glass, then use a short-wave ultraviolet high-energy electromagnetic wave radiation, such as glass paper on information, such as automatic memory when, in a dark background is isometric light waves sunlight, the original stored in the information on the glass (text, images, etc.) reappear.

4.Rare earth rotatory glass
In the glass based on barium barium silicate, 20% ~ 30% of CeO2, Eu2O3, Tb4O7, Dy2O3 etc. can be used to make farah's magnetic glass. The glass composition can be further made of paramagnetic and diamagnetic glass. Adding Er2O3 and Dy2O3 and Tb4O7 to the glass have high felder constants. The glass, developed by xi 'an optical machine in China, can reach 0.38 decibels/ost centimetre in 632.8 nanometer and room temperature, which is 52% higher than that of Japan's fr-5.

The glass can do all sorts of magneto optical functions, can be drawn magneto-optic polarization-maintaining optical fiber (to improve the quality of optical fiber communications, information processing, laser technology and the electric power industry to realize automatic measurement, such as magnetic optical current transformer), in high power laser nuclear fusion device used to make segregation r everse laser isolator, used as a holographic photoelasticity, circular laser magnetometer, optical communication system of optical isolator, etc.

5.Lanthanum optical glass
Lanthanide optical glass has high refractive index and low dispersion degree, which can simplify the lens of optical instrument, eliminate the difference of ball, chromatic aberration and image quality distortion, enlarge the Angle of the field of view, and improve the image quality. It is widely used in aerial camera, high-end camera, high-end telescope, high power microscope, photocopier, scanner, zoom lens and wide Angle mirror. Japan, France and other recently began two-thirds of its domestic and international market to China, they say "photoelectric materials in the 21st century is the century of China" and light equipment factory in chengdu alone from July 1999, 225 tons of receiving orders from abroad (formerly China's export to zero).

Now in the world of lanthanum glass, for example, requirements about 4000 tons a year, and a rising trend, every tons of lanthanum glass need lanthanum oxide 50% ~ 70%, namely lanthanum glass with lanthanum oxide 2000 tons every year, every tons of lanthanum oxide (99.95%), the price of 60000 yuan/ton (99% ~ 99.9% in August, 2002, lanthanum oxide 1.7 ~ 21000 yuan/ton), average selling price 200000 yuan/ton, lanthanum glass pay tax is one hundred million yuan or more every year; At the same time, we can solve the problem of the surplus of lanthanum in domestic rare earth. Chengdu ogg optics glass co., LTD. Has a product rate of over 90%, mainly sold abroad.

6.Radiation resistant glass
A certain amount of cerium oxide in the glass can improve the stability of the glass irradiated. Chengdu light equipment factory according to the state nuclear power technology development needs, research and production of the glass more than 70 products, including 53, 500, 600, 13, 700, 4, 800, 2, met the atomic energy industry, aerospace industry, nuclear power and other industries demand.

7.Rare earth color glass and special glasses glass
Rare earth ions due to the migration within 4 f electronic, except La3 +, Gd3 +, Y3 + and Lu3 + electronic excitation of a colorless, other rare earth ions have different degree of absorption of 380 ~ 780 nm spectral characteristics, and presents the color of their respective characteristics, alone or together with can make glass in various colors, can be used as decorations, instruments and photographic lens filter, lights, special glasses (UC slice, Bronx, g, fatigue resistance, laser protective, ultra-thin glass, etc.).

8.Whole color chameleon glass
The change of color change and brightness of the color change of color change with the temperature and time of treatment.

9.Infrared glass
Infrared glass is used for infrared photography and night fighting.

10.rare earth fiber glass
Rare earth fiber glass is used for communication, night vision devices and optical fiber amplifiers, and it is used in data storage, printing display and medicine.

11. rare earth polishing powder
Rare earth polishing powder is mainly used in television glass shell, cathode ray tube, display, optical instrument, integrated circuit boards, glass lens, optical glass mask polishing, it is the largest traditional market color TV cathode-ray tube. In recent years, with LCD flat display technology, electron optics industry the development of high-performance rare earth polishing powder in liquid crystal display, flat rectangular plane display products such as large screen color TV, computer, word processor, and car navigation systems, photomask, auto industry etc widely application, especially Europe and the United States, Japan, South Korea and other developed countries and regions for liquid crystal displays, large screen high definition television sets, photomask of high-performance rare earth polishing powder increased demand.

Although there is an increasing demand for polishing powder of, but demand direction in the event of a major change, the quality of product requirements higher, better uniformity, better performance, the production of domestic traditional polishing powder quality can not meet the requirements. Giving full play to the advantages of rare earth resources in our country, therefore, the use of advanced technology and equipment of the technical renovation of production line, to lead the polishing powder, rare earth products in the development of high-tech fields, such as change of rare earth resource-rich countries import a lot of high quality long-term passive situation of rare earth products has important strategic significance.

Rare earth polishing powder is one of the important extension products in rare earth products. It has long history, good performance and wide application. In the 1950s, China began to develop rare earth polishing powder and small production. In the late 1960s, rare earth polishing powder began to move toward industrial production.

Since 1990, due to the increasing demand for rare earth polishing powder at home and abroad, driven by rare earth polishing powder industry in our country, the production capacity, production, production technology and market development has achieved great development.

Especially in 1997, baotou steel (group) company and the Japanese qing mei chemical co., Japan's m itsubishi corporation three jointly formed the baotou tianjiao after rare earth polishing powder co., LTD., production capacity and production of rare earth polishing powder had a larger increase, at present our country of rare earth polishing powder production has more than 30 enterprises, thousands of tons, the size of the enterprise has four. 2003 production capacity of 8000 tons of rare earth polishing powder, is 10.7 times that of 700 tons in 1995 was 400 tons in 1990 to 20 times, the actual output of 4800 tons in 2003, a 1995 increase from 670 tons in 1995, a 1990 increase from 232 tons in 1990. At present, we can produce 14 varieties and 24 kinds of cerium series polishing powder. At present, the production capacity and output of rare earth polishing powder are the highest in the world.

Due to the main device in all kinds of optical glass, the TV picture tube, optical lenses, oscilloscope tube, flat glass, semiconductor chips, and metal precision instruments and crystal harmonic oscillator, disks, advanced optical glass production increases, the rising popularity of application of rare earth polishing powder, capacity and output of rare earth polishing powder have been expanded. In 2003, the consumption of rare earth polishing powder in China was about 3500 tons, and the amount of rare earth polishing powder in the world reached 15,000 tons. The consumption of rare earth polishing powder in 2005 is expected to reach 20,000 tons. With the rapid development of China's electronic information industry, China will become a major producer, exporter and consumer of rare earth polishing powder. At present, baotou tianjiao qingmei rare earth polishing powder co., LTD.

Has a capacity of 2,200 tons, and the company has built a new production line of 820 tons of TE-500 rare earth polishing powder. China rare earth holding co., LTD., a production line of 500 tons of high quality rare earth polishing powder has been tested in December 2003.

To the market changes, gansu rare earth group use their production scale and production of polishing powder technology and experience for many years, in our country the first rare earth polishing powder production line and process on the basis of the existing technology, the introduction of foreign advanced equipment, and Japan, South Korea, Australia, the three advantages and advantages of polishing powder production line technology, successfully developed and built equipment with higher levels of high-performance rare earth polishing powder production line, the company of new and old (300 tons/year) system has formed a 1500 tons/year production capacity of rare earth polishing powder, has officially entered the stage of mass production in the second half of 2003, the product is mainly used for liquid crystal display, large-screen high-definition color television of the cathode ray tube, photomask polishing, etc.

At present, the production of rare earth polishing powder more than 20 enterprises, annual production capacity of over 1000 tons of scale have four, five between 500 ~ 1000 tons, has more than 10, between 100 ~ 500 tons of real output over one hundred tons of have more than 10.

Rare earth ceramics
Ceramics are one of the long history of scientific and technological products in China, which are synonymous with international "China" and "China". The application of rare earth in ceramic materials is the earliest application of rare earth in ceramic color materials (the development of colored pottery in yangshao culture period).

1 nanometer ceramics
Nano ceramic although there are many key technologies need to be solved, but in the microstructure, grain, grain boundary and combination are at the nanoscale level of grain refinement, grain boundary number increase, make the room temperature and high temperature mechanical properties, bending strength and fracture toughness increased significantly, in cutting tools, bearings, automobile engine parts, etc, are widely used; It plays an irreplaceable role in the harsh environment of ultra-high temperature and strong corrosion. It also has an important influence on the electrical, thermal, magnetic and optical properties of ceramics, and has opened up a new field for the use of ceramics.

2.superplastic ceramics
Shanghai institute of silicate, superplasticity of fine-grain Y - TZP ceramics research shows that when the grain size is 300 nm, temperature under 1400 ℃, the initial strain rate of s. 1 x 10-2-1, compressive strain was 350%; When the grain size decreases to 150 nm, temperature under 1250 ℃, the initial strain rate for 3 x s. 10-2-1, compressive strain of 380%.

It is used to make ceramic parts of precise size by forming methods such as forging press, extrusion, stretching, bending and air pressure. Superplastic ceramics can be divided into the phase transition superplastic ceramics and superplastic ceramics.

3.intelligent ceramics
Intelligence of ceramic easier, before put forward the concept of intelligent materials, some ceramics has become intelligent, such as multi-functional ceramic, can both sensor, magnetic, temperature and gas with executive functions such as dielectric element; Ceramics have been able to like life substances such as people's facial features, perception of the objective world, and to work abroad, acoustic emission, electromagnetic wave radiation or heat energy, chemical reaction and change the color for the promotion of the wisdom of life make similar material response.

After put forward the intelligent materials, then USES the integration means, the ceramic sensing signals, through the electronic processing, feedback to ceramic components, reusing ceramic special features inherent in the foreign to react. In the development of sensor and actuator, occupies a large part of the ceramic materials: such as piezoelectric, acoustic, photoelectric, thermoelectric heat, magnetic, electric or magnetic striction, phase change, biological, thermoelectric ceramics, etc.

4. super hard ceramics
Ceramics, ceramics, decorative ceramics and structural ceramics can be classified into super hard, high and high temperature ceramics according to the performance of structural ceramics.

Ceramic has the hardness of material is much higher than normal, superhard ceramic refers to diamond and boron nitride, or both, in addition, sintered metal carbide ceramics such as WC, TiC as superhard tool material is widely used. Superhard ceramic can cutting and grinding stone, glass, concrete, all kinds of crystal type and structure of new type materials (high hard metal, hard ceramic Si3N4, SiC, etc.), can also be used for geological drilling, precision cutting (lead, copper, stainless steel, carbon fiber and boron fiber composite materials, etc.). It can also be used for ball pen, golf boot nail, watch shell, small aperture, etc.

5. High strength ceramics
The high strength mechanical properties of ceramics are better than metal, but they are vulnerable to brittle fracture due to the complexity and inhomogeneity of the composition, process and microstructure of ceramics. In recent years, the research and application of rare earth high strength and high toughness ceramics have been widely carried out. The typical high-strength ceramics are Si3N4, SiC and some stable ZrO2, mainly military and aerospace applications.

6. high temperature ceramics
High temperature ceramics have the following characteristics: (1) high strength in high temperature and harsh environment conditions which are not able to be subjected to existing metals; (2) the toughness is not reduced at high temperature; (3) high creep resistance; (4) excellent corrosion resistance; (5) high resistance to thermal shock; (6) good wear resistance, etc. High temperature ceramic used in rockets and missiles, jet spray pipes, casing, end cap, and poor satellite front, aviation aircraft skin skin, heat-resistant, turbine blade, aircraft, high temperature bearing, melting metal crucible, valve, pump, pipe, electrode in high temperature and high temperature heating elements, power generation and energy, thermocouple protection tube, mould, etc. High temperature ceramics are divided into two categories: (1) oxide series: Al2O3, MgO, BeO, ZnO, etc. (2) non-oxide systems: Si3N4, SiC, BN, AlN, etc. Rare earth is additive in the above materials.

7.electronic ceramics
Ceramics have entered many fields of modern electronic industry: (1) the PZT ferroelectric ceramics used in force, sound, location, speed sensor, infrared sensor, electro-optical sensor, various piezoelectric vibrator and transducer; (2) microwave dielectric ceramics (microwave communication and satellite communication), capacitor ceramics; (3) fast ion conductor (solid electrolyte) : zirconium oxide sensor, LaF3 gas sensor, for energy storage and conversion; (4) the thermal properties of applications, including with all kinds of thermal properties of insulating ceramics, pottery and porcelain, sensitive to temperature resistance coefficient of thermal expansion and metal type mutually close of forsterite ceramics, MHD generator with electrode materials, thermal power generation components and electronic refrigeration components with ceramics, pottery and photoelectric (PLZT) electro-optic ceramic, etc.

8 superconducting ceramics
Exploration of superconducting materials, mainly in metal kingdom, from metal, alloy and gradually developed to the middle type metal compounds (carbide and nitride) and metal content, high Tc = 23.2 K value, in the metal and NbTi, Nb3Sn, V3Si, explorer eyes have turned to oxide, sulfur and other inorganic compounds and organic matter; Now some organic compounds have a low Tc value. During the 12 years from 1973 to 1985, the superconducting critical temperature Tc did not improve 1K. Subsequently, four high temperature superconducting systems were discovered in a short period of one year, with dozens of different superconducting phases, and Tc from 30K to 290K. These high temperature superconductors have been developed from the structure of perovskite.

According to the different distribution of copper, the superconductor is divided into three types: (1) la2-xmxcuo4 (lanthanide high-temperature superconducting ceramics), M= B, Sr or Ca; (2) YBa2Cu3O5 (yttrium 123 phase, high temperature superconducting ceramics), including triad La, Nd, Sm, Gd, Dy, Ho, Er, Tm, Yb, Lu, partly or even completely mixed to replace Y formed by the compound; (3) Ba, La intergenerational solid solution compound la1-xyxbacu2oy.

9.semiconductor ceramics
Semiconductor ceramics have unique electrical properties and have excellent mechanical properties, thermal properties and good chemical stability. In the case of Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho or Er, BaTiO3 ceramics can be semiconductor.

10.optical ceramics
Photons travel much faster than electrons, and the role of light in future technology will be increasingly important. Optical ceramics have: (1) transparent ceramics; (2) infrared optical ceramics; (3) photochromatic ceramics; (4) the fluorescent glass ceramic, it is a complex and microcrystalline glass, also has the advantages of glass, crystal and ceramic is a kind of very good luminescence substrate material, it has high quantum efficiency, wide range of absorption and emission, and fluorescence long life, easy molding, low cost, stable chemical performance, using a wide temperature range, good mechanical properties and thermal performance, are expected by the laser light, solar energy utilization, mask, electronics, display, decoration and other fields is widely used;

(5) luminescent ceramics, made from isopropanol aluminium, synthesized by sol - gel method, Al2O3: Eu3 +, Tb3+ luminescent ceramic powder and luminescent ceramics; Synthesis of Al2O3- SiO2: Ln3+ luminescent ceramics by sol - gel method; Using arc method to prepare SrAl2O4: Eu2+ long afterglow ceramic; (6) photochromic ceramics, which change color when light irradiated, stop irradiating the original color after irradiation, and the PLZT transparent ceramics appear to change color when exposed to light; (7) rare earth ceramic color glaze, using rare earth as a colorant or a colorant to make various ceramic pigments and colored glaze.

Ferroelectric ceramics and anti-ferroelectric ceramics
The piezoelectric constant d31 of lanthanum and bismuth doped PBSZT relaxation ferroelectric ceramics can be controlled by applied dc bias. Under a certain electric field induction, La doping Pb (Zr, Sn, Ti) O3 ferroelectric ceramics with pyroelectric effect, by controlling the size of the bias field implementation of pyroelectric current can switch, can control, can be used in pyroelectric detector; Its electric hysteresis loop thin and narrow, forcing phase change in a relatively wide range of field intensity gradually completed, electrically induced strain of small, low dielectric loss, suitable for high voltage, high energy storage density, long working life of the energy storage capacitor.

Other applications of rare earth in ceramics
Magnetic ceramics (divided into polycrystalline ceramics and magnetic amorphous magnetic ceramics), biological ceramics, sensitive ceramic coating, high thermal conductive ceramics, ceramics, porous ceramics, ceramic matrix composites (inorganic, organic, nano metal), etc.

In recent years, the consumption of rare earth in glass ceramics industry has increased with the development of China's electronic TV glass shell and building materials industry. The production capacity of rare earth optical glass in China has reached 3000 tons/year. The quality of the products is comparable to that of Japanese products, and the cost is only 1/3 of Japan's, and about 1/10 of the products are exported to the United States, Japan and South Korea.

At present, there are dozens of rare earth polishing powder factories in our country, and there are more than 10 of them. China's rare earth consumption in glass ceramics industry is increasing year by year.