Glass-ceramics is a glass with a specific composition that undergoes microcrystallization heat treatment to induce the precipitation of microcrystalline phases at a certain temperature to form a multi-phase complex of dense microcrystalline phases and glass phases.
Crystallized glass, also known as glass ceramics, is a material made by controlled precipitation of microcrystals as the base glass for certain specific glass systems. Its microcrystalline phase is evenly distributed in the glass phase. Glass-ceramics is composed of fine crystals and residual glass phases, contains a large amount of glass phases, and can be highly crystallized. The interior of glass-ceramics contains at least one glass phase and one microcrystalline phase. At the same time, the atoms inside ordinary glass are randomly arranged, while the inside of crystallized glass has a regularly arranged fine crystal structure. The size of the crystallites is generally between tens of nanometers to tens of microns, and has the dual characteristics of glass and ceramics.
Crystallized glass not only has the basic advantages of glass such as high softening temperature, good electrical insulation properties, and chemical stability, but also has the advantages of ceramics such as good wear resistance, high hardness, high mechanical strength, good thermal stability, and adjustable expansion coefficient. . The basic properties of glass-ceramics are mainly determined by two points: one is the properties of the constituent phases, such as the oxide ratio of the basic glass, the type of generated crystal phase, the content and performance of the remaining glass phase; the other is due to the heat treatment process The different systems are caused by the number of microcrystals and the length of the average crystal size.
Ultra-low expansion glass-ceramic is one of the materials with the best dimensional stability and is an indispensable key material for manufacturing laser gyroscopes. Laser gyro is the core component of inertial navigation and is widely used in the precise navigation of moving carriers such as aircraft, rockets, and satellites. Therefore, ultra-low expansion glass-ceramic plays an important role in modern national defense.
Ultra-low expansion glass-ceramic is also the preferred material for space camera mirrors. Ultra-low expansion glass-ceramic with excellent dimensional stability is used to manufacture the reflector of the space camera, allowing the Gaofen satellite to clearly see objects 200mm in size on the ground in an orbit 600 kilometers above the earth.
Characters of glass-ceramic:
1. Has more stable chemical properties: anti-hydration, anti-hydration ability, anti-cation exchange ability
2. Has higher mechanical strength;
3. It has better electrical properties: the lowest dielectric loss rate;
4. It has good thermal properties: low thermal expansion coefficient, good thermal vibration stability, and high high-temperature softening temperature point.
Harnessing the properties of glass-ceramics
| Application areas | |
Mechanical materials
| Utilize the mechanical and thermal properties of glass-ceramics such as high temperature resistance, thermal shock resistance, and adjustable thermal expansion
| 1. Automobile metal bearings 2. Piston, rotating blade, blowing tool 3. Structural materials for aircraft, rockets and artificial earth satellites |
Optical materials
|
Utilizing the low expansion and optical sensitivity of glass-ceramics
| 1. Housings of telescopes and lasers 2. Optical fiber connector 3. Transparent infrared instrument 4. Touch screen.
|
Electronic and Microelectronic Materials
| Utilizing the wide thermal expansion coefficient of glass-ceramics | Glass-ceramic substrates, capacitors, thin film circuits and thick film circuits used in high-frequency circuits are widely used in electronics, precision components, aerospace and other fields; 2. Polar crystallized glass has broad dual-use prospects in hydroacoustic, ultrasound and other fields. |
Biomedical materials
|
Utilizing the antimicrobial properties of glass-ceramics
| 1. Substitute for human bones; 2. Use zirconia-toughened CaO-A1203-SiO2 series glass-ceramics to manufacture new dental materials |
Chemistry and chemical materials
|
Utilizing the chemical stability of glass-ceramics
| 1. Pipes and tanks used to transport corrosive liquids; 2. Sealant for sodium sulfide batteries 3. Jet burner for automobiles |
Building materials
| Take advantage of the high strength, hardness, closed pores and low water absorption, frost resistance and thermal conductivity of glass-ceramics | New green decorative materials |
Nuclear industry materials
| Utilizing the characteristics of high temperature resistance, chemical stability and good electrical insulation of glass-ceramics
| Used in the manufacture of materials on atomic reactor control rods, reactor sealants, nuclear waste storage materials, etc. |
With the continuous development of science and technology, brittle materials such as various optical glasses, single crystal silicon, crystallized glass and ceramics are increasingly used in aviation, aerospace and military equipment, and the surface quality of parts is extremely demanding. In order to obtain high-quality processing surfaces of brittle material parts, methods such as ultra-precision grinding, grinding and polishing are often used. However, when grinding and polishing methods are used to process brittle materials, they inevitably have shortcomings such as low production efficiency and low surface accuracy of the processed surface.
In recent years, ultra-precision grinding processing technology has been greatly developed, which can greatly improve the processing accuracy and processing efficiency of parts. However, for the grinding of brittle materials, the way the material is removed will have a great impact on the quality of the machined surface. According to the latest research on the grinding of brittle materials, although brittle materials are very brittle, when choosing the appropriate Under certain parameter conditions, brittle materials can still be ground by plastic removal. Plastic grinding of brittle materials can greatly improve the surface quality of parts.
Crystallized glass has excellent properties such as high mechanical strength, good wear resistance, stable chemical properties, and adjustable thermal expansion coefficient. It is widely used in aerospace, military, medical and other fields. Due to the hard and brittle nature of glass-ceramics, it is a typical difficult-to-process material and is prone to surface and sub-surface damage during processing, thus posing new challenges to ultra-precision processing technology.
Moresuperhard can proivide turnig, milling and grinding solutions for glass-ceramic material, any requirments welcome to contact Moresuperhard.
---EDITIR: Doris Hu
---POST: Doris Hu
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