What Is Structural Ceramic
Structural ceramics are advanced ceramics with excellent mechanical, thermal and chemical properties such as high temperature resistance, erosion resistance, corrosion resistance, high hardness, high strength and low creep rate, and are commonly used in various structural components.
Structural ceramics have the characteristics of superior strength, hardness, insulation, heat conduction, high temperature resistance, oxidation resistance, corrosion resistance, wear resistance, high temperature strength, etc.
Therefore, in very harsh environments or engineering application conditions, they exhibit high Stability and excellent mechanical properties have attracted much attention in the material industry, and its application range is also expanding.
The global and domestic industries have increasingly stringent requirements for high-precision, high-wear, high-reliability mechanical components or electronic components, so the demand for ceramic products has received considerable attention, and its market growth rate has also been considerable.
Specialty ceramics as structural components. It is composed of single or composite oxides or non-oxides, such as Al2O3, ZrO2, SiC, Si3N4, or composites with each other, or combined with carbon fibers. For the manufacture of ceramic engines and special components that are wear-resistant and high-temperature resistant.
The Application Of Structural Ceramic
Structural ceramics mainly refer to a large class of new ceramic materials that exert their mechanical, thermal, chemical and other properties. They can serve in many harsh working environments, and thus become the key to the realization of many emerging science and technology.
In the field of space technology, the manufacture of spacecraft requires structural materials and protective materials that can withstand high temperature and rapid temperature changes, high strength, light weight and longevity. In this regard, structural ceramics have an absolute advantage. Carbon-quartz composite ablative materials have been successfully used to launch and recover artificial earth satellites since the first spacecraft used high-temperature and low-temperature insulation tiles. In the future, the development of space technology will rely more on the application of new structural materials. In this regard, structural ceramics, especially ceramic matrix composites and carbon/carbon composites, are far superior to other materials.
The application of high-tech is the magic weapon for winning modern warfare. In the development of the military industry, high-performance structural ceramics play a pivotal role. For example, the success of advanced subsonic aircraft depends on the application of structural ceramics and fiber-reinforced ceramic matrix composites with high toughness and high reliability.
Optical Communication Industry
The optical communication industry is one of the fastest growing high-tech industries in the world, with a global output value of more than 3 billion US dollars. Its rapid development mainly depends on the research on the mechanism of optical fiber loss and the use of structural materials for optical fiber joints. Our institute has successfully used zirconia toughened ceramic materials to develop optical fiber connectors and sleeves, which have excellent performance and well meet the development needs of my country’s optical communication industry.
With the high density and high power of semiconductor devices, the development of integrated circuit manufacturing industry urgently needs to develop a new type of substrate material with good insulation and fast heat conduction. The high thermal conductivity aluminum nitride and silicon carbide substrate materials that came out in the mid-to-late 1980s are gradually replacing the traditional alumina substrate. In this field, the thermal conductivity of the high thermal conductivity aluminum nitride ceramics developed by our institute has reached 228 W/m ×K, the performance ranks the forefront at home and abroad. Aluminum nitride-glass composite material has become a research hotspot in the field of contemporary electronic packaging materials. Its thermal conductivity is 5-10 times that of alumina-glass, and the sintering temperature is within 1000°C. It can be used with wiring materials such as silver and copper. Co-fired to produce multilayer wiring boards with good thermal conductivity and electrical properties. The aluminum nitride-glass composite material developed by me has a thermal conductivity of 10.8 W/m×K, which is in a leading position in the world. It meets the requirements of miniaturization and densification of large-scale integrated circuits.
The Related Terms For Structural Ceramic
Special structural ceramics are an important branch of ceramic materials. They are mainly characterized by high temperature resistance, high strength, super hardness, wear resistance, corrosion resistance and other mechanical properties. Therefore, they are important in metallurgy, aerospace, energy, machinery, optics and other fields. Applications. The special structural ceramics produced by our company include the following types:
- Nitride ceramics is a new type of engineering ceramics developed in the past 20 years. The difference from general silicate ceramics is that the combination of nitrogen and silicon is a covalent bond, so it has strong binding force and good insulation. Features.
- Silicon nitride has high strength and high hardness. It is one of the hardest substances in the world. It has good temperature resistance, and its strength can be maintained up to 1200°C without decreasing, until 1900°C. It decomposes, and it has amazing chemical resistance, while being a high-performance electrical insulating material. The overall performance of various silicon nitride ceramic products produced by the company using microwave sintering technology has reached the international advanced level.
- The theoretical thermal conductivity of aluminum nitride is 320W/m·k, which is about 80% of that of copper. At the same time, aluminum nitride has low dielectric constant, high resistance, low density and thermal expansion coefficient close to that of silicon, and its comprehensive performance is better than Al2O3, BeO, SiC, etc., are used for high thermal conductivity insulators and electronic substrate materials. The density of various aluminum nitride ceramic products produced by the company is greater than 3.25, and the thermal conductivity is 120-200W/m·K. Various specifications of aluminum nitride ceramics can be produced according to requirements.
It can be divided into two categories: metalloid carbides (such as titanium carbide, zirconium carbide, tungsten carbide, etc.) and non-metallic carbides (such as carbon tetraboride, silicon carbide, etc.).
Carbide is a high temperature resistant material. Many of the carbides have softening points above 3000°C. Most carbides are more resistant to oxidation than carbon and graphite. Many carbides have high hardness and good chemical stability.
Usually has a high melting temperature and is very stable in an oxidizing atmosphere. High mechanical strength, electrical insulating properties and chemical stability. Except for beryllium oxide ceramics, its thermal conductivity is low. Usually, superfine powder is used and a small amount of sintering accelerator and modification additives are added.
According to the product shape and performance requirements, various molding methods such as High Pressure Hot Injection Molding, dry pressing, isostatic pressing, casting, extrusion and grouting can be used. Most products are fired in an oxidizing atmosphere, and sometimes vacuum, hydrogen, or controlled atmosphere are used.
Composite Structural Ceramics
Microwave ultra-high temperature sintered boron carbide ceramic armor material
The high-density silicon carbide/boron carbide composite ceramic has a bending strength of 500-600MPa even at a high temperature of about 1400°C. The company’s silicon carbide/boron carbide composite special ceramic materials produced by microwave-enhanced reactive infiltration process have the characteristics of small specific gravity, high hardness, high modulus, and impact resistance, and are used in a new generation of ceramic armor.
High temperature resistant, high strength, high toughness ceramics
Zirconia toughened ceramics have made significant progress in the research of structural ceramics. The toughened matrix materials, in addition to stable zirconia, are common oxide ceramics such as alumina, thorium oxide, spinel, mullite and so on. . The company can use microwave high-temperature equipment to mass produce various oxide special structural ceramics at a lower cost.
High temperature and corrosion resistant transparent ceramics
The composition of modern electric light sources has high requirements on high temperature resistance, corrosion resistance and light transmittance of materials. The company uses microwave sintering to produce alumina and aluminum nitride transparent ceramic materials. The overall light transmittance and mechanical properties exceed traditional methods. produced products. It is used in various high temperature optical windows, probes and lamps.
Other Structural Ceramics
Other Materials Related to Structural Ceramics
Electronic ceramic steel Structural ceramics Insulation materials Wear-resistant wear-resistant materials Wear-resistant pipes Wear-resistant ceramics Wear-resistant elbows Special ceramics Alumina Ceramics Development History
Special Structural Ceramics
Among the materials, there is a class called structural ceramic materials, which are mainly made of various materials made of mechanical properties such as strength, hardness and toughness. Metals have been widely used as structural materials. However, since metals are susceptible to corrosion and are not resistant to oxidation at high temperatures, they are not suitable for use at high temperatures. The emergence of high-temperature structural materials has made up for the weakness of metal materials. This kind of material has the advantages of being able to withstand high temperature, not afraid of oxidation, acid and alkali corrosion resistance, high hardness, wear resistance, low density, etc. It is very suitable as a high temperature structural material.
Alumina ceramic (artificial corundum) is an extremely promising high temperature structural material. It has a high melting point and can be used as advanced refractory materials, such as crucibles, high-temperature furnace tubes, etc. Taking advantage of the high hardness of alumina, it is possible to manufacture corundum ball mills used in the laboratory to grind materials that are less hard than it. Using high-purity raw alumina ceramic materials and using advanced technology, alumina ceramics can also be made transparent, which can be used to make lamps for high-pressure sodium lamps.
Silicon Nitride Ceramics
Silicon nitride ceramic is also an important structural material. It is a superhard substance with low density, lubricity and wear resistance. Except for hydrofluoric acid, it does not react with other inorganic acids and is resistant to corrosion. Strong ability; can also resist oxidation at high temperature. And it can also resist the shock of cold and heat, it can be heated to more than 1000 degrees in the air, cooled sharply and then heated sharply, and it will not break. It is silicon nitride that has such good properties that people often use it to manufacture mechanical components such as bearings, turbine blades, mechanical seal rings, and permanent molds.
Boron nitride ceramics, boron carbide ceramics
Boron nitride ceramics is an emerging industrial material, which is a hexagonal crystal with a scaly structure. It looks like ivory. Boron nitride ceramics are developed with the development of aerospace and electronic industries, and have a wide range of industrial uses. It has been discovered as early as 2000. A lot of research work has been done on this material since the Second World War. It was not developed rapidly until the hot pressing method was solved in 2010. Our country has successfully researched the raw materials from 2010, and successfully developed it in 2018. Hot-pressed ceramics, and has been applied to our mouth industry and Eryi technology.
The main components of ruby and sapphire are Al2O3 (corundum). Ruby is red due to a small amount of chromium-containing compounds mixed with it; sapphire blue is due to a small amount of titanium-containing compounds mixed in it. In 1900, scientists used the method of melting alumina and adding a small amount of chromium oxide to produce a ruby with a mass of 2g-4g. Now, rubies and sapphires as large as 10g can be produced.