1. Material structure, performance and application relationship
The fundamental difference in material structure makes ceramic materials have a greater emphasis on applications than solid materials such as organic polymers and metals.
2.Silicon carbide (SiC) ceramic structure and performance
Ceramic materials are composed of highly directional and covalent covalent bonds and ionic bonds, so they exhibit high melting points, high hardness, good chemical stability, and abrasion resistance. As one of the ceramic materials, silicon carbide ceramics have a Si-C covalent bond ratio of 88%, showing the excellent performance of general ceramic materials. In addition, it also exhibits exceptionally good performance due to its inherent structural reasons. As shown in Figure 2, the structure of the silicon carbide ceramic material is a tetrahedron composed of Si / C diatoms; Si / C results in a lower density; compared to other ceramic materials, silicon carbide is a lightweight ceramic material. The silicon carbide composed of two atoms of Si / C also has the characteristics of low thermal expansion coefficient, high thermal conductivity and thermal shock resistance.
3. Application of silicon carbide ceramics
Thanks to a series of excellent properties of silicon carbide ceramics, silicon carbide ceramics have been applied in many modern industrial fields, mainly focusing on four aspects such as refractory materials, wear-resistant high-temperature parts, abrasive molds and bullet-proof armor.
1) Refractory materials: Compared with abrasives, silicon carbide ceramics are more widely used as refractories abroad; and China has gradually expanded the application of silicon carbide ceramics in refractory materials. There are generally three grades of refractory silicon carbide, and their application directions are shown in Table 1.
2) Wear-resistant high-temperature parts: Because silicon carbide ceramics have high hardness, resistance to acid and alkali chemical corrosion, good wear resistance and thermal conductivity, they are often used in wear-resistant high-temperature parts, such as high-temperature heat exchangers and steel rolling. Rollers on the machine.
3) Abrasive mold: Silicon carbide is the hardest material after diamond and boron carbide; therefore, in the machining industry, many abrasive cloths, wheels, abrasive paper and various abrasives are made of silicon carbide ceramics. Made of materials.
4) Bulletproof armor: modern bulletproof materials pursue the trinity of good bulletproof effect, light material and low price; and the high hardness, relatively small density and low price of silicon carbide make it great for bulletproof armor. In the fields of tanks, ships, fighters, bullet-proof helmets and body armor, there is a place for silicon carbide ceramics.
Silicon carbide ceramics in the 4.5G era
For example, human evolution is accompanied by the development of intelligence and the use of tools. The 1G to 5G mobile communication innovation is generally the upgrade of software and hardware. As an author of learning materials, I pay more attention to key materials (hardware) that are compatible with 5G development. The core of the 5G era is not around semiconductor chips; SiC, as the latest third-generation semiconductor material, helps the development of 5G mobile communications. Among the key materials in the 5G era, ceramic materials also make a big difference; then, when SiC is used as a ceramic material, can it be a part of the 5G era? Combining the characteristics of key materials and the properties of silicon carbide ceramics in the 5G era, here are a few of the possible applications of silicon carbide ceramics in the 5G era.
1) Electromagnetic shielding materials for mobile phones: The size and spacing of internal chips of smartphones in the 5G era are getting smaller and smaller, and it can be said that the integration level and signal transmission density are high; this has led to more serious electromagnetic interference inside mobile phones. An integral part of the smartphone in the 5G era. According to reports, silicon carbide ceramic composites have wave absorbing properties, coupled with its small density and high mechanical strength, so it is expected to be a small and lightweight wave absorbing device inside 5G smartphones.
2) Cell phone heat dissipation material: Due to the increasingly powerful functions of smartphones in the 5G era, the integration and density of chips and modules within the cell phone has increased, which has led to a sharp increase in heat generation during the operation of semiconductor devices. One of the key reasons for the failure of semiconductor devices is thermally induced. Therefore, it is very urgent to develop a good supporting heat conduction and heat dissipation material. As far as thermal and thermal ceramics are concerned, alumina ceramics are currently the most mature materials. However, alumina ceramics still have the disadvantages of low thermal conductivity and large difference in thermal expansion coefficient of semiconductor chips. It is easy to accumulate internal stress and cause chip failure, so it is difficult to adapt to the requirements of 5G era for thermal and heat dissipation materials. Silicon carbide ceramics have a high thermal conductivity, a small thermal expansion coefficient, and a high degree of matching with the thermal expansion coefficient of the chip. In addition, if the chip material uses the latest generation of SiC semiconductors in the 5G era, the thermal expansion coefficient will be perfect. SiC ceramics have good prospects in the field of thermal conductivity materials for mobile phones in the 5G era.