Application and characteristics of special ceramics
Special ceramics is a general term for a new type of ceramics that is different from traditional ceramics such as household ceramics, architectural ceramics, and sanitary ceramics. It mainly refers to ceramic materials with unique and excellent properties prepared by modern material technology using high-purity synthetic inorganic compounds as raw materials. There are many kinds of special ceramics and they are widely used. The following will briefly sort out the classification methods and application fields of some special ceramics.
Special ceramics can be divided into two categories according to materials: oxide ceramics and non-oxide ceramics. According to the characteristics of materials, special ceramics can be divided into three categories: structural ceramics, functional ceramics and ceramic matrix composites.
1. Structural ceramics. Mainly use the characteristics of high temperature resistance, corrosion resistance, wear resistance and stable chemical performance of special ceramic materials, such as high temperature structural ceramics; ceramic tools, abrasive tools, ceramic seals, ceramic bearings, abrasives and other high hardness and wear-resistant structural ceramics; artificial teeth , bone and other biological structure ceramics.
2. Functional ceramics. Take advantage of the special electrical, magnetic, thermal, optical and biological properties of some ceramic materials.
3. Special ceramic materials Through material design, the performance of single-component ceramics can be improved or the advantages of multi-component materials can be obtained, and the application range of special ceramics can be expanded. There are three types of reinforcement in ceramic matrix composites: particle dispersion reinforcement, whisker reinforcement, and fiber reinforcement. Its application fields include: ceramic cutting tools, engine parts, aircraft brake pads, rocket nozzles, space shuttle ablation materials, etc.
According to the application field of special ceramic materials. Due to their different chemical composition and microstructure, special ceramic materials have different special properties and functions, such as high strength, high hardness, high temperature resistance, corrosion resistance, insulation, conductivity, and various electrical, magnetic, optical, and biocompatibility wait. Widely used in machinery, electronics, aerospace, medical engineering and other aspects.
The main preparation process of special ceramics includes three steps of billet making, molding and sintering. After the forming process is completed, sintering can control the growth of grains, which has a crucial impact on the performance of the material. So far, ceramic sintering technology has been a breakthrough field.
The sintering of special ceramics means that under the action of high temperature, the molded body gradually transforms into a sintered body with a certain geometric shape and firmness through the mutual adhesion and material transfer between the body and the body, eliminating pores, volume shrinkage, and strength improvement. densification process. It can be seen from the macroscopic and microscopic observation of the sintering phenomenon that the volume of the sintered product shrinks, the density increases, and the strength increases. Microscopically, the pore shape changes, the crystal grows, and the composition changes (doping elements).
The above are some knowledge points about special ceramics , I hope it can help you.