As a professional manufacturer of structural ceramics, Mingrui Ceramics has found that there is an increasing demand for porous ceramics, and customers from the high-tech industry have a greater demand for customization of porous ceramics. Mingrui Ceramics will quickly introduce the preparation process and application of porous ceramics through this article.
Porous ceramics are a new type of ceramic material, also known as pore functional ceramics. It is a ceramic material that has a large number of interconnected or closed pores in the body after being formed and fired at a high temperature. According to the hole forming method and voids, porous ceramics can be divided into: foam ceramics, honeycomb ceramics, granular ceramics, and the shapes can be divided into tubular, honeycomb block, plate and film product types.
Porous ceramics have the characteristics of corrosion resistance, high temperature resistance, and oxidation resistance of traditional ceramic materials, as well as low density, high open porosity, and large specific surface area. Therefore, porous ceramics have a wide range of applications in the fields of catalyst support, fluid filtration, separation and purification, sound absorption and sound insulation, fuel cells, sensors and biological materials. Silicate, aluminosilicate, diatomaceous earth, corundum and emery, cordierite, aluminum titanate, etc. are the main materials for preparing porous ceramics.
Porous ceramic preparation
The preparation methods of porous ceramics are divided into traditional preparation process and new preparation process. The traditional preparation process includes adding pore former process, organic foam impregnation process, foaming process, extrusion molding process, particle accumulation process and sol-gel process; new preparation process The process includes the use of ceramic fibers to prepare porous ceramics, a pore gradient preparation method and an ion exchange method.
The mechanical and chemical properties of porous ceramics are subject to factors such as porosity, strength, and high-temperature stability. The above-mentioned factors also determine the application fields of porous ceramics.
Porous ceramic applications
1. Catalyst carrier
Porous ceramics have an excellent pore structure, a large number, and a large specific surface area. As a catalyst carrier, the contact area between the catalyst and the reactant can be increased, and the catalytic efficiency and speed can be improved. The characteristics of strong adsorption capacity and good thermal stability can prolong the service life of the catalyst and reduce the use cost. It is widely used in automobile exhaust purification and inorganic and organic production fields.
2. Biological materials
Porous bioceramics have the advantages of good biocompatibility, good combination with bone tissue, and no rejection reaction. They are well used in medical fields such as postoperative cavity recovery, improvement of angiogenesis, and promotion of bone repair. In addition, the porous ceramic has a pore structure that is convenient for loading drugs, and its durability can play a supporting role for a long time.
3. Filtration, separation and purification
As a new material for filtration, separation and purification, porous ceramics have the characteristics of long service life, strong antimicrobial ability, corrosion resistance, high temperature resistance, and reusability. In the demanding fields, porous ceramics have been widely used, such as filtering milk, liquid-solid separation, molten metal removal of impurities, industrial wastewater purification, etc.
4. Fuel cell materials
Porous ceramics can be used as cathode materials in fuel cells to provide oxygen transport channels and activation sites to improve reaction efficiency. At the same time, porous ceramics can work stably under the high temperature of fuel cells and provide channels for heat dissipation. The above-mentioned advantages of porous ceramics improve the performance of fuel cells and extend their lifespan, so that the application of porous ceramics in fuel cells will become a research hotspot.
5. Thermal insulation materials
Traditional ceramic materials have low thermal conductivity and can be used as thermal insulation materials. The gas filled in the porous structure of the porous ceramic further strengthens the thermal insulation performance of the porous ceramic. At present, porous ceramics have been widely used as thermal insulation materials in traditional gas furnaces and high-temperature electric furnaces at 1600℃; in Shenzhou series spacecraft and Long March series rockets, multilayer thermal insulation materials composed of porous ceramics and metal thermal insulation materials have been very popular. Good application; the thermal insulation shell of the space shuttle is composed of porous ceramics that are evacuated. Vacuum porous ceramics is currently the best thermal insulation material in the world.
6. Sound-absorbing materials
During the propagation of sound waves, porous ceramics act as a sound barrier, which can change the direction of sound waves so that the sound waves are confined in the cavity. The sound waves in the cavity cause the vibration of the air and overcome the friction of the air to convert the work into heat, which greatly reduces the energy of the sound.
7. Aerospace materials
Porous ceramics have good chemical stability, thermal shock resistance, corrosion resistance and low thermal conductivity, making them an ideal heat-resistant and thermal insulation material used in aircraft and spacecraft.