Properties and Applications of Porous Silicon Carbide Ceramics

porous ceramics, as a new type of material with excellent performance and broad prospects, are widely used in petroleum and chemical industries, environmental protection, metallurgy, machinery, mining, food, medicine, and biology as filtration, separation, gas distribution, sound absorption, sensitive materials and separators, bioceramics, and catalyst carriers. Silicon carbide porous ceramics, which combine the characteristics of high temperature resistance, corrosion resistance, and good thermal shock resistance of silicon carbide, are receiving increasing attention. Nowadays, countries have invested a large amount of manpower, material resources, and financial resources in this field of research. In addition, the demand for porous ceramics in various application fields is constantly expanding and there is an urgent need for high-performance porous ceramics, Especially in this century, the call for the development of biotechnology and the control and improvement of the environment continues to rise, which will promote the rapid development of porous ceramics and ultimately create a better prospect for the application of porous ceramics.
(1) Heat exchange materials
Due to the huge porosity of this kind Silicon Carbide Ceramics, they exhibit considerable thermal conductivity under high temperature conditions, used as a heat exchange material, with sufficient heat exchange. Due to the advantages of heat resistance, corrosion resistance, non pollution, and economy, ceramic substrates are widely used in the heat recovery of metallurgy, ceramics, petroleum, and chemical industries. For example, placing the ceramic body at the flue port of a heating furnace allows high-temperature gas to enter the flue through porous ceramics, while heating the ceramic body to a temperature close to that inside the furnace. So, the porous ceramic body will radiate heat energy into the furnace, reducing heat dissipation. According to relevant information, it can save 30% energy. Some units have been using foam ceramics as porous ceramics for the above heat exchanger in the continuous steel heating furnace, which has opened up a broad prospect for its application.
(2) Heating device
If the prepared porous silicon carbide ceramics material matrix can generate electricity and heat, it can be applied to fluids Heating. This type of heating device has high heating efficiency and speed, and can be used in technologies such as HVAC.
(3) Catalytic carrier
Due to its high thermal conductivity, high specific surface area, and good chemical stability, silicon carbide foam can be used as a catalyst carrier. Moreover, it has the advantages of heat resistance, corrosion resistance, non pollution, high mechanical strength, high hardness, processability and low cost. After controlling its surface, the catalyst can be fixed. Therefore, it has been widely valued and applied in chemical processes such as petroleum, food hygiene, and environmental protection, and thus promotes the development of porous ceramics. In the field of chemical engineering, including organic and inorganic chemical engineering, porous ceramics can be used as catalyst carriers. As a carrier for contact combustion catalysts, silicon carbide foam can be used for the treatment of toxic and odorous gases in chemical plants, printing factories, food factories, animal husbandry and other departments. Especially in the oxidation treatment of automotive exhaust, porous ceramics exhibit unparalleled excellent properties. The core component of the automotive exhaust purification device is the catalytic oxidation system. In order to improve catalytic efficiency, exhaust efficiency, and long service life, ceramic porous bodies are generally used as catalytic carriers, which can convert harmful gases such as CO, HC, and HOx emitted from automobiles into CO2, H2O, N2, and the conversion rate can reach over 90%.
(4) Molten metal filtration
The number, shape, distribution, and size of inclusions in metals all have an impact on the strength, plasticity, and toughness of the material, therefore, the study of metal purification methods has attracted great attention due to their extremely high comprehensive benefits. Research has shown that using silicon carbide foam to filter metal can significantly remove impurities and gases in the metal, thereby improving the internal quality of the metal. Especially recently, the increasing requirements for aluminum and copper in food packaging, electronic components, and wires have promoted this use.
(5) Various chemical filtration
silicon carbide foam filter are particularly corrosion-resistant, and in addition, the processed three-dimensional network structure has better performance, the filtration effect can be well applied in chemical filtration.
(6) Gas filtration
The exhaust gases such as smoke and oil mist emitted from the exhaust outlets of households and catering kitchens are also one of the sources of atmospheric pollution. For the treatment of such waste gas, silicon carbide foam filter can be installed at the exhaust port, and the waste gas can be decomposed by heating it with electricity (>400 OC). The large amount of radioactive waste generated by atomic power plants can be burned to form chemically stable solid powder, which is solidified using ceramic filters. It is convenient and economical to store. silicon carbide foam filter with a pore size of about 40um made from silicon carbide can be used for filtration during the combustion treatment of low radioactive waste in nuclear power plants.
(7) Sound-absorbing material
Using porous ceramics as a sound reduction and soundproofing barrier for tunnels, subways, cinemas, recording rooms, etc. The sound environment provides excellent results. For example, using the damping effect of porous ceramics to reduce the exhaust speed of high-speed exhaust pipes, if the exhaust speed is reduced by half, the noise will be reduced by 24 decibels. China has achieved a noise reduction effect of 25-35 decibels in practical applications.
(8) Filter for diesel engine oil smoke collection
Diesel engine exhaust contains floating particulate matter and NOx, which are one of the causes of atmospheric pollution. Honeycomb ceramics can be used as a substrate for catalyst carriers for automotive exhaust purification, installed in the engine exhaust system. They can catalyze the purification of exhaust gas, purify and filter CO and HC in the exhaust gas, and reduce exhaust noise. The filtration efficiency of porous SiC ceramics is better than that of cordierite honeycomb ceramics.
(9) Used as a sensitive component
The use of porous ceramics as sensitive components has attracted attention from the scientific and technological community. Soil made using porous ceramic probes.  water measuring device can quickly detect changes in soil moisture, and the sensitivity of its probe depends on the porosity and pore size of the material. After electrodes are plated on both sides of the porous ceramic sheet and inserted into the soil, the salt content will be reflected by the changes in the resistance value of the ceramic sheet:
The humidity sensor made by utilizing the performance of porous ceramics to adsorb moisture has been applied in practice. For porous ceramics, It is also a current research and development topic to use as components for measuring pressure and infrared emission and absorption.
(10) Other applications
this kind of silicon carbide ceramics can also be used as shed plates for heat treatment of electronic components, powder flow bed bottom plates, humidifiers Boilers, microbial carriers, etc. In addition, porous silicon carbide ceramic materials are all electrical conductors, which can be used for induction heating in addition to electric heating. There is also great hope for their application in this field.

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