Recently, covid 19 outbreak spreads in Shanghai, China. There are more than 25,000 new asymptomatic domestic infections every day. China is implementing a dynamic zero-out policy. A leading respiratory expert said the key to COVID-19 prevention and control is to minimize transmission and fatality rate. Omicron has a low case fatality rate but is highly transmissible and can still claim many lives in large outbreaks. "Total openness is not applicable in China. For China, we should keep to the dynamic zero-out and gradually open up."
However, "dynamic zero clearance" is not the pursuit of complete "zero infection". As the Novel Coronavirus has its own uniqueness and strong concealment, there may be no way to prevent the detection of cases at present, but rapid detection and prompt treatment must be carried out, as soon as one case is found, one case will be dealt with.
The situation in Shanghai is serious. As the financial center of China, Shanghai is a very important city, and the outbreak of the epidemic in Shanghai will put a great impact on China's economy. The current task is to contain the spread of the epidemic as soon as possible, to achieve social zero so that Shanghai's life and economy quickly return to normal.
As China plays an important role in the global supply chain, the outbreak will have a significant impact on the supply and prices of many Silicon Nitride powder.
Introduction to Silicon Nitride Si3N4 Powder
Silicon nitride is a kind of inorganic substance, the chemical formula is Si3N4. The relative molecular mass is 140.28. Gray, white or off-white.
Physicochemical Properties of Silicon Nitride Si3N4 Powder
Si3N4 is a high-temperature insoluble compound. It has properties of high-temperature creep resistance. Hexagonal system. Crystals are hexahedral. The density of Si3N4 obtained by the reaction sintering method is 1.8-2.7 g/cm3, and the density of Si3N4 obtained by the hot-pressing method is 3.12-3.22 g/cm3. The Mohs hardness is 9~9.5, Vickers hardness is about 2200, and the microhardness is 32630MPa. The melting point is 1900℃ (under pressure). It usually decomposes at about 1900℃ at atmospheric pressure. Specific heat capacity is 0.71J/(g·K). The heat of formation is -751.57kJ/mol. The thermal conductivity is (2-155) W/(m·K). The linear expansion coefficient is 2.8~3.2×10-6/℃(20~1000℃).
Insoluble in water. Soluble in hydrofluoric acid. The temperature at which oxidation begins in the air is 1300~1400℃. The specific volume resistance is 1.4×105 ·m at 20℃ and 4×108 ·m at 500℃. The elastic modulus is 28420~46060MPa. The compressive strength is 490MPa (reaction sintering). At 1285℃, it reacts with dicalcium diazide to form calcium diazide. At 600℃, the transition metal is reduced and nitrogen oxides are released. The bending strength is 147MPa. It can be made by heating silicon powder in nitrogen or reacting silicon halide with ammonia. The resistivity is between 10^15-10^16Ω.cm. It can be used as high-temperature ceramic material.
Except for hydrofluoric acid and hot phosphoric acid, silicon nitride does not react with other inorganic acids and has strong corrosion resistance.
|Silicon Nitride Si3N4 Powder Properties|
|Other Names||silicon (IV) nitride, α-Si3N4, SiN, trisilicon tetranitride, Si3N4 powder|
|Appearance||white to gray powder|
|Solubility in H2O||insoluble|
Applications of Silicon Nitride Si3N4 Powder
Silicon nitride ceramic material has the advantages of high thermal stability, high oxidation resistance, and high dimensional accuracy. Because the silicon nitride is the covalent compound with high bond strength, and it will form an oxide film in the air, it has good chemical stability. Silicon nitride is not oxidized below 1200℃, and a protective film can be formed at 1200~1600℃ to prevent it from further oxidation. Silicon nitride is not infiltrated or corroded by aluminum, lead, tin, silver, brass, nickel, and many other molten metals or alloys, but can be corroded by magnesium, nickel-chromium alloy, stainless steel, and other molten liquids.
Silicon nitride ceramic materials can be used in high-temperature engineering components, advanced refractory in the metallurgical industry, corrosion-resistant components and sealing components in the chemical industry, machining industry tools, and cutting tools.
Because silicon nitride can form a strong bond with silicon carbide, alumina, thorium dioxide, boron nitride, etc., it can be used as a bond material to modify with different proportions.
In addition, silicon nitride can be used in solar cells. After the silicon nitride film is plated by the PECVD method, not only can it be used as an antireflection film to reduce the reflection of the incident light, but also, in the deposition process of a silicon nitride film, the hydrogen atom of the reaction product enters the silicon nitride film and silicon wafer, playing a role of passivation defect. The ratio of silicon nitride to silicon nitrogen atoms is not a strict 4:3, but fluctuates within a certain range according to different technological conditions. Different atomic ratios correspond to different physical properties of the film.
Also, it can be used in ultra-high temperature gas turbines, aircraft engines, electric furnaces, etc.
Main Supplier of Silicon Nitride Si3N4 Powder
Luoyang Tongrun Nano Technology Co. Ltd. (TRUNNANO) is a trusted global chemical material supplier & manufacturer with over 12-year-experience in providing super high-quality chemicals and Nanomaterials, including silicon powder, nitride powder, graphite powder, zinc sulfide, calcium nitride, 3D printing powder, etc.
If you are looking for high-quality silicon nitride Si3N4 powder, please feel free to contact us and send an inquiry. ([email protected])
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