What is silicon nitride? Silicon nitride is resistant to oxidation at high temperatures. Moreover, it can resist cold and hot shocks. When heated to above 1000 ℃ in the air, it will not be broken after sharp cooling and heating. Because silicon nitride ceramics have such excellent characteristics, people often use them to manufacture mechanical components such as bearings, turbine blades, mechanical seal rings, permanent molds, etc. Suppose silicon nitride ceramics that are resistant to high temperatures and not easy to heat transfer are used to manufacture the heating surfaces of engine components. In that case, It can improve the quality of engines, save fuel, and improve thermal efficiency. The relative molecular weight is 140.28. It is gray, white, or gray-white. It is a high-temperature insoluble compound with no melting point and strong resistance to high-temperature creep. The load softening point of reaction sintered silicon nitride without binder is above 1800 ℃; Hexagonal crystal system. The crystal is hexahedral. The density of Si3N4 obtained by reaction sintering is 1.8~2.7 g/cm3, and the density of Si3N4 obtained by hot pressing is 3.12~3.22 g/cm3. The Mohs hardness is 9~9.5, the Vickers hardness is about 2200, and the microhardness is 32630 MPa. The melting point is 1900 ℃ (under pressure). It is usually decomposed at 1900 ℃ under normal pressure. The specific heat capacity is 0.71 J/(g · K). The heat of formation is -751.57 kJ/mol. The thermal conductivity is (2-155) W/(m · K).
How to produce silicon nitride? There are two production methods for silicon nitride ceramic products, namely, the reaction sintering method and the hot pressing sintering method. The reaction sintering method is to form silicon powder or a mixture of silicon powder and silicon nitride powder according to the general ceramic product production method. Then, in the nitriding furnace, pre-nitriding at 1150~1200 ℃. After obtaining a certain strength, mechanical processing can be carried out on the machine tool, and then further nitriding at 1350~1450 ℃ for 18~36h until they become silicon nitride. The size of the products made in this way is accurate, and The volume is stable. The hot pressing sintering rule is that silicon nitride powder and a small number of additives (such as MgO, Al2O3, MgF2, AlF3, or Fe2O3) are pressed into hot shape sintered at a pressure of more than 19.6 MPa and a temperature of 1600~1700 ℃. Generally, the products produced by hot pressing sintering have higher density and better performance than those produced by reaction sintering.
Application of silicon nitride Silicon nitride ceramic materials have excellent properties such as high thermal stability, strong oxidation resistance, and high dimensional accuracy of products. As silicon nitride is a covalent compound with a high bond strength and can form an oxide protective film in the air, it also has good chemical stability. It will not be oxidized below 1200 ℃. The protective film generated at 1200~1600 ℃ can prevent further oxidation and will not be oxidized by aluminum, lead, tin, silver, brass, Nickel, and many other molten metals or alloys that are soaked or corroded. Still, they can be corrupted by magnesium, nickel-chromium alloy, stainless steel, and other molten liquids. Silicon nitride ceramic materials can be used for high-temperature engineering components, advanced refractories in the metallurgical industry, anti-corrosion components and sealing components in the chemical industry, tools and cutting tools in the machining industry, etc. Because silicon nitride can form a strong combination with silicon carbide, aluminum oxide, thorium dioxide, and boron nitride, it can be used as a bonding material and modified with different proportions.
Price of silicon nitride Silicon nitride particle size and purity will affect the product's price, and the purchase volume can also affect the cost of silicon nitride. A large amount of large amount will be lower. The price of silicon nitride can be found on our company's official website.
Silicon nitride supplier Luoyang Tongrun Nano Technology Co. Ltd. (TRUNNANO) Luoyang City, Henan Province, China, is a reliable and high-quality global chemical material supplier and manufacturer. It has more than 12 years of experience providing ultra-high quality chemicals and nanotechnology materials, including silicon nitride, nitride powder, graphite powder, sulfide powder, and 3D printing powder. If you are looking for high-quality and cost-effective silicon nitride, you are welcome tocontact usor inquire at any time.
