Denka Silicon Nitride SN-F 2
Silicon nitride(IV)
CAS: 12033-89-5
Molecular Formula: N4Si3
Denka Silicon Nitride SN-F 2 - Names and Identifiers
| Name | Silicon nitride(IV) |
| Synonyms | E 05 E 10 Silicon nitrid E 05 (nitride) E 10 (nitride) Silicon nitride Silicon nitride(IV) Denka Silicon Nitride SN-F 2 |
| CAS | 12033-89-5 |
| EINECS | 234-796-8 |
| InChI | InChI=1/4H3N.3H4Si/h4*1H3;3*1H4/q4*-3;; |
Denka Silicon Nitride SN-F 2 - Physico-chemical Properties
| Molecular Formula | N4Si3 |
| Molar Mass | 140.2833 |
| Density | 3.44 g/mL at 25 °C (lit.) |
| Melting Point | 1900 °C |
| Water Solubility | Insoluble water. |
| Appearance | off white lens |
| Specific Gravity | 3.44 |
| Color | Pale gray |
| Merck | 14,8497 |
| Storage Condition | Room Temprature |
| Stability | Stable. |
| Sensitive | 1: no significant reaction with aqueous systems |
| Refractive Index | 2.8 |
| MDL | MFCD00011230 |
| Physical and Chemical Properties | Off-White alpha crystalline form powder. Because of its diamond-type three-dimensional lattice structure, it has high temperature thermal stability, thermal shock resistance, chemical stability and good electrical insulation and hardness. Silicon nitride has a melting point of 1900 ° C. And a relative density of 3.44. It is stable when heated to 1450-1550 °c in air. Soluble in hydrofluoric acid, insoluble in cold, hot water and dilute acid, for concentrated sulfuric acid and concentrated sodium hydroxide solution is also very slow. |
| Use | It is mainly used as raw materials of functional ceramic materials, refractory materials of non-ferrous metals, high-temperature structural materials and heat-resistant coatings for aircraft engines, gas delivery nozzles, bearings, etc. |
Denka Silicon Nitride SN-F 2 - Risk and Safety
| Hazard Symbols | Xi - Irritant |
| Risk Codes | 37 - Irritating to the respiratory system |
| Safety Description | S22 - Do not breathe dust. S24/25 - Avoid contact with skin and eyes. |
| WGK Germany | 3 |
| RTECS | VW0650000 |
| FLUKA BRAND F CODES | 10 |
| TSCA | Yes |
Denka Silicon Nitride SN-F 2 - Nature
Open Data Verified Data
silicon nitride has two crystal forms: a and β. a-Si3 N4 is granular Crystal, p-S13 N4 is acicular crystal, both belong to hexagonal system, relative density 3. 18, Mohs hardness 9. Small thermal expansion coefficient, good chemical stability, and has excellent oxidation resistance. Decomposition to nitrogen and silicon at 1900 °c. The strength of silicon nitride is very high and resistant to high temperature. Even at a high temperature of 1200 ° C, the strength will not change, and it will not melt into a molten body after heating, and will not decompose until 1900 ° C, can resist almost all inorganic acids and a variety of organic acid corrosion I silicon nitride hard, thermal expansion coefficient is small, thermal shock stability is excellent, good insulation, chemical stability, high mechanical strength.
Last Update：2024-01-02 23:10:35
Denka Silicon Nitride SN-F 2 - Preparation Method
Open Data Verified Data
with silicon powder as raw material, preliminary nitridation is carried out in nitrogen and at a high temperature of 1200 ℃, and a part of silicon powder reacts with nitrogen to form silicon nitride, A second cyanation reaction is then carried out in a high-temperature furnace at 1350-1450 °c to form silicon nitride. Alternatively, silica, nitrogen and carbon are used as raw materials, silica and carbon are mixed in a certain proportion, and nitrogen is added to heat up to 1400 ° C for nitridation to prevent the formation of SiC, it is necessary to add a small amount of Fe2 0a to inhibit the formation of SiC. After the reaction, the iron-containing compound is removed with hydrochloric acid. The silicon nitride powder prepared by this method has a high content of oral phase, but there is often a small amount of Si02 impurity in the powder. Silicon tetrachloride and ammonia gas may be used as raw materials to react silicon tetrachloride and ammonia gas in hexane at 0 ° C. To thermally decompose the product in an inert gas to produce silicon nitride. It is also possible to use silane (SiH4) and ammonia to form amorphous Si3 N4 at 1050-1350 °c and to form silicon nitride in the oral phase at 1450 °c.
Last Update：2022-01-01 09:05:27
Denka Silicon Nitride SN-F 2 - Introduction
There are two kinds of crystals, α-and β. Soluble in hydrofluoric acid. Insoluble in water. It is a covalently bonded compound with very stable binding. It is still stable when heated to 1450~1550 ℃ in air. High strength. Hardness is high. Silicon powder is made at high temperature in a nitrogen atmosphere. It can also be irradiated by silicon halide and ammonia through carbon dioxide laser beam to generate amorphous silicon nitride, and then heated in an electric furnace at 1450°C and nitrogen atmosphere to prepare high-purity silicon nitride powder. Mainly used as raw materials for functional ceramic materials, refractory materials for non-ferrous metals, high-temperature structural materials such as aircraft engines, gas transmission nozzles, bearings, and heat-resistant coatings, as well as materials for grinding, cutting, and electric furnaces.
Last Update：2022-10-16 17:12:37
Denka Silicon Nitride SN-F 2 - Use
Open Data Verified Data
used for insulating materials, mechanical wear-resistant materials, heat engine materials, cutting tools, advanced refractory materials and corrosion-resistant, wear-resistant sealing parts. The silicon nitride ceramic can be used as the combustion chamber of the gas turbine, the mechanical seal ring, the pipeline and valve of the electromagnetic pump for conveying liquid aluminum, the permanent mold, the liquid steel separation ring, etc. Silicon nitride friction coefficient is small, for high temperature bearings, the working temperature of up to 1200 degrees Celsius, than the ordinary alloy bearing working temperature increased by 2.5 times, and the working speed is 10 times of ordinary bearings. The use of silicon nitride ceramic good electrical insulation and resistance to rapid cooling and rapid heat can be used as a glow plug, with which the ignition of the car can make the engine starting time is greatly shortened, and can start the car quickly in cold weather. Silicon nitride ceramics also have good microwave transmission properties, dielectric properties and high temperature strength, and are used as radar radomes for missiles and aircraft.
Last Update：2022-01-01 09:05:28
Denka Silicon Nitride SN-F 2 - Reference Information
| EPA chemical information | Information provided by: ofmpub.epa.gov (external link) |
| ceramic material | silicon nitride (Si3N4) is a dense, high strength and high toughness ceramic material developed by scientists in the 2070s. It was originally hoped to replace metal with ceramics in advanced turbine and reciprocating engines to provide higher operating temperatures and efficiency. Although the ultimate goal of ceramic engines has not been achieved so far, silicon nitride has been used in many industrial applications, such as engine components, bearings and cutting tools. Silicon nitride has better high temperature performance than most metals, and has high strength stability, creep resistance and oxidation resistance. In addition, compared with most ceramic materials, its lower thermal expansion coefficient makes it have good thermal shock resistance. |
| Composition and structure | The molecular formula of silicon nitride is Si3N4, which is a covalently bonded compound. Silicon nitride ceramics are polycrystalline materials, and the crystal structure is hexagonal. The crystal system is generally divided into two crystal directions, α and β, both of which are composed of [SiN4]4-tetrahedron. Among them, β- Si3N4 has higher symmetry and smaller molar volume, it is a thermodynamically stable phase in temperature, while α- Si3N4 is easier to generate in dynamics. At high temperature (1400 ℃ ~ 1800 ℃), α phase will undergo phase change and become β type. This phase change is irreversible, so α phase is conducive to sintering. |
| appearance | the appearance of silicon nitride obtained from different crystal phases is different. α- Si3N4 is white or off-white loose wool or needle-like, β- Si3N4 is darker in color and is dense granular polyhedron or short prism. Silicon nitride whiskers are transparent or translucent, and the appearance of silicon nitride ceramics is gray, blue gray to gray, it varies with density and phase ratio, and also due to other colors of additives. After polishing, the surface of silicon nitride ceramic has metallic luster. |
| electrical insulation | silicon nitride ceramics can be used as high-temperature insulating materials. the performance indexes of silicon nitride ceramics mainly depend on the synthesis method and purity. free silicon that has not been nitrided in the materials, alkali metals, alkaline earth metals, iron, titanium, nickel and other magazines brought in in the preparation, can deteriorate the electrical properties of silicon nitride ceramics. Generally, silicon nitride ceramics have a specific resistance of 1015~1016 ohms and a dielectric constant of 9.4~9.5 at room temperature. At high temperatures, silicon nitride ceramics still maintain a high specific resistance value. With the improvement of process conditions, silicon nitride can enter the ranks of commonly used dielectrics. |
| sintering of silicon nitride | pure silicon nitride is difficult to make completely dense materials. This covalently bonded material is not easy to sinter, and because it is easily decomposed into silicon and nitrogen at high temperatures, it cannot be heated to above 1850°C. Therefore, to obtain dense silicon nitride can only be bonded by indirect methods, such as adding a small amount of chemical substances to help it densify. These chemical substances are called sintering aids, and a certain degree of liquid phase sintering usually occurs. |
| type | common silicon nitride has the following three main types: reactive bonded silicon nitride (RBSN), hot pressed silicon nitride (HPSN), sintered silicon nitride (SSN). Reactive bonded silicon nitride is produced by direct nitriding of compact silicon powder, and since it is difficult to ensure its complete reaction, it is difficult to achieve high density, usually at about 2.5g.cm-3, while hot pressed and sintered silicon nitride can reach 3.2g.cm-3. The higher density makes HPSN and SSN materials have better physical properties, which also means that they can meet higher requirements for applications. The volume change during the nitriding process is extremely small, so the RBSN component does not need to be reprocessed after manufacturing, and complex and precise-sized components can be manufactured in a single process stage. |
| application field | silicon nitride materials are currently mainly used in some special scenarios, such as reciprocating engine parts and turbochargers, bearings, metal cutting and Shaping tools and molten metal processing, etc. Reciprocating engine components: The largest market for silicon nitride components is for combustion components and vulnerable reciprocating (diesel and spark ignition) engines. Due to cost factors and the technical difficulty of industrial production of complex ceramic components, as well as concerns about the reliability of ceramic components, this material is relatively cautious in design and use, which affects the large-scale application of silicon nitride ceramics. Small and dense silicon nitride sintered parts can be used in automobile and truck engines for scenarios where stress and temperature are relatively low and the consequences of failure are not serious. Including: diesel engines, glow plugs, etc., which can speed up the starting speed, reduce emissions, and reduce noise; turbochargers (about 10cm in diameter) can reduce engine lag and emissions. At present, most of these components are manufactured in Japan and the United States, and it is estimated that 300,000 sets of sintered silicon nitride turbochargers are produced each year. In the United States, the demand for energy conservation and emission reduction has promoted the development of ceramic components. In Japan, it is based on the improvement of light engine performance brought by ceramic components. The development focus of various countries is now in applications that require light weight or wear resistance (such as exhaust valves and valve springs). Bearings: The wear resistance, low friction and high rigidity of completely dense silicon nitride ceramics improve the performance of high temperature non-lubricated roller and ball bearings. Compared with traditional high-density steel and cemented carbide bearings, HPSN bearings have longer bearing life, better speed performance and stronger corrosion resistance. Most silicon nitride ceramic bearings are used for hybrid ball bearings (ceramic ball and steel ring bearings). Applications include machine tool spindles, vacuum pumps, etc. Ceramic bearings can be used for corrosion, electric field or magnetic field and other occasions where metal cannot be used. For example, in tidal flow meters with seawater erosion problems, or electric field detectors, etc. Although the reliability of the application of silicon nitride in bearings has been widely recognized, its manufacturing cost is high. How to reduce the production cost has become the biggest problem in its popularization and application. In many conventional industrial applications, reactive bonded silicon nitride (RBSN) is usually used because of its lower working conditions, especially some automotive non-wear components. For example, the fixing device used to locate and transfer metal parts in the process of induction heating and resistance welding uses the electrical insulation, wear resistance, low thermal conductivity and thermal shock resistance of silicon nitride; the need for metal purity control makes silicon nitride widely used in thermocouple sheaths and melting crucibles to process molten aluminum, zinc, tin and lead alloys; based on the strength, resistance and thermal shock resistance of silicon nitride materials, arc welding nozzles are also one of its stable markets; they can also be used in professional kiln furniture with light weight and high thermal shock resistance, and need to repeat the thermal cycle of fired parts, such as dental prostheses. |
| toxicity | see β silicon carbide powder. |
| use | silicon nitride powder is widely used in industry as an engineering ceramic material. Mainly used in ultra-high temperature gas turbines, aircraft engines, turbine blades, heat exchangers, electric furnaces, etc. It can also be used as a heat-resistant coating for rockets and atomic energy reactors. Mainly used as raw materials for functional ceramic materials, refractory materials for non-ferrous metals, high-temperature structural materials such as aircraft engines, gas transmission nozzles, bearings, and heat-resistant coatings, as well as materials for grinding, cutting, and electric furnaces. |
| production methods | mainly include silicon powder direct nitriding method, silicon dioxide reduction method and silicon chloride method. In large-scale industrial production, the silica reduction method is more important. Silicon dioxide reduction method: 100 parts by weight of silicon dioxide powder, 35 parts by weight, 100 parts by urea resin, then 800 parts by water, 0.1 parts by alumina (for reaction core), 1 part by ammonium oxalate and 0.3 parts by nonionic surfactant (as dispersant) are added for strong stirring, and ammonia water is added in the stirring to adjust the Ph value to 9.0. The mixed slurry is spray dried, and the obtained dried product is subjected to a 3 h nitriding reduction reaction at 1480 ℃ in an electric furnace and nitrogen atmosphere. Then reduce the reaction product in. At 720 ℃, the finished silicon nitride powder was prepared by decarbonization treatment in the air. SiO2 C→SiO CO3SiO2 3C N2→Si3N4 3CO |
Last Update：2024-04-09 21:21:28
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Tel: 18301782025
Email: 3008007409@qq.com
Mobile: 18021002903
QQ: 3008007409
Wechat: 18301782025
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