By lql | 09 February 2023 | 0 Comments
How is silicon nitride made?
What is Silicon nitride?
Silicon nitride is an inorganic substance with the chemical formula of Si3N4. It is an important structural ceramic material with high hardness, lubricity, and wear resistance, and it is an atomic crystal.
Silicon nitride is an inorganic substance with the chemical formula of Si3N4. It is an important structural ceramic material with high hardness, lubricity, and wear resistance, and it is an atomic crystal.
Preparation method of Silicon nitride powder
There are two production methods of silicon nitride ceramic products, namely, the reaction sintering method and the hot pressing sintering method.
1.The sintering method is to mold silicon powder or a mixture of silicon powder and silicon nitride powder according to the general production method of ceramic products. Then, it is pre-nitrided at 1150~1200℃ in a nitriding furnace. After obtaining a certain strength, it can be machined on a machine tool. Then, it is further nitrided at 1350~1450℃ for 18 ~ 36 hours until it becomes silicon nitride. The manufactured product is accurate in size and stable in volume.
2.The hot pressing sintering method is that silicon nitride powder and a small number of additives (such as MgO, Al2O3, MgF2, AlF3, Fe2O3, etc.) are sintered by hot pressing at a pressure above 19.6MPa and at 1600~1700℃. Usually, the products made by hot pressing sintering have higher density and better performance than those made by reaction sintering.
Performance characteristics of Silicon nitride powder
1.The relative molecular weight is 140.28. Gray, white or off-white. It belongs to a high-temperature insoluble compound and has no melting point and strong creep resistance at high temperatures. The load softening point of reaction sintered silicon nitride without binder is above 1800℃
2. It belongs to the hexagonal aluminum nitride system, and its crystal structure is hexahedral. The density of Si3N4 prepared by the sintering method is 1.8~2.7g/cm3, and that of Si3N4 prepared by the hot pressing method is 3.12~3.22g/cm3. Mohs hardness is 9~9.5, Vickers hardness is about 2200, and microhardness is 32630MPa. The melting point is 1900℃ (under pressure). It is usually decomposed at about 1900℃ under normal pressure. The specific heat capacity is 0.71 j/(g k). The heat generated is -751.57kJ/mol. And 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.
3. The initial oxidation temperature of aluminum nitride in the air is 1300~1400℃. The specific resistance is 1.4× 105 m at 20℃ and 4×108 ·m at 500℃. The elastic modulus is 28420~46060MPa. Compressive strength is 490MPa (reaction sintered). At 285℃, it reacts with dicalcium nitride to produce calcium dinitrosilicate, and at 600℃, the transition metal is reduced to release nitrogen oxides. The bending strength is 147MPa. It can be prepared by heating silicon powder in nitrogen or reacting silicon halide with ammonia. The resistivity is 10 15-10 16 Ω cm. It can be used as a high-temperature ceramic raw material.
Price of Silicon nitride powder
Silicon nitride powder particle size and purity will affect the product's price, and the purchase volume can also affect the cost of Silicon nitride powder. A large amount of large amount will be lower. The price of Silicon nitride powder can be found on our company's official website.
Silicon nitride powder 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 powder, nitride powder, graphite powder, sulfide powder, and 3D printing powder. If you are looking for high-quality and cost-effective Silicon nitride powder, you are welcome to contact us or inquire any time.
There are two production methods of silicon nitride ceramic products, namely, the reaction sintering method and the hot pressing sintering method.
1.The sintering method is to mold silicon powder or a mixture of silicon powder and silicon nitride powder according to the general production method of ceramic products. Then, it is pre-nitrided at 1150~1200℃ in a nitriding furnace. After obtaining a certain strength, it can be machined on a machine tool. Then, it is further nitrided at 1350~1450℃ for 18 ~ 36 hours until it becomes silicon nitride. The manufactured product is accurate in size and stable in volume.
2.The hot pressing sintering method is that silicon nitride powder and a small number of additives (such as MgO, Al2O3, MgF2, AlF3, Fe2O3, etc.) are sintered by hot pressing at a pressure above 19.6MPa and at 1600~1700℃. Usually, the products made by hot pressing sintering have higher density and better performance than those made by reaction sintering.
Performance characteristics of Silicon nitride powder
1.The relative molecular weight is 140.28. Gray, white or off-white. It belongs to a high-temperature insoluble compound and has no melting point and strong creep resistance at high temperatures. The load softening point of reaction sintered silicon nitride without binder is above 1800℃
2. It belongs to the hexagonal aluminum nitride system, and its crystal structure is hexahedral. The density of Si3N4 prepared by the sintering method is 1.8~2.7g/cm3, and that of Si3N4 prepared by the hot pressing method is 3.12~3.22g/cm3. Mohs hardness is 9~9.5, Vickers hardness is about 2200, and microhardness is 32630MPa. The melting point is 1900℃ (under pressure). It is usually decomposed at about 1900℃ under normal pressure. The specific heat capacity is 0.71 j/(g k). The heat generated is -751.57kJ/mol. And 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.
3. The initial oxidation temperature of aluminum nitride in the air is 1300~1400℃. The specific resistance is 1.4× 105 m at 20℃ and 4×108 ·m at 500℃. The elastic modulus is 28420~46060MPa. Compressive strength is 490MPa (reaction sintered). At 285℃, it reacts with dicalcium nitride to produce calcium dinitrosilicate, and at 600℃, the transition metal is reduced to release nitrogen oxides. The bending strength is 147MPa. It can be prepared by heating silicon powder in nitrogen or reacting silicon halide with ammonia. The resistivity is 10 15-10 16 Ω cm. It can be used as a high-temperature ceramic raw material.
Price of Silicon nitride powder
Silicon nitride powder particle size and purity will affect the product's price, and the purchase volume can also affect the cost of Silicon nitride powder. A large amount of large amount will be lower. The price of Silicon nitride powder can be found on our company's official website.
Silicon nitride powder 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 powder, nitride powder, graphite powder, sulfide powder, and 3D printing powder. If you are looking for high-quality and cost-effective Silicon nitride powder, you are welcome to contact us or inquire any time.
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