A kind of preparation method of high α-phase silicon nitride powder body and ultra-long silicon nitride nanowire

A technology of phase silicon nitride powder and silicon nitride nanometer is applied in the field of preparation of non-oxide ceramic materials to achieve the effect of shortening the nitriding cycle and speeding up the nitriding rate

Active Publication Date: 2022-02-11
NANCHANG UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] At present, there is no literature report on the one-step simultaneous preparation of high α-phase silicon nitride powder and ultra-long silicon nitride nanowires by directly nitrided silicon powder and regulating gas conversion without any additives.

Method used

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  • A kind of preparation method of high α-phase silicon nitride powder body and ultra-long silicon nitride nanowire
  • A kind of preparation method of high α-phase silicon nitride powder body and ultra-long silicon nitride nanowire
  • A kind of preparation method of high α-phase silicon nitride powder body and ultra-long silicon nitride nanowire

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037](1) Loosely pack silicon powder with an average particle size of 1.96 μm in a silicon nitride sagger with a loose thickness of 20 mm, and place it in the uniform temperature zone of the atmosphere furnace;

[0038] (2) Exhaust gas with a purity of 99.99% ammonia at a flow rate of 100ml / min for 30 minutes, raise the temperature to 1280°C at a rate of 5°C / min, and keep it warm for 1 hour for oxidation and nitriding pretreatment; then the ammonia valve Closed, and simultaneously open nitrogen with a purity of 99.99%, argon with a purity of 99.999%, and hydrogen with a purity of 99.9999%, and the gas flow ratio is N 2 :Ar:H 2 =10:85:5ml / min, keep warm at 1280°C for 6 hours; then rise to 1300°C at a rate of 0.1°C / min, the gas flow ratio is N 2 :Ar:H 2 =20:75:5ml / min, keep warm at 1300°C for 4 hours; then rise to 1320°C at a rate of 0.5°C / min, the gas flow ratio is N 2 :Ar:H 2 =30:65:5ml / min, keep warm at 1320°C for 8 hours; then rise to 1340°C at a rate of 1°C / min, the ga...

Embodiment 2

[0043] (1) Loosely pack silicon powder with an average particle size of 0.78 μm in a high-purity corundum sagger with a loose thickness of 40 mm, and place it in the uniform temperature zone of the atmosphere furnace;

[0044] (2) Exhaust gas at a flow rate of 99.999% ammonia at 100ml / min for 20 minutes, rise to 1250°C at a heating rate of 2°C / min, and keep warm for 5 hours for oxidation and nitriding pretreatment; then high-purity ammonia The gas valve is closed, and nitrogen with a purity of 99.99%, argon with a purity of 99.9999%, and hydrogen with a purity of 99.99% are opened at the same time, and the gas flow ratio is N 2 :Ar:H 2 =15:80:5ml / min, keep warm at 1250°C for 5 hours; then rise to 1300°C at a rate of 0.2°C / min, the gas flow ratio is N 2 :Ar:H 2 =30:65:5ml / min, keep warm at 1300°C for 4 hours; then rise to 1330°C at a rate of 0.5°C / min, the gas flow ratio is N 2 :Ar:H 2 =55:40:5ml / min, keep warm at 1330°C for 4 hours; then rise to 1350°C at a rate of 1°C / min...

Embodiment 3

[0048] (1) Loosely pack silicon powder with an average particle size of 2.25 μm in a silicon carbide sagger with a loose thickness of 60 mm, and place it in the uniform temperature zone of the atmosphere furnace;

[0049] (2) Exhaust gas at a flow rate of 99.9999% ammonia 100ml / min for 60 minutes, rise to 1240°C at a heating rate of 6°C / min, and keep warm for 2 hours for oxidation and nitriding pretreatment; then high-purity ammonia The gas valve is closed, and nitrogen with a purity of 99.9999%, argon with a purity of 99.999% and hydrogen with a purity of 99.999% are opened at the same time, and the gas flow ratio is N 2 :Ar:H 2 =25:70:5ml / min, keep warm at 1240°C for 8 hours; then rise to 1280°C at a rate of 0.1°C / min, the gas flow ratio is N 2 :Ar:H 2 =35:60:5ml / min, keep warm at 1280°C for 4 hours; then rise to 1320°C at a rate of 0.1°C / min, the gas flow ratio is N 2 :Ar:H 2 =50:45:5ml / min, keep warm at 1320°C for 4 hours; then rise to 1340°C at a rate of 0.5°C / min, th...

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Abstract

The invention provides a method for preparing high-alpha-phase silicon nitride powder and ultra-long silicon nitride nanowires, belonging to the technical field of preparation of non-oxide ceramic materials. In the present invention, the silicon powder with a certain particle size is converted into nitrogen, hydrogen and argon mixed gas after pretreatment with ammonia gas without any diluent, metal and metal salt catalyst, and then heats up slowly and keeps warm in sections. , Gradually reduce the auxiliary argon gas to react to form a high-α-phase silicon nitride accumulation soft block, which is covered with a large number of ultra-long silicon nitride nanowires. After the ultra-long silicon nitride nanowires are peeled off, the loose accumulation body The soft block can obtain high α-phase silicon nitride powder through refining treatment. The invention can directly and synchronously prepare high-alpha-phase silicon nitride powder and ultra-long silicon nitride nanowires through silicon powder nitriding without any additives.

Description

technical field [0001] The invention relates to a method for preparing high-α-phase silicon nitride powder and ultra-long silicon nitride nanowires, and belongs to the technical field of preparation of non-oxide ceramic materials. Background technique [0002] Silicon nitride materials have excellent comprehensive properties such as high temperature resistance, high strength, high hardness, corrosion resistance, oxidation resistance, thermal shock resistance, creep resistance, and structural stability. They are not only widely used in traditional industries such as metallurgy, machinery, and chemical industry, It also occupies a place in strategic emerging fields such as aerospace, electronic appliances, photovoltaics, wind power, military industry and nuclear industry. The synthesis of high α-phase silicon nitride powder raw materials is the key to the preparation of silicon nitride ceramics with excellent properties. Ultra-long silicon nitride nanowires are a one-dimensio...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/591C04B35/626D01F9/08
CPCC04B35/591C04B35/587C04B35/6265D01F9/08C04B2235/5436C04B2235/5445C04B2235/465C04B2235/46C04B2235/428
Inventor 尹传强周浪李晓敏魏秀琴兰宇
Owner NANCHANG UNIV
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