Synthetic method of silicon nitride nanopowder

A nano-powder and synthesis method technology, applied in nitrogen compounds, chemical instruments and methods, inorganic chemistry, etc., can solve the problems affecting powder particle size and purity, small production scale, high production cost, etc., and achieve low production cost and high production scale Great, low-cost effect

Inactive Publication Date: 2009-01-28
LIAONING UNIVERSITY OF TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The above synthesis process is analyzed from several aspects such as product quality, production cost and production scale: the solid phase reaction method is a relatively mature process, but its product quality is limited to a certain extent and it is difficult to break through; the liquid phase reaction method has developed rapidly in recent years , foreign countries have established industrial-scale Si 3 N 4 Powder production line, but on the whole, there are still some technical problems and further cost reduction problems; various gas phase reaction methods can produce high-quality Si 3 N 4 powder, but their production cost i...

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] 1.1. Take 80ml of silica sol (SiO 2 Mass fraction is 28%), urea 16g, hexamethylenetetramine 20g, stir and mix to form a solution, and add 0.01g dispersant cetyltrimethylammonium bromide. Then 1:1 sulfuric acid was added dropwise, and the temperature of the solution rose to 55°C. At this time, the pH value of the solution is controlled to be 6.5-7.0, and the reaction is carried out for 30 minutes at heat preservation, and the addition reaction is carried out to generate stable hydroxymethylurea.

[0016] 1.2. Continue to add the catalyst dilute sulfuric acid (1:1) dropwise, a total of 16ml before and after, control the pH value to 3-3.5, raise the temperature to 85°C, carry out condensation polymerization, and generate the precursor.

[0017] 1.3. Dry and ball mill the precursor until the particle size of the powder is 200nm.

[0018] 1.4. Put the precursor in a nitriding furnace and calcinate for 2.2 hours at 1480°C with a nitrogen flow rate of 2.0L / min to synthesize ...

Embodiment 2

[0021] 1.1. Take 4L of silica sol (SiO 2 The mass fraction is 28%), urea 0.8Kg, hexamethylenetetramine 1.2Kg, stir and mix to form a solution, and add 1g dispersant cetyltrimethylammonium bromide. Then 1:1 sulfuric acid was added dropwise, and the temperature of the solution rose to 50°C. At this time, the pH value of the solution was controlled to be 7-7.5, and the reaction was carried out for 15 minutes at a heat preservation time, and an addition reaction was carried out to generate stable methylol urea.

[0022] 1.2. Continue to add the catalyst dilute sulfuric acid (1:1) dropwise, a total of 1.3L before and after, control the pH value to 3.5-4, raise the temperature to 80°C, carry out condensation polymerization, and generate the precursor.

[0023] 1.3. Dry and ball mill the precursor until the particle size of the powder is 200nm.

[0024] 1.4. Put the precursor in a nitriding furnace and calcinate for 2 hours at 1500°C with a nitrogen flow rate of 2.5L / min to synthes...

Embodiment 3

[0027] 1.1. Take 8L of silica sol (SiO 2 The mass fraction is 28%), urea 2.4Kg, hexamethylenetetramine 3.2Kg, stir and mix to form a solution, and add 2g dispersant cetyltrimethylammonium bromide. Then 1:1 sulfuric acid was added dropwise, and the temperature of the solution rose to 60°C. At this time, the pH value of the solution was controlled to be 6.8-7.2, and the reaction was carried out for 20 minutes at a heat preservation time, and an addition reaction was carried out to generate stable hydroxymethylurea.

[0028] 1.2. Continue to add the catalyst dilute sulfuric acid (1:1) dropwise, a total of 3.0L before and after, control the pH value to 3.3-3.7, raise the temperature to 90°C, carry out condensation polymerization, and generate the precursor.

[0029] 1.3. Dry and ball mill the precursor until the particle size of the powder is 200nm.

[0030] 1.4. Put the precursor in a nitriding furnace and calcinate for 1.8h at 1520°C with a nitrogen flow rate of 3L / min to synt...

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PUM

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Abstract

The invention relates to a silicon nitride nano-powder synthesis method. Silica sol, urea and methenamine are evenly mixed to obtain solution, wherein the mol ratio of the urea to the methenamine is 4.7:3-5.6:3, the mol ratio of carbon to silicon is 2.5:1-4:1; the solution is added with cetyl trimethyl ammonium bromide and dilute sulfuric acid for addition reaction, and the acidity of a reaction medium is 6.5-7.5, and the reaction temperature is 50-60 DEG C; then condensation reaction is carried out for the mixture to generate a precursor, wherein the pH value is 3-4, the condensation temperature is 80-90 DEG C; the precursor is dried and ball-ground, and is positioned in a nitriding furnace for calcinations in 2-3L/min nitrogen flow at the temperature of 1480-1520 DEG C for 1.8-2.2 hours to synthesize Si3N4 powder; the silicon nitride nano-powder is prepared by decarbonizing the synthetic Si3N4 powder at the temperature of 570-630 DEG C for 3.7-4.2 hours. The silicon nitride nano-powder synthesis method takes organic carbon as a carbon source, organic nitrogen and nitrogen as a nitrogen source, and the silica sol as a silicon source, and has the advantages of high product quality, low production cost and large production scale. The average particle size of the prepared Si3N4 powder is 43-100nm, and the purity of the Si3N4 powder can be up to 100%.

Description

technical field [0001] The present invention relates to a kind of nano-Si used in the fields of automobile, machinery, metallurgy, chemical engineering, space technology, marine development, electronic technology, medical and health, non-destructive testing, automatic control, radio and television, etc. 3 N 4 Synthetic method of silicon nitride nanometer powder needed for base ceramics. Background technique [0002] Si 3 N 4 As a high-temperature structural material, base ceramics have the characteristics of high density, small thermal expansion coefficient, high hardness, high elastic modulus, thermal stability, chemical stability and electrical insulation. Silicon nitride is not only an excellent high-temperature structural material, but also a new type of functional material. As a high-temperature structural material, it has been applied to the fields of automobile, machinery, metallurgy and chemical engineering, and has gradually penetrated into many cutting-edge sci...

Claims

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Application Information

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IPC IPC(8): C01B21/068
Inventor 穆柏春陈宏
Owner LIAONING UNIVERSITY OF TECHNOLOGY
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