Method for producing complex-shaped porous silicon nitride ceramic product

A technology of silicon nitride ceramics and complex shapes, which is applied in the field of ceramic materials, can solve the problems such as the difficulty in preparing porous silicon nitride ceramic products with complex shapes, and achieve the effects of small size shrinkage, easy machining, and simple operation

Inactive Publication Date: 2015-12-30
NORTHWESTERN POLYTECHNICAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] In order to avoid the deficiencies of the prior art, the present invention proposes a method for preparing porous silicon nitride ceramic products with complex shapes, which overcomes the problem that the existing preparation methods are difficult to prepare porous silicon nitride ceramic products with complex shapes

Method used

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  • Method for producing complex-shaped porous silicon nitride ceramic product

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example 1

[0028] Example 1: Select α-Si with a particle size of 0.4 μm 3 N 4 powder, Si powder with a particle size of 0.5 μm, and Lu powder with a particle size of 0.3 μm 2 o 3 powder and silica sol (in powder, α-Si 3 N 4 Powder, Si powder, Lu 2 o 3 The mass fraction of the powder is 70%, 25%, and 5%, respectively, and the mass ratio of the powder to the silica sol is 1:1), and the Si 3 N 4 Powder and Si powder mixed slurry. Put the slurry into a sealed tank, vacuumize and defoam for 30min. A radome-shaped metal mold (the maximum diameter of the mold is 60 mm and a height of 100 mm) coated with a layer of paraffin wax is immersed in the slurry, so that the surface of the mold is evenly coated with a layer of slurry with a thickness of about 0.5 mm. Take out the mold and spray α-Si with a particle size of 20 μm above the slurry on the surface of the mold 3 N 4 powder, so that the slurry is evenly and low-adhesively coated with a layer of Si 3 N 4 meal. Place the mold in a ...

example 2

[0029] Example 2: Select α-Si with a particle size of 0.4 μm 3 N 4 powder, Si powder with a particle size of 0.5 μm, and Lu powder with a particle size of 0.3 μm 2 o 3 powder and silica sol (in powder, α-Si 3 N 4 Powder, Si powder, Lu 2 o 3 The mass fraction of the powder is 55%, 40%, and 5%, respectively, and the mass ratio of the powder to the silica sol is 1:1), and the Si 3 N 4 Powder and Si powder mixed slurry. Put the slurry into a sealed tank, vacuumize and defoam for 30min. A radome-shaped metal mold (the maximum diameter of the mold is 60 mm and a height of 100 mm) coated with a layer of paraffin wax is immersed in the slurry, so that the surface of the mold is evenly coated with a layer of slurry with a thickness of about 0.5 mm. Take out the mold and spray α-Si with a particle size of 20 μm above the slurry on the surface of the mold 3 N 4 powder, so that the slurry is evenly and low-adhesively coated with a layer of Si 3 N 4 meal. Place the mold in a ...

example 3

[0030] Example 3: Select α-Si with a particle size of 1.2 μm 3 N 4 powder, Si powder with a particle size of 0.5 μm, and Lu powder with a particle size of 0.3 μm 2 o 3 powder and silica sol (in powder, α-Si 3 N 4 Powder, Si powder, Lu 2 o 3 The mass fraction of the powder is 70%, 25%, and 5%, respectively, and the mass ratio of the powder to the silica sol is 1:1), and the Si 3 N 4Powder and Si powder mixed slurry. Put the slurry into a sealed tank, vacuumize and defoam for 30min. A radome-shaped metal mold (the maximum diameter of the mold is 60 mm and a height of 100 mm) coated with a layer of paraffin wax is immersed in the slurry, so that the surface of the mold is evenly coated with a layer of slurry with a thickness of about 0.5 mm. Take out the mold and spray α-Si with a particle size of 20 μm above the slurry on the surface of the mold 3 N 4 powder, so that the slurry is evenly and low-adhesively coated with a layer of Si 3 N 4 meal. Place the mold in a v...

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Abstract

The invention relates to a method for producing a complex-shaped porous silicon nitride ceramic product. The method includes: using Si3N4 powder, Si powder, sintering auxiliaries, pore forming agent and silica sol to prepare mixed slurry; producing a male die with an outer surface identical with the appearance and size of the inner cavity of the product, and coating paraffin on the surface of the die; soaking the die into the slurry to allow the slurry to be adhered to the surface of the die, and then spraying Si3N4 coarse powder to the surface of the die to allow a layer of Si3N4 coarse powder to be evenly adhered to the slurry adhered to the surface of the die; drying the die in a ventilated environment for 1-3 hours to consolidate and harden the slurry on the surface of the die; repeating the soaking, spraying and drying process for multiple times until the thickness of the outer powder layer of the die meets the requirement; placing the die into an oven to melt the paraffin so as to separate a ceramic green body from the die; performing nitridation sintering on the green body to obtain the porous silicon nitride ceramic product. The bending strength of the porous silicon nitride ceramic product produced by the method is not lower than 50MPa, and the porous silicon nitride ceramic product is good in wave transmission performance.

Description

technical field [0001] The invention belongs to the field of ceramic materials and relates to a method for preparing porous silicon nitride ceramic products with complex shapes. Background technique [0002] The wave-transparent material is a kind of structure and function integration material, which is mainly used in the radomes and radomes of aircraft. The wave-transparent material needs to be able to isolate the external environment, ensure the normal operation of the radar and antenna, and at the same time have a high electromagnetic wave transmittance, so that the aircraft can realize functions such as detection and guidance. In order to meet the needs of the continuous development of aerospace technology and military technology, wave-transparent materials need to have good mechanical properties, thermal stability, environmental behavior and wave-transmitting properties. Porous silicon nitride ceramics have attracted people's attention because of their excellent compre...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B38/00C04B35/584C04B35/622
Inventor 成来飞李明星张立同
Owner NORTHWESTERN POLYTECHNICAL UNIV
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