Manufacturing method of high-performance silicon nitride sealing ring

A silicon nitride and sealing ring technology, which is applied in the field of preparation of high-performance silicon nitride sealing rings, can solve the problems of increasing the manufacturing cost of silicon nitride products and high sintering costs, and achieve the effect of promoting densification and improving mechanical properties

Inactive Publication Date: 2017-03-22
MATERIAL INST OF CHINA ACADEMY OF ENG PHYSICS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, hot pressing and hot isostatic pressing not only require expensive and complicated sintering equipment, but also have high sintering costs (water, electricity, gas, auxiliary consumables such as sheathing, etc.), which greatly increase the manufacturing cost of silicon nitride products and curb the Application of High Performance Silicon Nitride Materials in the Sealing Ring Market

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0029] The weight ratios of silicon nitride powder, magnesium oxide, aluminum oxide and yttrium oxide are 93%, 4%, 0.5% and 2.5% respectively, and the four are composed of mixed powder, and then 1% PVB of the mixed powder weight is added and mixed to obtain mixture. Then, configure grinding balls and absolute ethanol according to the weight ratio of mixture: grinding balls: absolute ethanol = 1: 2.5: 1.2, pour into a stirring ball mill, and ball mill for 6 hours to obtain a silicon nitride composite powder slurry.

[0030] Then, the silicon nitride composite powder slurry is pumped into the closed-loop granulation tower for granulation, and the process is N 2 atmosphere, the inlet temperature is 170°C, and the outlet temperature is 70°C to obtain silicon nitride granulated powder;

[0031] The obtained silicon nitride granulated powder is poured into a sealing ring mold, pre-molded at 20 MPa, and then subjected to 150 MPa cold isostatic pressing to obtain a high-density silic...

example 2

[0035] The weight ratios of silicon nitride powder, magnesium oxide, aluminum oxide and yttrium oxide are 90%, 5.5%, 1% and 3.5% respectively, and the four are combined to form a mixed powder, and then 1% of the weight of the mixed powder is added with PVB and 1% The PEGs are mixed to obtain a mixture. Then, configure grinding balls and absolute ethanol according to the weight ratio of mixture: grinding balls: absolute ethanol = 1:3:1.5, pour into a stirring ball mill, and ball mill for 4 hours to obtain a silicon nitride composite powder slurry.

[0036] Then, the silicon nitride composite powder slurry is pumped into the closed-loop granulation tower for granulation, and the process is N 2 atmosphere, the inlet temperature is 185°C, and the outlet temperature is 80°C to obtain silicon nitride granulated powder;

[0037] The obtained silicon nitride granulated powder is poured into a sealing ring mold, pre-molded at 40 MPa, and then subjected to 170 MPa cold isostatic pressi...

example 3

[0041] The weight ratios of silicon nitride powder, magnesium oxide, aluminum oxide and yttrium oxide are 95%, 2.5%, 1% and 1.5% respectively, and the four are combined to form a mixed powder, and then 0.5% of the weight of the mixed powder is added with PVB and 2% The PEGs are mixed to obtain a mixture. Then, configure grinding balls and absolute ethanol according to the weight ratio of mixture: grinding balls: absolute ethanol = 1:2:1, pour into a stirring ball mill, and ball mill for 8 hours to obtain a silicon nitride composite powder slurry.

[0042] Then, the silicon nitride composite powder slurry is pumped into the closed-loop granulation tower for granulation, and the process is N 2 atmosphere, the inlet temperature is 155°C, and the outlet temperature is 60°C to obtain silicon nitride granulated powder;

[0043] The obtained silicon nitride granulated powder is poured into a sealing ring mold, pre-molded at 60 MPa, and then subjected to 200 MPa cold isostatic pressi...

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Abstract

The invention discloses a manufacturing method of a high-performance silicon nitride sealing ring. The manufacturing method comprises the following steps: 1, preparing raw materials: silicon nitride powder, magnesium oxide, aluminum oxide and yttrium oxide; 2, adding the raw materials and an adhesive to absolute ethyl alcohol and mixing uniform so as to obtain silicon nitride composite powder slurry; 3, carrying out spray granulation on the silicon nitride composite powder slurry by adopting a closed-ring granulation mode so as to prepare silicon nitride granulated powder; 4, carrying out cool isostatic pressing treatment molding after carrying out compression molding on the silicon nitride granulated powder so as to prepare a silicon nitride ring blank; and 5, sintering the silicon nitride ring blank at a 1-8MPa nitrogen atmosphere and 1750-1850DEG C to prepare the silicon nitride sealing ring. The relative density of the made silicon nitride sealing ring is larger than or equal to 99.5%, the strength is larger than or equal to 800MPa, the HV hardness is larger than or equal to 1600, and the fracture toughness can reach 6.5-7.5MPa.m<1 / 2>. The manufacturing method greatly meets the application of the silicon nitride material in the aspects of sealing ring markets, particularly mechanical sealing.

Description

technical field [0001] The invention relates to a preparation method of a high-performance silicon nitride sealing ring. Background technique [0002] In mechanical seals, dynamic and static sealing rings often need to resist the influence of unfavorable factors such as the erosion and impact of solid particles, the instability of sealing parameters of the sealing surface caused by high speed and high pressure, and the corrosion of base structural parts. In order to meet the requirements of low wear and long life of mechanical seals, the seal ring material is often required to have high hardness, high fracture toughness and high stiffness (elastic modulus). [0003] Silicon nitride ceramics is a new type of sealing ring material. Compared with cemented carbide sealing rings, it has the advantages of low density and corrosion resistance. It has higher strength and higher fracture toughness than alumina ceramic sealing rings and silicon carbide sealing rings. And excellent we...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/584C04B35/622C04B35/634C04B35/645B28B3/00
CPCC04B35/584B28B3/003C04B35/622C04B35/63404C04B35/6342C04B35/645C04B2235/3206C04B2235/3217C04B2235/3225C04B2235/6022C04B2235/658C04B2235/66C04B2235/661C04B2235/77C04B2235/96
Inventor 白彬赖新春汪彩芬徐俊朱彩强岳映雷李先容杨少青
Owner MATERIAL INST OF CHINA ACADEMY OF ENG PHYSICS
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