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Preparation method of high-reliability long-life silicon nitride ceramic ball for aircraft bearing

A silicon nitride ceramic ball and reliability technology, applied in the field of silicon nitride ceramic ball manufacturing, can solve the problems of reducing the strength, hardness and other mechanical properties of the silicon nitride ceramic ball, affecting the reliability and fatigue life of the ceramic ball and the like

Pending Publication Date: 2020-12-04
SINOMA ADVANCED NITRIDE CERAMICS CO LTD +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Therefore, the agglomeration and segregation of sintering aids not only reduce the mechanical properties of silicon nitride ceramic balls such as strength and hardness, but also seriously affect the reliability and fatigue life of ceramic balls.

Method used

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  • Preparation method of high-reliability long-life silicon nitride ceramic ball for aircraft bearing
  • Preparation method of high-reliability long-life silicon nitride ceramic ball for aircraft bearing

Examples

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preparation example Construction

[0022] The invention provides a method for preparing high-reliability and long-life silicon nitride ceramic balls for aviation bearings, which comprises the following steps:

[0023] mixing aluminum isopropoxide, organic solvent, silicon nitride powder and metal acetate aqueous solution, followed by hydrolysis and first spray drying to obtain a mixed powder;

[0024] Calcining the mixed powder to obtain silicon nitride powder coated with sintering aid;

[0025] Grinding the sintering aid-coated silicon nitride powder, mixing it with a binder, and performing a second spray drying to obtain granulated powder;

[0026] The granulated powder is sequentially subjected to molding, debinding and sintering to obtain silicon nitride ceramic balls.

[0027] In the present invention, unless otherwise specified, the required preparation materials are commercially available products well known to those skilled in the art.

[0028] In the invention, aluminum isopropoxide, organic solvent,...

Embodiment 1

[0049] 12kg (the amount converted to alumina is 3kg) of aluminum isopropoxide (C 9 h 21 AlO 3 ) was dissolved in absolute ethanol (100kg), added 92kg silicon nitride powder, stirred for 3h, then added yttrium acetate (Y(C 2 h 3 o 2 ) 3 4H 2 (2) deionized water (concentration of yttrium acetate aqueous solution is 200g / L), stir 1.5h, carry out spray drying immediately afterwards, obtain the mixed powder body of silicon nitride and sintering aid precursor, described mixed powder body is in Calcined at 450°C for 3 hours to obtain alumina and yttrium oxide-coated silicon nitride powder (100kg);

[0050] Using absolute ethanol as a solvent and silicon nitride as a grinding ball, grind the aluminum oxide and yttrium oxide-coated silicon nitride powder in a stirring ball mill for 6 hours, so that the particle size of the powder is D 50 After reaching below 0.6 microns, add 1.5kg of binder PVB and 1kg of polyacrylic acid emulsion to the obtained slurry after grinding, stir for ...

Embodiment 2

[0055] 20kg (the amount converted to alumina is 5kg) of aluminum isopropoxide (C 9 h 21 AlO 3 ) was dissolved in dehydrated alcohol (120kg), added 92kg silicon nitride powder, stirred for 3h, then added yttrium acetate (Y(C 2 h 3 o 2 ) 3 4H 2 (2) deionized water (concentration of yttrium acetate aqueous solution is 200g / L), stir 2h, carry out spray drying immediately afterwards, obtain the mixed powder body of silicon nitride and sintering aid precursor, described mixed powder body is in 500 Calcined at ℃ for 2h to obtain aluminum oxide and yttrium oxide coated silicon nitride powder (100kg);

[0056] Using absolute ethanol as a solvent and silicon nitride as a grinding ball, grind the aluminum oxide and yttrium oxide-coated silicon nitride powder in a stirring ball mill for 6 hours, so that the particle size of the powder is D 50 After reaching below 0.6 microns, add 1.5kg of binder PVB and 1kg of polyacrylic acid emulsion to the obtained slurry after grinding, stir fo...

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Abstract

The invention provides a preparation method of a high-reliability long-service-life silicon nitride ceramic ball for an aircraft bearing, and belongs to the technical field of silicon nitride ceramicball manufacturing. Metal organic salt (aluminum isopropoxide and metal acetate) is used as a precursor of a sintering aid, and the surface of silicon nitride can be coated with the sintering aid through hydrolysis, spray drying and calcination processes, so that uniform dispersion of the sintering aid in silicon nitride is realized; therefore, the reduction of reliability and fatigue life of theceramic ball caused by agglomeration and segregation of the sintering aid is avoided. The result of the embodiment shows that the density of the silicon nitride ceramic ball prepared by the method reaches 99.9% or above, the Vickers hardness (HV10) is larger than 1500, the crushing load ratio is larger than 45%, the Weibull modulus is larger than 15, the rolling contact fatigue life (RCF) is 400 hor above, and the silicon nitride ceramic ball is particularly suitable for manufacturing rolling elements for aviation bearings.

Description

technical field [0001] The invention relates to the technical field of manufacturing silicon nitride ceramic balls, in particular to a method for preparing silicon nitride ceramic balls with high reliability and long life for aviation bearings. Background technique [0002] Aviation bearings are one of the key core components of aero-engines, which need to deal with extremely harsh environmental and working conditions such as high speed, high temperature, large maneuverability, large overload, and lean oil lubrication in the aviation field. The performance and quality of aviation bearings directly affect the service life and reliability of aircraft engines, and are also one of the main factors affecting the combat effectiveness of aircraft equipment. [0003] Silicon nitride ceramics have the characteristics of light specific gravity, high rigidity, high temperature resistance, corrosion resistance, wear resistance, self-lubrication and electrical insulation, etc., and have ...

Claims

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Application Information

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IPC IPC(8): C04B35/584C04B35/645C04B35/628
CPCC04B35/584C04B35/645C04B35/62802C04B2235/48C04B2235/449C04B2235/77C04B2235/96C04B2235/94
Inventor 张晶王文雪刘璐孙峰颜家森宋健杨文武杨凯宁刘富兵于安乐
Owner SINOMA ADVANCED NITRIDE CERAMICS CO LTD
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