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Preparation method of boron carbide ceramic material for aerospace gyroscope bearing and boron carbide ceramic material

A boron carbide ceramic and gyroscope technology, which is used in bearings, shafts and bearings, stone processing equipment, etc., can solve the problems of decreased mechanical properties of products, difficulty in reaching micron-level machining accuracy, and low relative density.

Active Publication Date: 2021-04-30
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] (2) and the relative density is lower than 97%. Although increasing the temperature in the high-temperature sintering stage can increase the density, it will lead to grain growth and the mechanical properties of the product will be greatly reduced;
[0006] (3) Difficult to achieve micron-level machining accuracy

Method used

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  • Preparation method of boron carbide ceramic material for aerospace gyroscope bearing and boron carbide ceramic material
  • Preparation method of boron carbide ceramic material for aerospace gyroscope bearing and boron carbide ceramic material
  • Preparation method of boron carbide ceramic material for aerospace gyroscope bearing and boron carbide ceramic material

Examples

Experimental program
Comparison scheme
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Embodiment 1

[0033] B 2 o 3 Add Al, Mg, Ti metal mixture to the powder raw material, the carbon source is carbon black, in molar ratio, B 2 o 3 : (Mg, Al, Ti mixture): carbon black = 2: 6: 1, wherein, in terms of molar ratio, Mg: Al: Ti = 18: 1: 1, the above raw materials are mixed and then ignited and burned in an Ar atmosphere to obtain carbonization Boron coarse powder, the yield of the obtained boron carbide coarse powder is 57%, and the purity is greater than 99%.

[0034] Coarse boron carbide powder is subjected to high-energy ball milling. The specific parameters are: use a ball mill to crush it, and then flush it with nitrogen after vacuuming. The ball milling speed is 540r / min, and the time is 36h. Pickling is carried out. Concentrated hydrochloric acid and concentrated nitric acid are used in a volume ratio of 4: The mixed solution of 1 ratio was pickled, the pickling time was 4.5h, and then sedimentation and classification were carried out, and polyethylene glycol was used as...

Embodiment 2

[0039]The difference between this example and Example 1 is that the ball mill was milled at a rotational speed of 240r / min for 36 hours, and boron carbide fine powder with an average particle size of 873nm was prepared by sedimentation and classification, and the rest of the conditions were the same as in Example 1.

[0040] The bending strength of the boron carbide product is 380.8Mpa, the relative density is 99.2%, and the surface roughness is Ra0.64μm.

Embodiment 3

[0042] The difference between this example and Example 1 is that boron carbide fine powder with an average particle size of 250 nm is prepared by sedimentation classification, and the rest of the conditions are the same as in Example 1.

[0043] The bending strength of the boron carbide product is 390.2Mpa, the relative density is 99.4%, and the surface roughness is Ra0.43μm.

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Abstract

The invention discloses a method for preparing a boron carbide ceramic material for aerospace gyroscope bearings and the boron carbide ceramic material, comprising: preparing boron carbide coarse powder: mixing B 2 o 3 Add Al, Mg, Ti metal mixture to the powder raw material, the carbon source is carbon black, and ignite and burn in an inert atmosphere after mixing; the boron carbide coarse powder is subjected to high-energy ball milling, pickling, and sedimentation classification to obtain an average particle size of 560-600nm The boron carbide fine powder is hot-pressed and sintered to obtain a blank boron carbide; the blank boron carbide is subjected to precision machining. The boron carbide bearing prepared by hot pressing and sintering in the present invention has a boron carbide bearing grain ≦1.5 μm, a bending strength of 466.7 MPa, a density of 99.9%, extremely high hardness, good corrosion resistance and excellent wear resistance Performance: The hot-pressed boron carbide bearing blank does not produce cracks, and the surface roughness of boron carbide reaches Ra0.1μm. Boron carbide bearings are used in aerospace gyroscope air bearings.

Description

technical field [0001] The invention belongs to the technical field of boron carbide ceramic materials, and in particular relates to a preparation method of a boron carbide ceramic material for aerospace gyroscope bearings and the boron carbide ceramic material. Background technique [0002] Boron carbide is a special ceramic with excellent performance. Because of its excellent properties such as excellent wear resistance, low density, high hardness, high temperature strength, and strong corrosion resistance, its typical application is the air bearing of aerospace gyroscopes. . This is because boron carbide is light in weight and has good wear resistance. The development goal of aerospace technology is to push into the far-reaching outer space. The important bottleneck is the low density, low precision and low mechanical properties of ordinary boron carbide bearings. Improving the strength and processing accuracy of boron carbide products poses a serious challenge to its p...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/563C04B35/622C04B35/626C04B35/645F16C32/06B28D1/00
CPCB28D1/00C04B35/563C04B35/622C04B35/6267C04B35/645C04B2235/3409C04B2235/401C04B2235/402C04B2235/404C04B2235/424C04B2235/6562C04B2235/6567C04B2235/786C04B2235/96C04B2235/963F16C32/06
Inventor 李瑞迪熊熠袁铁锤周志辉张梅牛朋达谢思遥
Owner CENT SOUTH UNIV