Si3N4 ceramic and preparation method thereof

A technology for ceramics and ceramic slurry, applied in the field of ceramics, can solve the problems of complexity, cracks, damage to the final structure, etc., to achieve the effect of ensuring accuracy, reducing manufacturing costs, and realizing net size forming

Active Publication Date: 2018-09-21
GUANGDONG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this method is not only complicated to implement, but also needs to ensure that the sample can shrink uniformly in the three-dimensional direction. What is more serious is that the shrinkage is too severe and may destroy its final structure, resulting in cracks or bulges.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0032] Si of the present invention 3 N 4 The preparation method of ceramics comprises the following steps:

[0033] 1. Ingredients

[0034] The mass ratio of silicon powder and nitriding catalyst is preferably (80~99):(1~20), more preferably (90~99):(1~100), most preferably 95:5; Nitriding catalyst is ZrO 2 、TiO 2 He Eu 2 o 3 any of the.

[0035] When the mass ratio of nitriding catalyst to silicon powder is lower than 1:99, incomplete nitriding may occur, and even silicon melting occurs at a faster heating rate, and the residual silicon is in Si 3 N 4 As a defect in ceramics, the performance of ceramic preparation will be greatly reduced; when the mass ratio of nitriding catalyst to silicon powder is higher than 20:80, although the nitriding catalyst can promote the rapid nitriding of silicon powder, excessive nitriding Catalysts introduce by-products such as TiO 2 When the amount of nitriding catalyst added exceeds 20%, too much TiO 2 Will be with Si 3 N 4 The re...

Embodiment 1

[0067] In this example, a Si 3 N 4 Ceramics, the specific steps of its preparation are as follows:

[0068] 1. Ingredients

[0069] In the present embodiment, silicon powder: nitriding catalyst=95wt%: 5wt%, Si 3 N 4 : Sintering aid (MgO-Y 2 o 3 )=90wt%:10wt%, MgO:Y 2 o 3 =55wt%: 45wt%;

[0070] The purity of silicon powder is 99%, and the particle size is 0.1μm;

[0071] Nitriding catalyst ZrO 2 The purity is 99%, the particle size is 0.5μm;

[0072] The purity of MgO powder is 99%, Y 2 o 3 The powder purity is 99%.

[0073] 2. Mixed ball mill

[0074] Mix the above proportioned silicon powder, nitriding catalyst and sintering aid, place in a planetary ball mill, use ethanol as solvent, and use Si 3 N 4 The ball is the ball milling medium, the ball mill is mixed for 8h, and after drying, Si 3 N 4 -ZrO 2 -MgO-Y 2 o 3 Mix powder.

[0075] 3. Spray granulation

[0076] Mix the mixed powder with 0.03% oleic acid as a dispersant, and carry out spray granulati...

Embodiment 2

[0091] The difference between this embodiment and embodiment 1 is: the nitriding catalyst TiO 2 ; The nitrogen pressure during high temperature sintering is 10MPa. The rest are basically the same as those in Embodiment 1, and will not be repeated here.

[0092] For the Si prepared in this example 3 N 4 The performance of ceramics is tested, and its relative density is 99%, its hardness is 20GPa, and its fracture toughness is 12MPa m 1 / 2 , The bending strength is 1200MPa.

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Abstract

The invention belongs to the technical field of ceramics, and particularly relates to a Si3N4 ceramic and a preparation method thereof. The provided Si3N4 ceramic comprises silicon powder, a nitridation catalyst and a sintering aid; the silicon powder is subjected to nitridation treatment via the nitridation catalyst to generate Si3N4, and the mass ratio of the nitridation catalyst to the siliconpowder is (1-20): (80-99); the nitridation catalyst is selected from ZrO2, TiO2 or Eu2O3; and the sintering aid is MgO and Re2O3, and Re is selected from Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy,Ho, Er, Tm, Yb or Lu. During preparation, ingredient mixing, granulation and ceramic slurry formation are carried out successively, and then photocuring forming, degreasing, nitridation treatment andhigh-temperature sintering are successively carried out to obtain the final product. Therefore, by the technical scheme, sample shrinkage is compensated by volume expansion due to nitridation of thesilicon powder, clear dimension forming of a silicon nitride ceramic in a complicated shape is realized, sources of raw materials are wide, the preparation cost is low, and the method is simple and convenient.

Description

technical field [0001] The invention belongs to the technical field of ceramics, in particular to a Si 3 N 4 Ceramics and methods of making them. Background technique [0002] Si 3 N 4 As a structural material, ceramic materials have excellent mechanical properties, such as high hardness, high strength, wear resistance, high temperature resistance, physical and chemical stability, etc., and can be widely used in structural parts, catalyst carriers, filter materials and heat dissipation materials, etc. Many aspects. However, it is precisely because of its excellent mechanical properties that it limits the diversity of its processing. If only relying on traditional processing techniques to obtain ceramic materials with complex shapes, it is difficult to meet the high-end demands for personalization, refinement, lightweight and complexity. The demand for rapid product manufacturing limits the development and application of high-performance ceramic products. Therefore, dev...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/591C04B35/622C04B35/634B33Y70/00
CPCB33Y70/00C04B35/591C04B35/622C04B35/63424C04B2235/428C04B2235/46C04B2235/6026C04B2235/6562C04B2235/6567C04B2235/658C04B2235/77C04B2235/96
Inventor 林锐霖牛文彬陈志伟吴利翔郭伟明林华泰
Owner GUANGDONG UNIV OF TECH
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