Si3N4-based compound ceramic and preparation method thereof

A technology of composite ceramics and mixed powders, applied in the field of ceramics, can solve the problems of low density of ceramics, and achieve the effects of high strength and toughness comprehensive mechanical properties, excellent comprehensive mechanical properties, and high density

Inactive Publication Date: 2018-02-06
GUANGDONG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] In order to solve the existing Si 3 N 4 This technical problem that ceramic compactness is lower, the object of the present invention is to provide a kind of Si with high compactness and excellent mechanical properties. 3 N 4 matrix composite ceramics

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] (1) with Si 3 N 4 powder (particle size less than 1 μm, purity 99.9%) as raw material, MgO powder (purity 99.9%) and Y 2 o 3 The powder (purity is 99.9%) is a sintering aid, which is mixed in a roller mill; batching is carried out in parts by weight, 90 parts of Si 3 N 4 powder, 5 parts of MgO, 5 parts of Y 2 o 3 .

[0039]During ball milling, ethanol was used as solvent and Si 3 N 4 The ball is the ball milling medium, the ball-to-material ratio is adjusted to 2:1, and the ball milling time is 24 hours. After mixing and drying, a well-mixed Si 3 N 4 -MgO-Y 2 o 3 Mix powder.

[0040] (2) Si 3 N 4 -MgO-Y 2 o 3 The mixed powder was put into a graphite mold, and after being pre-pressed at 10 MPa, it was hot-pressed and sintered under vacuum conditions and an inert gas protection environment; Continue to raise the temperature to the second temperature of 1600°C with a temperature increase rate of °C / min, then lower the temperature to 1200°C with a temperatu...

Embodiment 2

[0044] The difference between this embodiment and embodiment 1 is: in step (1), during batching: 92 parts of Si 3 N 4 Powder, 4 parts MgO, 4 parts Y 2 o 3 . The rest are basically the same as those in Embodiment 1, and will not be repeated here.

[0045] After testing, the Si of this embodiment 3 N 4 The relative density of matrix composite ceramics is 98.93%, and the phase composition is α-Si 3 N 4 and β-Si 3 N 4 , the hardness is 17.09GPa, the flexural strength is 1192.02MPa, and the fracture toughness is 7.29MPa. m 1 / 2 .

Embodiment 3

[0047] The difference between this embodiment and embodiment 1 is: in step (1), during batching: 94 parts of Si 3 N 4 Powder, 3 parts MgO, 3 parts Y 2 o 3 . The rest are basically the same as those in Embodiment 1, and will not be repeated here.

[0048] After testing, the Si of this embodiment 3 N 4 The relative density of matrix composite ceramics is 99.11%, and the phase composition is α-Si 3 N 4 and β-Si 3 N 4 , the hardness is 18.25GPa, the bending strength is 1188.92MPa, and the fracture toughness is 6.1MPa. m 1 / 2 .

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Abstract

The invention belongs to the technical field of ceramics and particularly relates to a Si3N4-based compound ceramic and a preparation method thereof. The Si3N4-based compound ceramic provided by the invention comprises Si3N4 and additives, wherein the additives are MxOy and Re2O3; M is selected from Mg or Al; x is more than or equal to 1 and less than or equal to 3; y is more than or equal to 1 and less than or equal to 3; Re is selected from Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb or Lu. According to the invention, MxOy and Re2O3 are selected as sintering additives and MxOy and Re2O3 are introduced for promoting the Si3N4 compaction and further improving the compactness of the Si3N4 ceramic. The invention also provides the preparation method for the Si3N4-based compound ceramic, the technology is optimized and the product quality is stable. An experiment proves that the Si3N4-based compound ceramic provided by the invention is high in compactness, has excellent comprehensive mechanical properties of high hardness and high toughness and can be widely applied to various fields of ceramics, metallurgy, electronics and chemical engineering.

Description

technical field [0001] The invention belongs to the technical field of ceramics, in particular to a Si 3 N 4 Matrix composite ceramics and its preparation method. Background technique [0002] Si 3 N 4 Ceramics have excellent properties such as high strength, high hardness, corrosion resistance, wear resistance, high temperature resistance, mechanical shock resistance and thermal shock resistance. They are important substrate packaging materials and high temperature structural materials, and are widely used in aerospace, chemical industry , metallurgy, military industry and machinery manufacturing and other fields. However, Si 3 N 4 Ceramics are difficult to sinter and densify because of their strong covalent bonds and low diffusion coefficients, so most of the existing Si 3 N 4 The low density of ceramics further confines the Si 3 N 4 Development and application of ceramics. Contents of the invention [0003] In order to solve the existing Si 3 N 4 This techn...

Claims

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Application Information

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IPC IPC(8): C04B35/584C04B35/645
CPCC04B35/584C04B35/645C04B2235/3206C04B2235/3225C04B2235/6562C04B2235/6565C04B2235/658C04B2235/6581C04B2235/96
Inventor伍尚华刘聪郭伟明赵哲
OwnerGUANGDONG UNIV OF TECH