Method for rapidly preparing high heat conduction Si3N4 ceramic with low cost

A high thermal conductivity and low cost technology, applied in the field of low cost and rapid preparation of high thermal conductivity Si3N4 ceramics, can solve the problems of long Si powder nitriding time, long holding time, high nitrogen pressure, and achieve rapid preparation, improved densification, low The effect of cost preparation

Inactive Publication Date: 2014-11-26
GUANGDONG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Preparation of Si by reactive pressure sintering of Si powder 3 N 4 There are two main problems in ceramics: (1) The nitriding time of Si powder is long, and it needs to be kept at 1400°C for 8 hours; (2) Si powder 3 N 4 Densification conditions are too harsh, high nitrogen pressure (10atm), high sintering temperature (1900°C), long holding time (12h)

Method used

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  • Method for rapidly preparing high heat conduction Si3N4 ceramic with low cost
  • Method for rapidly preparing high heat conduction Si3N4 ceramic with low cost

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Rapid and low-cost preparation of high thermal conductivity Si 3 N 4 Ceramics, the specific method is as follows:

[0031] (1) Si powder (particle size 2 powder (particle size 2 o 3 Powder (99.9% purity) is an additive, according to Si powder mass fraction of 80%, ZrO 2 The mass fraction is 10%, MgO-Y 2 o 3 The mass fraction of powder is 10% for batching, where MgO: Y 2 o 3 The mass fraction ratio is 55%: 45%, with ethanol as solvent and Si 3 N 4 The ball is the ball milling medium, mixed on a roller ball mill for 24 hours, after mixing and drying, a uniformly mixed Si-ZrO 2 -MgO-Y 2 o 3 Mix powder.

[0032] (2) Si-ZrO 2 -MgO-Y 2 o 3 The mixed powder is put into a mold for cold isostatic pressing molding, the cold isostatic pressing molding pressure is 200MPa, and the holding time is 5min.

[0033] (3) Si-ZrO 2 -MgO-Y 2 o 3 The green body is put into a boron nitride crucible, and the temperature is raised to 1400°C at a heating rate of 20°C / min for 2 h...

Embodiment 2

[0036] According to Si powder mass fraction is 60%, ZrO 2 Powder mass fraction is 20%, MgO-Yb 2 o 3 Powder mass fraction is 20% for batching, where MgO: Yb 2 o 3 The mass fraction ratio is 60%: 40%, and Si is prepared according to the method of Example 1 3 N 4 Ceramics, wherein the temperature is first raised to 1375°C for 4 hours, and then heated to 1700°C for 2 hours. The relative density of the prepared ceramic material is 99%, the hardness of the material is 16GPa, and the fracture toughness is 6.5MPa·m 1 / 2 , the bending strength is 750Mpa, and the thermal conductivity is 50W·m -1 ·K -1 .

Embodiment 3

[0038] According to Si powder mass fraction of 70%, ZrO 2 Powder mass fraction is 20%, MgO-La 2 o 3 The powder mass fraction is 10% for batching, wherein MgO: La 2 o 3 The mass fraction ratio is 75%: 25%, and Si is prepared according to the method in Example 1 3 N 4 Ceramics, wherein the temperature is first raised to 1375°C for 4 hours, and then heated to 1800°C for 2 hours. The relative density of the prepared ceramic material is 98%, the hardness of the material is 16GPa, and the fracture toughness is 7MPa·m 1 / 2 , the bending strength is 600Mpa, and the thermal conductivity is 60W·m -1 ·K -1 .

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Abstract

The invention discloses a method for rapidly preparing high heat conduction Si3N4 ceramic with low cost. The method is characterized in that Si powder is taken as a raw material, ZrO2 powder is taken as a nitridation catalyst, ZrO2-MgO-Re2O3 is taken as a sintering aid, wherein Re2O3 is taken as a rare earth oxide, Si, ZrO2 and MgO-Re2O3 are mixed according to mass fraction and then dried to obtain a Si-ZrO2-MgO-Re2O3 mixing powder; the mixing powder is subjected to a two-step insulation method and a pressureless sintering process to obtain the high heat conduction Si3N4 ceramic; According to the ceramic material, the relative density is higher than 95%, hardness is 8-20 GPa, fracture toughness is 3-8MPa.m<1/2>, bending strength is 200-1000Mpa, and the thermal conductivity is 20-100W.m<-1>,K<-1>. By introducing a ZrO2 catalyst, Si powder nitridation IS accelerated, the introduction of ZrO2-MgO-Re2O3 can improve the densification of Si3N4, and the high heat conduction Si3N4 ceramic can be rapidly prepared with low cost.

Description

technical field [0001] The invention relates to the field of non-oxide-based ceramic materials, and specifically discloses a low-cost, rapid preparation of high thermal conductivity Si 3 N 4 ceramic method. Background technique [0002] Si 3 N 4 Ceramics have excellent properties such as wear resistance, high temperature resistance, and high thermal conductivity, and are widely used in LED heat dissipation substrates, high-speed cutting tools, and key engine parts. Usually Si 3 N 4 Ceramics with high purity Si 3 N 4 The powder is prepared by hot pressing and sintering as raw material, the cost is high, and samples with complex shapes cannot be prepared. [0003] In order to reduce costs and prepare complex shapes, Si powder was used as raw material to prepare Si by reactive pressure sintering. 3 N 4 ceramics. On the one hand, the powder preparation and ceramic densification are combined into one step, which significantly reduces the cost; on the other hand, throug...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/584C04B35/65
Inventor 郭伟明马提游洋伍尚华林华泰
Owner GUANGDONG UNIV OF TECH
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