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Preparation method of eutectic, reinforced and toughened silicon nitride ceramic

A technology of silicon nitride ceramics and tough silicon nitride, which is applied in the preparation of high-performance silicon nitride ceramics and the field of silicon nitride ceramics with α/β eutectic structure, which can solve the problems of limiting the application and promotion of silicon nitride , to improve performance, relieve stress concentration, and improve brittleness

Active Publication Date: 2020-02-21
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the inherent brittleness of ceramic materials limits the further application and promotion of silicon nitride.

Method used

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  • Preparation method of eutectic, reinforced and toughened silicon nitride ceramic
  • Preparation method of eutectic, reinforced and toughened silicon nitride ceramic
  • Preparation method of eutectic, reinforced and toughened silicon nitride ceramic

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0048] (1) Mixing: Mix the dried ceramic raw materials evenly in proportion, and pass through a 60-mesh sieve. The ceramic raw materials are composed of the following components:

[0049] Silicon nitride powder: 90%;

[0050] Sintering aid: 9%;

[0051] Phase change inhibitor: 1%;

[0052] The sintering aid consists of the following components:

[0053] Al 2 o 3 : 60%;

[0054] Y 2 o 3 : 40%;

[0055] (2) Grinding: Put the powder to be mixed in a sand mill, add powder and ethanol according to powder: ethanol = 1:2, set the sand mill speed to 3000r / min, and sand mill for 2 hours.

[0056] (3) Sintering: Put the powder into the SPS mold and put the mold into the SPS device. After vacuuming, heat up to 1500°C at a speed of 150°C / min, keep it under 10MPa pressure for 5min, stop heating and cool with the furnace to room temperature. After taking out the sample, a primary sintered body was obtained, the relative density of the obtained primary sintered body was 99.1%, and th...

Embodiment 2

[0059] (1) Mixing: Mix the dried ceramic raw materials in proportion and pass through a 100-mesh sieve. The ceramic raw materials are composed of the following components:

[0060] Silicon nitride powder: 80%;

[0061] Sintering aid: 15%;

[0062] Phase change inhibitor: 5%;

[0063] The sintering aid consists of the following components:

[0064] MgO: 40%;

[0065] Y2O3: 40%;

[0066] SiO2: 20%

[0067] (2) Grinding: Put the powder to be mixed in a ball mill, add powder and ethanol according to powder: ethanol = 1:2, set the sand mill speed to 300r / min, and ball mill for 10h.

[0068] (3) Sintering: Put the powder into the SPS mold and put the mold into the SPS device. After vacuuming, heat up to 1500°C at a speed of 150°C / min, keep it warm for 5min under a pressure of 50MPa, stop heating and follow the furnace Cool to room temperature. After taking out the sample, a primary sintered body was obtained, the relative density of the obtained primary sintered body was 99.3...

Embodiment 3

[0071] (1) Mixing: Mix the dried ceramic raw materials in proportion and pass through a 200 mesh sieve. The ceramic raw materials are composed of the following components:

[0072] Silicon nitride powder: 70%;

[0073] Sintering aid: 20%;

[0074] Phase change inhibitor: 10%;

[0075] The sintering aid consists of the following components:

[0076] La 2 o 3 : 40%;

[0077] MgSiN 2 : 40%;

[0078] ZrO 2 : 20%

[0079] (2) Grinding: Put the powder to be mixed in a stirring mill, add powder and ethanol according to powder: water = 1:3, set the sand mill speed to 500r / min, and grind for 5 hours.

[0080] (3) Sintering: Put the powder into the SPS mold and then put the mold into the SPS device. After vacuuming, heat up to 1500°C at a speed of 200°C / min, keep it under 100MPa pressure for 5min, stop heating and follow the furnace Cool to room temperature. After taking out the sample, a primary sintered body was obtained, the relative density of the obtained primary sintere...

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Abstract

The invention discloses a preparation method of eutectic, reinforced and toughened silicon nitride ceramic, belonging to the technical field of ceramic preparation. According to the method, an alpha phase-beta phase eutectic structure is formed in a silicon nitride material, so the silicon nitride reinforced and toughened ceramic is obtained; and the ceramic has relative density of larger than 99%, fracture toughness of larger than 10 MPa.m<1 / 2>, Vickers hardness of larger than 18 Gpa and bending strength of larger than 600 MPa. The method comprises the following steps: 1) mixing a silicon nitride raw material, a sintering aid and the like in proportion, and performing spark plasma sintering (SPS) on the uniformly-mixed powder to obtain a primary sintered body with relative density of greater than 99% and an alpha phase content of greater than 90%; and then carrying out air-pressure sintering to generate the alpha / beta eutectic structure. The prepared silicon nitride ceramic has the same characteristics (high strength, good compactness, high temperature resistance and wear resistance) as traditional silicon nitride ceramic, is obviously improved in fracture toughness and plasticity, and can be widely applied to the field of special materials.

Description

technical field [0001] The invention belongs to the technical field of ceramic preparation, and relates to a method for preparing high-performance silicon nitride ceramics, in particular to a process technology for preparing silicon nitride ceramics with an α / β eutectic structure. Background technique [0002] Silicon nitride ceramics have many excellent properties such as low density, high thermal conductivity, high hardness, good thermal stability and chemical stability. Cutting tools, heat conduction substrates and other fields. However, the inherent brittleness of ceramic materials limits the further application and promotion of silicon nitride. Contents of the invention [0003] The purpose of the present invention is to provide a process for preparing silicon nitride ceramics with α / β eutectic structure, so that the relative density of the prepared silicon nitride ceramics is >99%, and the fracture toughness is >10MPa·m 1 / 2 , Vickers hardness> 18Gpa, flexu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/596C04B35/64
CPCC04B35/587C04B35/64C04B2235/3206C04B2235/3208C04B2235/3225C04B2235/3227C04B2235/3244C04B2235/3418C04B2235/3852C04B2235/3873C04B2235/3878C04B2235/3882C04B2235/5436C04B2235/5445C04B2235/6562C04B2235/6567C04B2235/661C04B2235/666C04B2235/96
Inventor 陈克新张杰刘光华崔巍
Owner TSINGHUA UNIV
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