Low-temperature preparation method of high-strength silicon nitride ceramic

A silicon nitride ceramic and high-strength technology, which is applied in the field of preparation of inorganic non-metallic materials, can solve the problems of inflammability, explosion, synthesis, and storage, and achieve the effects of low cost, lower sintering temperature, and high density

Inactive Publication Date: 2019-09-06
WUHAN UNIV OF TECH
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  • Abstract
  • Description
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  • Application Information

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Problems solved by technology

But MgSiN 2 Difficult to synthesize, high cost; Mg 3 N 2 Toxic, flammable and explosive, difficult to store

Method used

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  • Low-temperature preparation method of high-strength silicon nitride ceramic
  • Low-temperature preparation method of high-strength silicon nitride ceramic
  • Low-temperature preparation method of high-strength silicon nitride ceramic

Examples

Experimental program
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Effect test

Embodiment example

[0027] Table 1: Raw material ratios and related sintering parameters of silicon nitride ceramics in Examples 1-4 of the present invention.

[0028]

Embodiment 1

[0030] Set the mass fraction to 2.0% Mg 2 Mix Si powder and 98.0% silicon nitride powder, use absolute ethanol as the dispersion medium, put it into a nylon ball mill tank together with silicon nitride balls, and disperse for 24 hours by ball milling, take out the slurry and dry it, sieve it, and then put the powder into graphite Put the mold into a plasma activation sintering furnace and pressurize it to 30MPa, pass it into a nitrogen atmosphere for protection, raise the temperature to 1500°C, keep it warm for 5 minutes, and take out the sample after cooling to room temperature with the furnace to obtain silicon nitride ceramics. The XRD of the product see figure 2 . After testing, the density of the silicon nitride ceramic sample obtained in this embodiment is 97.2%, and the bending strength is 757 MPa.

Embodiment 2

[0032] Set the mass fraction to 4.0% Mg 2 Mix Si powder and 96.0% silicon nitride powder, use absolute ethanol as the dispersion medium, put it into a nylon ball mill jar together with silicon nitride balls, and disperse for 24 hours by ball milling. Take out the slurry and dry it, sieve it, and then put the powder into graphite Put the mold into a plasma activation sintering furnace and pressurize it to 30MPa, pass through a nitrogen atmosphere to protect and heat up to 1400°C, keep it warm for 5min, and take out the sample after cooling to room temperature with the furnace to obtain silicon nitride ceramics. The XRD of the product see figure 2 . After testing, the density of the silicon nitride ceramic sample obtained in this embodiment is 98.7%, and the bending strength is 644 MPa.

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Abstract

The invention relates to a low-temperature preparation method of high-strength silicon nitride ceramic. The silicon nitride ceramic is prepared by sintering at 1400-1500 DEG C in a nitrogen atmospherethrough a plasma activated sintering process with low-melting Mg2Si as a sintering aid. The silicon nitride ceramic prepared by the method has a density being higher than 97% and a bending strength of 644-1056 MPa. The method has the advantages of simple process, and low price of raw materials; and the prepared silicon nitride ceramic material has a high density and a high bending strength, and has broad application prospects in the fields of thermally conductive ceramic substrates, metallurgy and chemical engineering.

Description

technical field [0001] The invention belongs to the field of preparation of inorganic non-metallic materials, and in particular relates to a low-temperature preparation method of high-strength silicon nitride ceramics. Background technique [0002] Silicon nitride ceramics have excellent comprehensive properties such as low density, high specific strength, high specific modulus, high temperature resistance, oxidation resistance, wear resistance and thermal shock resistance, and are widely used in machinery, chemical industry, aerospace, electronic devices, etc. important areas. [0003] As a strong covalent bond compound, silicon nitride has a small sintering driving force. Only when the sintering temperature is close to its decomposition temperature (1850°C), the atoms have sufficient migration rate, but when the temperature rises to 1700°C, the nitride The silicon begins to decompose significantly. Therefore, it is difficult to prepare dense silicon nitride ceramics with...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/584C04B35/622C04B35/64
CPCC04B35/584C04B35/622C04B35/64C04B2235/3891C04B2235/6567C04B2235/658C04B2235/666C04B2235/96
Inventor 李俊国罗杰张睿成陈杨沈强李美娟
Owner WUHAN UNIV OF TECH
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