Method for preparing silicon nitride ceramic with high strength, high toughness and high thermal conductivity

A technology for silicon nitride ceramics and ceramic green bodies, which is applied to high thermal conductivity silicon nitride ceramics to prepare high strength and high toughness fields. Silicon sintering, the effect of improving thermal conductivity

Active Publication Date: 2020-06-09
浙江多面体新材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

At present, the reaction resintering technology (SRBSN) is usually used to prepare silicon nitride ceramics with high thermal conductivity, but high strength and toughness cannot b...

Method used

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  • Method for preparing silicon nitride ceramic with high strength, high toughness and high thermal conductivity
  • Method for preparing silicon nitride ceramic with high strength, high toughness and high thermal conductivity
  • Method for preparing silicon nitride ceramic with high strength, high toughness and high thermal conductivity

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Experimental program
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Effect test

Embodiment 1

[0043] 28.09g of silicon powder (particle size 1μm) and 3.22g of composite sintering aids (MgO and Sm 2 o 3 The molar ratio is 5:2) powder as raw material, absolute ethanol as solvent, placed in a ball mill tank for ball milling for 2h (the particle size of the ground silicon powder is 0.5 μm), and then the dried and sieved mixture Put it in the mold, dry press molding at 30MPa, carry out cold isostatic pressing of the obtained green body, the pressure is 300MPa, put the final obtained ceramic green body in a carbon tube furnace, and heat up at a rate of 10°C / min in a vacuum environment After heating up to 900°C for 2 hours, nitrogen was used as a protective atmosphere, and the temperature was raised to 1400°C for 6 hours at a rate of 10°C / min for nitriding to obtain a silicon nitride ceramic body with a nitriding rate of 97.55%. The density is 72%. The pressure sintering process is to raise the temperature to 1900°C under the condition of a nitrogen atmosphere with a pressu...

Embodiment 2

[0045] 27.96g of silicon powder (particle size 1μm) and 3.45g of composite sintering aids (MgO and Er 2 o 3 The molar ratio is 5:2) powder as raw material, absolute ethanol as solvent, placed in a ball mill tank for ball milling for 2h (the particle size of the ground silicon powder is 0.4μm), and then the dried and sieved mixture Put it in the mold, dry press molding at 30MPa, carry out cold isostatic pressing of the obtained green body, the pressure is 300MPa, put the final obtained ceramic green body in a carbon tube furnace, and heat up at a rate of 10°C / min in a vacuum environment After heating up to 900°C for 2 hours, nitrogen was used as a protective atmosphere, and the temperature was raised to 1450°C for 4 hours at a rate of 10°C / min for nitriding to obtain a silicon nitride ceramic body with a nitriding rate of 97.31%. The density is 72%. The pressure sintering process is to raise the temperature to 1900°C under the condition of a nitrogen atmosphere with a pressur...

Embodiment 3

[0048] 28.68g of silicon powder (particle size 15μm) and 2.25g of composite sintering aids (MgO, Y 2 o 3 and CeO 2 The molar ratio is 3.4:0.9:1.6) powder as raw material, absolute ethanol as solvent, placed in a ball mill tank for ball milling for 10h (the particle size of the ground silicon powder is 0.93 μm), and then the dried and sieved The mixture is placed in a mold, and dry-pressed at 30 MPa, and the resulting green body is subjected to cold isostatic pressing at a pressure of 300 MPa. The final obtained ceramic green body is placed in a carbon tube furnace, and the temperature of 10 ° C / min is increased in a vacuum environment. After the heating rate was raised to 600°C for 4 hours, nitrogen was used as the protective atmosphere, and the temperature was raised to 1420°C for 6 hours at a heating rate of 10°C / min for nitriding to obtain a silicon nitride ceramic body with a nitriding rate of 97.38%. The relative density of the body is 71.94%. The pressure sintering ...

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Abstract

The invention relates to a method for preparing silicon nitride ceramic with high strength, high toughness and high thermal conductivity. The preparation method comprises the following steps: uniformly mixing 94-88% by mass of silicon powder and 6-12% by mass of a sintering aid, grinding, drying, adding a binder, granulating, and carrying out compression molding to obtain a ceramic biscuit, wherein the sintering aid comprises a rare earth oxide and an alkaline earth metal oxide; after the ceramic biscuit is subjected to glue discharging, nitriding at a temperature of 1380-1450 DEG C to obtaina silicon nitride ceramic billet body; and sintering the silicon nitride ceramic billet body at a temperature of 1850-1950 DEG C under air pressure to obtain the silicon nitride ceramic material.

Description

technical field [0001] The invention relates to a method for preparing silicon nitride ceramics with high strength, high toughness and high thermal conductivity, and belongs to the technical field of preparation of non-oxide ceramics. Background technique [0002] Silicon nitride ceramics have excellent mechanical properties, including high flexural strength and fracture toughness, good thermal shock resistance, low high temperature creep, and good wear resistance and corrosion resistance. Used in the field of structural ceramics, such as automotive, aerospace and electronics. [0003] The crystal structure of silicon nitride consists of strong covalent bonds, which makes it difficult to sinter the material. Therefore, liquid phase sintering is usually used to prepare dense silicon nitride ceramic materials. In recent years, due to the high theoretical thermal conductivity of silicon nitride ceramics, it has become a candidate material for heat dissipation substrates for hi...

Claims

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Application Information

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IPC IPC(8): C04B35/584C04B35/591C04B35/622C04B35/64
CPCC04B35/584C04B35/591C04B35/622C04B35/64C04B2235/3225C04B2235/3224C04B2235/3227C04B2235/3229C04B2235/3206C04B2235/3208C04B2235/658C04B2235/6562C04B2235/6567
Inventor 张景贤段于森刘宁
Owner 浙江多面体新材料有限公司
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