Preparation method of silicon nitride ceramic with high thermal conductivity

A technology of silicon nitride ceramics and high thermal conductivity, which is applied in the field of ceramic preparation, and can solve the problems such as the stagnant application research of silicon nitride ceramics with high thermal conductivity

Active Publication Date: 2017-05-31
ANHUI TUOJITAI NOVEL CERAMIC TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This is the main reason why the application research of high thermal conductivity silicon nitride ceramics is stagnant

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] A method for preparing silicon nitride ceramics with high thermal conductivity, comprising the following steps:

[0021] 1) Calculated in parts by weight, weigh 70 parts of silicon nitride, 3 parts of yttrium oxide, 3 parts of lanthanum oxide and 3 parts of sintering aid, mix them evenly, add them to a ball mill to form a mixed powder, and then put them in an electric vacuum oven Dry continuously at a temperature of 110°C, and after complete drying, sieve in a hydrogen stream at a temperature of -10°C to obtain a composite powder; the sintering aid is a mixture of alumina, manganese oxide and boron oxide, and the mass ratio It is 1:1:8.

[0022] 2) Put the composite powder obtained in step 1) into the graphite mold of the discharge plasma sintering device, and conduct discharge plasma sintering after vacuuming. The heating rate is 10K / s, the heating temperature is 145°C, and the holding time is 6min. silicon nitride ceramics.

[0023] The thermal conductivity of the o...

Embodiment 2

[0025] A method for preparing silicon nitride ceramics with high thermal conductivity, comprising the following steps:

[0026] 1) Calculated in parts by weight, weigh 76 parts of silicon nitride, 4 parts of yttrium oxide, 3 parts of cerium oxide and 6 parts of sintering aid, mix them evenly, add them to a ball mill to form a mixed powder, and then put them in an electric vacuum oven Dry continuously at a temperature of 120°C, and after complete drying, sieve in a hydrogen stream at a temperature of -20°C to obtain a composite powder; the sintering aid is a mixture of alumina, manganese oxide and boron oxide, and the mass ratio It is 1.5:1.5:7.

[0027] 2) Put the composite powder obtained in step 1) into the graphite mold of the discharge plasma sintering device, and conduct discharge plasma sintering after vacuuming. The heating rate is 12K / s, the heating temperature is 1540°C, and the holding time is 3min. silicon nitride ceramics;

[0028] The thermal conductivity of the...

Embodiment 3

[0030] A method for preparing silicon nitride ceramics with high thermal conductivity, comprising the following steps:

[0031] 1) Calculated in parts by weight, weigh 78 parts of silicon nitride, 10 parts of yttrium oxide and 4 parts of sintering aid, mix them evenly, add them to a ball mill to form a mixed powder, and then put them in an electric vacuum oven at 110°C Continuous drying, after complete drying, sieve in a hydrogen gas stream at a temperature of -5°C to obtain a composite powder; the sintering aid is a mixture of alumina, manganese oxide and boron oxide, with a mass ratio of 2:2: 6.

[0032] 2) Put the composite powder obtained in step 1) into the graphite mold of the discharge plasma sintering device, and conduct discharge plasma sintering after vacuuming. The heating rate is 14K / s, the heating temperature is 1600°C, and the holding time is 6min. silicon nitride ceramics.

[0033] The thermal conductivity of the obtained silicon oxide ceramics was 100 W / mK, t...

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Abstract

The invention provides a preparation method of silicon nitride ceramic with a high thermal conductivity. The preparation method comprises the following steps that (1) 70-80 parts of silicon nitride, 5-10 parts of rare earth oxide and 2-6 parts of a sintering aid are weighed in parts by weight, evenly mixed, and then added into a ball mill to form mixed powder, then continuous drying is conducted in a vacuum electric heating drying oven at the temperature of 110 to 120 DEG C, the completely-dried mixed powder is sieved in hydrogen airflow under a temperature condition of minus 20 to 0 DEG C to obtain composite powder; and (2) the composite powder obtained in the step (1) is packaged into a graphite die of a discharge plasma sintering device, discharge plasma sintering is conducted after vacuumization is conducted with a heating speed being 10 to 15 K/s, a heating temperature being 1450 to 1700 DEG C and a thermal insulation time being 3-8 min, and then the compact silicon nitride ceramic is obtained, wherein the sintering aid is a mixture of aluminum oxide, manganese oxide and boric oxide. By adoption of the preparation method, silicon nitride crystalline grains can be purified, and the thermal conductivity can be increased.

Description

technical field [0001] The invention belongs to the technical field of ceramic preparation, in particular to a method for preparing silicon nitride ceramics with high thermal conductivity. Background technique [0002] Silicon nitride ceramics have excellent mechanical properties and have received widespread attention as structural materials. Generally, the flexural strength of silicon nitride can exceed 1000MPa, but its thermal conductivity is only 20-30W / mK, which is similar to alumina ceramics and far lower than high thermal conductivity aluminum nitride ceramics (180-260W / mK). The calculation of the document "J.S.Haggerty, A.Lightfoot, Opportunities for Enhancing the Thermal Conductivities of SiCand Si3N4Ceramics through Improved Processing, Ceram.Eng.Sci.Proc., 1995, 16(4): p475-487." shows that the intrinsic heat of silicon nitride Conductivity is 320W / mK. And the calculation of the literature "N. Hirosaki, S. Ogata, C. Kocer, H. Kitagawa, and Y. Nakamura, Molecular ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/584C04B35/64
CPCC04B35/584C04B35/64C04B2235/3217C04B2235/3225C04B2235/3227C04B2235/3262C04B2235/3409C04B2235/6022C04B2235/6562C04B2235/6567C04B2235/6581C04B2235/96C04B2235/9607
Inventor 宋晓超张天宇何东张天舒
Owner ANHUI TUOJITAI NOVEL CERAMIC TECH
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