Method for preparing high-thermal-conductivity silicon nitride ceramic by adding fluoride

A technology of silicon nitride ceramics and high thermal conductivity, which is applied in the field of preparing silicon nitride ceramics with high thermal conductivity by adding fluoride, which can solve the problems of high toxicity, restrictions, and inconvenience for production operators, and achieve high thermal conductivity and high mechanical strength.

Inactive Publication Date: 2017-11-28
HEBEI COREFRA SILICON NITRIDE MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Ceramic materials currently available as electronic substrates include Al 2 o 3 , BeO, AlN, etc., where Al 2 o 3 The highest thermal conductivity is only 31.7W / (m K), which is difficult to meet the requirements of the rapid development of integration technology
BeO has the highest thermal conductivity in ceramics, but one of BeO's Achilles' heels is its high toxicity, which brings inconvenience to production operators and greatly limits its use in industrial production
AlN ceramic is an excellent material with high thermal conductivity, and its theoretical value of thermal conductivity is similar to that of BeO (320W / (m K)), but AlN has problems such as easy oxidation and poor water resistance, which affect its application range

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] α-Si treated with nano-TiC 3 N 4 (α=92%, D50=0.55μm) 89.5g, silicon magnesium nitride 5g, yttrium fluoride 5g, β-Si 3 N 4 (D50=1.5μm) Put 0.5g of polyvinyl alcohol, tributyl phosphate, absolute ethanol and methyl ethyl ketone into a nylon ball mill jar for ball milling for 24 hours, and the balls used in the milling medium are silicon nitride balls. Then add acrylic resin and carry out secondary ball milling for 24 hours. After the ball milling, dry at 65° C. and pass through a 40-mesh sieve. The granulated powder is subjected to isostatic pressing at a pressure of 400 MPa. The green body was kept at 1900°C for 8h, and then heat-treated at 1400°C for 24h. After cooling with the furnace, silicon nitride ceramics are obtained, and the thermal conductivity reaches 102W / (m·K).

Embodiment 2

[0017] 87g treated α-Si 3 N 4 Powder (α=93.7%, D50=0.67μm), 5g silicon magnesium nitride, 3g rubidium fluoride, 3g samarium fluoride, 2g β-Si 3 N 4 (D50=2.5 ​​μm) powder, polyvinyl butyral, tributyl phosphate, absolute ethanol and methyl ethyl ketone mixture were ground in a ball mill for 18 hours, then added acrylic resin and ground for another 20 hours. The slurry was dried at a temperature of 60°C and passed through a 40-mesh sieve. First 20MPa dry pressing and then 200PMa isostatic pressing. Put it into a sintering furnace, keep it at 1950°C for 15 hours, then lower the temperature to 1300°C and keep it for 10 hours, then cool with the furnace. The thermal conductivity of the obtained silicon nitride ceramics is as high as 143 W / (m·K).

Embodiment 3

[0019] 87g treated α-Si 3 N 4 Powder (α=94.2%, D50=0.89μm), 4g silicon magnesium nitride, 4g ytterbium fluoride, 5g β-Si 3 N 4 (D50=4.5μm) powder, polyvinyl butyral, tributyl phosphate, absolute ethanol and methyl ethyl ketone mixture are put into a nylon ball mill jar for ball milling for 20 hours, then put into acrylic resin and ball milled for a second time for 20 hours A mixed slurry is obtained. Put the slurry into a sintering furnace after tape casting for 24 hours at 1750°C, then lower the temperature to 1650°C for 40 hours and then cool with the furnace. The thermal conductivity of the obtained silicon nitride ceramic was 125 W / (m·K).

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Abstract

The invention belongs to the technical field of ceramic material preparation and relates to a method for preparing silicon nitride ceramics with high thermal conductivity by adding fluoride. In the present invention, α-Si3N4 is used as a raw material, and a mixture of silicon magnesium nitride and rare earth fluoride is used as a sintering aid, and the additive amount is 1 to 15 wt%. First, use nano-TiC to pretreat the surface of Si3N4 powder, put the treated raw materials, additives, binders, crystal seeds, defoamers, and solvents into a ball mill and mix them evenly, and then add a dispersant for secondary Secondary ball milling, the mixed slurry after ball milling is dried, granulated, shaped, sintered, and heat treated to prepare silicon nitride ceramics with high thermal conductivity. The present invention prevents the oxygen in the auxiliary agent from entering into the crystal lattice of silicon nitride ceramics by adding rare earth metal fluoride, reduces the adverse effect of lattice oxygen impurity content on the thermal conductivity of ceramics, and the prepared silicon nitride ceramics has relatively high High thermal conductivity has great application potential in the field of electronic packaging materials.

Description

technical field [0001] The invention belongs to the technical field of ceramic material preparation, and in particular relates to a method for preparing silicon nitride ceramics with high thermal conductivity by adding fluoride. Background technique [0002] With the continuous development of integrated circuits and functional devices, people have put forward higher requirements for the heat dissipation of the circuit operating temperature. To solve this serious problem, new materials must be used to dissipate heat through the substrate. Ceramic materials currently available as electronic substrates include Al 2 o 3 , BeO, AlN, etc., where Al 2 o 3 The highest thermal conductivity is only 31.7W / (m·K), which is difficult to meet the requirements of the rapid development of integration technology. BeO has the highest thermal conductivity among ceramics, but one of BeO's Achilles' heels is its high toxicity, which brings inconvenience to production operators and greatly re...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/584C04B35/622C04B35/63C04B35/634
CPCC04B35/584C04B35/622C04B35/6303C04B35/63416C04B35/6342C04B2235/3852C04B2235/445C04B2235/96C04B2235/9607
Inventor 张红冉刘久明
Owner HEBEI COREFRA SILICON NITRIDE MATERIAL
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