Method for preparing high-thermal-conductivity silicon nitride ceramics

A technology of silicon nitride ceramics with high thermal conductivity, applied in the field of functional ceramics, which can solve the problems of high sintering temperature, introduction of lattice oxygen atoms and equal grain boundaries, achieve low preparation temperature, achieve densification, and reduce the effect of subsequent processing

Inactive Publication Date: 2016-01-20
NORTHWESTERN POLYTECHNICAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] In order to avoid the deficiencies of the prior art, the present invention proposes a method for preparing silicon nitride ceramics with high thermal conductivit

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  • Method for preparing high-thermal-conductivity silicon nitride ceramics
  • Method for preparing high-thermal-conductivity silicon nitride ceramics
  • Method for preparing high-thermal-conductivity silicon nitride ceramics

Examples

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[0028] Example 1: Select β-Si with a particle size of 1.2μm 3 N 4 Powder, at 1800℃, 0.3MPaN 2 Heat treatment in an atmosphere for 2 hours, and then use 5% HF acid to treat the heat-treated Si 3 N 4 The powder is pickled for 6 hours and dried for later use. Weigh 50g of processed Si 3 N 4 Powder, add 50g solvent, the solvent is anhydrous ethanol and methyl ethyl ketone mixed in a volume ratio of 1:1, 4g dispersant triethyl phosphate, put it into a nylon ball mill tank, then add silicon nitride grinding balls, on the drum ball mill Ball mill for 12 hours; then add 5g binder polyvinyl butyral, 5g plasticizer, plasticizer is glycerol and dioctyl phthalate in a volume ratio of 1:1 to mix and 4g Foaming agent, defoaming agent is n-butanol and ethylene glycol mixed in a volume ratio of 1:1; continue ball milling for 12 hours to obtain uniformly dispersed Si suitable for casting 3 N 4 Slurry. Cast the slurry to obtain a thickness of 0.4mm, Si 3 N 4 A thin layer with a volume fraction o...

Example Embodiment

[0029] Example 2: Select β-Si with a diameter of about 1μm and an aspect ratio of about 5 3 N 4 Columnar crystal, at 1800℃, 0.3MPaN 2 Heat treatment in an atmosphere for 2 hours, and then use 5% HF acid to treat the heat-treated Si 3 N 4 The powder is pickled for 6 hours and dried for later use. Weigh 50g of processed Si 3 N 4 Powder, add 50g solvent, the solvent is anhydrous ethanol and methyl ethyl ketone mixed in a volume ratio of 1:1, 4g dispersant triethyl phosphate, put it into a nylon ball mill tank, add silicon nitride grinding balls, and ball mill on a drum ball mill 12 hours. Then add 5g of binder polyvinyl butyral, 5g of plasticizer to the ball mill tank. The plasticizer is glycerol and dioctyl phthalate mixed in a volume ratio of 1:1 and 4g of defoamer to eliminate The foaming agent is n-butanol and ethylene glycol mixed in a volume ratio of 1:1, and ball milling is continued for 12 hours to obtain Si that is uniformly dispersed and suitable for casting 3 N 4 Slurry...

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Abstract

The invention relates to a method for preparing high-thermal-conductivity silicon nitride ceramics. The method comprises the steps that firstly, thermal treatment and acid pickling treatment are carried out on Si3N4 powder, and then Si3N4 slurry is prepared; an Si3N4 thin layer is prepared through a casting process technology, and porous silicon nitride powder prefabricated bodies are obtained after the thin layer is cut and overlapped; the prefabricated bodies are subjected to liquid silicon penetration through high-purity silicon powder, and compact Si3N4/Si is obtained; nitrogen treatment is carried out on Si3N4/Si in a nitrogenation oven, so that Si in the material is subjected to a nitriding reaction to generate Si3N4. Compared with frequently-used processes for preparing the high-thermal-conductivity silicon nitride ceramics, such as isostatic pressing sintering and hot pressed sintering, a tape casting method is combined with liquid silicon penetration forming and nitriding sintering processes, no or little machining is needed, preparation temperature is low, no sintering additive needs to be added, and the influence of a grain boundary on the thermal conductivity of the material is avoided. The thermal conductivity of the prepared silicon nitride ceramics can reach 80-120 Wm<-1>K<-1>.

Description

technical field [0001] The invention belongs to the field of functional ceramics, and in particular relates to a preparation method of silicon nitride ceramics with high thermal conductivity. Background technique [0002] With the continuous development of integrated circuits and power devices, the problem of heat dissipation has become more and more restrictive to the improvement of product performance, and people have put forward higher requirements for the comprehensive performance of electronic packaging substrates and heat dissipation materials. Silicon nitride ceramics have potentially high thermal conductivity (theoretical thermal conductivity can reach 200-320W m -1 ·K -1 ), good insulation, corrosion resistance, thermal shock resistance and excellent mechanical properties, it has good application prospects in the fields of electronic packaging materials and heat dissipation materials. [0003] Since silicon nitride is a compound with strong covalent bonds, it is d...

Claims

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Application Information

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IPC IPC(8): C04B35/584C04B35/65
Inventor 成来飞李明星张立同
Owner NORTHWESTERN POLYTECHNICAL UNIV
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