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Lightweight high heat conductive composite material and preparation method thereof

A composite material, high thermal conductivity technology, applied in heat exchange materials, chemical instruments and methods, etc., can solve the problems of high energy consumption and environmental pollution, high density of metal materials, high cost, etc., and achieve good mechanical strength and preparation technology. Simple, short production cycle results

Inactive Publication Date: 2009-10-07
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, metal materials have high density, high cost, easy corrosion, high energy consumption and environmental pollution in the process of smelting and processing. Therefore, a lightweight composite material with superior performance than metal is sought. If the energy consumption in the processing process is low, the impact on the environment Small, it will surely become a new generation of heat dissipation material, to partially or completely replace metal, its market prospect is very promising, in addition to the heat dissipation of electronic devices, it can also be used in the fields of LED, high-power electrical appliances, etc.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Natural flake graphite powder with an average particle size of 50 microns, multi-walled carbon nanotubes and carbon nanofibers purified by nitric acid, SiC with an average particle size of 100 nm, AlN with an average particle size of 80 nm and Si powder with an average particle size of 50 nm according to The weight percentage is 70:8:8:2:4:3 mixed, and the remaining 5% is methyl cellulose. Mixing is carried out in a stirrer with a rotating speed of 10000 rpm. While mixing, add a 10% methylcellulose aqueous solution, mix and stir for 1 hour; dry at 120 ° C, press and form, and vacuum at 300 ° C and 30 MPa pressure Under hot pressing, a lightweight high thermal conductivity composite material is obtained. At room temperature, the thermal conductivity along the hot pressing direction is 7.1W / m·K, and the thermal conductivity perpendicular to the hot pressing direction is 190W / m·K.

Embodiment 2

[0018] Pyrolytic graphite powder, single-walled carbon nanotubes and carbon nanofibers purified by nitric acid, and SiC, AlN, and Si powders are mixed according to the weight percentage of 70:10:10:2:3:1, and the remaining 4% is methyl cellulose. Mixing is carried out in a stirrer with a rotating speed of 11000 rpm. While mixing, add a 5% methylcellulose aqueous solution, and mix and stir for 1 hour; dry at 100 ° C, disperse, and press the powder steel mold into shape. Hot isostatic pressing at 300°C and 30MPa in an argon atmosphere to obtain a light weight and high thermal conductivity composite material. At room temperature, the thermal conductivity along the hot pressing direction is 7.5W / m·K, and the thermal conductivity perpendicular to the hot pressing direction is 211W / m·K.

Embodiment 3

[0020] Expanded graphite powder, multi-walled carbon nanotubes and carbon nanofibers after nitric acid purification, SiC, AlN, and Si powders are mixed according to the weight ratio of 75:2:2:3:10:3, and the remaining 5% is polyacrylamide. Mixing is carried out in a stirrer with a rotating speed of 10000 rpm. While mixing, add an aqueous solution of polyacrylamide with a mass concentration of 8%, and mix and stir for 2 hours; dry at 130°C, disperse, and press the powder steel mold into shape. Ultra-high pressure sintering at 600 degrees and 50 MPa pressure to obtain lightweight and high thermal conductivity composite materials. At room temperature, the thermal conductivity along the hot pressing direction is 8.0W / m·K, and the thermal conductivity perpendicular to the hot pressing direction is 268W / m·K.

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Abstract

The lightweight high heat conductive composite material disclosed in the present invention is characterized in containing the following components in weight percentages of: 50-95% of graphite powder, 1-45% of heat conductive nanometer material, and 4-5% of macromolecule binding agent; and the sum of the above components is 100%. The preparation method comprises the steps of: weighing graphite powder and heat conductive nanometer material according to the weight percentages, putting into a enclosed container, mixing while adding macromolecule binding agent, and standing for 0.5-24 hours; drying and making into base substrate; and thermoforming with the pressure over 8 MPa, at temperature above 200 degrees centigrade, in vacuum or under protection of argon, hydrogen or nitrogen. The invention has the advantages of simple preparation process, short production cycle, wide raw material source, and low cost; the obtained composite material finished product has low density, high mechanical strength, high thermal conductivity and no micro-crack inside material.

Description

technical field [0001] The invention relates to a heat-conducting composite material and a preparation method thereof. Background technique [0002] As the power of microelectronic systems continues to increase, the volume continues to decrease. The electronic components at the highest temperature point of the entire equipment are also heat sources, and excessive temperature rise is often a fatal factor leading to electronic system failure and failure. In order to make electronic systems (especially sensitive circuits and components) work continuously and stably, effective and reliable heat dissipation is obviously very important. Therefore, it is urgent to research and develop high-efficiency electronic heat dissipation materials and related technologies. [0003] Metal is the preferred thermally conductive material. Gold and silver with high thermal conductivity cannot be widely used due to their soft texture, high density, and high price; iron, due to its low thermal co...

Claims

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Application Information

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IPC IPC(8): C09K5/14
Inventor 程继鹏史丹安全福张孝彬
Owner ZHEJIANG UNIV