A high-pressure rapid preparation method of high thermal conductivity and high density silicon nitride material

Abstract

The invention relates to a high-pressure fast preparation method of a high-heat-conduction rate and high-compactness silicon nitride material. The method uses a high-temperature high-pressure sintering technology, and comprises the following concrete steps that under the high-pressure and high-temperature conditions (HPHT, 4.5 to 5.5 GPa, 1400 to 1500 DEG C), diamond, graphene, TiN, AlN, MgO, Y2O3powder and the like with the average particle diameter being 0.5 mu m are used as sintering auxiliary agents; silicon nitride (beta-Si3N4) powder with different mass ratios is used as framework materials for preparing high-heat-conduction rate and high-compactness silicon nitride block body materials. According to the method for preparing the high-performance structure material, sintering phasesof beta-Si3N4, diamond, ceramic hard phases and the like are formed through the mixed powder sintering technology of beta-Si3N4 and the auxiliary agents; the sintering body has high heat conduction rate and high compactness (low porosity). The method has the advantages that the operability is high; the process is simple; the ultrahigh temperature is not needed; the structure material synthesis time can be greatly shortened. The material is a novel ceramic material applicable to the fields of aerospace, war industry, electronics and the like.

Description

technical field [0001] The invention belongs to the field of block structure ceramic materials and device manufacturing, in particular to a method for preparing high-quality silicon nitride block ceramic materials with high compactness (low porosity) and high thermal conductivity. Background technique [0002] With the rapid development of my country's aerospace, military, electronics and other fields, the demand for high-power power electronic devices will also increase in the future. In order to adapt to more complex and harsh application conditions, high-power power electronic devices are developing in the direction of high temperature, high frequency, low power consumption, intelligence, modularization, and systematization, which puts more demands on the thermal shock resistance of the entire electronic device. Due to strict requirements, the preparation of high thermal conductivity ceramic substrate materials has become the key to the development of high-power module el...

AI Technical Summary

Problems solved by technology

The manufacturing cost of this method is relatively high, it requires ultra-high temperature conditions, the precision cannot be controlled, and the thermal conductivity is not high, which is 19.4 and 19.8W / (m K); , completed under the condition of 4h, there are too many types of binders, and too many metal impurities and oxygen elements are introduced; the equipment for spark plasma sintering is expensive, and the cost of each sintering is extremely high

In summary, it can be concluded that the process is complicated, and a-Si is mostly used 3 N 4 High temperature phase change or doped β-Si 3 N 4 The seeds are sintered, and then high-temperature nitriding treatment is carried out after sintering; ultra-high temperature is required, 1650-2000°C; it takes a long time to heat up, and the sintering time usually takes several hours to make a bulk material; at the same time, the compactness is not high. High (95-98%), it is difficult to reach more than 99%, the thermal conductivity is usually around 17.59–35W / (m K), and the cost of sintered materials in individual methods is relatively high

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