A kind of preparation method of self-catalyzed high-purity aluminum nitride

Abstract

The invention discloses a method for preparing self-catalyzed high-purity aluminum nitride, which belongs to the technical field of aluminum nitride synthesis, and comprises the following steps: (1) mixing materials: aluminum hydroxide powder, carbon powder, and aluminum nitride powder are used as the The raw materials are uniformly mixed according to a certain weight ratio to obtain a mixed material; (2) high-temperature synthesis: the mixed material is placed in a mixed gas flow of nitrogen and propane at a certain pressure at 1350-1420 ° C, and reacted for 1.5-3 hours to obtain a reaction product ; (3) Decarburization: remove the carbon in the reaction product to obtain aluminum nitride powder. In the preparation method of self-catalyzed high-purity aluminum nitride disclosed by the present invention, aluminum nitride is selected as a seed crystal, and the reaction is carried out in a mixed gas flow of nitrogen and propane at a certain pressure, the thermal motion of reaction molecules is enhanced, and the diffusion and penetration rate is increased. It has a self-catalytic effect, shortens the reaction synthesis time, and reduces the reaction synthesis temperature by 200-400°C; and avoids the pollution of impurity elements brought in by adding other additives, and ensures the purity of the prepared aluminum nitride.

Description

technical field [0001] The invention relates to a method for preparing self-catalyzed high-purity aluminum nitride, which belongs to the technical field of aluminum nitride synthesis. Background technique [0002] Aluminum nitride has excellent characteristics such as high thermal conductivity, low dielectric constant, good insulation, high mechanical strength, and expansion coefficient matching that of silicon chips. It is an excellent circuit substrate and white LED red phosphor (CaAlSiN3:Eu) One of the raw materials, the market demand is large, and the application prospect is broad. [0003] For aluminum nitride ceramic materials, the properties of aluminum nitride, such as morphology, purity, particle size, oxygen content and other impurities, directly affect the thermal conductivity and other properties of aluminum nitride ceramic materials and subsequent sintering and molding processes. For example, when the impurity content in the aluminum nitride powder is too high,...

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Problems solved by technology

[0004] Among the various methods of manufacturing aluminum nitride, aluminum powder direct nitriding method, carbothermal reduction method, chemical vapor deposition method, self-propagating combustion synthesis method and microwave synthesis method all have high cost, mass production and synthetic nitriding Aluminum crystal form has defects, low purity and other disadvantages, and the prepared aluminum nitride powder has complex morphology, which leads to poor fluidity and it is difficult to achieve a high filling density, which affects the thermal conductivity of the material

Although the traditional carbothermal reduction method can realize large-scale production, the synthesis temperature is high, the reaction time is long, and the purity of the obtained aluminum nitride is low.

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