Preparation method of aluminum nitride powder

Abstract

The invention provides a method for preparing aluminum nitride powder, which comprises the steps of: mixing and dispersing aluminum hydroxide powder and carbon powder, adding acid-containing aqueous solution, kneading or ball milling, forming, drying, roasting under anaerobic conditions, impregnating Sucrose or glucose solution and dried, roasted under anaerobic conditions, and / or through thermal cracking of introduced hydrocarbons, carbon deposits in the inner pores of the molding material, in a flowing nitrogen atmosphere, carry out reduction nitriding reaction at 1400‑1600 °C, and then Carry out low-temperature charcoal-burning treatment to produce aluminum nitride powder with low oxygen and carbon content. The present invention separates most of the alumina particles by generating carbon deposits in the inner pores of the alumina with larger specific surface area and inner pore volume, and significantly reduces the internal temperature of the alumina particles during the subsequent temperature rise and high-temperature reduction nitriding stages. And the sintering between particles, reduce the temperature of nitriding reaction or shorten the reaction time.

Description

technical field [0001] The invention belongs to the field of inorganic non-metallic materials, and in particular relates to a preparation method of aluminum nitride powder. Background technique [0002] Aluminum nitride (AlN) is a nitride material with rapid application development in recent years, which has high thermal conductivity, insulation performance and chemical stability. It can be kept stable at about 1500℃ in a non-oxidizing atmosphere and is not infiltrated and corroded by metals such as aluminum, copper, silver, and lead. It can be used as the basic ingredient for vacuum aluminum-plating evaporation boats, metal melting crucibles, and casting molds. It can be made GaAs crystal melting crucible. Properly prepared aluminum nitride ceramics have a thermal conductivity of over 180 w / m.k, good thermal shock resistance, and can be used as high-power circuit substrates; heat-conducting ceramics containing aluminum nitride also have a certain market. [0003] The basi...

AI Technical Summary

Problems solved by technology

Since alumina and carbon basically do not react below 1100°C, intermediate species are mainly formed between 1100-1300°C and the reaction is slow. Therefore, before the temperature of the mixture reaches 1300°C, the self-sintering of the alumina microparticles, the interparticle Merger is inevitable, and the surface area will drop sharply. This problem may be one of the main reasons for the high nitriding reaction temperature, large product particle size, and unstable quality.

On the other hand, in order to convert the alumina raw material as much as possible, more than 20% of the carbon powder is generally added. This part of the remaining carbon needs to be removed during the oxidation treatment process at 600-800°C, but there will be Partial aluminum nitride oxidation, this step is usually not easy to achieve a reasonable balance of carbon content and oxygen content; an appropriate amount of oxygen is conducive to the sintering of aluminum nitride, but if the oxygen content is more than 1.2m%, it will reduce the aluminum nitride ceramics thermal conductivity; for example, more than 0.2m% carbon residue may not only make the aluminum nitride powder darker, but also may reduce the electrical insulation performance of the prepared ceramics

The average particle size of aluminum nitride powder is more than 1μm, or the specific surface area is less than 5m 2 / g, it is usually difficult to prepare dense ceramic products with high thermal conductivity