What are the powder preparation methods for tungsten particles

The powder preparation of tungsten particles is a key link in the processing of tungsten materials, and its process level directly affects the performance of subsequent molding, sintering and final product. There are various methods for preparing tungsten powder, mainly including mechanical ball milling method, aerosol method, chemical reduction method, spray drying method and vapor deposition method. These processes have their own scope of application and technical characteristics, and can meet the needs of tungsten materials in different fields.

The mechanical ball milling method uses high-energy ball milling equipment to impact tungsten raw materials and grinding media at a high-speed rotation state to achieve refinement and uniformization of powder particle size. The advantage of this method is that the equipment is simple structure and flexible operation, and is suitable for the preparation of tungsten powder with medium particle size range. However, the energy consumption of this process is high and impurities or oxides are easily introduced during powder preparation, so it needs to be controlled.

The aerosol rule is to dissolve or suspend the tungsten raw material in gas to form fine aerosols or droplets, and then obtain powders through a drying process. This method can accurately control particle size at the micron or even nanometer level, has the advantages of narrow particle size distribution and high purity, and is widely used in the preparation of high-end tungsten powder, especially suitable for areas with high requirements for material performance.

Chemical reduction method uses reducing tungsten compounds (such as tungsten, tungsten hexafluoride or tungsten tetrachloride) to convert them into metal tungsten powder under controlled temperature and atmosphere conditions using reducing agents (such as hydrogen, methanol, ethanol, etc.). This method has the characteristics of mild reaction conditions, adjustable particle size and high purity, and is particularly suitable for the production of nano-scale tungsten powder.

The spray drying method is to spray the solution containing tungsten salt into fine droplets, and quickly evaporate the solvent in a hot air stream to form dried powder particles. This process is suitable for large-scale production, and can obtain tungsten powder with uniform particle size and good flowability, and is widely used in fields such as mechanical processing and high-temperature sintering. Vapor phase deposition law deposits tungsten vapor on the substrate surface under high temperature conditions to form a tungsten film or powder. It is suitable for the preparation of high-purity and high-performance tungsten powders, especially suitable for the production of micron or nano-level powders.

In specific process applications, the purity, particle size distribution, specific surface area and impurity content of the powder are important indicators for evaluating its quality. In order to obtain tungsten powder with uniform particle size and high purity, optimization is usually required in combination with a variety of processes. For example, tungsten powder prepared by aerosol or chemical reduction method can be screened and dried to achieve powders with narrow particle size distribution, meeting the requirements of high-end molding and sintering. The aerosol method has significant advantages in particle size control, and is especially suitable for the preparation of nanotungsten powder. It is widely used in electronic packaging, catalysis and high-end cemented carbides. Chemical reduction law can accurately control the particle size and morphology of the powder by adjusting the reaction temperature, reducing agent concentration and reaction time, and is suitable for the production of high-purity and fine-grained tungsten powder.

The high efficiency and large-scale production capacity of the spray drying method make it excellent in industrial applications. By adjusting the spray parameters and drying airflow conditions, tungsten powder with uniform particle size and good flowability can be obtained to meet the needs of mechanical processing and high-temperature sintering. The vapor deposition method is excellent in the preparation of micron- or even nano-scale high-purity tungsten powders, and is particularly suitable for application scenarios that have strict requirements on powder purity and microstructure.