Understanding the Application of Spherical Tungsten Powder

Due to the irregular shape of conventional tungsten powder particles, not only is the stacking density low, but also the poor flowability limits its application. In recent years, with the development of thermal spraying, porous tungsten materials, and powder metallurgy injection molding technology, the demand for spherical tungsten powder has been increasing.
In the preparation of porous tungsten materials, the morphology and size of tungsten powder have a significant impact on the pore structure of the porous W matrix, thereby affecting the emission performance of the W cathode. The porous tungsten matrix made of spherical dense tungsten powder can provide sufficient storage space and migration channels for barium, as well as a uniformly connected pore structure. It can improve the performance of the entire cathode component, effectively increase the emission current density, and promote the development of modern microwave vacuum devices. When regular and dense spherical tungsten powder is pressed and sintered into a porous tungsten matrix, the voids formed between the spherical particles are not only interrelated, but also have sufficient void space to store more barium emission materials.
On the contrary, when using irregular tungsten powder to make sintered tungsten matrix, not only will the channels in certain gaps be blocked, resulting in open diffusion of barium and reducing the storage space of barium, but small regular channels may also affect the distribution uniformity of barium migration to the surface, leading to unstable electron emission. Therefore, spherical tungsten powder can replace conventional tungsten powder to manufacture porous tungsten parts. For example, high-power pulsed microwave tube cathodes, electronic barium tungsten cathodes, rocket sweating materials, catalysts or catalyst carriers, high-temperature gas distribution plates, and gas filtration materials.
In the field of thermal spraying, spherical tungsten powder not only has good flowability, but also the coating is more uniform and dense. Therefore, this product has better wear resistance. In the powder metallurgy process, the compact of spherical tungsten powder shrinks very evenly during the sintering process, which can achieve good size control. Spherical tungsten powder is gradually replacing conventional tungsten powder for satellite positioning thrusters, high-power pulse microwave tube cathodes, rocket nozzle liners, etc. The rocket nozzle liner made of spherical tungsten powder has good fracture resistance and corrosion resistance under thermal stress.
In the manufacturing industry, spherical tungsten powder has attracted great attention due to its unique properties and has been applied in fields such as electronic information, sheet metal industry, porous material preparation, thermal spraying, automotive, military, powder metallurgy, etc. By controlling the process parameters of the equipment, the permeability of spherical tungsten powder porous materials is improved.
In the powder metallurgy process, the compact of spherical tungsten powder shrinks very evenly during the sintering process, which can effectively achieve size control. Spherical tungsten powder and its alloys are used in the military industry to manufacture crankshafts, high-end automotive cylinder barrels, armor piercing shells, and other materials due to their high temperature resistance. Meanwhile, due to the improved flowability of spheroidized tungsten powder, the coatings prepared in the field of thermal spraying have good compactness and better wear resistance. Although tungsten can be used as a high-temperature material, its oxidation resistance is poor, and it will be oxidized to form W trioxide above 1000 ° C. Therefore, when used at high temperatures, inert gas protection is required. Given the promising industrial prospects of spherical tungsten powder, further research is needed on its preparation process, technology, and practical applications.