Satellite Formation on Metal Powders
Satelliting on metal powders is the adhesion of small particles to larger powder grains during the atomization process. This can reduce flowability in the powder bed and cause problems in welding.
Physicochemical Mechanism of Action
During atomization of molten metal, small crystal nuclei form that gather around other particles. This gathering force leads to the formation of satellites on larger powder grains.
Metallurgical Relevance & Welding Risks
Satellite formation can reduce powder bed flowability, as small particles hinder the movement of larger grains. This causes uneven powder consumption and can lead to irregular weld bead structure and quality. Additionally, it can increase stress between powder grains, raising the risk of cracking and fracture.
Workshop Practice & Instructions
To minimize satellite formation, the atomization process should be designed to keep particle size homogeneous. This can be achieved by optimizing temperature and speed. A powder bed with high flowability is crucial for uniform weld formation. If problems occur, the powder should be re-atomized or a powder with lower satellite tendency should be chosen.