Influence of Current Modulation on Particle Sizes by Wire Arc Atomizing

Additive manufacturing with metal powders enables a high degree of design diversity and an enormous material flexibility for components. The development of new products using special alloys requires just a small amount of powder. Therefore, a wire arc spraying process using nitrogen is applied for powder production by atomizing. The remaining oxygen content, the nitrogen temperature and pressure in the atomizing chamber are monitored to ensure consistent quality. The power source enables direct current (DC) and alternating current (AC). Further parameters like basic current Iground, pulse current Ipulse, pulse duration tpulse, impulse frequency fpulse and alternating current frequency fAC can be varied. On the process side, the following parameters are recorded during the tests: current, voltage, wire feed speed and flow rate of the atomizing gas as well as oxygen content and temperature inside the spray chamber. These parameters have an influence on particle size and composition. The aim is to influence the melting behavior by electrical and other process parameters. The investigations are carried out on solid wires made of an iron-based alloy EN ISO 14341-A: G42 4 M21/2 C1 3 Si1, AWS A 5.18: ER 70-6.