A novel convergent-divergent annular nozzle design for close-coupled atomisation

作者:Schwenck Daniel*; Ellendt Nils; Fischer Buehner Joerg; Hofmann Peter; Uhlenwinkel Volker
来源:Powder Metallurgy, 2017, 60(3): 198-207.
DOI:10.1080/00325899.2017.1291098

摘要

Additive manufacturing processes such as selective laser melting and electron beam melting require small particle sizes. A widely used technique to produce suitable powders is close-coupled atomisation. To further decrease the achieved particle sizes, the annular geometry of the gas nozzle is changed to a convergent-divergent (CD) profile. This novel configuration is capable of operating stably at low pressures of 0.8 MPa and above. Beyond that, the unwanted effects of lick-back are avoided. Different nozzles with conventional and convergent-divergent annular geometry have been designed based on fluid-flow calculations. The aspiration pressure was measured to determine stable process windows. Powders from a CuSn alloy were produced using cold and hot gas atomisation to show the influence on the process stability, particle size and morphology. High-speed recordings are used to investigate the process conditions of the different nozzle configurations.

  • 出版日期2017