Enhancing niobium powder quality for additive manufacturing through ultrasonic atomization and calibrated rolling

This study presents the ultrasonic atomization (UA) of niobium as a novel and efficient method for producing high–quality, spherical powders for additive manufacturing (AM). A niobium rod was first examined to confirm its purity, then subjected to calibrated rolling to obtain square wire 2.4 × 2.4 mm. This process achieved 79.6% cumulative engineering strain without introducing contamination or structural defects, demonstrating its suitability for precision feedstock preparation of high–melting, reactive metals such as niobium. Atomization was carried out using the ATO Lab+ system under an inert argon atmosphere, with a 35 kHz sonotrode. Theoretical droplet sizes were estimated using a resonance–based model considering surface tension, liquid density, and ultrasound frequency. The resulting powder was characterized via optical and SEM–EDS microscopy. Key metrics such as particle size distribution (Span = 0.413) and sphericity (mean ≈ 0.94) indicate excellent flowability and uniformity. SEM analysis confirmed the production of highly spherical, smooth–surfaced particles, free of satellites, agglomerates, or structural defects. The work confirms ultrasonic atomization, supported by real–time control systems, as a promising and scalable technique for advanced powder production tailored to next–generation additive manufacturing technologies.