Detection of surface oxide transformation during LPBF Re-Use of AlSi10Mg powder via triboelectric charging and its effect on moisture interaction

• Triboelectric charging assesses surface chemistry of re-used AlSi10Mg powders. • Moisture uptake lowers work function and charge retention in early cycles. • Repeated reuse accelerates amorphous-to-γ-Al 2 O 3 oxide phase transformation. • Auger parameters and work function confirm oxide crystallization beyond cycle 6–8. • Triboelectric response has potential as a low-cost tool for oxide phase detection. This study explores the effect of the number of re-use cycles in Laser Powder Bed Fusion (LPBF) on the surface chemistry and triboelectric charging behavior of AlSi10Mg powders. The work reports the evolution of the oxide layer and crystallinity, and its impact on charge dynamics utilizing X-ray photoelectron spectroscopy (XPS), Auger parameter analysis, inert gas fusion, and work function measurements. For the first few re-use cycles, environmental humidity adsorption is the main effect, reducing the work function and charge retention due to the formation of surface dipoles. With increasing the number of re-use cycles, moisture adsorption progressively slowed, and its prolonged presence triggers an accelerated phase transformation from amorphous Al 2 O 3 to γ-Al 2 O 3 , as evidenced by sharp drops in Auger parameters, increase in work function, and stabilization of hydrogen concentration. This crystallization correlates with a distinct triboelectric charging response, reflected by a gradual increase in the triboelectric n-exponent of the developed charging model. These findings demonstrate that triboelectric charging can serve as a tool for subtle differences detection in the surface scale including humidity and crystal structure.