Binder Jetting of Lunar Regolith: Densification Optimization in Air and Vacuum, and Mechanical Performance Evaluation

Binder jetting has emerged as a compelling approach for processing lunar regolith, as it is well-suited for low-energy environments and requires lower amounts of organic binder, compared to the competitive technologies. This study investigates the feasibility of binder jetting lunar regolith simulants from micrometric particles, focusing on the interplay between sintering conditions, especially atmosphere and temperature, and the resulting microstructural and mechanical properties. Sintering was explored across a range of conditions to elucidate the evolution of porosity and phase composition. Microstructural characterization revealed void morphologies varying due to progressive coalescence, while energy-dispersive x-ray (EDX) and x-ray diffraction (XRD) identified the primary presence of bytownite with other minor oxides, partially subjected to redistribution and reduction as in the case of ilmenite and pyroxene. Mechanical testing revealed the influence of sintering conditions on mechanical properties. While the compression samples, sintered at 1150°C, yielded 228.7 ± 100.9 MPa of strength, the performance of the samples sintered at 1200°C in air degraded down to 180.6 ± 53.7 MPa.