Fabrication and characterization of architected porous silicon by LPBF for potential reactive gas-solid applications

Pure silicon is an attractive material for reactive gas-solid systems because of its high thermal stability and ability to participate directly in selected chemical reactions, while complex porous architectures can enhance gas transport and accessible reactive surface area. However, fabricating such structures by Laser Powder Bed Fusion (LPBF) remains challenging because of silicon’s high melting point, high thermal conductivity, intrinsic brittleness and limited laser absorptivity. In this study, monolithic porous silicon structures were fabricated by LPBF by varying the laser current from 1300 to 2000 mA to establish a suitable processing window. The specimens were characterized in terms of density, microstructure, electrical conductivity, microhardness and morphological evolution after thermal treatment at 1350°C. Relative density increased from 83.0 % at 1300 mA to a maximum of 96.9 % at 1800 mA, before decreasing to 91.2 % at 2000 mA, indicating the onset of excessive energy input and defect formation. The 1800 mA condition provided the most favorable combination of consolidation and preservation of the interconnected pore network. The optimized structures exhibited an average electrical conductivity of 0.29 S/m and a Vickers microhardness of approximately 1400 HV0.1. Thermal treatment promoted surface smoothing and local interparticle consolidation while preserving the essential porous morphology. The results demonstrate the feasibility of producing well-consolidated, architected porous silicon by LPBF and identify 1800 mA as a suitable processing condition for subsequent investigation of gas transport and reactive behavior in gas-solid systems.