Abstract: Poly-ether-ether-ketone/nano-silicon nitride (PEEK/nSN) composite scaffolds, fabricated by laser powder bed fusion (LPBF), show great potential for orthopedic applications due to their excellent biological per-formance and mechanical adaptability. However, the effect of nSN on LPBF processability and scaffold properties remains unclear. This study systematically investigates the processability and mechanical per-formance of PEEK/nSN composites to enable reliable clinical fabrication. The results show that adding nSN improves powder flowability and inhibits crystallization, enhancing LPBF processability. The introduc-tion of nSN reduces PEEK's non-isothermal crystallization Avrami exponent from 3.04 to 2.01, suggesting a transformation from a three-dimensional spherulitic to a two-dimensional lamellar crystal structure. Tensile tests reveal that the presence of nSN alters the optimal process parameters, reducing the op-timal laser power from 25 W to 22 W due to increased energy absorption efficiency, as shown by an increase in absorbance at 843 cm-1 from 0.27 to 0.35 as the nSN content increases to 2 wt%. Porous diamond-structured scaffolds were fabricated using optimal parameters for pure PEEK, PEEK/1 wt% nSN, and PEEK/2 wt% nSN. Diamond-structured scaffolds fabricated with 1 wt% nSN showed a 12.2 % increase in elastic modulus compared to pure PEEK, highlighting the enhanced mechanical performance. Over-all, this study offers key insights into the stable and customizable LPBF fabrication of PEEK/nSN porous scaffolds, providing a foundation for future research on their bioactivity and antibacterial properties for orthopedic applications.

Key words: Poly-ether-ether-ketone (peek), Nano-silicon nitride (nsn), Composite, Laser powder bed fusion (LPBF), Scaffold