On the use of magnetite nanoparticles as filler for <scp>3D</scp> printing of polyether‐ether‐ketone‐based soft magnets

Abstract In this work, polyether‐ether‐ketone (PEEK) – magnetite nanocomposites, having filler content of 50, 60, and 70 wt%, have been developed and 3D‐printed via Fused Filament Fabrication to manufacture high‐performance space‐compliant soft magnetic parts. The nanocomposites present high thermal stability and high transition temperatures typical of the high‐performance PEEK matrix. Mechanical properties show increased stiffness up to 12.6 GPa of elastic modulus, but reduced tensile strength and ductility due to the high content of ceramic nanofiller. The 3D‐printed magnets present soft magnetic features, matching the properties of bare magnetite particles but with a lower, although still high, saturation magnetization (up to 52 Am 2 /kg), which scales with the particle percentage in the non‐magnetic polymer matrix. This confirms the effectiveness of both the extrusion and 3D printing processes in upholding the structural integrity of the magnetic filler. The electrical insulating nature, which prevents eddy current losses, ease of manufacturing complex shapes, and recyclability make these materials promising for 3D‐printed magnetic components in space applications, supporting sustainable future space exploration. Highlights Magnetite/high performance polymer 3D‐printable nanocomposites were developed. Magnets with interesting soft magnetic properties were 3D‐printed. The polyether‐ether‐ketone matrix grants suitability for space applications.