Friction and wear behavior of NiCu-diamond composites fabricated by defect-controlled powder bed fusion (PBF) process

The influences of printing process on metallurgical quality and wear resistance of NiCu-diamond composites were quantitatively analyzed. The NiCu-diamond composite with low porosity (∼1.6 vol%) and low loss of diamond particles (only 0.5 vol%) was successfully fabricated, at an electron beam current of 2.4 mA, and a scanning rate of 1 m·s⁻¹. The wear rate of the NiCu-diamond composite was as low as 5.0 × 10⁻⁷ mm³·N⁻¹·m⁻¹, and coefficients of friction (COFs) within 0.02–0.05. These values represent a substantial reduction compared to the corresponding values of 43.7 × 10⁻⁷ mm³·N⁻¹·m⁻¹ and 0.18–0.28. The dense tribofilm formed during wet friction (in 3.5 wt% NaCl solution) hinders further wear of the substrate, leading to lower COFs and wear rates than those of dry friction. The PBF-ed NiCu-diamond composites show excellent wet friction and wear properties with COFs lower than 0.04 and a wear rate of 1.6 × 10⁻⁷ mm³·N⁻¹·m⁻¹. © 2026 Elsevier Ltd.