Alignment and wear debris effects between laser-patterned steel surfaces under dry sliding conditions

• Laser textures with different periodicities (5, 9 and 18 µm) were achieved in steel.
• Dry sliding tests with a ball-on-disk configuration were performed.
• Alignment effects were studied by means of a newly developed positioning method.

In this experimental study periodic line-like patterns with different periodicities (5, 9 and 18 µm) were fabricated by laser-interference patterning on stainless steel samples (AISI-304) and on 100 Cr 6 steel balls. Linearly reciprocating dry sliding tests with a ball-on-disk configuration were performed on patterned pairs and on patterned-substrate/unpatterned-ball pairs Alignment effects were studied by means of a newly developed positioning method, which ensures an optimal alignment. The number of cycles was set to 200 and 20,000 to study the run-in and stability behaviour of the patterned surfaces, all of which exhibited a lower kinetic coefficient of friction than the unpatterned reference. Depending on the respective alignment, different friction and wear mechanisms can be distinguished. Differences in the real contact area, the possibility to store wear particles and the time needed to remove the native or laser-induced oxide layer can be well correlated with the temporal evolution of the coefficient of friction.