Picosecond Laser Processing of Hierarchical Micro–Nanostructures on Titanium Alloy upon Pre‐ and Postanodization: Morphological, Structural, and Chemical Effects

Abstract

Recent publications indicate that the order of electrochemical anodization (before or after the laser processing step) plays an important role for the response of bone‐forming osteoblasts—an effect that can be utilized for improving permanent dental or removable bone implants. For exploring these different surface functionalities, multimethod morphological, structural, and chemical characterizations are performed in combination with electrochemical pre‐ and postanodization for two different characteristic microspikes covered by nanometric laser‐induced periodic surface structures on Ti–6Al–4V upon irradiation with near‐infrared ps‐laser pulses (1030 nm wavelength, ≈1 ps pulse duration, 67 and 80 kHz pulse repetition frequency) at two distinct sets of laser fluence and beam scanning parameters. This work involves morphological and topographical investigations by scanning electron microscopy and white light interference microscopy, structural material examinations via X‐ray diffraction, and micro‐Raman spectroscopy, as well as near‐surface chemical analyses by X‐ray photoelectron spectroscopy and hard X‐ray photoelectron spectroscopy. The results allow to qualify the mean laser ablation depth, assess the spike geometry and surface roughness parameters, and provide new detailed insights into the near‐surface oxidation that may affect the different cell growth behavior for pre‐ or postanodized medical implants.