Selective and noncontaminated surface polishing of medical Ti-6Al-4V titanium alloy by laser chemical processing

Selective and noncontaminated surface polishing of titanium alloy implants is crucial in the biomedical field. We employed a pulsed laser as a localized and selective heat source and dilute phosphoric acid as a corrosion solution for laser chemical polishing (LCP) of medical Ti-6Al-4V titanium alloy surface. The effect of laser fluence on the removal groove morphology of titanium alloy surfaces was systematically studied, and the characteristics and mechanisms of material removal were further discussed. The results show that the groove morphology of the workpiece surface at different laser fluences can be classified into three categories, depending on the two-dimensional removal profile. The removal mechanism of LCP is a combination of laser etching and chemical corrosion, and chemical etching can completely remove the residues and melts produced by laser ablation. Finally, selective polishing of medical Ti-6Al-4V titanium alloy was achieved by setting appropriate process parameters. Moreover, the energy-dispersive x-ray spectroscopy analysis showed that there was no detectable chemical impurity contamination on the polished surface.