Study Of Laser Coloration On Titanium Surface Based On Pulsed Laser Processing

Color generation on metals are currently of more interest in whether industry or science.Its wide range of applications,and information storage.Laser coloration technique is commonly described as the transparent oxide grow in which substrate species are heated via laser light absorption.The color generate with laser is rich and with strong adhesion.Via galvanometer scanning system,laser can create pattern with much more exquisite design.Gradually,traditional methods like anodic oxidation and atmospheric oxidation are replaced by laser coloration technique.Based on Nd:YAG nano-second fiber laser,laser coloration on titanium is studied.The effects of laser parameters,which include scanning speed,hatch size,laser fluence and overlapping were investigated.The mechanism of laser coloration is studied through analyzing the color oxide surface in micro scale.Several conclusions can be drew about laser metal coloration.In order to create richer color,thermal annealing is performed as a post treatment to tune the color generated by pulsed laser processing of a titanium substrate surface.Microscope image shows that additional blue and yellow colors on the titanium surfaces are generated through the thermal annealing treatment.A comparison of the reflectance spectra before and after the thermal annealing shows the peak shift as well as increase in overall reflectance,which demonstrates that the color changes and becomes richer.Chemical composition analyses reveal the mechanism behind.SiO₂ deposition is also performed as a post treatment to tune the color.Simulated and experimental results all demonstrated that SiO₂ can change the color generated by laser.Color coordinates were reported on CIE space and demonstrated the color are tuned to be richer.This method also provided a new idea of tuning laser generated color.