Robust and feasible color two-dimensional code fabricating method by nanosecond laser on titanium

Laser-induced coloring is an effective technique to achieve in situ coloring of various materials, which can apply to fabricating a color two-dimensional code with the benefit of increasing information capacity and promoting efficiency. Herein, we propose a method for fabricating a color two-dimensional code with quaternary numbers by a nanosecond laser. Two-dimensional color patch matrices on titanium (TA2) plates were obtained by changing laser power and scanning speed. The effect of laser parameters on surface morphology and color was investigated. In addition, yellow and blue were chosen as the pattern color of the two-dimensional code according to experimental results, and each pattern was decoded through hue, saturation, brightness color analysis. In addition, the tolerance to temperature and chemical environment of the color two-dimensional code was tested, indicating robustness to extreme environment and temperature. Finally, the appearances of color two-dimensional codes under different wavelengths were investigated. This research validated that a nanosecond laser marked two-dimensional code is a feasible, noncontact, and promising method, which is of great significance to improve the robustness and expand the capacity and accuracy of a two-dimensional code.