Effect of nanosecond pulsed laser parameters on the color making of 304 stainless steel

Nanosdecond pulsed laser (532 nm) was used to irradiate stainless steel, resulting in various colors permeating the sample surface. The surface morphology, element composition, phase composition, film thickness and surface reflectivity were analyzed by field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), ellipsometer and diffuse reflection spectroscopy (DSR). The effect of laser scanning speed and hatch distance on the resulting surface coloring of stainless steel was investigated. The results showed that a thin oxide film was formed on the sample surface irradiated by the laser. The sample surface presented different colors due to thermal absorption effect caused by the different laser scanning speed and the hatch distance. Furthermore, the effect of laser parameters on the stability of coloration was studied by using the chromatic aberration evaluation formula CIEL*a*b*.