An increase in surface absorptivity can be helpful with a number of laser heat treatment processes. Absorptivity can be increased by, for example, absorption coating or surface oxidation. The method of controlled laser oxidation was developed after a series of experiments. A scanning laser system was used to create an oxide layer on steel EN 10083-2: C45 surface. Subsequently, the absorbency and thickness of the formed oxide layer were measured, depending on the irradiation energy emitted into the surface. It has been found that higher the thickness of the oxide layer increases absorption, but the growth is not linear. For the wavelength of 808 nm, there is a local absorption maximum for irradiation energy around 2 J/mm2. The wavelength of 808 nm was taken as a reference because we own a laser for heat treatment emitting at that wavelength. These results have shown that the use of surface oxidation increases the coupling of laser energy to material surface in the order of tens of percent. This advantage can be used to process complex workpieces where individual components need to be processed with different parameters.Keywords: Oxide layer, NIR absorption, IR radiation, surface oxidation, controlled heating
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