Temperature-dependent absorptance of painted aluminum, stainless steel 304, and titanium for 1.07 μm and 10.6 μm laser beams

We measured the temperature-dependent absorptance of metals (Al, Ti, SS304) for continuous beams from 1.07 μm fiber laser and 10.6 μm CO2 laser using power sensors and infrared (IR) pyrometers. The absorptance measurements were repeated for metals with three different paint coatings. For measurements at elevated temperatures up to the melting point, integrating sphere is not practical since high temperature radiation from a heated target disturbs weak output from the sphere considerably. Our results provide how each metal, whether coated or uncoated, absorbs the infrared beams as temperature is elevated to a melting point. A polynomial approximation to the measured absorptance of each target is provided for modeling of the laser–metal interaction at elevated temperatures.

► Temperature dependent absorptances of painted Al, STS304, Ti are presented.
► Integrating sphere is not practical for high temperature measurement of absorptance.
► Painted metals showed enhancement due to surface roughness change.
► Surface oxidation due to high temperature irradiation enhances absorptance.
► Polynomial approximation to measured absorptances is provided.