CO2-LASER LIGHT-ABSORPTION CHARACTERISTICS OF METAL POWDERS

Absorption characteristics of metal powders for 10.6 mu m CO2 laser ra diation were examined. Using a calorimetric method, absorptance measur ements were performed on four different powder materials, including al uminum, copper, iron, and titanium aluminide. The experimental results showed that laser absorptance depends on powder porosity and material . The measured absorptance values at low laser intensities ranged betw een 28% and 43%. The titanium aluminide powders showed the highest abs orptance values, and aluminum powders the lowest. As laser intensity w as increased, the copper and iron powders showed strong signs of oxida tion when irradiated in air, resulting in an increase in absorptance. Neither oxidation nor increased absorptance were observed when helium or argon were used as shielding gas. (C) 1996 American Institute of Ph ysics.