Effects of the Particle Size Variety of Metal Oxide on the Absorption Property of Long-Wavelength Infrared Laser

In order to study the influences of aggregate size on CO2 laser absorption property, several special absorbing coatings were prepared from four kinds of different particle sizes (45 μm, 13 μm, 6.5 μm and 1.6 μm) TiO2 powder. The CO2 laser absorption capacities of these coatings were studied by comparative analysis of the surface morphology and laser heated areas. The results show that the absorbing capacity increases with particle size dwindling. In all samples, the 1.6 μm specimens display the best performance with the largest laser heated area on cross section. The analysis indicate that, the decreasing of particle size will lead to an increase on absorbing surfaces, which is benefit for improving the absorbing capacity. Furthermore, smaller size particles also can cause the temperature increased faster than large particles, which lead to a further increase on absorbing performance for the positive feedback effects between the temperature and the absorbing capacity. Finally, the effects of particle size variety on designing absorbing coatings are also discussed.