Microstructural Morphological Changes in LaserIrradiated Platinum

The micro structural morphological investigations of the laser exposed samples of Platinum are presented. Q-Switched Nd: YAG laser (1064 nm, 1.1 MW, 9 14 ns) represented by Gaussian profile, power density 3 × 10 15 Watt/m 2 and focal spot size 12 μm is used to irradiate the targets (4 N, 1 × 1 × 0.3 cm 3 ). Surface modifications are observed and examined for optimized 50 pulses in air (1 atm) as well as under vacuum (~10 torr) by analyzing SEM micrographs. Ripples, cones, crater and hillocks formation, splashing, sputtering, solidification and redeposition are observed as main modifications at the irradiated surface. It is explored that material is ejected with explosive expel. Motic digital microscope is used for the measurements of ablated micron sized droplets. The average distance between the adjacent cones is larger near the crater region. Topographical changes are characterized applying Atomic Force Microscopy. RMS surface roughness, hillocks and crater sizes on the irradiated surfaces are also calculated. The structural analysis is mainly focused on measurements of grain sizes, diffracted X-Rays intensity and interplanar distance. The results thus obtained determine that IR radiations are unable to change interplanar distance of the target where as changes in diffracted x-rays intensity and grain sizes for irradiated platinum are noticed.