| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 5364513 | Applied Surface Science | 2012 | 9 Pages |
The effect of laser fluence and an ambient environment on the formation and development of the micro and nano-structures on the laser irradiated stainless steel (AISI-304) targets have been investigated. For this purpose KrF excimer laser (λ = 248 nm, t = 20 ns, repetition rate 20 Hz) has been used. The targets are exposed for various laser fluences ranging from 0.72 J cmâ2 to 1.27 J cmâ2 under the vacuum condition and in the oxygen environment at a pressure of 133 mbar. Various features of treated targets, such as surface morphology, chemical composition and crystalline structure are analyzed by scanning electron microscope, energy dispersive X-ray spectroscopy and X-ray diffraction techniques, respectively. Scanning electron microscope analysis reveals the formation of laser-induced periodic surface structures (LIPSS), cavities, hillocks in both ambient environments (vacuum, oxygen). Cone-formation on the top of wave like ridges is observed under vacuum condition. In case of oxygen only redeposition is observed. Energy dispersive X-ray spectroscopy analysis exhibits that there is variation in chemical composition in both environments. When the target is treated in oxygen environment enhancement of the surface oxygen content is observed. X-ray diffraction exhibits that no new phases are formed under vacuum condition but a phase change in oxygen ambient is observed. For various fluences the variation in the peak intensity, crystallinity and d-spacing is observed under both ambient conditions.
⺠Effect of ambient environment on micro/nanostructuring of laser irradiated stainless steel targets has been investigated. ⺠The surface morphology and crystallinity are investigated for various laser fluences. ⺠Various features, such as laser-induced periodic surface structures, cavities and hillocks are observed by SEM analysis. ⺠From XRD analysis it is revealed that no new phases are formed under vacuum condition. ⺠A phase change in oxygen ambient is observed.
