M Z Butt

Surface topography and structure of laser-treated high-purity zinc

We irradiated 99.995% pure zinc specimens in a vacuum with 50, 60, 70, 80, 90, and 100 nanosecond visible laser shots. SEM images of irradiated specimens were analyzed using Gwyddion 2.29 software. The average length of surface microcones formed at the periphery of the ablated area increases linearly from 30 to 56 μm on the increase in number of laser shots from 50 to 100. Nano-size droplets (16–40 nm) are formed in the vicinity of ablated area; the greater the number of droplets, the smaller is their mean diameter. XRD patterns of un-irradiated and irradiated specimens reveal changes in the intensity of diffracted peaks on laser irradiation. Harris analysis was done to determine texture coefficient; crystallographic planes (002) and (004) get preferentially oriented on laser irradiation. Williamson–Hall analysis was carried out to evaluate the structural parameters, namely crystallite size, dislocation line density, and microstrain.

Optical, structural, and chemical properties of CR-39 implanted with 5.2 MeV doubly charged carbon ions

Poly-allyl-diglycol-carbonate (CR-39) specimens were irradiated with 5.2 MeV doubly charged carbon ions using Pelletron accelerator. Ion dose was varied from 5 × 1013 to 5 × 1015 ions cm−2. Optical, structural, and chemical properties were investigated by UV–vis spectroscopy, x-ray diffractometer, and FTIR/Raman spectroscopy, respectively. It was found that optical absorption increases with increasing ion dose. Absorption edge shifts from UV region to visible region. The measured opacity values of pristine and ion implanted CR-39 range from 0.0519 to 4.7959 mm−1 following an exponential growth (9141%) with the increase in ion dose. The values of direct and indirect band gap energy decrease exponentially with an increase in ion dose by 59% and 71%, respectively. However, average refractive index in the visible region increases from 1.443 to 2.864 with an increase in ion dose, by 98%. A linear relation between band gap energy and crystallite size was observed. Both the number of carbon atoms in conjugation length and the number of carbon atoms per cluster increase linearly with the increase in ion dose. FTIR spectra showed that on C+2 ions irradiation, the intensity of all bands decreases gradually without appearance of any new band, indicating degradation of polymer after irradiation. Raman spectra revealed that the density of −CH2− group decreases on C+2 ions irradiation. However, the structure of CR-39 is completely destroyed on irradiation with ion dose 1 × 1015 and 5 × 1015 ions cm−2.