Laser-induced breakdown spectroscopy; Microscope optics; Mn; Quantitative analysis;SPECTROMETRY; SAMPLES; LIBS

Manganese in the low alloy steel was analyzed quantitatively using micro-laser-induced breakdown spectroscopy. The spatial resolution of 20 mu m and the single pulse limit of detection of 0. 10% were obtained. The calibration curve of Mn was established with basic calibration method, with determination coefficient (R-2) of 0. 97. The average relative error of Mn concentration prediction on 7 samples is 12. 91%, and the root-mean-square error of cross-validation (RMSECV) is 0. 11%. The R2 reaches 0. 99 when using internal calibration method, as well as the average relative error of Mn concentration prediction on 7 samples and RMSECV were decreased to 7. 25% and 0. 07%, respectively. These results show that MicroLIBS technique is an effective approach for material surfaces quantitative microanalysis.

laser-induced breakdown spectroscopy; ageing layer depth; silicone polymer surface;SPECTROMETRY; LIBS

Silicone rubber composite materials have been widely used in high voltage transmission lines for anti-pollution flashover. The aging surface of silicone rubber materials decreases service properties, causing loss of the anti-pollution ability. In this paper, as an analysis method requiring no sample preparation that is able to be conducted on site and suitable for nearly all types of materials, laser-induced breakdown spectroscopy (LIBS) was used for the analysis of newly prepared and aging (out of service) silicone rubber composites. With scanning electron microscopy (SEM) and hydrophobicity test, LIBS was proven to be nearly non-destructive for silicone rubber. Under the same LIBS testing parameters, a linear relationship was observed between ablation depth and laserpulses number. With the emission spectra, all types of elements and their distribution in samples along the depth direction from the surface to the inner part were acquired and verified with EDS results. This research showed that LIBS was suitable to detect the aging layer depth and element distribution of the silicone rubber surface.

INDUCED BREAKDOWN SPECTROSCOPY; DOUBLE-PULSE; OPTICAL-EMISSION; CAVITY CONFINEMENT; TEMPERATURE; IMPROVEMENT; SILICON

The effect of spatial confinement on femtosecond laser-induced Cu plasmas was investigated by time-resolved spectroscopy. The cylindrical cavities with various diameters (2 and 3 mm) and various heights (2, 3, and 4 mm) were placed on the sample surface. An obvious enhancement in the emission intensity of Cu atomic lines was observed when a cylindrical cavity was used to confine the femtosecond laser-induced Cu plasmas. The results showed that enhancement ratios in femtosecond laser-induced breakdown spectroscopy with spatial confinement varied with cavity diameters and atomic emission lines selected. The spatial confinement effect was not significantly influenced by the cavity height because the height of plasma plume is lower than the cavity height. The maximum enhancement ratio for the emission intensities of the Cu atomic lines was measured to be around 3 at a time delay of 3.5 mu s when the cavity diameter is 2 mm. The spectral enhancement is attributed to the compression of the plasma by the reflected shock wave. Published by AIP Publishing.