Calibration-free elemental analysis combined with high repetition rate laser-ablation spark-induced breakdown spectroscopy

Abstract

Calibration-free (CF) method combined with high repetition rate laser-ablation spark-induced breakdown spectroscopy (HRR LA-SIBS) was first utilized to realize elemental analysis of alloy samples. A compact fiber laser operated at 30 kHz pulse repetition rate was used to ablate the sample and the spectra were recorded with a compact fiber spectrometer in non-gated signal recording mode. Three standard aluminum alloy samples were analyzed to evaluate the performance of this technique. Median filtering method was applied to reduce the contribution of the continuum background to the intensity of the atomic lines. The averaged electron density was determined to be (2.36–2.49) × 1017 cm−3 according to the Stark broadening of four ionic lines. 11,800 K averaged plasma temperature was estimated from the Saha-Boltzmann plots. The plasma could be verified to be in a state close to local thermodynamic equilibrium. The analytical error was <0.5% for the major element and <35% for minor elements with >0.1% concentrations. It was demonstrated that CF method combined with HRR LA-SIBS was possible to realize reliable quantitative elemental analysis for aluminum alloy samples.