Quantitative elemental analysis of nickel alloys using calibration-based laser-induced breakdown spectroscopy

This work reports on the quantitative elemental analysis of nickel alloys using laser-induced breakdown spectroscopy (LIBS) in air at atmospheric pressure. The LIBS plasma is generated using a Q-switched ultraviolet Nd:YAG laser, which evolves with time. The LIBS spectra of three samples with known composition are recorded at five detector gate delays. Employing the internal standardization method, the calibration curves for Cr present in the samples are produced. The Cr concentration in the samples is determined using the generated linear calibration curves having varying slopes and regression coefficients at different delays. The effect of slopes and regression coefficients of the linear calibration curves on the analytical predictive capability of the LIBS system is studied through the correlation of the LIBS determined concentration of Cr with its known value. The analytical predictive capability of the LIBS system is noted to be the best when the calibration-based analysis is performed at an appropriate delay (2000 ns in the present experiment) where the linear calibration curve has both the regression coefficient and the slope close to the ideal value.