Laser induced breakdown spectroscopic measurements of oxygen to metal (O/M) ratio in metal oxides samples

Abstract

We report on laser induced breakdown spectroscopic study for oxygen to metal (O/M) ratio determination on vanadium oxides and uranium oxides samples. The measurements have been made under Ar atmosphere using three laser energies 20 mJ, 40 mJ and 60 mJ. The metal (V or U in respective metal oxides samples) emission lines were used for determination of plasma temperature using Boltzmann plot. Oxygen emission lines (777.194) and metal emission lines recorded in Ar atmosphere were used for oxygen to metal ratio calculations. The changes in the intensity of the emission are consistent with the changes in the relative masses of the metal and oxygen arising from the different oxide concentrations. We have developed a method based on determination of correlation factor (ρ) in one standard sample, and then apply the obtained factor on other samples for O/M calculations. We have also evaluated the relationship between “ρ” values and oscillator strength of emission lines. The fast measurement capability, on-line measurements and minimum sample preparation of LIBS, as compared to thermo-gravimetric measurements make it ideal candidate for O/M analysis of metal oxide samples. The study presented here suggests that the O/M measurements of metal oxides samples can be done using LIBS technique with ~5% accuracy and precision.