Silicon Determination In Steel With Molecular Emission Using Laser-Induced Breakdown Spectroscopy Combined With Laser-Induced Molecular Fluorescence

Silicon is an essential element for industry, but it is hard to accurately and rapidly determine a high silicon content with conventional laser-induced breakdown spectroscopy (LIBS), due to the matrix and self-absorption effect. Using molecular emission is an alternative method for silicon content analysis, but its weak spectra are major challenges. In this work, silicon monoxide (SiO) molecules were used to establish calibration assisted by LIBS and laser-induced molecular fluorescence (LIBS-LIMF). Two types of SiO molecular excitations, vibrational ground state excitation (LIMFG) and vibrational excited state excitation (LIMFE), were compared. The results showed that LIMFE eliminated the self-absorption effect and achieved better sensitivity. This work demonstrates LIBS-LIMF as a capable and potential approach for fast determining the silicon element in steel industries.