Physics of selective evaporation of components during laser ablation of stainless steels

A physical mechanism of the deviation of plasma composition from stoichiometry during laser ablation of multicomponent alloys is proposed and experimentally verified. This mechanism takes into account the difference in the work functions of the alloy components in the heating — melting — evaporation cycle and makes it possible to take into account selective evaporation when determining the composition of four-component bronzes and substantiate conservation of stoichiometry when analysing the composition of stainless steels. The proposed mechanism of selective evaporation allows one to improve precision of the analysis for multicomponent alloys without reference calibration, which increases the practical importance of the calibration-free laser-induced breakdown spectroscopy (CF LIBS).