Evaluation of Ultraviolet-Femtosecond-Laser Ablation-ICP-TOFMS for fast, sensitive and high-spatially resolved multi-elemental mapping of laser-deposited Hastelloy coated carbon steel

Ultraviolet Femtosecond Laser Ablation-Inductively Coupled Plasma-Time of Flight Mass Spectrometry (UV-fs-LA-ICP-TOFMS) is critically evaluated for fast multi-elemental mapping of Hastelloy coated carbon steel that was immersed in a liquid corrosive environment for two months. The Hastelloy coating, which is a multi-elemental Cr-Fe-Ni-Mo-W matrix, is produced using laser cladding technology. A UV-fs laser is employed to reduce the ablation thermal effects improving the spatial resolution in the elemental analysis of the coating, interface and substrate. Moreover, the TOFMS is equipped with ion beam attenuation grids to expand its linear dynamic range, allowing the determination of major, minor and trace elements. In particular, spatial distribution of major (e.g., Co, Ni, Fe), minor (e.g., Mn, Si) and trace (e.g., Cu, In, Zn) elements from two sequential mapping analysis were determined. Quantification is achieved through Relative Sensitivity Factors calculated using matrix-matched external reference materials and making use of measurements carried out by SEM-EDX to determine the concentration of internal standard elements. Qualitative and quantitative elemental maps highlight diffusion processes at the coating-substrate interface. Moreover, correlated spatial distributions of ion signals from external corrosive elements (e.g., 32S, 138Ba, 202Hg, 205Tl, and 209Bi) were detected in localized regions within the material and on the external surface.