Improving the analytical performance of pulsed-GD-SFMS for multi-elemental depth profile analysis of heat-treated Zn coatings on extruded aluminium.

Fast characterization of coated materials requires direct solid analytical techniques able to provide high sensitivity and high depth resolution. Well-established techniques, such as Glow Discharge Optical Emission Spectroscopies (GD-OES), show great capabilities for fast depth profiling but with limited sensitivity for the detection of relevant trace elements. Therefore, in this work, an improved analytical method based on the combination of a pulsed glow discharge with a sector field mass spectrometer (pulsed-GD-SFMS) is investigated for fast and sensitive depth profiling. Different parameters, including glow discharge source design, discharge conditions and mass spectra acquisition conditions, are evaluated to achieve low sputtering rates, high mass spectra acquisition rates, high sensitivity and improved depth resolution compared to standard GD-SFMS analytical performance. This method is applied to determine multi-elemental in-depth distributions of major, minor and trace elements in Zn-coatings, which are of great interest in the aluminium industry. Additionally, Zn-coatings are analysed using femtosecond laser ablation (fs-LA)-ICP-MS, which provides complimentary information about the spatial distribution of different elements in the coating and substrate.