title: Depth analysis of polymer-coated steel samples using near-infrared femtosecond laser ablation inductively coupled plasma mass spectrometry.
abstract: The viability of near-infrared femtosecond laser ablation (fs-LA) inductively coupled plasma mass spectrometry (ICPMS) for the in-depth analysis of polymer coatings over galvanized steel substrates has been studied. A good depth resolution was obtained modifying the femtosecond Gaussian beam to a flat-top beam by using a liquid-crystal display. In order to avoid mixing of information coming from successive shots, a low repetition rate was accomplished and signals were monitored shot by shot. Different kinds of coatings were used to demonstrate the capability of femtosecond ablation for depth-profiling analysis. Ablation was conducted under He atmosphere, after sample cell Ar was admixed. The depth profiles obtained by LA-ICPMS are in good agreement with those obtained by GD-OES for the three analyzed samples. In cases where due to averaging over several millimeter sample roughness determines the depth resolution of GD-OES, it was found that LA-ICPMS achieves better depth resolution due to the better lateral resolution. The depth resolution obtained by LA-ICPMS was found to be 240 nm and 2.3 microm, for a hot-dip galvanized steel (HDGS) and a polymer-polymer-coated HDGS, respectively, compared to the 2.2 and 4.5 microm achieved with GD-OES for the same samples.
authors.affiliation: Laboratorio de Aplicaciones Industriales del Laser, Universidad de A Coruña, C/ Mendizabal s/n, 15403 Ferrol (A Coruña), Spain.
authors.forename: M Paz
authors.initials: MP
authors.lastname: Mateo
authors.forename: Carmen C
authors.initials: CC
authors.lastname: Garcia
authors.forename: R
authors.initials: R
authors.lastname: Hergenröder