Dependence of LIBS spectra on the surface composition and morphology of W/Al coatings

•The study is a step of LIBS application for the quantitative estimation of the fuel retention at ITER walls.•Besides LIBS, samples with ITER-relevant coatings were characterized by SEM, XRD and SIMS techniques.•Depending on micro-and nanoscale properties of samples the ablation rate of samples with mono-component coatings could differ by an order of magnitude.•The total emission of the ablated material is related to the surface morphology.•Due to the ablation non-stoichiometry of Al/W coatings (Al is proxy for beryllium), Al and W depth profiles differ remarkably. Laser induced breakdown spectroscopy (LIBS) has been applied to study ITER-relevant coatings with different surface morphology and crystallinity. LIBS elemental depth profiles were compared with those obtained by secondary ion mass spectrometry (SIMS). Depending on surface morphology and crystallinity, the laser ablation rate of the coatings changed by an order of magnitude, the highest ablation rate had samples prepared by thermoionic vacuum discharge. The inclusion of aluminum (proxy for beryllium) increased the ablation rate by a factor of>6. In addition, for W-Al coatings the ablation was non-stoichiometric.