Inhaltszusammenfassung

Laser-Induced Breakdown Spectroscopy (LIBS) with pulsed laser excitation is an established method for analyzing the elemental composition of unknown samples based on their characteristic emission spectra. However, heterogeneous samples like concrete require high spatial resolution for a proper classification of the matrix phases. An automated LIBS imaging system is used to provide high spatially and spectrally resolved images of the elemental distribution with a lateral resolution of 100 µm c...Laser-Induced Breakdown Spectroscopy (LIBS) with pulsed laser excitation is an established method for analyzing the elemental composition of unknown samples based on their characteristic emission spectra. However, heterogeneous samples like concrete require high spatial resolution for a proper classification of the matrix phases. An automated LIBS imaging system is used to provide high spatially and spectrally resolved images of the elemental distribution with a lateral resolution of 100 µm corresponding to the laser spot size. The system is able to analyze both the atomic and molecular emission with several spectrometers over a broad spectral range simultaneously. Critical corrosion effects like chloride induced pitting corrosion in concrete can substantially reduce the lifetime of infrastructure buildings. Since chlorides only diffuse into the cement phase of the concrete the diffusion profile of chlorides is of great interest. The "LIBS microscope" is able to visualize the elemental spatial distribution of chlorine in concrete by evaluating both the atomic and molecular emission. Measurements with the LIBS microscope are compared to the results of the standard wet-chemical potentiometric titration which, however, provides a reduced spatial resolution of only 10 mm. Another drawback of the chemical analysis is the need of a correction factor to estimate the aggregate fraction because the matrix phases cannot be separated before performing the analysis. In practical applications this concrete-dependent factor is not known exactly. LIBS analysis, however, does not need any correction factor.» weiterlesen» einklappen

Autoren

Klassifikation

DFG Fachgebiet:
Optik, Quantenoptik und Physik der Atome, Moleküle und Plasmen

DDC Sachgruppe:
Physik