Analytical and Bioanalytical Chemistry

, Volume 385, Issue 2, pp 225–233

New approach to online monitoring of the Al depth profile of the hot-dip galvanised sheet steel using LIBS


    • Fraunhofer-Institut für Lasertechnik (ILT)
  • Manuela Hoehne
    • Fraunhofer-Institut für Lasertechnik (ILT)
  • Reinhard Noll
    • Fraunhofer-Institut für Lasertechnik (ILT)
  • Volker Sturm
    • Fraunhofer-Institut für Lasertechnik (ILT)
Special Issue Paper

DOI: 10.1007/s00216-006-0347-z

Cite this article as:
Balzer, H., Hoehne, M., Noll, R. et al. Anal Bioanal Chem (2006) 385: 225. doi:10.1007/s00216-006-0347-z


In this study a new approach to the online monitoring of the Al depth profile of hot-dip galvanised sheet steel is presented, based on laser-induced breakdown spectroscopy (LIBS). The coating composition is measured by irradiating the traversing sheet steel with a series of single laser bursts, each at a different sheet steel position. An ablation depth in the same range as the coating thickness (about 10 μm) is achieved by applying a Nd:YAG laser at 1064 nm in collinear double-pulse and triple-pulse mode. The ablation depth is controlled by adjusting the burst energy with an external electro-optical attenuator. A fingerprint of the depth profile is gained by measuring the LIBS signals from zinc, aluminium and iron as a function of the burst energy, and by post-processing the data obtained. Up to three depths can be sampled simultaneously with a single laser burst by measuring the LIBS signals after each pulse within the laser burst. A concept for continuously monitoring the Al depth profile during the galvanising process is presented and applied to different hot-dip galvanised coatings. The method was tested on rotating sheet steel disks moving at a speed of up to 1 m/s. The potential and limitations of the new method are discussed.


Laser-induced breakdown spectroscopyDepth profileGalvanized coatingZnOnline analysisCollinear double pulsesTriple pulses

Copyright information

© Springer-Verlag 2006