Laser induced breakdown spectroscopy (LIBS) involves transforming a small volume of an object into plasma by means of a pulsed laser. The atoms contained in this volume, which is in the order of some µm3, are ionized and some of their electrons are dissolved. Capturing the electrons in a second step produces an emission spectrum emitted from the plasma which is characteristic of the material in question. This recombination involves a spectral fingerprint typical of the element under investigation, thus delivering information about the chemical composition of the material.
As soon as the chemical composition is determined, it can be evaluated for analytical purposes or compared to target values, which makes it a useful tool for quality control. The relative share of some elements is determined within milliseconds: A zinc phosphate coating on an iron component e.g. can be reliably analyzed in real-time. Coating processes can be controlled in order to ensure the quality of the workpiece.
The spatial distribution and homogeneity of the surface composition is provided by directing the laser to different spots of the workpiece surface. By applying repeated pulses at the same spot, even third dimension data of the elemental composition of the component can be retrieved: each pulse removes a small volume of the surface, thus enabling the layer underneath to be analyzed.