Surface analyses of strip surfaces by way of FTIR spectroscopy

The tasks performed at the Salzgitter Flachstahl chemical laboratories include, for example, examining the identity of oils, and the assessment of lubricants already deployed in terms of oxidation, as well as contamination of strip surfaces. So-called FTIR spectroscopy (Fourier-Transform-Infrared-Spectroscopy) is an important working method in view of the relative modest time input involved, the high information content of a spectrum and the multitude of options available for investigating samples.

According to this technique the material to be examined is radiated with infrared light that either penetrates the sample or is reflected (reflection or transmission). Infrared-active materials absorb infrared light in a specific manner, while the intensity loss is recorded in a spectrum.

The use of FTIR microscopy within the context of surface analyses of contaminations is a special and particularly interesting application. Subsequent to appropriate preparation, it is possible to identify organic contaminations on the surface, investigate fibers, determine the materials involved in small amounts of organic substances on surfaces, as well as analyzing organic inclusions in paint systems.

Accordingly, it is possible to directly ascertain a polymer mixture on a Pretex^® surface:

Proceeding in this manner, a multicomponent search of the FTIR spectrum obtained at the reference point determines that in this case, a mixture of the polymers, namely polyisobylene and polyethylene, employed in processing, as in the use of foils, for example, may have been deposited on the product as contamination.  

FTIR spectroscopy is one of the techniques deployed at Salzgitter Flachstahl in order to analyze and improve manufacturing processes in order to provide customers with optimal products.