Project 13 (TKS)

 

Title: Determination of hydrogen  in steels

Type of researcher: Simone Weyler (ESR)

Coordinator: ThyssenKrupp Steel AG;

Other partners: Swerea KIMAB, FoPB, ULMET

Responsible Scientist: Gregor Müller, Martin Raulf, ThyssenKrupp Steel AG

Location: Dortmund and Stockholm

 

State of the Art:

Hydrogen can cause severe problems concerning the mechanical properties of steels. The determination of low hydrogen contents in steels is therefore one of the most important tasks to solve. The origin of hydrogen in steel products can have many causes, which have to be monitored closely, e.g. annealing in hydrogen atmosphere and galvanizing are known to increase the content of hydrogen. This hydrogen enrichment has a significant role if new types of steels are coated with zinc and the steel could show delayed fracture.

The first step to a solution for the problem of hydrogen embrittlement is to monitor and to analyse the hydrogen distribution in coated materials.

However, the accurate determination and depth profiling of hydrogen in the sample using GD-OES is difficult, above all due to the lack of suitable reference materials and the influence of hydrogen on the spectra of other matrix elements.

Reached Goals, Objective and Innovation: 

At TKS, Simone Weyler joined the working group of surface analysis at the Centre of Materials Excellence in Dortmund.

A first goal was to investigate the influences of the contamination of the source. An important necessity for the analysis of hydrogen in steels is the avoidance of gases in the discharge from outside the sample.

Different attempts were tested in a systematic study to find the best measuring preconditions. Beside optimization of flushing and pumping times, the most significant improvement on avoiding the contamination with molecular gases can be achieved by using pre-sputtering on the sample followed by moving of the sample on the sealing ring without loosing the vacuum.

Recently, Simone Weyler changed her working place to join the material analysis working group of Arne Bengtson at Swerea KIMAB, Stockholm, a leading institute within corrosion and metals research. There, she will examine in detail the effects of hydrogen on the spectral background, line interferences and the relative intensities of spectral lines of other elements.

First experiments concerning the influence of hydrogen on emission yields were carried out and the analysis of the data is in progress.

In the plans for the near future further investigations on the influence of hydrogen on the emission yields as well as experiments with a specially designed high vacuum GDL for measurements of molecular gases under optimized vacuum conditions are included.

Long-term plans involve comparative studies with the LIBS (Laser Induced Breakdown Spectroscopy) equipment which is as well available at Swerea KIMAB.

About Simone Weyler

I studied at the University of Bonn, Germany, where I obtained my diploma degree in physics. During the work for my diploma thesis I performed mainly X-ray absorption spectroscopy (XANES), in particular experiments with iron oxide nanoparticles. In addition to these experiments, I also used other analytical methods, e.g. HPLC, IR and TEM measurements.
My interests during the main study courses were and until now still are in material science; therefore I am glad to work in the field of Glow Discharge Spectroscopy. To work in a project with firsthand connection to industry is very interesting; beside abstract research one does not lose the focus to direct application possibilities.
The opportunities which GLADNET offers are immense, first of all, the contact to other
PhD students from all over Europe: Beside social encounter, the sharing of knowledge is an important feature which I do not want to miss. Getting to know other ways of living and working within Europe gets more and more important. Therefore I am very glad to profit from GLADNET and to use this great opportunity.

Publications :

S. Weyler, A. Bengtson; "The Hydrogen effect as a function of discharge parameter - investigations of the variation of emission yield in glow discharge plasmas"; J. Anal. At. Spetrochem. (2010);  25; 849 - 855; DOI