Determination of diffusible and total hydrogen concentration in coated and uncoated steel

Dateibereich 25055

2,77 MB in einer Datei, zuletzt geändert am 27.10.2010

Dateiliste / Details

DateiDateien geändert amGröße
Mabho_PHD.pdf18.10.2010 09:09:352,77 MB
The new trend in the steel industry demands thin, flexible, high strength steels with low internal embrittlement. It is a well known fact that the atomic hydrogen which is picked up during production, fabrication and service embrittles the steel. This has led to an extensive research towards the improvement of the quality of metallic materials by focusing on total and diffusible hydrogen concentrations which are responsible for hydrogen embrittlement. Since the internal embrittlement cannot be foreseen, the concentrations of diffusible hydrogen work as indicators while the total hydrogen characterizes the absorbed quantities and quality of that particular product. To meet these requirements, the analytical chemistry methods which include the already existing carrier gas melt (fusion) extraction methods that use infrared and thermal conductivity for total hydrogen detection were applied. The newly constructed carrier gas thermal desorption mass spectroscopy was applied to monitor the diffusible concentration at specific temperatures and desorption rates of hydrogen which will contribute towards the quality of materials during service. The TDMS method also involved the characterization of the energy quantity (activation energy) required by hydrogen to be removed from traps of which irreversible traps are preferred because they enhance the stability of the product by inhibiting the mobility of hydrogen which is detrimental to the metallic structures. The instrumentation for TDMS is quite simple, compact, costs less and applicable to routine analysis. To determine total and diffusible hydrogen, the influence of the following processes: chemical and mechanical zinc coating removal, sample cleaning with organic solvents, conditions for hydrogen absorption by electrolytic hydrogen charging, conditions of hydrogen desorption by storing the sample at room temperature, solid CO2 and at temperatures of the drier was analysed. The contribution of steel alloys towards diffusible and total hydrogen concentration was studied including the metallurgical microstructure formed by differently alloying metals.
Permalink | Teilen/Speichern
Wissenschaftliche Abschlussarbeiten » Dissertation
Fakultät / Institut:
Fakultät für Chemie
Dewey Dezimal-Klassifikation:
500 Naturwissenschaften und Mathematik » 540 Chemie » 540 Chemie und zugeordnete Wissenschaften
Prof. Telgheder, Ursula [Betreuer(in), Doktorvater]
Priv.-Doz. Dr. Kuß, Heinz-Martin [Gutachter(in), Rezensent(in)]
Kollektion / Status:
Dissertationen / Dokument veröffentlicht
Promotionsantrag am:
Dokument erstellt am:
Dateien geändert am:
Datum der Promotion: