Oxidationsverhalten von Al- und Mg-legierten Zinkschmelzen unter dynamischen Bedingungen

Translated title of the contribution: Oxidation behavior of Al- and Mg-alloyed zinc melts under dynamic conditions

Fabian Friedl

Research output: ThesisMaster's Thesis


In the galvanizing process, some of the surface defects of coated steel strip can be attributed to metal oxides floating on the molten zinc in the snout and adhering to the steel surface during immersion. Thus, the oxidation kinetics of the coating melt under conditions such as occur in the snout of a hot-dip galvanizing line are important for quality optimization and process reliability. In this thesis, the oxidation behavior of a molten zinc alloyed with 1.5 wt.-% Mg and 2.5 wt.-% Al was investigated under dynamic conditions. This is an alloy for hot-dip galvanizing of steel sheets. The oxidation behavior was determined with an atmosphere as used in the snout of a hot-dip galvanizing line. These normally have a composition of 95 vol.-% N2 and 5 vol.-% H2 and a selectively adjusted water content corresponding to a dew point of -20 °C. Dynamic conditions were created by injecting the gas into the melt. The influence of the dew point in the range between -65 °C and 0 °C and the melt temperature between 430 °C and 490 °C on the reaction rate was determined. The bromomethanol method was used to determine the mass of the formed oxides. The oxide formation rate changes linearly in the dew point range between -30 °C and 0 °C with a slope of 0.88 mg¿min-1¿°C-1 and the intercept 29 mg¿min-1 with an estimated generated contact area of 0.3 m²¿min-1. Lowering the dew point to -65 °C had shown no significant decrease in the oxide formation rate. The influence of melt temperature can be described using an exponential approach with the activation energy of 73 kJ¿mol-1 and a pre-exponential factor K' of 396.73 ¿ 103 mg¿min-1. The chemical analysis of the filtered oxides showed an almost ideal ratio for the thermodynamically most stable oxidation product, the spinel MgO¿Al2O3.
Translated title of the contributionOxidation behavior of Al- and Mg-alloyed zinc melts under dynamic conditions
Original languageGerman
Awarding Institution
  • Montanuniversität
  • Antrekowitsch, Helmut, Supervisor (internal)
  • Strutzenberger, Johann , Supervisor (external), External person
  • Gerold, Eva, Co-Supervisor (internal)
Award date21 Oct 2022
Publication statusPublished - 2022

Bibliographical note

embargoed until 11-10-2023


  • Hot-Dip Galvanizing
  • Zn-Al-Mg
  • bromomethanol method
  • Oxidation kinetics
  • EDX

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