LAUSR

Abstract A novel technique with a ring-shaped water-cooled copper tube was used to study dynamic oxidation on melts of pure zinc, Zn4Al and ZA27. The thickness of the oxide layers was estimated by kinetic and thermodynamic calculations and measured using scanning electron microscopy on cross sections and energy-dispersive X-ray spectrometry (EDS). The most stable oxide phases on pure zinc, Zn4Al and ZA27 are ZnO, Al2O3 and again Al2O3, respectively. The theoretical thickness of the oxide layer (~5.3 nm) contradicts the experimental results. The dynamically formed oxide layers are an order of magnitude thicker. EDS analysis results in an oxide thickness of 50 nm, 60 nm and 36 nm for Zinc, Zn4Al and ZA27 alloys, respectively. Moreover, the measured thickness of oxide layers established upon cross section method in Zinc, Zn4Al and ZA27 are followed as 90 nm, 70 nm and 55 nm, correspondingly. Based on the appearance of the oxide layers, cracking of the layer which can provide uninterrupted contacts between gas phase and melt, considered as major factor responsible for the significant difference between experimental and theoretical results.