کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5366021 1388342 2007 13 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Thermodynamic and kinetic aspects on the selective surface oxidation of binary, ternary and quarternary model alloys
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
Thermodynamic and kinetic aspects on the selective surface oxidation of binary, ternary and quarternary model alloys
چکیده انگلیسی

Segregation and selective oxidation phenomena of minor alloying elements during annealing of steel sheets lead to the formation of bare spots after hot dip galvanizing. In order to understand the influence of common alloying elements on the surface chemistry after annealing, model alloys of binary (Fe-2Si, Fe-2Mn and Fe-0.8Cr), ternary (Fe-2Mn-2Si, Fe-2Mn-0.8Cr and Fe-2Si-0.8Cr) and quarternary (Fe-2Mn-2Si-0.8Cr) systems were investigated. The specimens were annealed for 60 s at 820 °C in N2-5% H2 gas atmospheres with different dew points −80 and −40 °C, respectively. Surface chemistry of the annealed specimens was obtained by using X-ray photoelectron spectroscopy (XPS). The field emission scanning electron microscopy (FE-SEM) was used to view surface morphology. At low dew point −80 °C, apart from the thermodynamical calculations such as solubility product of oxides and their critical solute concentrations, kinetics play a decisive role on the selective oxidation, i.e. oxygen competition. As expected, the amount of external selective oxidation of alloying elements are well pronounced at higher dew point −40 °C. An attempt has been made to explain the dominant process of Si and Mn on Cr-oxidation and segregation. It is observed that annealing of quarternary system at higher dew point shifts the Cr-oxidation from external to internal.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Applied Surface Science - Volume 253, Issue 10, 15 March 2007, Pages 4607-4619
نویسندگان
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