The effect of dual phase steel surface roughness on selective oxidation and surface wettability

Surface roughness effect on the morphological characteristics of the dual phase (DP) steel surfaces selectively oxidized during recrystallization annealing at 820 degrees C under 5vol.%H-2-95vol.%N-2 gas atmosphere was investigated in this study. Oxidation behaviour of DP steel was examined using X-ray photoelectron spectrometer (XPS) and scanning electron microscope (SEM) equipped with energy-dispersive spectrometer (EDS). It was found that on the unpolished steel sheets the thicker and more uniformly distributed surface layer of Mn, Al, Si and Cr oxides is formed. As a result, wettability of unpolished steel surface was considerably decreased. According to the results of this paper the presence of BN surface particles at the polished steel surface affects the full surface coverage by external oxides and in that way improves surface wettability