• Investigation of correlations between topography parameters and corrosion progression • Description of correlation strengths using effect size measures • Rating of topography parameters according to their correlation strengths • 3D feature parameters show the strongest correlations with corrosion progression Progressive corrosion on a steel structure affects its surface topography and reduces the remaining service life until component failure due to the increasing mechanical surface notch effect and the extensive loss of material. The calculation of topography parameters on the corroded surfaces could provide an approach for the development of objective and quantitative description methods of the corrosion state of steel structures, to which this paper aims to contribute. Since previous studies mostly considered a small selection of well-known and broadly applied parameters such as Ra, Rz, Sa, Sq, or Sz for this objective, nearly all parameters defined in the standards for profile and areal surface texture (ISO 21920-2:2021 and ISO 25178-2:2021) were now considered in this study in order to identify the most suitable ones for the description of corrosion progression. For this purpose, steel plate specimens were examined on which five different degrees of corrosion were achieved by means of neutral salt spray testing. All considered parameters were determined on the specimens and then subjected to statistical evaluation by means of effect size estimation as a novel evaluation method. In this manner, the parameters that correlated best with the corrosion progression of the steel specimens were identified. It was found that the areal parameters from the category of feature parameters showed the strongest correlations. The previously used topography parameters mentioned above, on the other hand, showed significantly weaker correlations.
Koller et al. (Fri,) studied this question.