The effect of chemical treatment on contact angle and surface roughness parameters

The aim of the study was to determine the effect of etching time on surface roughness parameters and wettability of the tested surfaces, particularly in relation to the study of extremely long etching times. Samples made of stainless steel, hot-dip galvanized steel, structural steel, and aluminum alloy were used as test materials. The following etching baths were used: 5% and 10% hydrochloric acid, and 5% and 10% sulfuric acid, with etching times of 20 minutes, 7 days, 14 days, and 28 days. The novelty of this research lies in the analysis of extremely long etching times (up to 28 days), which simulate long-term exposure of materials to aggressive environments rather than short-term surface preparation. This study focuses on the analysis of contact angle and surface roughness parameters of material samples etched in acid solutions, as well as on the observation of phenomena occurring during the etching process. The conducted study showed that extending the etching time in 5% and 10% hydrochloric acid and 5% and 10% sulfuric acid VI solutions caused an increase in the surface wettability and contributed to an increase in the values of the surface roughness parameters.