Assessment of Boron-Modified Semicarbazide and Thiosemicarbazide Resins as Corrosion Inhibitors for Carbon Steel Alloy in Acidic Environment

This study aims to synthesize two types of resins derived from semicarbazide and thiosemicarbazide for use as corrosion inhibitors. boron-Modified semicarbazide-formaldehyde resin (SFB) derived from semicarbazide, formaldehyde, and boric acid, and the other inhibitor boron-Modified thiosemicarbazide-formaldehyde resin (TSFB) derived from thiosemicarbazide, formaldehyde, and boric acid, they were studied using FTIR and TGA techniques. They were evaluated as inhibitors of corrosion of carbon steel alloy in a corrosive acidic environment of 0.1 M hydrochloric acid at several temperatures (25, 35, 45, 55) °C and at different concentrations for both inhibitors separately, using the Tafel extrapolation method. Where (SFB) gave the best inhibition efficiency at a concentration of 4 ppm, whereas the best inhibition efficiency was For (TSFB) at a concentration of 10 ppm. The investigation focused on activation parameters like E_a, 〖∆H〗^* and 〖∆S〗^*. It was observed that the activation energy was higher when an inhibitor was present than when it was absent. Additionally, the research revealed that the corrosion reaction is exothermic. The activation entropy demonstrated an increase in the number of corrosive species at elevated temperatures, which is attributed to the increased kinetic energy of these species as they interact with the alloy surface.