EVALUATION OF SELF-HEALING CORROSION PROTECTION USING BENZOTRIAZOLE-LOADED MESOPOROUS SILICA NANOCONTAINERS FOR APPLICATION ON ARCHAEOLOGICAL BRONZE ARTEFACTS

This work evaluates the effectiveness of coating bronze coupons, with 3% Benzotriazole (BTA) -loaded nanocontainers mixed with Paraloid polymer. Mesoporous silica nanoparticles (MSNs) were prepared and loaded with 3% BTA (BTA@MSNs) followed by dispersion in 3% Paraloid B72 and B44. Bronze disc samples with the chemical composition of Cu 85%, Sn 10% and Pb 5% simulating archaeological artifacts were coated with a single and double layer of BTA@MSNs in Paraloid B72 and B44 and evaluated using several techniques. Colorimetric measurements (CM) were used to evaluate changes in the surface appearance following the coating with single and double protective layers. The corrosion inhibitive performance of the coating was investigated using electrochemical impedance spectroscopy (EIS). Transmission electron microscope (TEM) was performed to characterize the shape and size of the prepared SiO2 nanoparticles, while X-ray Diffraction (XRD) was performed to confirm the presence of amorphous mesoporous SiO2 nanoparticles. The specific surface area, pore volume and pore size distribution were measured by nitrogen adsorption– desorption technique, while the release rate of benzotriazole at various experimental pH values was estimated using UV–Vis spectroscopy. Results confirmed the sustained release of benzotriazole to varying pH levels. The release was higher with an increase in the pH of the medium, which signifies that the release rate rises in the alkaline medium. The best corrosion inhibitive performance was for the double layer BTA@MSNs – B72 samples at 91.73% efficiency, while single layer BTA@MSNs – B72 samples displayed the least change in color ΔE 3.28.