Powder organic coatings functionalized with calcium ion-exchanged silica corrosion inhibitors

Abstract

Improved durability in organic coatings could partially solve the important problem of metal corrosion. For this reason, this work has sought to manufacture powder organic coatings after their functionalization with inhibitors, particularly calcium ion-exchanged silica microparticles. The objective is to obtain high-performance coatings with better corrosion resistance, as well as to make them more resistant to abrasive and erosive wear to reduce the likelihood of suffering damage during exposure. Different properties of the original epoxy coating and coatings with two different percentages of calcium ion-exchanged silica inhibitors (1 and 2 % by wt.) were analyzed. The corrosion protection of the new organic coatings was evaluated after performing a controlled mechanical damage. The delamination suffered by each coating was measured using scanning Kelvin probe (SKP) for 26 days, after the addition of a 3.5 % NaCl drop on the provoked defect. In addition, scratch resistance, universal hardness, and wear resistance (sliding and erosive) were studied for all organic coatings to evaluate the effect of the additions on their mechanical properties. The results obtained in this work indicate that small additions of these inhibitors manage to reduce the delamination rate of the coating from a defect and improve the results of the scratch test after immersion in NaCl solution. Moreover, 2 % silica particle additions to the epoxy improve the erosive and the sliding wear performances of the coating.