Mechanical and Corrosion Protection Characteristics of CNTs/epoxy resin Nanocomposite Coating on Buried API 5L X65 Steel Storage Tank

Abstract

The storage of petroleum products in buried metal tanks to ensure safety is common practice. However, the integrity of these tanks could be compromised by soil corrosion with economic and environmental consequences. This study examines carbon nanotubes mechanical and anti-corrosive capabilities (CNTs) and epoxy resin coating on steel tanks. The presence of corrosive ions, resistivity, and pH values were all tested in the soil sample. CNT was mixed in proportions of 1.5, 2.5, 3.5 and 4.5 weight percent of epoxy resin to create the coatings. The morphology of uncoated steel, epoxy, and CNTs/ epoxy resin-coated steel specimens was studied using high-resolution scanning electron microscopy (HRSEM) equipment with energy dispersive x-ray spectroscopy (EDX). Electrochemical impedance spectroscopy (EIS) was used for corrosion analysis, and the morphological result was established. The average ions content soil samples showed 272 mg/kg chloride, 467.20 mg/kg sulphate and 167.40 Ω-m for the average resistivity value. The sample’s pH was acidic because it fell within 6.11–7.48. The tensile strength, hardness, and tensile modulus of epoxy resin with CNTs increase with CNTs. The addition of 3.5% CNTs has the best effect on the mechanical strength of the composite. The nanocomposite coatings exhibited considerably superior conductors, according to the EIS investigation. Thus, the hybrid of epoxy and CNTs increases the hydrophobicity of the coated surface.