Investigations using potentiodynamic polarization measurements, cure durability, ultra violet immovability and abrasion resistance of polyamine cured ilmenite epoxy coating for oil and gas storage steel tanks in petroleum sector

Abstract

To uphold the corrosion protection of oil and gas steel tanks in petroleum sector, different high build epoxy coating formulations cured by polyamine hardener were modified by incorporation various concentrations of processed micro-sized ilmenite particles (FeTiO3) obtained by a solid phase milling process as a pigment to form a highly cross linked ilmenite epoxy adduct in three dimensional network. The lamellar shape of micro-sized ilmenite particles was emphasized by transmission electron microscopy (TEM) investigation. Flaky-like nature and the arrangement in overlapping plates of ilmenite particles were characterized by scanning electron microscopy (SEM) micrographs. The electrochemical behavior of cured ilmenite epoxy coated steel films against unmodified conventional epoxy in oil-wells formation water has been studied by potentiodynamic polarization measurements. From the obtained electrochemical results for the coated steel films it was found that, the maximum performance was exhibited at 100% treatment of the processed ilmenite ore at which the corrosion current (Icorr) was less than the value 15nA·cm−2 and exhibited the highest value of the protection efficiency (η) 99%. Cure durability test was implemented for appreciation the organic solvents resistance of the investigated cured coated films to confirm their application efficiency. The recorded data ensured the improvement in cure resistance with increasing the amount (%) by weight of micro-sized ilmenite particles against softening, wrinkling and loss of adhesion in case of unmodified conventional cured epoxy. Accelerated ultra violet (UV) exposure coating test was accomplished to measure the ability of the cured coated films to resist UV weathering and sun light damage. From the obtained exposure results it was found that, there is no blistering, no rust, no cracking, no flaking and no loss in adhesion in addition to the glossy variation at 60° was from 22.9° to 21.65° in case of the cured ilmenite epoxy coated films against complete deterioration in the film properties of conventional unmodified cured epoxy. The abrasion test was performed to determine the scraping resistance of the cured coated films. The results indicated that, there is a decrease in the weight loss of the coated films as a function of abrasion resistance with increasing the loading level (%) by weight of ilmenite pigment.