Improved corrosion resistance, mechanical and wear behaviors of particulate composite coating of steel pipeline for marine environment

Abstract

The use of agricultural wastes, which are cost-effective and environmental-friendly materials as composites coating, is growing fast in various engineering fields. This research investigates the possibility of improving corrosion resistance, mechanical, and wear behaviors of particulate composite coating of steel pipeline with zinc alloys reinforced with groundnut shell ash (GSA) for the marine environment. Different weight percentages of 5, 10, 15, 20, and 25 wt.% GSA of particle size 75 μm were used for the coatings. The groundnut shell ash was characterized by X-ray fluorescent (XRF). The morphology of the steel pipeline before and after coatings was studied using scanning electron microscope/Energy Dispersive Spectroscopy (SEM/EDS). The XRF results revealed that calcium oxides (CaO), silica (SiO₂), alumina (Al₂O₃), and iron oxide (Fe₂O₃) being the major oxides present. The results showed that average coating thickness and hardness value were 45.50, 98.50, 99.67 μm, and 80.45, 108.60, 118.60 HBV for Zn-10ZnO/0, 20, and 25 wt. % GSA respectively. Their corresponding current corrosion (i_corr) were 38.52, 10.56, and 2.98 mA/cm². The morphologies revealed that reinforcement with GSA protected the surface of the system analyzed. The corrosion rate of the steel pipeline of 38.52 mA/cm² values decreased to 10.56 mA/cm² and 1.98 mA/cm² for 0, 20, and 25 wt. % GSA with the protection efficiency of 72.59% and 81.25%, respectively. The wear rate improvement between 0-25 wt. % GSA was 49.75%. The work established Zn-10ZnO/GSA composite coating on steel pipeline can improve the corrosion resistance, hardness, and wear rate of the studied steel pipeline coated.