Corrosion Protection of Buried Steel Pipe Coated with Cordia Boraginaceae Exudates

This study investigates the corrosion protection of buried steel pipes coated with Cordia Boraginaceae exudates. Utilizing galvanized steel pipes with an initial diameter of 168.3 mm and a wall thickness of 7.11 mm, the effectiveness of the coatings was evaluated through mechanical and corrosion assessments. Coated samples demonstrated a significant reduction in corrosion rates, averaging approximately 0.5 mm/year, compared to 2.5 mm/year for uncoated samples. Weight loss measurements indicated an average of 3 grams for coated samples versus 15 grams for uncoated samples, highlighting substantial protection. Mechanical tests showed a tensile strength reduction from approximately 400 MPa to 280 MPa for coated samples post-exposure, while yield strength and elongation were also impacted. Adhesion strength measured around 8 MPa, indicating robust bonding between the coating and substrate. Coating porosity was assessed at approximately 5%, demonstrating effective barrier properties against corrosive agents. Environmental factors, such as chloride content (up to 19,500 mg/L) and pH levels (ranging from 7.1 to 8.2), were shown to significantly influence corrosion dynamics. The findings confirm the potential of Cordia Boraginaceae exudates as a sustainable alternative to synthetic corrosion inhibitors, providing effective protection in aggressive environments. This research contributes valuable insights into the application of natural coatings for enhancing the longevity and reliability of buried steel infrastructure.